RE: [Repeater-Builder] Mitrek Channel Elements Wanted
I'm looking for some high stability Mitrek channel elements to use in several link and repeater transmitters we have. The part number is KXN- 1095. I can use about 15 of these channel elements. The standard elements we are currently using are not very stable and allow the transmitter to drift +/- 5 kHz as the transmitter heats up. Any help in locating these would be much appreciated. Feel free to contact me off-list. Thanks. Rich, N6CIZ Did you install the crystals in your existing channel elements yourself, or did you send them to the crystal manufacturer to have them compensated? If you did it yourself, and you plan to do the same with the high-stab elements, the results you get will likely be no better than what you're experiencing now. Unless the element is compensated to the specific crystal that is installed, all bets are off. --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.392 / Virus Database: 268.5.6/338 - Release Date: 5/12/2006 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.392 / Virus Database: 268.5.6/338 - Release Date: 5/12/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Dayton Hamvention
Avoiding it like the plague Sir!! If you don't go, how are you going to earn any Dayton spending money? WN3A's Las Vegas motto: There's no such thing as a loser, just winners that quit too early. --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.4.3/317 - Release Date: 4/18/2006 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.4.3/317 - Release Date: 4/18/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Looking for N connector jam nuts
I'm trying to find about 40 hex jam nuts for bulkhead N connectors. The thread on N connectors is 5/8-24, and most of the jam nuts are 3/4 hex, roughly 1/8 thick. I'm trying to find stainless steel. I've tried a number of places on line, including McMaster-Carr and others, but came up empty at all but one place, and they quoted me $10.50 EACH!???!? Anyone have a favorite vendor that they could recommend? --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Deltas as repeaters and Channel Guard thoughts.
Being new to repeaters, I've been doing a lot of research and reading though the LBI's available in repeater-builder.com (thank you to all who contributed, btw). I have learned LOTS. For my first VHF learning repeater I plan to use a couple GE Deltas (an SX for transmit and an S for receive due to the helical filters). First question: has anyone experienced issues with turning the PA on the 110-Watt delta transmitter down to 50 to 60 Watts with a fan for full duty cycle? I'm concerned with spurs of course. The Delta-S's, both on highband and UHF, seem to be very stable at any power level. I've had issues with lowband Delta-S's programmed at the high end of 6m (52/53 MHz pairs) sometimes getting unstable at certain power levels. However, even with the TPO turned down, there are still thermal issues. You're better off with a low-power radio (or even better, putting a low-power PA in a high-power chassis to take advantage of the bigger heatsink). or advice to give? I don't mind learning from my mistakes, but I'd rather learn from others'. :) If you haven't already found it, go to http://www.ka9fur.net/delta/delta.html for additional info beyond what is on repeater-builder.com. Some of it is specific to UHF, but there is a lot of good general info there, including dissection of the EEPROM storage format. Secondly, more often than not I have read that people toss the Channel Guard boards in these radios for HAM use. Why is that? I don't know, I've never heard of anyone doing that. The software decoder in the Delta-S is very good. Anyone actually use the board for tone squelch? Most definately. You can I'm curious why someone would go with something like a TS- 64 when the CG board accomplishes the same task. I don't know, the ComSpec PL boards aren't the greatest as far as decode performance, and the encoders have higher THD than most other designs. Incidentally, I am considering replacing the micro/prom in the Delta with a micro of my own (I fancy the Atmel line, though any would do.) While we haven't totally replaced the uP, Dave (KA9FUR) and I have come up with some software mods to facilitate customization of radios for non-standard uses such as locking to external frequency references (for simulcasting) among other things. Finding windowed (EPROM) parts (8749H) is getting difficult though. As you can tell I'm loving these radios (and similarly, the Phoenixes) so far... They're great radios. The Delta-S front end is very good, and is virtually identical to the front end in GE Mastr III's. Transmitters are extremely clean with low phase/sideband noise. I was told that the design criteria of the Delta-S/SX series included the requirement that sideband noise was to be less than current protection crystal-based transmitters (at the time, Mastr II series), and from all indications, they have exceeded that specification. Duplex operation on 2m seems to be comparable to the Mastr II PLL exciter, which represents about a 22 dB reduction in noise over the standard multiplier Mastr II exciter at 600 kHz T/R spacing. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.385 / Virus Database: 268.2.4/282 - Release Date: 3/15/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] 4 Bay antenna
Sounds like an old Cushcraft AFM-4DA array. Bad news. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Sunday, March 12, 2006 3:10 PM To: [EMAIL PROTECTED]; repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] 4 Bay antenna I have a 4 bay vhf antenna, with each antenna straight and not folded. The harness is old and cracked. Some one has used electrical tape on some of the harness. There is no label or markings anyplace to know what brand it might be. If I made a new harness, can I use T connectors? Each antenna has a gama match for tuning. and using mobile size coax; no markings on the coax either. Rod KC7VQR Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.2.1/279 - Release Date: 3/10/2006 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.2.1/279 - Release Date: 3/10/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Best broadband VHF antenna
Have a question for the list. Is there an antenna (VHF) that will cover a 30mhz bandwith? (Reasonably) There is a system in Georgia incompassing the entire state using various tall towers. On the towers will be antennas that will be used for VHF Repeaters and VHF digital. (in the ham band) T he NWS is hoping to use the same antennas on a Mesonet. (like this one http://www.mesonet.ou.edu/) They are looking at the government freq.s right now but thinks there may be something in the 175mhz band. Sinclair wideband dipole arrays are probably our best bet (SD214-HL as an example). They cover 138-174 MHz, available with either 1/4 wave or 1/2 wave spacing from element to mast (go with half-wave if you want to get close to omni, quarter-wave for a more unidirectional pattern). Built like a tank. Telewave also has broadband dipole arrays, but personally I like Sinclair's construction better. --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.0.0/267 - Release Date: 2/22/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Best broadband VHF antenna
I would agree the Sinclair Antennas are well built and very broadband, but I had a horible time with a number of 4 bay vhf broadband units installed (and removed) in 2005. We bought a large number of VHF SLR-235 units new. The part number has changed but the antenna is the same current 4 dipole current model. The performance stank, with wild patterns and imd generation from all the brand new antennas we bought and installed at different locations. What a let down vs the good performance of other Sinclair antennas we've purchased in the past. Geez Skipp, that's pretty unusual. I've never had anything but good luck with Sinclair's dipole arrays, both on highband and UHF. I'm not a big fan of their whitesticks though. As I'm sure you know, most of their antennas are available in low PIM versions, though I've never had any IM problems with even their older, standard models. I figured it might be something we did, so I had a number of people check everything at least twice over. Yes we checked the harness phasing, element spacing yadda, yadda. But the same problem with 6 brand new antennas at 3 different locations? The only thing that comes to mind is maybe a quality control issue at the factory that resulted in one or more of the dipoles being assembled upside-down resulting in severe cancellation. I know they usually mark one side of each element with a band of red tape to ensure they are properly phased, but somebody could have screwed this process up (or maybe they marked them after assembly instead of before). If you have nothing else to do (hi), maybe you could do some tests to ascertain whether or not this is the case, perhaps by transmitting a few hundred mW into the input and using a scope to look at the relative phase between elements (i.e. check to see that the upper side of the feedpoint is in-phase between each of the elements). --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.0.0/267 - Release Date: 2/22/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Looking for MRF648's
Anyone have a surplus of Motorola MRF648 UHF power transistors that they'd sell or trade? --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 268.0.0/267 - Release Date: 2/22/2006 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Andrew connector on Eupon cable
Title: Message I'm almost sure it does, as I've used those connectors before on either Andrew or Cablewave 7/8" foam. If you have an older Tessco catalog (say, from 3 or 4 years ago), I'm pretty sure they had a chart in there that showed which connectors work on which cable. Most of the 1/2" and 7/8" heliax connectors are interchangable between cable manufacturers; it's when you get above 7/8" and/or go to air dielectric line that there are more differences. An exception to this is Andrew LDF5-50A versus LDF5-50B; the center conductors are slightly different diameter, and although you can generally make the connectors for one work on the other, the fit of the center pin isn't perfect. The odd varieties 7/8"cables like Andrew VXL series and Commscope uncorrugated cable require connectors specific to those types. --- Jeff -Original Message-From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jeff CorkrenSent: Sunday, February 12, 2006 2:16 AMTo: Repeater BuilderSubject: [Repeater-Builder] Andrew connector on Eupon cable Does anyone know ifaAndrew 7/8 inchconnector (type L5PNF) will fitEupen 7/8 inch heliax cable ? Thanks in advance for your reply. Jeff Corkren/W5PPB Raymond, Mississippi YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
RE: [Repeater-Builder] UHF Power
I still contend that in a mobile environment, under motion, that the user will not detect the 6 dB difference. It will be barely distinguishable most of the time. I'm not arguing this point. There have been times when I've had a 75 watt Micor PA die and I've had to run the output of the low-level amp (about 1.5 watts) to the antenna for a few days. A few users noticed, but most didn't. The point is that the system should be designed to be balanced, and unless your coverage needs or limitations dictate otherwise, we try to build repeaters that perform as well as possible. We worry about fractions of a dB of insertion loss when tuning a duplexer, spend more money to run 7/8 instead of 1/2 to the antenna, buy a SuperStationmaster for $750 rather than a two-bay for $250, even though we know that few users would ever notice the difference. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Cheap Tunnel Heatsink
I picked up an electronic load on Ebay a number of years ago, and have gotten more use out of it than I ever thought I would. Here's a well-done article on building an electronic load. The general design could be easily expanded to handle higher current by using a beefier transistor and/or multiple devices. http://www.siliconchip.com.au/cms/A_30506/article.html --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Tony King, W4ZT Sent: Sunday, February 12, 2006 9:06 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Cheap Tunnel Heatsink Here is my version of a 12 Volt dummy load: http://astron.w4zt.com/dload.html And, for those of you that are like me and would like to load test HIGH VOLTAGE supplies, here's my high voltage dummy load: http://gs35b.com/hvload/index.html Careful... either of them can burn you... BAD. The high voltage dummy load can KILL you if you get into it. 73, Tony W4ZT Mike Morris wrote: Years ago I saw a homebrew version of that: Twenty tungsten auto headlights in a metal box, with a switch for each bulb, and a couple of heater blowers. Bulbs were 50 cents at the auto junkyard, as were the headlight switches. They were wired so that the parking light position (half-way out) lit up the low beam, and the headlight position (all the way out) lit up the high beam as well. A regular wall thermostat was used along with a relay to run the heater blowers (off of the 12v input). Cheap to build and worked just fine Mike WA6ILQ At 10:46 PM 2/11/06, you wrote: Brett, I have a copy of a commercial Load Bank which is nothing more than a bunch of large resistors in a case controlled by switches. I'll dig it out and scan it for you These people get $3,000.00 for this package ! I have the stuff to build one and have about $75.00 invested so far. 73 John VE3AMZ - Original Message - From: Brett mailto:[EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Sent: Saturday, February 11, 2006 9:28 PM Subject: Re: [Repeater-Builder] Cheap Tunnel Heatsink Hi guys does anyone have that circuit diagram I need to build one to test 12 to 60 volt supply. Thanks in advance. Brett - Original Message - From: [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com Sent: Sunday, February 12, 2006 10:01 AM Subject: Re: [Repeater-Builder] Cheap Tunnel Heatsink In a message dated 2/11/2006 3:10:54 PM Eastern Standard Time, [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] writes: http://www.ve3tjd.com/pictures/tech%20stuff/ What a perfect heatsink for that variable power supply load that was bouncing around on R-B about a year or two ago. You could vary the Amp Load on your power supply using a variable pot control. Gary K2UQ Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: Radio quality (was RE: [Repeater-Builder] UHF Power)
Did you try the V7A with AIP on? No, I didn't, but I'll do that later today if I get a chance. The other ham rig in my truck is the other Kenwood dual bander (TM-708? getting old and don't remember model #'s like I used to). I'm not sure but I think that has the AIP function too. I never dug into it to see how it's designed - is the AIP feature just a switchable attenuator or something else? --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] UHF Power
I have enjoyed this thread and hope that no one has taken anything to be any kind of personal attack on how anyone runs their repeater. Of course not. No matter how much I or anyone else nit-picks technical details, it's still supposed to be a fun hobby. My point was is it needed? I think you were debating the issue from the functional standpoint, while I was looking at it from the technical standpoint. All things being equal, I guess I'm more comfortable comparing numbers than trying to ascertain what users might perceive. Thank you to all. Thank you for motivating me to go tinker with ham radio stuff for a change; it was a nice diversion from what was otherwise a paperwork-laden work-at-home weekend. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] UHF Power
No. A typical UHF ham rig will have better sensitivity than most repeaters with a preamp. A commercial mobile (without preamp) will have sensitivity slightly worse than the repeater with the preamp. 99% of hams will be using a ham rig, not a commercial one. OK, tell you what. It's snowing like hell here this weekend, I've got some time to kill. Tomorrow I'm going to put a couple test subjects on the bench and will report back what I measure. Yep. You may experience more intermod with the hotter receiver, but the intermod is most likely going to swamp the mobile receiver no matter what power level the repeater is running, at least most of the time. Which is why a mobile receiver with a real front end and less sensitivity is better... I'd be interested in someone actually trying this with a UHF system that is running 200+ watts. Drop it to 100 watts without telling anyone. Leave it there for a week or two and see if anyone notices. Chances are nobody will notice. But then again, they probably wouldn't notice if you put a 3 dB pad between your duplexer and receiver either... --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] UHF Power
OK, here are the results of my quick bench measurements for whatever it's worth. All receivers were on the same frequency (448.800 MHz). Signal source was a Fluke/Philips 6060A sig gen locked to a rubidium reference oscillator, modulated by 1 kHz AF at +/- 3 kHz peak deviation. The output of the sig gen had a 10 dB pad on it for isolation -- all sensitivity values below have already been corrected for this 10 dB offset. SINAD measurement done on an HP 8920B using the speaker output of each radio (standard EIA test method), AF PA terminated with an 8 ohm speaker, with a transformer in parallel with the speaker to provide isolation to the test equipment. I used the averaging function on the 8920B to help smooth out the inherent variation in the SINAD measurement. The commercial radios (Micor, M2, Delta) were tuned using the factory tuneup procedure without a preamp in line, i.e. no optimization of the front end tune was done to improve sensitivity when the preamp was added. RF patch cables for all tests included a 4' piece of RG-400 with type N connectors on each end connected to the sig gen. A short secondary patch cable (less than 2') with the appropriate connector on the other end (RCA for Micor and M2 receivers, UHF for Delta-S and Kenwoods, N for Icom, etc.) was connected to the main 4' cable, either with the preamp serving as the connecting point of the two cables, or a type N barrel was used when the preamp was out of line. All commercial radios were the standard 450-470 MHz split models, with no mods done to them. All sensitivity measurements are for 12 dB SINAD. In other words, I did everything I could to make the test setup as close to identical for all of the scenarios. My goal here wasn't to determine which receiver/preamp was more sensitive than another - even though I've shown resolution down to a tenth of a dB, there is at least a few tenths of a dB of inherent uncertainty in the measurements. SINAD readings fluctuate on a signal that noisy, even with averaging, so you have to take the absolute values with a grain of salt (i.e. any of the readings that are within maybe 0.5 dB of each other should be considered too close to call). REPEATER RECEIVERS -- GE Mastr II Rx -- -116.3 dBm (0.34 uV) without preamp -127.7 dBm (0.092 uV) with TE Systems model 4420N GaAsFET -127.5 dBm (0.094 uV) with Angle Linear 448GNT PHEMT Motorola Micor Rx - -116.2 dBm (0.35 uV) without preamp -126.3 dBm (0.11 uV) with TE Systems preamp -126.6 dBm (0.10 uV)with Angle Linear preamp GE Delta-S -- -117.9 dBm (0.28 uV) without preamp -127.5 dBm (0.094 uV) with TE Systems preamp -127.6 dBm (0.093 uV) with Angle Linear preamp The simple average of the linear (microvolt) sensitivities WITHOUT a preamp for the repeater receivers is 0.32 uV (-116.6 dBm). The simple average of the sensitivies WITH a preamp is 0.097 uV (-127.3 dBm). MOBILE RECEIVERS Kenwood TM-732A (my bench radio): -121.1 dBm (0.20 uV) Kenwood TM-731A (retired, collecting dust for the last few years): -123.5 dBm (0.15 uV) Icom IC-45A (really old, but a workhorse in its day): -115.6 dBm (0.37 uV) Kenwood TM-V7A (my most-hated radio): -125.0 dBm (0.13 uV) Syntor X9000 (with internal preamp): -122.3 (0.17 uV) As you can see, the repeater receivers with low-noise preamps out-performed all of the mobile radios. Even if you throw out the relatively-deaf Icom IC-45A, the repeater receivers beat the mobiles by a margin of anywhere from 1.3 dB to 6.6 dB. Personally I'd argue that the TM-V7A should be disqualified too; it has to have the most intermod-prone receiver of any UHF radio I've ever used. Side note: for the heck of it, I also tried using the sig gen in the 8920B when I had the Delta-S on the bench, and I got SINAD measurements within a couple of tenths of a dB difference. I also wish I could have found an ARR preamp and thrown that into the mix, I know I have one around here somewhere. I don't claim any of these tests to be indisputible either in terms of absolute accuracy of the values, nor reproducibility by others. I'm just giving you what I came up with. Run your own tests and publish the results if you don't like my methods (or results :-). --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] UHF Power
And mine too. Just because the unwashed masses don't notice it doesn't make it right, better, worse, or otherwise. -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Kelsey Sent: Saturday, February 11, 2006 8:46 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] UHF Power And that's my whole point. Chuck WB2EDV Jeff DePolo WN3A wrote: I'd be interested in someone actually trying this with a UHF system that is running 200+ watts. Drop it to 100 watts without telling anyone. Leave it there for a week or two and see if anyone notices. Chances are nobody will notice. But then again, they probably wouldn't notice if you put a 3 dB pad between your duplexer and receiver either... --- Jeff Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Duplexer weirdness
Well, I'm going to go out on a limb disagree with Jeff, perhaps for the first time ever. That's OK, we'll still let you hang around our tent and drink our beer at Dayton :-) Are you going again this year Bob?. My conclusion is that if whatever you're using to measure amplitude is sensitive enough everything is close to 50 ohms, tuning for max. trans. is good enough. My take on the situation is that I'd rather have everything as close to 50 ohms as possible. If there is any variation in the system outside the duplexer/cavities that you can't control (such as Z changing due to antennas icing up), the transformation effects of the cavities should be minimal. Also, by keeping all of the passives at 50 ohms in and out, it eliminates much of the uncertainty when adding additional cavities (e.g. pass cavity ahead of a receiver) or when adding an isolator that was bench-tuned with 50 ohm loads. I'll take consistent performance over optimum performance when we're talking a one or two tenths of a dB in insertion loss difference. As far as using cavities as matching networks to eek more power out of a PA, without actually looking at the efficiency at different load Z's, there's no telling what the PA is truly happy with. Just because you can squeeze an extra dB out of the amplifier by providing it with an some odd load Z doesn't mean that's the ideal load Z to operate it at. If you have to burn up 50 more watts in heat to get an extra 10 watts out of the PA, that's bad. So, if you lack test equipment and have no choice but to use high-level signals for tuning the pass, you should still be tuning for minimum reflected power. Yes, you can tune your RX cans to maximize power transfer into your RX. But then what happens to your notches which you've just moved as well? You can also tune Rx front ends with a network analyzer or SG/TG and RLB. You will also see that the window response of the front end of your typical two-way radio (Micor, M2, whatever) can be tuned to favor the side away from interference sources (e.g. your transmitter or other co-located transmitters) without any significant detriment to insertion loss at the desired Rx pass frequency. Sounds like a nice piece of test equipment to have around: a 50 dB non-directional coupler. Bird 4274-025 non-directional coupler element. I keep one in each of my 43 cases. Handy to have. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Duplexer weirdness
I thought consistent and optimum performance were pretty much the same animal? Only under lab conditions :-) Using a vague definition, I'm thinking consistent = best operation over the long term, optimum = best short-term. I've accidentally made a 75 watt Micor UHF PA crank out 200 watts short term by overdriving it, but the long-term performance will eventually degrade to 0 watts... --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Duplexer weirdness
So, if you lack test equipment and have no choice but to use high- level signals for tuning the pass, you should still be tuning for minimum reflected power. So bird inbetween TX and cans, tuning on a source like an HT? Yes. To take it one step further, a 6 dB pad (with suitable power rating of course) between the HT and the Bird would help minimize the Z variation that the PA in the HT sees, thereby reducing the variation in output power, and possibly help save the PA from destruction if the cans are severely detuned. So that's what that is.. Never could find the exact same thing. A rare bird :) With the part number, I see that RF parts carries them. Yeah, and Bird makes other varieties too, including directional coupler elements. I have the directional ones for 1 5/8, 3 1/8, etc. line sections for broadcast work. The one for the Bird 43 is rated for 500 watts maximum thru-line power. The ones for 1 5/8 and larger are rated for much more (I think the 1 5/8 is rated for 25 kW or thereabouts). --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Duplexer questions
Here's a thought -- if you put a isolator between the PA and the duplexer, and a isolator between the duplexer and the antenna, wouldn't your duplexer see a near perfect 50 ohms at all times? The isolator in the output of the duplexer would have to replace the output TEE - else you would have 25 plus db of rec loss - REC signal would go into the isolator load.ssb And even then it wouldn't work, because the receive side of the duplexer (connected where a reject load would normally be) doesn't provide a good match at the Tx frequency, so the isolator ends up providing no isolation (i.e. the isolator will no longer be the ideal 50 ohm virtual load that you were hoping for). --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Dupelxer wierdness
If I take all the opinions I've seen in the last month as fact, then the pass adjustments on duplexers can't be tuned. I'll take most of what you said as being sarcastic, but your point is taken. If tuned with a quality network analyzer, or with a return loss bridge and high return loss terminations and pads, you will have pass performance properly tuned. The only question is whether or not your transmitter likes a real 50 ohm load. If so, great, you're done. If not, fix it. With the cavities tuned to resonance, cable lengths are no longer an issue. Needing to use magic cable lengths should be a red flag that you've got a Z mismatch somewhere. (Except by wizards at Mount Wacom, who use equipment that resides in the fifth dimension.) Even the demigods that hail from Waco, Marlboro, and Angola aren't infallible, especially after the evil Brownshirt Brigade percussively retunes their products while en route to you. All Hail Maxwell! All Hail Maxwell! --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Mastr II UHF Base Station
The power dividers/combiners are just Wilkinsons. They are built into little square chassis with perforations for cooling, with a monolithic 100 ohm resistor mounted to the chassis and the usual quarter-wave 75 ohm matching sections. Nothing fancy. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Coy Hilton Sent: Tuesday, February 07, 2006 8:41 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Mastr II UHF Base Station Jeff, how's the driver PA harness built and how are the 2 PAs outputs combined? Do you have any information or specs on the RF and matching harnesses and how they are built? --- In Repeater-Builder@yahoogroups.com, Jeff DePolo WN3A [EMAIL PROTECTED] wrote: I am looking at acquiring a GE Master II UHF Base station. This is a 300 watt solid state transmitter, which how I understand it, has 2 PAs running in parallel. It's actually 200 watts, and yes, there are two final PA's, each capable of 100 watts output, that are combined. However, each final PA requires around 35 watts of drive - the final PA's are really the same as a 100 watt station PA, but without the 40 watt driver board. Drive to the PA's is provided by a standard 100 watt PA. So, what you have is the exciter (200 mW) driving the intermediate PA (100 watt, attached to the main station chassis), which gets power-divided to feed the two final PA's, the output of which then are combined to yield 200 watts. What I am wondering is, can these amps be run separately, or do they always have to run together in parallel? Not really, since each requires about 35 watts drive, so you still need something to drive them with. If you only want 100 watts, then just run the 100 watt IPA to the antenna and leave the two final PA's on the shelf as spare parts. --- Jeff Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Mastr II UHF Base Station
I am looking at acquiring a GE Master II UHF Base station. This is a 300 watt solid state transmitter, which how I understand it, has 2 PAs running in parallel. It's actually 200 watts, and yes, there are two final PA's, each capable of 100 watts output, that are combined. However, each final PA requires around 35 watts of drive - the final PA's are really the same as a 100 watt station PA, but without the 40 watt driver board. Drive to the PA's is provided by a standard 100 watt PA. So, what you have is the exciter (200 mW) driving the intermediate PA (100 watt, attached to the main station chassis), which gets power-divided to feed the two final PA's, the output of which then are combined to yield 200 watts. What I am wondering is, can these amps be run separately, or do they always have to run together in parallel? Not really, since each requires about 35 watts drive, so you still need something to drive them with. If you only want 100 watts, then just run the 100 watt IPA to the antenna and leave the two final PA's on the shelf as spare parts. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Micor Recrystalled Element Problem
I am moving a 463/468 MHz Micor repeater to 444/449 MHz. I ordered new xtals from ICM and the receive xtal is OK. However I can't get the xmit xtal to pull onto freq. It will pull within 3 KHz above 444.350 MHz. I'm assuming this is a real Micor repeater, not a converted mobile, so you should have a KXN1052 transmit channel element. Open it up again, and ;ook behind the trimmer cap. You should see a ceramic disc cap that is not quite parallel with the back of the trimmer cap - that's your target. Further behind the ceramic disc is a plastic-case transistor (just to verify we're on the same page). Look at the value of the ceramic disc; it should be somewhere in the tens of pF range. Increase its value by approximately 20% and you should be in the ballpark for moving from 463 to 444 (i.e. if it was 22 pF originally, use 27 pF instead). Lacking any other means of real compensation, use an NP0 cap. As others have pointed out, this doesn't give you any form of accurate temperature compensation. This only lets you center range of the trimmer cap so you can put the transmitter on frequency. If the repeater will be in a temperature-stable environment (say, +/- 10 or 15 degrees ambient as a ballpark), you might be OK. Next time, spend the money and send the element to ICM and let them do it right. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Micor has me stumped
I'm not sure if I'm undertsanding correctly, but you're saying that the UHF repeater works fine with either A/S board, but the VHF one doesn't? If so, it sounds to me like you have a VHF base station and not a VHF repeater, and my first guess is you didn't remove the diode that mutes the receiver when PTT is active. Lookee here: http://www.repeater-builder.com/rbtip/micorrxintcon.html --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of let_cyber Sent: Sunday, January 29, 2006 11:13 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Micor has me stumped I have both a vhf and uhf Micor repeater that I'm interfacing. I now know a whole lot more about Micor repeaters than I really wanted to. The short version of the problem is as follows: The COS signal from the audio/squelch board goes away when the TX is enabled. If you transmit a continuous carrier on the input, The COS comes up for a split second, keys the TX then goes away. After the hangtime expires and the TX drops, the whole things starts again. I have the exciter and RX into 50 ohm loads. If i put the A/S board and squelch gate into the uhf unit, it works fine. I have checked and double checked everything. It just doesnt make any sense. Any ideas would be greatly appreciated. Al KB2AYU Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] OT - NOW NOT SO funny interference story
Nate, I'd start by doing some office DF'ing before spending time on the hill this time of year. My first guess would be local oscillator leakage from something on the hill. Try doing an FCC ULS database search for anything within a mile or so of the site, make a list of the Rx frequencies in a spreadsheet, and make colums for the usual suspect IF offsets (+10.7, -10.7, 11.2 for M2's, 11.7 for Micors, etc.) and see if you find anything on 147.825 +/- 10 kHz or thereabouts). A local two-way shop here got a visit from the FCC because of excessive LO leakage. They were using Mitreks in a repeater installation, and the LO leakage was strong enough to bother another receiver several miles away. The FCC wasn't happy with them for using mobile radios in station operation... Probably 15 years or so ago I had a dead carrier holding open one of my UHF ham repeaters (it ran carrier squelch back then). The repeater is 443.800+, input 448.800. The carrier was there for an hour or more, so I figured I'd take a drive up to the site (it was about 1AM, but hey, I was bored, and the site was only 10 minutes away). I couldn't hear the carrier on the input on my drive to the site until I pulled in the gate, then it started getting stronger and stronger as I got closer. Then I saw a Motorola service van parked next to the shelter with the lights on, engine running, and a girl in the passenger seat. I walked into the site, scaring the bejesus out of the tech, to ask him what he was doing. He was working on an 800 MHz Ardis box. I nosed around a bit, trying to find this dead carrier with an HT. Then all of a sudden it went away, and a few seconds later, the girl that had been sitting in the Motorola van came into the site. Long story short, the girl in the van was the tech's girlfriend. He got the service call, and she decided to come along for the ride to keep him company. While he was working, she turned on the radio in the van and was listening to 101.5FM. The LO in the FM radio, like many FM radios, is 10.7 MHz high-side, so that's 112.2. The fourth harmonic would be, you guessed it, 448.8. And the mystery was solved. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Nate Duehr Sent: Thursday, January 12, 2006 7:19 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] OT - NOW NOT SO funny interference story We're also hunting a dead carrier on the repeater input of our 147.225 system in Denver. Total pain in the ***. The only antenna that appears to hear it reliably is the one that's up on the tower, on the mountain... of course. Nothing at ground level has been able to pick it up yet, and it's too cold/windy to really be up the tower with a receiver and yagi this time of year. The carrier/mix is not toned, of course, and the repeater is -- so the system is still usable but boy does it sound bad when weak-signal users use the system. Sigh... Nate WY0X Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Looking for 800/900 hybrid
Anyone have a hybrid out of an 800/900 MHz combiner or the like? Needs to work at 950 MHz. I don't need an entire combiner, just a hybrid. Thanks. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: interface to shut off a radio on temporaly base
Title: Message Kitchen dishwashers are also great for cleaning gunked-up mobile radio accessories like control heads, speakers, mics, mounting brackets, etc. Remove the speakers, mic elements, PC boards that contain switches, and other electronics that don't take kindly to water first of course. Even cable harnesses can go into the dishwasher - just put a baggie over the cable ends and seal with electrical tape (better to put these on the top rack away from the electric heater/dryer). Avoid agressive automatic dishwasher detergents if there are metallized parts like brushed aluminum estucheons and the like. Back in the day, afterwe had collected several PC or terminal keyboards that had suffered "coffee contamination" I'd run them through the dishwasher, key-side-down to assist in drainage/drying. Probably 3/4 of them survived and could be returned to service. A simple and non-time-consuming fix when you have nothing to lose and can't justify the time or cost to take apart and clean manually. I'd like to second Skipps comments and add one of my own. At the factory we used ordinary dish washers (until we got the commercial washers) to clean PC boards. Most components are water safe. Exceptions, are non hermetic parts like switches and transformers; things with paper or bakalite coil forms. Spic and Span is a little harsh. For general cleaning, including automatic dish washers, useArm and Hammer baking soda. If you think someone has used an acid flux (sometimes necessary to solder nickel or steel) clean with ammonia before the baking soda. Finally if you have rosin flux isopropyl alcohol works well. Don't use rubbing alcohol (contains water) or use alcohol in the automatic dish washer (it will burn). YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
RE: [Repeater-Builder] Bad 4 Heliax (Was Polyphaser Help)
A) not enough hoisting grips were used and b) the cable had pulled away from the tower in a number of places (a mish-mash of butterflies, tie wires, and even rope were used to attach it). The end result was that the line stretched, plus there were several holes in the outer conductor where it had been rubbing against a tower member. It had been blowing air for probably a year or more, but the station waited until it started arcing over before they decided it was finally time to replace it... --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon Sent: Saturday, December 31, 2005 11:26 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Bad 4 Heliax (Was Polyphaser Help) Jeff, How does 4 Heliax go bad? If the feedline was properly installed and pressurized, what else besides a bullet hole would prompt the removal of that cable? That size Heliax is probably $40 per foot, plus the labor...Geez! 73, Eric Lemmon WB6FLY snip I've got a better one. A number of years ago we changed out a 1500' run of 4 Heliax that had gone bad on an FM station. Upon taking down the old line and looking at the damage, one of the problems we found was that the ground kits (approximately 8) were all installed without removing the outer jacket from the cable... --- Jeff Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] polyphaser Help
I actually saw an install where a MSS did just that - they had the ground connected to a plastic water pipe! Joe M. I've got a better one. A number of years ago we changed out a 1500' run of 4 Heliax that had gone bad on an FM station. Upon taking down the old line and looking at the damage, one of the problems we found was that the ground kits (approximately 8) were all installed without removing the outer jacket from the cable... --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Duplexer tuning with Return Loss Bridge
The Bird is a directional wattmeter. It's not a return loss bridge (it's not a bridge at all). Yes, you can compute a spot-frequency measurement of return loss that way, that doesn't help you with swept-frequency analysis using a spectrum analyzer and tracking generator. -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Dick Sent: Wednesday, December 21, 2005 12:01 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Duplexer tuning with Return Loss Bridge Yes, really. You measure the forward power, then turn the element around and measure the reflected power. Then use 10 log (FP/RP) and you have the return loss in dB. Dick - Original Message - From: Jeff DePolo WN3A [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: 21 December, 2005 08:46 Subject: RE: [Repeater-Builder] Duplexer tuning with Return Loss Bridge The Bird Model 43 is a typical RLB. Oh really???!??!? The Eagle return loss bridges are a good value for the buck. www.eagle-1st.com. They have a whitepaper on tuning duplexers too. http://www.eagle-1st.com/notes/duplex/body.htm I believe IFR (now Aeroflex) sells (or at least sold) the Eagle RLB's. --- Jeff Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Hamtronics T301 220 exciter Final and microphonics
If the PA microphonic AM'ming is severe enough, there could be enough power supply modulation, due to the PA current varying by the AM occuring in the PA, that FM at the same modulation rate can occur in preceding exciter stages (such as in the crystal oscillator, modulator, active temperature compensation circuits, etc.). Not knowing how a T301 is designed I don't know how likely this is, but it's quite possible. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Bryan Fields Sent: Tuesday, December 20, 2005 2:11 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Hamtronics T301 220 exciter Final and microphonics On Monday 19 December 2005 11:48 pm, Ken Arck wrote: Don't forget that in both PM and FM schemes, the modulation is done early on and multiplied. So for a typical multiplication scheme of x 9, the modulation introduced only needs to be 550 Hz or so (for a 5 Khz spec). And even a paultry 550 Hz requires a fair amount of audio voltage to accomplish. In most PLL units I have worked with in the ham market the vco is modulated directly on the loop op amp. There in no multiplication the VCO runs at the output frequency. As to the origional question, anyone fixed the microphonics problems with the exciter? -- Bryan Fields, KB9MCI 01:07:04 up 3 days, 14 min, 2 users, load average: 0.31, 0.23, 0.26 Somewhere in DOWNTOWN BURBANK a prostitute is OVERCOOKING a LAMB CHOP!! Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Old duplexer tuning question
I'm assuming that if the old RG-8 cables are being replaced with RG-214 cables that are the same length, that the velocity factors of both types of cable are the same. Yep, 66%. Unless it's RG-8 foam, but I'm 99% sure that PD used regular solid dielectric RG-8. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Multiple receivers one antenna ???
It's called a Wilkinson splitter. Here is a link to some of the theory. I don't think it's fair to call it a Wilkinson without a resistor across the output ports. A real Wilkinson provides port-to-port isolation due to the addition of the resistor. A tee and 75 ohm cables doesn't provide any appreciable isolation; it's just two transmission line transformers teed together to yield a proper match assuming that the ends of the cables are terminated into 50 ohm loads. In the real world, receivers don't have 50 ohm Z across a wide range due to front end filters and other factors, so you may end up with additional loss (above and beyond the theoretical 3 dB power-dividing loss) due to the lack of isolation between receivers. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Multiple receivers one antenna ???
You can handle the impedance matching by using 1/4 wave sections of 75 ohm coax between the receiver input and the T. The 1/4 wave 75 ohm section steps the 50 ohm receiver input impedance up to 100 at the other end, two of those in parallel at the T gets you back to 50 to match the feedline. Any number of receivers other than 'powers of 2' is more complicated. This does nothing for the loss of course. Roger Grady K9OPO The math works in the case of the tee being at the antenna connection, but the ASCII drawing that accompanied the previous email put the tees on the backs of the receivers, sort of like old-style thin Ethernet 10base2, except instead of having terminations at the ends of the backbone, one end is connected to the last receiver, and the other end is connected to the antenna. Matching goes out the window with this design. The problem with even doing the tees with odd quarterwave 75 ohm transformers is that you have virtually no isolation between receivers. If your receivers have tight front ends, unless all of the receivers are very close in frequency, you may end up with more than 3 dB of theoretical loss due to phase cancellation back at the tee. If you're really pinching pennies, Kevin's recommendation of using 75 ohm CATV/MATV splitters is better since they provide port-to-port isolation, and the losses due to the impedance mismatch (50 versus 75) are insignificant (theoretically approx. 0.4 dB + normal dividing loss). --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Old duplexer tuning question
I have been pulling my hair out (I don't have that much more to go) over an old Celwave 6 cavity 526-4 pass reject duplexer. I can get the notches to tune properly one by one but when I put it all back together it just does not seem to sum out right. Is there a procedure someone can point me to? 526's usually tune up pretty straightforward. If it's an older 526, it may have RG-8 interconnects, which can get noisy (better to replace with RG214). As far as tuning the notches, they are generally a PITA to tune to begin with due to the mechanical design (almost as much fun as Motorola T1504's), but as far as tuning them up separately and then putting it back together and having it not work right, I can't say that I've seen that effect, but then again, that's not how I would tune it. You can get in the ballpark by doing it that way, but in the end, you'll need to look at return loss to know when the pass is really tuned right, and you may need additional amplification to really see the notches, since when it's properly tuned, notch depth will be over 100 dB (although if yours has RG8 interconnects, you may not realize that kind of notch depth). In fact, if yours has RG8, it wouldn't suprise me if some of the problems you're fighting are related to cable leakage coupling. Just to confirm, the one you've got was the 440-470 split model, right? If not, then the cable lengths will be wrong and you can expect to see problems like you're experiencing (notches won't line up, insertion loss high, etc.). As always, isolate your test equipment from the DUT with pads when tuning. Also, I am curious if I need to use the same high frequency and low frequency ports which would be the opposite for ham radio out here, or if I need to keep the transmitter port for the transmitter and the receiver for the receiver. The 526 is symmetrical - you can use either side for high pass or low pass. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: UHF Preamplifier
Speaking of UHF preamps, does anyone have any experience/recommendations for tower mounted preamps? Al, My experiences with tower-mounted preamps have been less than perfect. Good designs will have dual amplifiers (redundant) and/or a bypass relay. Aside from amplifier damage due to lightning, a number of tower-top preamps I've seen fail did so because of problems with the window filters due to moisture causing corrosion and other problems, even in well-sealed enclosures. IMHO, in most situations you're better off in the long run with lower-loss feedline than adding gain upstairs. Unless you *really* like to climb :-) Since you're probably not going to want to change out your 7/8ths, here's what I'd do. I'm assuming that this is a receive-only installation (i.e. you're not duplexing in one or more transmitters to the antenna in question). First, measure the levels of the offending signals (paging Tx's and whatnot) at the end of the hose with a spectrum analyzer. The trace peak-hold function of most analyzers comes in handy here; let the analyzer sit there and record for a few hours or days while you go do something else. This will dictate how much attenuation of those signals you will need before any gain stages. Based on the results of those measurements, and the frequencies involved (both desired and undesired), determine the appropriate filtering and system design. The few most common designs would be: a) A window filter to pass your range of interest followed by the gain stage and power divider. This would be the simplest solution IF the offending signals are low enough after the window filter to prevent overloading the preamp. b) Same as a) above, but with reject filters after the window filter to attenuate undesired signals in the passband c) A combination of narrower-range window filters and/or spot-frequency pass cavities connected in a star configuration or a backbone configuration (a la the TX-RX T-pass design) using critical-length cables, the output of each filter then feeds its own preamp and power divider. d) Depending on how close the offending signals are to desired frequencies, you may need reject cavities after window filters or pass cavities, or pass/reject cavities after pass cavities in c) above. The FM problem will likely go away due to the rejection of the pass cavities and/or window filters, or if not, a high-pass filter ahead of everything would be the cure-all. Sometimes system designs can be altered to improve performance (noise figure) of certain bands/frequencies over others. For example, if one of your receivers is for a point-to-point link that has a lot of signal margin, you might be able to sacrifice performance on that frequency sans ill effect while improving performance for other frequencies/receivers. Without going into a lot of detail at this point, directional couplers, asymmetrical power dividers, coupling loop adjustments/cavity Q, etc. can come into play. Most multicoupler designs (and what I was envisioning when I wrote the above) place the filtering BEFORE any gain stages. However, if the offending signals are low enough in amplitude, you may be able to get away with a high dynamic range preamp without filtering, or possibly immediately after a wide low-loss window filter that passes everything in your range of interest as in example a) above. Usually the trade-off with high-level preamps is that noise figure is sacrificed for strong-signal handling capability (higher TOI/compression points), but if the filtering that would have been required in a pre-filtering design would have increased the system noise figured by a greater amount, then it may be a viable option. If you want to make some measurements and report back, I'll offer my suggestions if you want. The solution may be simple, or complex, depending on what you measure and the frequencies involved. --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: UHF Preamplifier
On a somewhat related note, has anyone used LNA Technology's (Chet Pierson K3TV) preamps? He has some interesting designs. www.lnatechnology.com --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] UHF Preamplifier
Like others have said, Lunar doesn't exist any more. Angle Linear is the current company, and Chip Angle makes great products. However, if your ARR is working, you are likely not to experience any measurable improvement in performance by switching to something else (assuming the ARR you have is a GaAsFET). Personally I like Angle Linear's preamps a) because they work well, and b) I've never had one fail out of probably 30 or 40 in service on various bands, both ham and and otherwise. YMMV. And as others have mentioned, proper filtering before the preamp is almost always necessary (pass/reject duplexers often aren't enough). --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of mdnosliw Sent: Saturday, December 17, 2005 11:18 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] UHF Preamplifier I am currently running a AR2 preamp on my MSF5000 repeator with a cellwave 526 duplexor. I was thinking if uogrsding to Lunar preamp, but can find no reference to them on the internet. If anyone has any contact information it would be appreciated. Thanks Mark KB1IOZ Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Looking for VHF Duplexers
I have a set of either WP-639 or WP-641, I forget which is which. 4 cavities, pass/reject. They're in decent shape from what I remember; been in storage for probably 10 years or more now. I can dig them out if you're interested and give them a once-over. I also have a 6-cavity Decibel duplexer (I forget the model #) in the Decibel factory cabinet in very nice condition. They were on a commercial pair at 525 kHz split if I remember correctly. They might be reject-only though, I'd have to check. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of ag4uw Sent: Monday, December 12, 2005 8:58 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Looking for VHF Duplexers Hi Everyone I am in need of a set of BP BR VHF duplexers. Prefer a set of Wacom 641's But e-mail me what you have, Must tune for 2 meters and please no junk Thanks Freddy Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] GM300 Deviation
Does anyone know which pot in the gm300 adjusts the rx deviation? Thanks. Andy KC2GOW The one labeled Volume. Sorry, couldn't resist. Seriously, I don't know what you mean. You mean Tx deviation? It's adjusted in software. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Need Advise: 6m Repeater Antenna
Title: Message Will the antenna be top-mounted or side-mounted? -Original Message-From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]Sent: Friday, December 09, 2005 7:17 AMTo: Repeater-Builder@yahoogroups.comSubject: [Repeater-Builder] Need Advise: 6m Repeater Antenna Hi All, I will soon be putting up a 6m repeater. It is a Hamtronics REP-200 with stock 20 Watt PA, using Wacom BrBp duplexer ordered for the repeater frequency. Both Units were new in 1999, and have been stored since around 2001. I have been slowly chasing all the gremlins out of the setup. I have added a Storm Watch WX receiver on the aux receiver port, as well as a Midland Vehicular repeater unit (minus PA) in the cabinet to provide a wireless link for 2M Simplex input into the repeater. The antenna will be approximately 300 feet. I would like to get some suggestions for an antenna; based on the experiences of others. Also, choice of Coax. TIA, David KD4NUE YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Repeater-Builder] Looking for data on old heliax
Trying to help a friend locate some data on Phelps-Dodge FX-14-50 (or FX-14-50H) cable, probably from the early or mid 70's. It's 1/4, aluminum shield, jacketed cable. In particular he's looking for the velocity factor. The cable is in use as buried sample lines in AM array, and he needs an accurate Vf figure to locate a fault by TDR. Anyone have an old Phelps-Dodge catalog on hand? --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Looking for data on old heliax
T Thanks for the offer Tony. My friend has that same catalog which lacks a Vf spec which is why I thought I'd try checking here. Does anyone remember if ComProd (before it became Phelps-Dodge) made coax? That was before my time. Anyone have an old CommProd catalog? -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Tony Faiola Sent: Thursday, December 01, 2005 10:16 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Looking for data on old heliax Jeff DePolo WN3A wrote: Trying to help a friend locate some data on Phelps-Dodge FX-14-50 (or FX-14-50H) cable, probably from the early or mid 70's. It's 1/4, aluminum shield, jacketed cable. In particular he's looking for the velocity factor. The cable is in use as buried sample lines in AM array, and he needs an accurate Vf figure to locate a fault by TDR. Anyone have an old Phelps-Dodge catalog on hand? --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Hello Jeff: I found a 1974 Phelps Dodge catalog in my library. It covers the 50 Ohm Aluminum Sheathed foamflex cables, FX12-50 and FX 12-50H, but nothing on the FX-14-50. Interesting thing is that the specs don't mention the VF, only dimensions, loss, etc. If you would like, send me your fax number, and I'll fax you the pages of the cables from the catalog. Ciao, 73, Tony, K3WX Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Source for RF enclos
Sounds like a regular Bud diecast aluminum enclosure would fit the bill. Try here: http://www.budind.com/view.php?part=n4 Hammond and others make comparable boxes. Available from Mouser, Digikey, Newark, et al. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jim, K8COP Sent: Thursday, December 01, 2005 9:51 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Source for RF enclos I have a Hamtronics LNP VHF Preselector board. I would like to install it in a RF tight box. Checked with Hamtronics and they have no such item and no advise as to where to find one. I want to install the board in a metal box and have the antenna leads come out to two female N connectors, and a 12 vdc through a feed-thru connector for power. Their is no room to install it within the receiver. Thanks, Jim, K8COP Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Duplexer loss different with more power, Why?
The other thing All of the RF power being produced at the 200 watt level may not be on the operating frequency. Remember that a watt meter reads total power, not just the power on the repeater frequency. If the transmitter or PA or both are spurious or dirty to some degree, you may actually have less power (on your transmitter frequency) than you think, even though the power 'reads' higher. Since the duplexer provides filtering, the power leaving the duplexer may show less due to the removal of the spurious energy. Kevin Custer And to add to that, bear in mind that if you only have one wattmeter and you use it to first measure the input power to the duplexer, and then disconnect it and move it to the output of the duplexer that you've changed the electrical length of the cabling between the devices. Unless everything is tuned and operating at exactly 50+j0, changing the effective length of any of the cables is going to change the Z that the transmitter sees. To get around this problem you have two options: 1. Make up a short patch cable with the same connectors as your wattmeter, and substitute it in place of the wattmeter to maintain a constant electrical length when moving the wattmeter between devices in the system. The cable must be the same electrical length as the wattmeter's effective electrical length. For something like a Bird 43, the length is known (and published by Bird) making this easy. For other wattmeters, particularly non-thruline types, this becomes more difficult. 2. Use two wattmeters, calibrating the differences in readings by first connecting the two back-to-back (preferably without an jumper cable). Transmit through the wattmeters into a dummy load and record the forward power readings of both wattmeters. Determine the error between the two in dB. Then put the wattmeters into the system at their appropirate locations, determine the measured loss based on their readings, and then correct that value by the difference you originally recorded. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Duplexer loss different with more power, Why?
You guys are missing something... no one asked him what size cavities he's using. If they are the smaller TX/RX units... the reported lower power output values are probably normal when using the higher insertion loss settings with smaller cavities. cheers, skipp Maybe I misunderstood the original post, but I read it to mean that TX-RX spec'ed the duplexer for 2.2 dB insertion loss and he was trying to figure out why his measurements weren't meeting spec. I think his goal (and mine would be the same) is to meet or beat the original specs when retuning it. Or did I miss something? --- Jeff Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] How Accurate is Radio Mobile?
I keep hearing about this better data from commercial propagation software but can't find any reference to it on any of their marketing material nor references to how they actually do it -- even assuming it's proprietary, I don't even see hints about it anywhere. A lot of the original 30 and 3 data obtained from the Gummint had problems with it. The biggest problems seem to have been at the edge of latitude/longitude boundaries (e.g. right at 40.000 degrees N). I've run models for clients and found what looks like a weird ridge line blocking the signal, where I knew there wasn't one, only to determine that there were erroneous terrain elevations in the data set along that line. RadioSoft and others have hand-edited a lot of the 3 data and also supplemented it with 10-meter and 30-meter data to improve the accuracy. Keep in mind that the NGDC 30 and 3 second data was derived by digitizing topo maps (quite often 1:250,000 scale maps which have wide contour inverals), so, at best, it's only as accurate as those maps were. There is also a newer 30-meter and 3-second data set called NED (National Elevation Dataset) that is quite a bit more accurate than the old NGDC 30-second database. There is also a new data set from SRTM (the Shuttle Radar Topography Mission) where a majority of the earth's surface was measured using microwave interferometry. The accuracy isn't necessarily superior to existing data (I think 50 feet was the predicted elevation accuracy), but the nice (or bad) thing about the data is that it includes obstructions (buildings, water tanks, etc.). Maybe Bob NO6B knows more about it - I think JPL was involved in it? I always wonder if it's just Bravo Sierra from the people trying to sell the software. No, really, it's not. Never met anyone who said their job was driving around gathering geologic data better than USGS who worked for a software company. The editing of the data is mainly limited to fixing problems in the digital domain, not going out and doing survey work. Geographical data for Geocoding and mapping at one company I worked at was all from the same commercial providers -- all our competitors used the same data, too. We could confirm it by looking at their output after one of our users reported a data error... yep, they have the same error we do. We'd fix ours, and not too far into the future we'd notice all the competitors had fixed theirs also, even without that fix being sent to the upstream data provider. (In other words, we all watched each other's changes and then double-checked them for ourselves, but we didn't have any better raw data to start out with than the next guy.) Non sequitur follows, read only if you're bored. Back in my mispent youth I wrote software for a company (in Denver by the way, Nate) that catered to the oil exploration industry. One of the aspects of the business was the hand-digitizing of USGS 7.5' topo maps. The reason these maps had to be hand digitized (at least at that time, back in the mid 80's) was that in many western states oil and gas well locations were surveyed with respect to a gridding system whereby territories were broken town into 1 mile x 1 mile sections. Sections were grouped into 6x6 clusters called townships. Each township was numbered by township (Y) and range (X). This township/range/section system was created shortly after the Lousiana purchase so the government could sell tracts of land to the public in quasi-uniform pieces. The next time you fly over a western state take notice how so much of the landscape is square - roads run perfectly north/south/east/west, tracts of land are squares, etc., for the most part at 1 mile intervals along section boundaries. It's because of this system. Anyway, in a perfect world, each section would have been perfectly square, thereby making the lat/lon of its corner points determinable by automated means, but in reality, the surveys were done by guys that probably spent most of their paycheck on whiskey. They were out there wandering around pounding iron pegs in the ground and making little rock piles in uninhabited territory - what else was there to do? And quite often, when they ran into some kind of terrain irregularity, river, stream, pond, etc., they took whatever shortcut they wanted, such as just using the stream as one edge of the section rather than crossing over the stream to tags points to form a square. The boundaries of all of these township/range/sections wasn't in any USGS, NGDC, or state BLM database with any degree of accuracy, yet all of the wells were surveyed based on their distance from the side or corner of the section in which they were located. As analysis of all of the data from all of these wells became done more and more by computer than by geologists, geophysicists, and geochemists, knowing the exact location of the well (in terms of lat/lon) became extremely important, hence the need to digitize all of these
RE: [Repeater-Builder] Two Tone Sequential Paging
I believe the spec is defined in EIA-374 but I don't have a copy of that document (EIA/TIA documents aren't distributed freely). Maybe somebody else has a copy. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of dallasreact112 Sent: Sunday, November 27, 2005 3:11 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Two Tone Sequential Paging Hi, Does anybody in group know the frequncy tolerance of generated audio tones used in two tone sequential paging? I know one can get away with +/- 1hz on PL encoding and it will generally still work. 73 Bernie Parker K5BP Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: 6 meter repeater duplexer (not used)
Yeah, when Mobilecomm (now Arch) decomissioned their 30 and 40 MHz paging systems here on the east coast, lowband Decibel and Celwave pass cavities were a dime a dozen (or often free). I scooped up as many as I could store, probably 50 or so. All but a few are in service on 6m repeaters, most of which were converted to pass/reject and used to make duplexers. Every now and then I still see them pop up at hamfests, but not like it was 6 or 7 years ago. There was a guy that used to be on this list (K4YC?) who drove up from George and hauled away all the lower-frequency cavities I had since I was out of storage space, probably 20 or more of them. Now that my supply is starting to run out I'm wishing I hadn't given them all away; they could have been cut down to 6m. Maybe he's still lurking? --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Sunday, November 27, 2005 12:58 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: 6 meter repeater duplexer (not used) Before Ebay came on line... people were giving away low band cavities at the flea markets. I hauled about 8 home while my friends laughed at the trailer full of large tubes. Although they still laugh about it... I have the cavities in service. Well... maybe they were also laughing at the TRS-80 Model One Computer I had on the back seat. :-) cheers, skipp Mike Perryman K5JMP [EMAIL PROTECTED] wrote: I sure wish I could locate cans for that price.. If you hear of any let me know.. mike True ... Before 6 meter repeaters became really popular in Oregon - last several years - DB Products 40-50 MHz cans were going for $25 or $50 at the local swapmeets. Neil Paul Finch wrote: Neil, In Texas it's 1 MHz. At least it's better than 500 KHz. Paul Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Looking for a UHF Circulator and load
(having email issues today, so if this is a dupe, please ignore) RE: cell mixes and 440 repeater I had a 440 repeater at a site with no other UHF transmitters for probably a mile or two. On an adjacent tower was a cell site (this was back in the early 90's AMPS days). When certain cell channels were active I would get a mix product that fell on or near my receive frequency, manifesting as either feedback squealing or sudden increases in noise levels that made it sound like desense. My transmitter was a Micor driving a GE 1/4 kW tube amp, the duplexer was a 4-cavity Antenna Specialists pass/reject, and rx was a Micor with an ARR GaAsFET. I found that putting a harmonic notch filter (one of those little tunable Celwave jobs) on the output of the duplexer, tuned to the center of the cell site B carrier transmit band, got rid of all of the problems. I didn't investigate further to determine if the mix was happening in my Tx, in the preamp, or the Rx. Before spending money an isolator (which will also require a harmonic filter after it), you might try a cheap test using a shorted quarter-wave stub tee'd into the feedline at the output of your duplexer to see if it makes any improvement. I'd suggest using a piece of 1/2 Heliax for the stub. If you have a spare pass cavity (a real pass cavity, not pass/reject), you might experiment with it on the tx leg of your duplexer, and then on the rx leg, to help determine if you're experiencing a mix in your tx, or in your rx, or perhaps neither. Keep in mind that what appears to be an overall increase in the noise floor might actually be a mix involving wideband digital cellular (e.g. CDMA). FWIW, I've had substantial (and that's an understatement) problems with Henry SS amplifiers being unstable on VHF, UHF, and FM. I've also received amplifiers from Henry that had the wrong low-pass filter in them - an FM amp with a LPF cutoff around 210 MHz comes to mind. I also had a UHF 200 watt ham-band amp that was shipped with NO low pass filter in it. When I called the factory to complain, I was told that Part 97 had no spectral purity specifications for anything operating above 225 MHz so they didn't bother with a filter. The second harmonic was only about -30 dBc. Eventually they took the amp back and put in an LPF. Take a real close look at the spectral output of the Henry while it's operating into the antenna system before spending any substantial time or money trying to fix a non-existant problem elsewhere in the system. --- Jeff -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.362 / Virus Database: 267.13.5/177 - Release Date: 11/21/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Motorola Repeater DC Power Plugs
Mmmm...are you sure they're Anderson? The ones I have say AMP on them. Maybe they're interchangable, but I haven't tried it. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Kimball Sent: Thursday, November 10, 2005 5:48 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Motorola Repeater DC Power Plugs Good Day: Anyone know off the top of their head which of the Anderson Power plugs motorola uses on the stations (MTR2000, etc.)? Looking at the web site, I'm guessing the 75 Amp, but want to verify with someone who might have actually researched this. It's going to take a couple of months to get these delivered, and I don't want to get it wrong. Thanks Chuck Kimball n0nhj Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] 220 Repeater Stuff
I have a brand new TPL 100 watt continuous duty RXR series 220 amp available. I think it was around $850 or $900 new. I'd trade for a UHF amp of comparable quality and condition, 100 watts or more. I think I have a 4-cavity Wacom duplexer for 220 in storage too but I'd have to go digging to be sure. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Andrew Sent: Friday, August 19, 2005 3:41 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] 220 Repeater Stuff Guys, If anyone has any 220 repeater equipment they would like to get rid of (sell/working) such as amplifiers, RX or TX stuff and things of that nature please contact me direct off list. I am in need of 220 gear for a repeater project. Thanks in advance. My email is kc2gow at yahoo dot com Andy KC2GOW Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.11/74 - Release Date: 8/17/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.11/74 - Release Date: 8/17/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Pin/contacts for Radius/GE/RC-1000
Headers on Mastr II's are 0.156 spaced Molex, standard parts available from Digikey, Mouser, et al. Never had an RC-100x so can't help there. GM300's and the like I've always bought connectors from Mo', but Batlabs says they're Amp parts: Connector, with locking tab 16 pin, 104422-1-ND (AMP 104422-1) Contact, A3007-ND(AMP 1-87309-3) Housing, 5 pin, 455-1186-ND (AMP VHR-5N) Connector terminal crimp, 455-1319-1-ND (AMP SVH-41T-P1.1) --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of kc4fwc Sent: Thursday, August 18, 2005 5:40 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Pin/contacts for Radius/GE/RC-1000 Does anyone know where I can find part numbers (such as Digikey) for the pins contacts that fit into the connectors for: - Headers in GE Mastr Exec and Mastr II's - Headers on the RC-100 and RC-1000 controllers - Plugs that fit into the back of Motorola GM-300's and 1225 16 pin connector Digikey has so many types of contacts and pins that I thought maybe it would be quicker to ask than to sit here and search all day.. with dialup.. Thanks, KC4FWC Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.11/74 - Release Date: 8/17/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.10.11/74 - Release Date: 8/17/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Help needed with TX combiner problem
Not knowing what the Telewave and Sinclair part numbers translate into in terms of the actual hardware in use, you'll need to provide some details. First of all, what kind of filtering is done on the tx combiner and rx multicoupler? Is the tx combiner hybrid-ferrite or cavity-ferrite? What is the measured isolation between antennas (if known)? Since all of the tx's are spaced at 200 kHz and all of the rx's are also spaced at 200 kHz, if there is any nonlinearity in the receive portion of the system (due to preamp overload, front end overload, etc.), there is a good chance that the desired signal is mixing with the transmitters, yielding new products that fall onto the other receive channels. Not knowing any other details, that would be my best-guess as to what's happening. If this is, in fact, the case, then there needs to be additional isolation between transmitters and receivers, either by increasing the antenna-to-antenna isolation, or adding additional filtering ahead of the preamp/power divider in the rx multicoupler to further attenuate the tx carriers. The less-likely cause would be a passive (external) mix such as in a rusty tower joint or guy wire hardware, but that type of mix is usually of the variety of only the transmitter carriers mixing, i.e. the much weaker receive signal transmitted by a user in the far field wouldn't contribute an appreciable level to the mix. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of vintageaudio2004 Sent: Wednesday, August 03, 2005 10:52 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Help needed with TX combiner problem Hello, I just installed a new 6-ch VHF MPT1327 system using MTR2000 Motorola repeaters (100W) with optional preselectors installed, a Telewave M101-150-6TRM combiner, and Sinclair RM201-112S1B RX multicoupler. Antenna system is two DB228, one RX, one TX. RX antenna in on top of tower, RX is a bit lower from about half the tower down. Tower is 90FT. Frequencies used are: CH1 - T160.125 R165.125 CH2 - T160.325 R165.325 CH3 - T160.525 R165.525 CH4 - T160.725 R165.725 CH5 - T160.925 R165.925 CH6 - T161.125 R166.125 Yesterday we finished putting together the system, and coverage is currently more than was expected. But we are having a big problem (I suspect) with IM products, as when I for example have the control channel on CH1 (160.125) and key repeater CH6 (161.125) my carrier indicator on CH1 opens up, and this also happens when doing other combinations by keying the other channels in different combinations and see other carrier indicators opening up on other channels. The interfering signals are very weak in most cases, barely opening the squelch of the receivers, but even so they are a problem. When I look at the spectrum analyzer with a small antenna I see all kinds of spikes left and right of the main carriers (most of them 40 or 50db, or more, bellow carrier), but if I hook up the combiner output into a dummy load and sample it into the analyzer display it looks much cleaner, and of course the interference problem disapears. I don't want to jump into conclusions, but it seems the IM (if it is) is being generated somewhere outside the equipment. Furthermore, if I scan the 160-170MHz segment (with a Icom IC-2GAT) while transmitting with more than one repeater channel, I can pick up a lot of signals, so it seems to be all over the place. I know they come from the system as I can hear the control channel signaling. BTW, this is a very remote location, and the only other system that operates anywhere near ours is anothe VHF conventional repeater (a plain GR300) at 157.700 and 162.700. The other tower is located about half a mile away. I'm really a bit concerned about this problem, as it disrupts communications between channels when for example two groups are using separate channels at the same time, as audio from one group will show up on the others, and so forth. Please if you have any suggestions as to where to start looking for solutions, they would be very appreciated. So far as a test I tried to lower the TX power of the repeaters, but even at 25W I still see some interference as described above. Much less but still it is there, besides there are still numerous combinations of TX that I even have tried so I'm sure the solution is not there. Since the interfering signals are weak, as another test I tried to raise the squelch setting of the repeater receivers to the maximum, but still some interference gets trough. Thanks very much in advance for any help. Alex Yahoo! Groups Links -- Internal Virus Database is out-of-date. Checked by AVG Anti-Virus. Version
RE: [Repeater-Builder] carrier drop pulse
Title: Message I'd look at the comp line on the ICOM and see if it's doing anything strange when PTT drops. You'll probably need a DSO or something similiar to capture it since it's such a short duration. While you're at it, monitor the 10V line as well. Is this a converted mobile or a station? --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED]Broadcast and Communications Consultant -Original Message-From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED]Sent: Monday, July 25, 2005 2:05 PMTo: Repeater-Builder@yahoogroups.comCc: [EMAIL PROTECTED]Subject: [Repeater-Builder] carrier drop pulse Here is one for you guru's and BMOC problem solvers. Must admit there are a lot of good ones in this group. A 2 meter repeater 15 miles away using a Mastr2 PLL exciter emits a carrier drop pulse of about500 ms in duration on a frequency 225 khz down from the repeaters xmit freq. Unfortunately this pulse is on the output of another repeater I continuously monitor. The repeater trustee is very knowledgeable and cooperative and is attempting to solve this problem. He did say the PLL is not quite 5 volts but otherwise seems to work well.Thedrop pulse on CORis definitely coming from the exciter and can be observed on a SA with PA installed and removed.It was replaced with another exciter and the secondexciter is doing exactly the same thing. Gary K2UQ --No virus found in this incoming message.Checked by AVG Anti-Virus.Version: 7.0.338 / Virus Database: 267.9.4/57 - Release Date: 7/22/2005 YAHOO! GROUPS LINKS Visit your group "Repeater-Builder" on the web. To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.338 / Virus Database: 267.9.4/57 - Release Date: 7/22/2005
RE: [Repeater-Builder] Re: OT: NC man charged with 'driving a cop car' due to ham antennas
K-55's on X band are still very much in use in New Jersey, which, at one time (maybe still) had the highest per-capita number of radar units in service. NJ state law still requires X band radar for the State Police! They're still using most of the units that they bought when the national 55 speed limit was enacted, including the early-version K-55's with the square antenna. I used to have a KR-10SP in a Volvo 4-door sedan, but was never accused of impersonating a police officer...I wonder why? :-) --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.1/51 - Release Date: 7/18/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Simulcast High Band Micor
There's not a high-stab channel element per se, but Micor PURC (paging) stations used an external high-stability or ultra-high-stability oscillator for simulcast operations. These were external rack-mount units. A special channel element plugs into the exciter that has two pigtails on it - one for audio (coming from the exciter to the UHSO), and the other for modulated RF (coming from the UHSO into the exciter). I have some (both complete stations as well as spare UHSO's) if you're interested. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of n6icw Sent: Monday, July 18, 2005 2:01 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Simulcast High Band Micor Is there high precision channel element for simulcasting a micor transmitter. I have a heated micor 800 kxn1071a and since it is 12 mhz based trying to figure if there is away to get Bowan to cut one for high band. Yes Skipp I could just net the transmitters. :-) Chris n6icw Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.0/50 - Release Date: 7/16/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.9.0/50 - Release Date: 7/16/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Splatter?
What kind of repeater and ID'er are you using? And where in the transmitter audio circuitry is the ID audio being injected? I've dealt with several problems, mostly with commercial-band repeaters, where a cheap CW ID'er was hooked up to a run-of-the-mill repeater (Micor, Mastr II, MSR2000, etc.), and rather than coming up with a clean way of mixing the CW ID audio with the transmit audio, someone injected the ID into the tx audio stages after the limiter/LPF. The IDer's produced something resembling distorted square waves. Even though the deviation may be tame, the high-frequency components pushed the modulation sidebands out far enough to cause adjacent-channel splatter. Remember, the bandwidth you occupy is a function of both deviation and maximum modulating frequency. Something as un-clean as a square wave tone (rich in odd-order harmonics), or an unfiltered synthesized speech generator, will cause you to spill over onto adjacent channels even if the peak deviation is under 5 kHz. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Dave VanHorn Sent: Saturday, June 25, 2005 5:14 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Splatter? At 04:10 PM 6/25/2005, Dave VanHorn wrote: At 03:15 PM 6/25/2005, Eric Lemmon wrote: Dave, You have done all of the right things, except you did not mention how much deviation your IDer is causing, or how pure its signal is. Many IDers deviate much more than is necessary. My personal preference is something around 1 kHz, and no more than 2 kHz deviation. When I set up an IDer, I first set the code speed as slow as it will go, like one word per minute, so that a Morse dash lasts for several seconds and makes it easy to set the deviation. It's a voice unit, set to 3kHz average deviation, IOW it's roughly as loud as a user's voice. Another thing to look at, if you tweaked the PA, is to make certain that your PA is not generating any spurious signals. Since you did adjust the duplexer tuning, the load impedance seen by the PA may have changed enough to cause PA instability. That's a thought, but then I should pick it up on my radio, sitting near the repeater. Finally, is it certain that your repeater and the complainers' radios are exactly on frequency? Even if your repeater output is right on frequency, one or more of the complainers might have a radio that is off far enough that it picks up a fringe of your channel. Well, I know the repeater was set to a calibrated SM within the last couple months. The user's radios were last calibrated in Japan. Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.8.1/28 - Release Date: 6/24/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.8.1/28 - Release Date: 6/24/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Simulcast: Anyone done this for ham repeaters
I posted the following message once before when simulcast transmitters were being discussed but I don't think it made it to the list: I've taken cell-site-surplus rubidium oscillators with 10 MHz outputs and used them as the reference for GE Delta-S synthesized radios. If memory serves the stock reference oscillator in the Delta-S VHF and UHF is 13.2 MHz. I made some firmware changes so that I could just program the radio normally after hooking up the 10 MHz reference in its place. The UHSO oscillators out of Micor/Purc stations are OK, but require more frequent adjustment as they age, and of course, you need test equipment that is high-stability as well. I have one of the rubidium oscillators on my bench that all of my test equipment is locked to, and I verify the frequency periodically with a GPS timebase just to make sure the rubidium hasn't drifted. Although I don't know what the specs are for the rubidiums I have (all of which are made by Ball/Efratom), carrier frequencies (as measured at UHF) have never differed by more than 0.1 Hz. If you're at a site with GPS-disciplined equipment already there (modern simulcast paging transmitters, HD/IBOC FM transmitters, etc.), you might be able to convince the owners to give you a split off their 10 MHz reference to save on the cost of having to come up with your own. I have three repeater transmitters running with the rubidium/Delta combination, but I haven't tackled the audio delay issue yet. The rubidium/Delta marriage and on-air testing has been more or less just a proof-of-concept excercise up to this point. When I have more time I'll get back to the project. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of JOHN MACKEY Sent: Sunday, June 05, 2005 7:37 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Simulcast: Anyone done this for ham repeaters That's just it, resources!! I would love to put up a simulcast system. But the time, money, other resources make it basically impossible. To do it right, you need to have it syn'ch to GPS. The OLDER systems that used high accuracy crystals in ovens needed regular attention. I make it to my repeaters about twice a year. -- Original Message -- Received: Sun, 05 Jun 2005 05:24:31 PM CDT From: Steve Bosshard \(NU5D\) [EMAIL PROTECTED] SNIP Most ham clubs do not have the resources for a simulcast system, but it would be nice. Also a trunked 2 or 3 channel system could be viable. Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.6.2 - Release Date: 6/4/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.323 / Virus Database: 267.6.2 - Release Date: 6/4/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Poor Repeater RX
Not trying to be a smart A$$, but why would you put a preamp in line and then an attenuator? To prevent receiver overload. If the noise level received by the antenna is sufficiently high (i.e. higher than the natural thermal noise floor of the receiver/preamp), an attenuator ahead of the preamp will lower the risk of overload from strong off-channel signals *without* degrading the S/N performance of the system. Any attenuation ahead of the preamp adds directly to the noise figure of the system, so you want to keep the combined noise figure of the attenuator+preamp lower than that of the receiver would otherwise have without them if any improvement is to be realized. Or in other words, if the amount of attenuation inserted results in a noise figure that is too high, the received signal will end up having a lower S/N than it would at lower attenuation values. An attenuator after the preamp has its place too, and is often a better place to put it if the preamplifier has excessive gain, the background noise (as received by the antenna) is naturally low, and/or if there aren't any strong off-channel signals to contend with. In some cases, the best scenario is attenuation both before and after the preamp. The value of the attenuator before the preamp is chosen based on the ambient noise floor, and the one after based on how much gain is really necessary to realize any S/N improvement (i.e. to negate excessive preamp gain). Maximizing both of those to point where S/N just starts to degrade would give you the best overload protection. Noise levels will vary at a given site depending on what other emitters are keyed up, weather-related effects, unintentional radiators generating RFI perodically, etc., will all affect the noise floor over time. Bench tests for receiver performance with a high-gain, low-NF preamp don't give a good indication of how the system will perform when hooked up to an antenna. Selectivity (e.g. pass cavities) ahead of the preamp is almost always preferable to after it unless you're blessed with being at a site with a very low noise floor, no other strong off-channel signals to contend with, and sufficient Tx/Rx isolation to prevent overloading the preamp. Also, some preamps that aren't unconditionally stable may oscillate or act squirrelly with a high-Q filter after them. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.322 / Virus Database: 266.11.15 - Release Date: 5/22/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Need a GE Master II ??? or 2???
The shady looking guy is Kevin and the even shadier looking guy is Scott. Close-up picutres of both of them can be seen hanging in your local post office. Cold 807's for Repeater Builder subscribers at spaces 1758-1761 again this year. See y'all there. --- Jeff -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Neil McKie Sent: Monday, May 16, 2005 11:58 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Need a GE Master II ??? or 2??? Ok, who is who in the picture? Neil - WA6KLA Scott Zimmerman wrote: All, We at Repeater-Builder have just taken delivery of literally a ton (2500 lbs. to be exact) of Mastr II VHF 'E' chassis mobile radios. See attached Photo. We will be taking a number of these to Dayton Hamvention spaces 707-710. (number depending on interest) Most of these have PLL type exciters and factory UHS preamps. These have 100W PA's and are in the 150.8-174Mhz split. Some have the 4 transistor PA and others have the 2 transistor PA. The radios will come with one EC PLL TX ICOM and one 5C RX ICOM, while supplies last. (Sorry they didn't come with any) They have been tested, are in good working order, and are in good cosmetic shape. These radios are great candidates for building either 2M or 220 repeaters. There is plenty of room for mounting controllers, option boards, etc. Price Each: $100.00 We also have a number of UHF and VHF MVP's. All types of power ratings. These are all tested and in working order. They are in good shape physically. These radios make great link transceivers or low power portable repeaters. More details at the show. Price Each: $50.00 We will also be bringing a large assortment of misc parts and pieces for both MVP's and Mastr II radios. (Anything you need to get that spare radio back in action??) Channel elements, tone filters, etc. The above prices are cash and carry. (by whatever means necessary) If there are any left after Dayton, they can be shipped for reasonable shipping costs. Hope to see everyone at the show. Repeater Builder - The company (Kevin Custer W3KKC - Scott Zimmerman N3XCC) Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.11.10 - Release Date: 5/13/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.11.10 - Release Date: 5/13/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Heliax for 6m duplexer; other free stuff
1. If anyone is looking for any 1 5/8 air dielectric feedline for making 6m notch duplexers (WB5WPA style), I have about 30 feet of new Andrew 1 5/8 air left over from an install, and will be taking down a run of Cablewave on Monday. If anyone can use some/all of it, pick up in either northeastern PA (Scranton/Wilkes-Barre area), or I can bring small (6' max) pieces back to Philadelphia. Goes in the dumpster on Monday if nobody is interested. If U pick up at the site in NE PA, there is some 7/8 line, a Decibel VHF yagi, and maybe some other stuff laying around too that you can have. 2. Have a lowband Decibel cavity on 30-some MHz that needs to go away. Pickup in Philadelphia. About 7' tall if I remember right. 3. Micor/PURC UHF 250 watt (tube) station taking up room in my garage (Philadelphia surburbs). Haven't tested it, and don't care to. Taker must have a strong back. I will NOT ship any of this stuff, it's pickup only. Email direct. Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.9.10 - Release Date: 4/14/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] estimating duplexer requirements
Dave has them on his site for all bands - http://www.ka9fur.net/geduplex/duplex.html --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Neil McKie [mailto:[EMAIL PROTECTED] Sent: Wednesday, March 16, 2005 10:42 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] estimating duplexer requirements Do you have the curves for the GE Mastr II 450-470 MHz ?? Neil - WA6KLA DCFluX wrote: Try this: http://www.repeater-builder.com/pdf/GE_Isolation_Curves.pdf But this is assuming you are running MASTR-II equipment. Yahoo! Groups Links -- Internal Virus Database is out-of-date. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.5.5 - Release Date: 3/1/2005 -- Internal Virus Database is out-of-date. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.5.5 - Release Date: 3/1/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] WTB Decibel Products 4041 H-2 Cavities
I have a few of the dentless variety on 43.something MHz. How would you get them to you from Philadelphia? --- Jeff -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Monday, March 14, 2005 12:48 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] WTB Decibel Products 4041 H-2 Cavities I Want (want -my foot) - I NEED two PD 4041 Cavities. They are in the 40-50 MHz range. No sell-a-dent please. Roger Hansen, W6TOZ Auburn, WA 98092 _ Yahoo! Groups Links * To visit your group on the web, go to: HYPERLINK http://groups.yahoo.com/group/Repeater-Builder/http://groups.yahoo.com/gro up/Repeater-Builder/ * To unsubscribe from this group, send an email to: HYPERLINK mailto:[EMAIL PROTECTED]Rep [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to the HYPERLINK http://docs.yahoo.com/info/terms/Yahoo! Terms of Service. -- Internal Virus Database is out-of-date. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.5.5 - Release Date: 3/1/2005 -- Internal Virus Database is out-of-date. Checked by AVG Anti-Virus. Version: 7.0.308 / Virus Database: 266.5.5 - Release Date: 3/1/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ attachment: winmail.dat
RE: [Repeater-Builder] OT- Cushman CE5
Anyone know of a cheap replacement CRT for IFR 1500's? I've more or less retired my 1500 because the CRT has gotten so dim, but still I prefer the 1500's spectrum analyzer over my other SM's (HP 8920B's) so I'd like to rejuvenate it at some point. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Neil McKie [mailto:[EMAIL PROTECTED] Sent: Monday, February 28, 2005 9:30 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] OT- Cushman CE5 There are two versions of the scope module, the 301 and the 301A. Neil - WA6KLA Burt Lang wrote: Is the scope in the CE5 a plug-in model 301 module? If so, the CRT is a 3RP1A tube. If not that module, please disregard. Burt VE2BMQ hwingate wrote: The CRT display in my old CE5 has gotten so dim that I have to turn the lights off to use it. Does anyone know the CRT tube number used in it so I can start looking for one? (It is much easier asking than taking it apart and looking !!) Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Colocating second UHF rptr
With frequency spacings that close (only 25 kHz away), you won't have any problems as far as desense goes, but you WILL need to run multiple-stage isolators to prevent IM. Concidentally, the 3rd harmonc of 147.39 is 442.17, but that shouldn't be a problem since that's near your UHF Tx frequencies (it would definately be a problem if it were your Rx frequency). --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: johnmichaelwelton [mailto:[EMAIL PROTECTED] Sent: Monday, February 28, 2005 9:22 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Colocating second UHF rptr I have a site on top of the local hospital with 3 2in galvanized mounts attached to the roof separated by ~5ft each. On the first two I have a DB404 on 442.150/R [abt 50 watts out of the duplexer] and the middle mount is a DB224 on 147.390/R [also abt 50 watts out of the duplexer]. I'd like to put a second UHF rptr at the site on the open third mount and dedicate to VOIP application [I have a dedicated LAN on emergency power and T3 lines to campus]. I'm considering putting up a DB411 and using either 442.125 or 442.175 as potential freqs (both are available here) thinking that the respective duplexers will help notch out the adjacent tx signal some and will still have ~5Mhz split between TX and RX. The only other options I have is a roof vent that could support maybe an X50 or something equivalent that is very small and this is on the main roof one floor below and abt 100 ft away from the main 442.150 antenna (I have 1/2 in LDF4 to run there). Any comments if the 10ft or so between the two UHF antennas will work? John/N4SJW Charleston, SC Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: Re IFR 1500 CRT (was RE: [Repeater-Builder] OT- Cushman CE5)
Didn't know about him, thanks for the info Bob. I dropped him an email. -Original Message- From: Bob Dengler [mailto:[EMAIL PROTECTED] Sent: Monday, February 28, 2005 3:41 PM To: Repeater-Builder@yahoogroups.com Subject: Re IFR 1500 CRT (was RE: [Repeater-Builder] OT- Cushman CE5) At 2/28/2005 07:06 AM, you wrote: Anyone know of a cheap replacement CRT for IFR 1500's? I've more or less retired my 1500 because the CRT has gotten so dim, but still I prefer the 1500's spectrum analyzer over my other SM's (HP 8920B's) so I'd like to rejuvenate it at some point. Have you checked www.kgelectronics.com? Kurt specializes in 1200s 500s, but may have info on the 1500 CRT. Bob NO6B Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.300 / Virus Database: 266.5.1 - Release Date: 2/27/2005 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Outlet for RG214/U
I checked a few sources - BOR (Bust-Out Retail) real Belden Silver Plated RG214 *is* about $5.50 a foot. Others, like Coleman, are allot less. Standard (nickle plate) RG214 was in Tessco's Outlet at $0.89 a foot. So if making jumpers, not going hundreds of feet, nickle plated would do fine for me. (BTW - half-inch hardline, like the venerable Andrews LDF4-50, is about $2-$3 a foot if you shop.) The whole reason for using RG-214 or similar cables in a repeater installation is for their low-noise and high-shielding properties, not loss characteristics. You lose the low-noise part when you go with the commercial RG-214 which has a copper or tinned copper braid. In reality, if you wander hamfests and Ebay, you can find real RG-214/U as well as 1/4, 3/8, and 1/2 Superflex for a whole lot less. 1/2 Superflex, in particular, seems be particularly plentiful, and cheap. The connectors are usually around $5 on Ebay which is comparable to high-quality silver/teflon type N's for RG-214. As far as regular Heliax, I usually pay around $1.25 a foot for LDF4-50A new, and sometimes under $1.00 if it's part of a bigger order. I usually buy from Tessco or Harris. If you're looking for 1/2 LDF, go on Ebay and search for a user named valuesurplus. Last time I talked to him he had several thousand feet of new 1/2 and he was selling it for under $1/ft in small quantities, less for longer lengths. --- Jeff -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.296 / Virus Database: 265.6.7 - Release Date: 12/30/2004 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] How d'ya Avoid Multiple IDs with Remote Sites and/or Links?
A few options: 1. Send the ID at, for example, 2600 Hz, and have notch filters to remove 2600 Hz at the link receiver at the main site. You need to notch the ID's before voting lest you confuse the comparator. 2. Use smart ID'ers on the aux link transmitters without encoding PL such that they only ID after a period of inactivity (yet still within the 10 minute timeframe), and/or have an interrupt scheme whereby if the remote receiver goes active while it's ID'ing, it quits ID'ing, allows the user transmission to pass across the link and then re-attempts to fully ID after the user unkeys. This way CW tones aren't heard on the user's transmissions, and likewise won't mess up the voting. 3. Send the ID as MCW-AM. This is perfectly legal - MCW is the same as phone for the sake of ID'ing (see 97.305(a) and 97.3(c)(5)). Since you're AMming the carrier, the FM detector in the link receiver shouldn't detect it (unless the receiver has a problem, is off frequency, or has poor AM rejection). This is usually pretty easy to do by modulating the power control line (which usually feeds the collector of the first transistor in the PA through a pass transistor, a la Micor, Mastr II, and many other designs). In some cases you might have to modify the filtering of the power control line to let enough AC through to yield enough AM, but usually that's pretty trivial. We're not looking for high-fi AM here, just something discernable enough to be a legal ID and yet still clean spectrally. 4. Send the ID as pure CW by simply keying the FM transmitter on and off, again without encoding PL. Use this in conjunction with a smart ID'ing heuristic to avoid ID's from affecting user traffic. 5. There have been discussions whereby the resulting interpretation from the Commission that it may not be necessary to identify each link separately as you can consider the users to be the control operators of those auxiliary stations (i.e. the link transmitters) in which case they don't need a separate ID anyway. Since this isn't the place for interpreting and debating rules, I'll leave it at that. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Bob [mailto:[EMAIL PROTECTED] Sent: Thursday, November 04, 2004 3:35 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] How d'ya Avoid Multiple IDs with Remote Sites and/or Links? Say you have a central repeater with a voting system and a handful of satellite receivers, each of which has its own discrete UHF path back to the receivers feeding the voter. Each remote site has to ID its transmitter when active and, unless filtered out, this ID will then be relayed via the repeater transmitter. Assuming all transmitters in the system have the same ID, this wouldn't be a problem (legally, morally, ethically), but could be a pain in the patoot if, for example, a mobile station travelling through the area brought up a string of remote sites in succession; then you might have a whole slew of IDs including that of the repeater itself! Now, I guess you could have each satellite transmit ID without CTCSS, but inevitably you'll get bits and pieces of it anyway. Likewise in a linked repeater system you may well end up retransmitting a distant repeater's ID, but this can be confusing at times to someone listening to the hub. My question is...well...the subject line says it all! Tnx es 73, Bob Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] db comparisons
In theory, +3dB gets about 40% range increase; to double requires +6dB. In theory, yes, but your coverage is usually limited not by the inverse-square law (unless you're really running flea power), it's by terrain and earth curvature, so in reality, 3 dB increase in ERP usually provides only a minimal increase in usable service area. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] IFR 1200
You can buy in-line RF fuse holders; maybe the mod was using a chassis-mount RF fuse holder? I have one that is a regular (not chassis mount) BNC male to BNC female; I think it says Anritsu on it but was probably OEM'ed by someone else. JFW and Alan Industries also make RF fuse holders. I don't know how the BNC connector mounts on a 1200, and forget how it mounts on my 1500, but maybe you can find an in-line chassis mount one that would fit. Do some web searches for Alan Industries or JFW and you might find what you need. You can get external ones like I have from HP, Anrtisu, Tek, etc.. Might be an easier solution than trying to fit one inside the box. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant -Original Message- From: Chuk Gleason [mailto:[EMAIL PROTECTED] Sent: Thursday, June 03, 2004 5:40 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED]; Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] IFR 1200 Regarding IFR 1200, and maybe the COM 120; Several years ago I heard about someone who had developed a pico-fuse holder antenna input for the 1200; kinda like is in the M. R2600 monitor (little 1/8 or even 1/16 amp green picofuse behind the BNC Female connector. Anyone else ever hear about this? Have info? Can share??? Chuk Gleason Cary, NC Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Looking for 3/8 Superflex
Anyone have any pieces of 3/8 Superflex (FSJ2-50) to sell or trade? Could use 100-200' total; several shorter lengths OK. -- Jeff DePolo WN3A Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Audio Reproduction
I think we're on two different wavelengths here. What I am talking about is practical application, not theoretical mumbo-jumbo. OK, yes, I'm talking about the theoretical limitations. Your earlier post said that even theoretical PM falls apart at low frequencies, and that's where I disagree. But compared to a volt P to P that is a small signal. We wouldn't run volts of audio down the same system, with no changes. You wouldn't put speaker level audio on a line designed for 10 uV, and expect everything to play fine. 100 dB of dynamic range is about the best we can expect out of a good CD changer. That limit is imposed by quantization noise due to the 16 bit word length for the samples; it's not an analog limitation. The theoretical limit for 16 bits is 98.08 dB. For 24 bits (common nowadays in audio work), it's 146.24 dB. Anyway, what I am talking about is real world limitations on the theoretical PM. Sure theoretically you could build a modulator that would do .01 to 3 KHz. Would it be expensive? duh. Would it be complex? duh. Considering that a PM Mastr II station originally cost more than what you can get a digital broadcast exciter for nowadays, I don't consider the cost to be the limiting factor. As far as complexity, it depends on how you define the term. To some, digital logic and DSP is less complex than analog circuit design. Let's face it, in either case you put audio and DC into the box and you get modulated RF out of it. The complexity of the circuitry that does that conversion is subjective. Think about it - in a digital implementation you don't need analog circuitry to high-pass filter, preemphasize, limit, deemphasize, low-pass filter, gain-adjust, buffer, generate PL/DPL and sum it in, modulate, multiply, key on and off, etc. - one DSP chip and maybe a few thousand lines of code would replace most of the analog circuitry in a traditional PM (or FM) exciter, and once written, it could be re-used for multiple bands in many models and generations of radios. Cost effective to manufacture? Hell yeah! I guess this begs the question - at that point, where you're doing preemphasis and modulation via math versus analog circuitry and synthesizing the modulated carrier, do you call it PM or preemphasized FM? I would argue the latter since you could have response that includes DC. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Audio Reproduction
I guess I'm not following your logic. If you could get a PM exciter to produce a .01 Hz tone at 5 KHz deviation, the amount of audio required at 1 Hz would be 40 dB below that. The amount of audio required to modulate 5Khz deviation at 1KHz tone would be 60 dB below the 1 Hz level, or 100 dB below the .01 Hz level. This means that a modulator that could produce a .01 Hz tone at 5 KHz of modulation for 1 volt P to P would only require 10 micro volts P to P at a 1 KHz tone. Thats a very small level in anyone's book, and the SNR would be garbage, since most audio type amps only have 120 to 130 dB of maximum dynamic range. I'm not limiting the PM designs to varactor. Any true PM modulator has a 6 dB/octave curve, and therefore falls under this calculation. If the audio deviation doesn't increase by 6 dB/octave, you don't have a true PM. 1. It seems that you keep reverting to logic that is bound by limitations in audio dynamic range and S/N rather than sticking to what we were originally discussing - the theoretical capabilities of PM (which, again, has an LF cutoff of DC). 2. You can create PM via digital techniques that wouldn't be constricted by analog world limitations like dynamic range and S/N. This isn't black magic; modern FM broadcast exciters have been doing this for years. 3. Even in an analog design, there's nothing to say that you have to have one audio path/stage that the audio passes through. You can have a low-level amplifier that is used for high frequencies (those requiring less amplitude), and a high-level amplifier for lower frequencies, the output of which two would be summed prior to the modulator. Again, this is a moot point since we're debating the theoretical capabilities of PM, not the real-world implementations. 4. Regarding your comment that 10 microvolts P-P is a very small level and the SNR would be garbage, a typical dynamic mic has an output around -100 dBV (10 microvolts) at an SPL of 50. It's not a ridiculously-low audio level to deal with in the AF domain... One more time for the folks in the cheap seats - THERE IS NO THEORETICAL LF LIMIT FOR PHASE MODULATION! --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Z-Matcher adjustment
Because the meter and its cable's electrical length will change the tuning. You can read it at the antenna port of the duplexer if youre using one. This has already been covered in previous posts. 73,Lee I must be dense . From what I understand you have the transmitter (no tuning in the amplifier stages) , then the swr meter ,the Z-matcher , and then the duplexer. It will not change the tuning of anything if you tune fhr z-matcher for minimum reflected power and then remove the swr meter. It will only change what the transmitter sees and it is not tunable anyway. That is all that the matching section does in the duplex transmitter. It does not tune for maximum efficiency if you follow the GE tuning instructions. This discussion has gone full-circle and is now to the point of confusion. The original premise was that a Z-matcher was needed on the output of some PA's because the PA itself was *not* properly matched when terminated in a 50 ohm load. Wasn't that the original discussion? The goal wasn't to minimize VSWR looking into the cavities. With that in mind, the best match isn't necessarily that which produces the least reflected power. The best match is the load Z that the amplifier is most happy transferring power to, and the only way to know that is by looking at PA efficiency. GE's procedure which is based on the least-reflected-power method is only correct IF we assume that the output stage of the Mastr II PA is best matched when looking into a perfect 50+j0 load. But that's not what we're trying to accomplish here. The original premise was that many PA's, especially when operated outside their design range or at reduced power, were NOT best-matched when terminated in a purely-resistive 50 ohm load. So, if you tune your GE Mastr II matching network for least reflected power as indicated by the test pin on the onboard directional coupler, you're not accomplishing what you set out to do. Contrary to popular belief, and over-simplification by manufacturers, least insertion loss and maximum power output aren't always the right answers when tuning amplifiers, filter cavities, and other devices in the transmission system. Maximum return loss in filter cavities and antenna systems, and maximum efficiency in PA tuning, are steps in the right direction if the goal is to have a transmission system that is stable and the least immune to external influences including temperature. Now, if you have a PA that runs away when presented with a known-good load, then you've got a problem that needs to be fixed IN THE PA. Using a Z-matcher, or the crude equivalent of feedline pruning, to help tame an unstable PA isn't a fix, it's a band-aid that will eventually come off... --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Z-Matcher Component Values
Tune for the least current draw at the rated (or de-rated, if that's what you want) power output. --- Jeff -Original Message- From: Chuck Kelsey [mailto:[EMAIL PROTECTED] Sent: Monday, January 26, 2004 8:58 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Z-Matcher Component Values Would that mean to tune for the highest power level out at the lowest current draw? Chuck WB2EDV - Original Message - From: Jeff DePolo WN3A [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Monday, January 26, 2004 3:16 PM Subject: RE: [Repeater-Builder] Z-Matcher Component Values Tune for best PA efficiency, not maximum output. --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Z-Matcher Component Values
Tune for best PA efficiency, not maximum output. --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant -Original Message- From: Tony King - W4ZT [mailto:[EMAIL PROTECTED] Sent: Monday, January 26, 2004 9:42 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Z-Matcher Component Values Very nice pictures and good job getting component values for the EMR Z-matcher. One question comes to mind and that is, how are you going to adjust it? Lacking a built in directional coupler it would appear that the only thing you could do would be to adjust for maximum transfer of power as measured on the output of the duplexer. Any thoughts on this subject? 73, Tony W4ZT Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater- Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Bad price from Cook!
Title: Message Decibel quit making the ham-band DB420 (S-420-440-450) as of Jan 1 this year. From what I was told, the harnesses for that antenna and other low-volume custom jobs were hand-made in Mexico. Either that plant was closing, or the contract house in Mexico that was making them was closing, whichever the case. The standard DB420B (450-470) works well in the ham band anyway, usually better than 15 dB return loss down to 442 MHz. The low-split DB420A (406-420) works OK up to about 433 MHz. The broadband Sinclair dipole arrays are excellent antennas, but they are pricey. If anybody is building a 420/430 link hub or the like and needs any low-split dipole arrays, I have a DB411 (brand new) and a DB420 (used, very good condition) for 406-420 (pickup only in Philadelphia area). --- Jeff -Jeff DePolo WN3ABroadcast and Communications Consultant -Original Message-From: Chuck Kelsey [mailto:[EMAIL PROTECTED] Sent: Friday, January 23, 2004 6:52 AMTo: Repeater-Builder@yahoogroups.comSubject: Re: [Repeater-Builder] Bad price from Cook! If my memory is correct (and it may not be) I seem to recall that Decibel was going to discontinue selling antennas directly to hams, on ham frequencies, on a small volume basis. However, it seems that someone said that they would do a run of antennas on ham frequencies if someone wanted to order a large quantity. Chuck WB2EDV - Original Message - From: Russ Stafford To: Mike Pugh Cc: Repeater-Builder@yahoogroups.com Sent: Friday, January 23, 2004 5:04 AM Subject: Re: [Repeater-Builder] Bad price from Cook! I do not know. You mite want to send them e-mail. [EMAIL PROTECTED] or toll free 877-992-2665 Like I said I do not work for them just passing the MSG. But I do know that we (Metro-Comm) bought two of them and got them inabout 3 weeksor so and they where shipped from Cook Towers in Delaware. They are marked with our repeater pairs on them and work well. When I tried to get the DB-420 from Tessco they told me on the phone that they did not sell enough to stock any in the Hams bands. I call DB and they gave me Cooks number. So that is all I know. I have been happy with all my repeater parts that we have gotten from Cook. We have bought Duplexers, Hard-line (Coax) RFS-455's and yes DB-420's for the Ham bands. It's owned by Hams so they are easy to talk to as well. Very Best of 73, Russ, W3CH Trustee, W3PS Metro-Comm Repeater Net Work, Echo-Link node number 119660 (w3ps-r) - Original Message - From: Mike Pugh To: [EMAIL PROTECTED] Sent: Thursday, January 22, 2004 6:25 PM Subject: Re: [Repeater-Builder] Bad price from Cook! Hey Russ, how is she ordering them from DB? I thought that they quit making them for the ham bands. MikeRuss Stafford wrote: Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
RE: [Repeater-Builder] Purc 5000 programming??
If it's an Advanced Controller, you have to flip a dip switch in order to change channel frequency settings if memory serves. I don't have the manual here and it's been a few years since I set one up; I'm sure somebody else here will give you the details. --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant -Original Message- From: Larry Williams [mailto:[EMAIL PROTECTED] Sent: Wednesday, January 14, 2004 11:32 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Purc 5000 programming?? Hi, I have acquired a purc 5000 with the enhanced drawer that is programmable (supposedly without having to reprogram the eprom) from th e front panel of the unit. A friend is trying to program it and so far when he puts the new freq in, it seems to take, but when you go back in, it's still on the old freq. Someone suggested to us that the actual operating freq could only be changed by motorola. Anyone know for sure? I can provide all the unit numbers you might need. Thanks in advance Larry Williams KE4PCZ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater- Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Identify this antenna manufacturer
Both Butternut and Hy-Gain made j-pole arrays for VHF and UHF. It's hard to tell from the picture - does it appear to be ham-grade construction or something more significant? -Original Message- From: Mike Perryman [mailto:[EMAIL PROTECTED] Sent: Thursday, January 08, 2004 12:44 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Identify this antenna manufacturer Looks like a DB-201 that is missing the radial kit... see attached PDF and tell me if you agree.. mike At 04:07 AM 01/08/2004 +, you wrote: Replaced a commercial antenna with electrical characteristics of a Decibel DB-224 or Celwave PD-340, four dipole array. Elements are much larger in diameter, only 3/4 of a folded dipole. Bottom counterpoise is only a stright stick instead of a fold. Took the antenna apart and have picture on this web site: http://www.w4dex.com/ant.htm Who made this thing and how old is it? Trying to find more information about it to satisfy my mind. Thanks, Derek KC4FWC - Mike PerrymanCavell, Mertz Davis, Inc. [EMAIL PROTECTED] Consulting Engineers http://www.cmdconsulting.com 7839 Ashton Avenue K5JMPManassas, VA 20109 USA (703) 392-9090; (703) 392-9559 fax; DC Line (202) 332-0110 - Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater- Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Info needed - 220 duplexers
It's been a while since I worked on one, but isn't there just a UHF connector at the top end? If so, just add a double-male and a double-female adapter in line to extend the length. Note it's not a stub, it's a piece of transmission line that is less than 1/4 wave in length, therefore it is a capacitor. The dielectric is slid in and out to vary the dielectric constant between the center and shield, i.e. it is a dielectric-tuned variable capacitor. --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant -Original Message- From: Vincent McKever [mailto:[EMAIL PROTECTED] Sent: Tuesday, January 06, 2004 10:04 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Info needed - 220 duplexers Call Dana Brown at TXRX for the info. His number is 1-800-866-8979. A real nice fella and I sure will be happy to help you out. Vincent N6OA/2 - Original Message - From: [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Monday, January 05, 2004 10:50 PM Subject: [Repeater-Builder] Info needed - 220 duplexers Would anybody out there have a set of Wacom's WP-625 duplexers? I am especially looking for the model with the tuning stubs. No - not to buy! I need some info - the length of the tuning stub(s)! It seems a previous owner of my duplexers trimmed the stub! OUCH! To make matters worse, when TXRX took over Wacom, they only have information concerning the latest Wacom products. That is, 625's WITHOUT a tuning stub! 73, ...Kim - WG8S Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater- Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] 2m VHF antenna needed
Bill, The obvious suggestion is: Not another Hustler G-7! It is a mediocre performer in duplex service, even when new, and its relatively fragile construction is not appropriate for hilltop repeaters. One of the best antennas for 2m repeater service is the RFS / Celwave (formerly Phelps-Dodge) 220-2 Super Stationmaster Omni fiberglass antenna. The -2 suffix identifies the model that covers 142-150 MHz. I have one of these models in service, and it works like a dream. Although it is listed as a 5.25 dBd gain antenna, the fine print note states that the gain below 150 MHz is 4.8 dBd. Its overall length is 19.2 feet. Expect to pay about $580 plus taxes and shipping from TESSCO or other commercial radio equipment suppliers. 73, Eric Lemmon WB6FLY The PD220-2 Super Stationmaster is a good antenna, but for single-frequency repeater use, a PD200 Stationmaster offers more gain (5.5 dBd versus 4.8 dBd). The downside is its narrower bandwidth (about 1.3 MHz in the 2m band at the 1.5:1 VSWR points), which isn't a problem unless you get it cut for a 147 pair and later decide to move to a 145 pair or vice versa. At one time the PD200 was a little cheaper than the PD220, but I think that now the opposite is the case, probably because the PD220's are produced en masse while the PD200's are cut/tuned one at a time to the customer's frequency. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Looking for connectors
Anyone have a surplus, or can refer me to a source, of *75 ohm* type N connectors? I've run my stock dry and need a few. I can use some for RG59 as well as RG11 (either CATV type RG11 or regular RG11). The only place I've found any in stock is Pasternak and they're $12 each which is kind of steep. I could use a few or a few dozen depending on the price. Come to think of it, I could use a few for LDF4-75A too if anyone has any. Thanks. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Micor Delay Line
Just in case you aren't aware, if the Micor came with an Allen Avionics delay unit, chances are it was a Micor PURC station built for paging. Longshot, it could have been a simulcast voice repeater, but those are extremely rare. If, in fact, it's a PURC, it has a different backplane and a few different cards in the shelf. If you can get your hands on a PURC manual (it's a supplement manual, like the Micor control shelf orange book), it will make the conversion go much easier. I have a lot of Micor PURC's and have converted several to standard repeater use; once you understand the idiosyncracies between the PURC and the standard Micor RT, it's no big deal, but without the book, you'll spend a lot of time chasing down traces on the backplane... --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Tuesday, December 16, 2003 6:50 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Micor Delay Line For a check to cover to cover shipping,I will sell the one I have. I am working on trying to convert a Micor Compa station into a UHF repeater and it came with the delay brick. Contact me directly off-list, Joe N1EZO/8 Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater- Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Micor Delay Line
The original application was a tone and voice paging system. You'd have to know what this delay line was orignally spec for. I have two different models. I found the datasheets for both and they were spec'ed for something like 300-2800 Hz frequency response at something like +/- 3 dB. There were no specs for distortion or group delay/phase distortion. Nice, but one must start with the initial system preformance and align it right. Most people don't know how to properly align simulcast systems. I know the prerequisites for both RF and audio performance, including the potential benefits of staggered frequency offsets, optimization for the worst overlap area(s) versus simple geographic distance/time delay, maintaining consistant frequency response and proper AF bandwidth limiting, minimizing receiver IF distortion/group delay, etc. I'm not saying what I have on the air right now, without audio delay, is correct...I was just saying that the transmitters are still on the air GPS-locked, the packages are all built identically (with well-tuned IF's on the link receivers listening to the same outbound source transmitter, transmitter AF mods, etc.) but I haven't dealt with the audio delay issues yet. Probably sounds rough in areas with overlap. It's not great, but it's not terrible. Fortunately the sites are within a few miles' difference in distance from the origination point so the delay error is only a few tens of ms. It sounds a bit watery in the worst overlap areas where both signals are relatively weak and compete with each other by probably only a few dB. In areas where there is a bigger delta in signal strengths the effect is obviously much less noticible due to capture. Still sounds better than Nextel anyway :-) S-Comm makes a killer digital delay board that's really cheap (cost wise) with excellent preformance. The resolution in the delay settings is way too coarse though. The old BBD devices theoretically could provide the resolution needed, but they have inherent drawbacks on their own, let alone the time delay stability issues. Better digital delays are available from Simulcast Solutions and others. You could not tell it was a simulcast system, other than it was loud in all places and sounded great. Sounds like it worked better than many of the systems that have been installed within the last few years on 800 MHz around here... Then something was not done right. Every one of them should sound good, else its back to the drawing board. I think the intentional frequency offets that were done to improve digital paging worked against them when sending voice pages. What is best for FEC and minimizing inter-symbol interference for simulcast digital paging isn't necessarily the most pleasant-sounding when sending voice pages...it may have been a tradeoff. --- Jeff Jeff DePolo WN3A - [EMAIL PROTECTED] Broadcast and Communications Consultant Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: UHF Links with Voters
I set up a couple of low-power (12 watt) UHF Moxy's for broadcast telemetry use maybe 8 years ago and they've been running continuous key-down with no failures since. They have a small muffin fan blowing on the heatsink and are turned down to a couple of watts. --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant -Original Message- From: Jim [mailto:[EMAIL PROTECTED] Sent: Friday, December 05, 2003 9:41 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: UHF Links with Voters franknmiss wrote: Thanks Steve, Was hoping to find a UHF link system I could run continuously to eliminate the delay and noise (and not burn up!). Good info though, I didn't think the voter would work well with the initial noise on remote key up. I wanted to use the Doug Hall voter too. I also like your initials ... SSB thats great to have in the ham business! Thanks, Frank, KO5S We've been using Maxar-80's turned down to abt 5-7W. Also for low power HT-90/440's work well at abt 2-2.5W on a 4W unit, or 1W or less for the 2W units. -- Jim The higher you are, the harder it is to pump. -Cleveland Mayor Jane Cambell, after the big black-out of 2003 Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
RE: [Re: [[Repeater-Builder] Spectrum Communication SCR1000 VHF Manual]]
I'm not knocking Spectrum - I'm just relating experience. I have yet to see one that stayed clean over the long haul. Any that aren't clean surely can't meet the type acceptance they once had. Well said, very well said. Humor: I have a Spectrum repeater on the air. Oh really? What frequency is it on? All of them. Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Re: Tuning of DB4613-1A Circulator
Even pass cavities don't necessarily attenuate harmonics produced by a circulator sufficiently. A 1/4 wave cavity will have a very good pass response at 3/4 wave (3rd harmonic). Even at other harmonics, or between harmonics, a bandpass cavity isn't necessarily going to give you adequate attenuation of the harmonics. A pass can is always good practice on any transmitter, but a one-stop-shopping cure for isolator harmonics it is not. And be careful of the varieties of harmonic filters out there. Some of the cheaper ones are just 2nd harmonic traps. They'll knock down the 2nd harmonic by 40 dB or so, but do nothing for the 3rd and higher harmonics, which can really be a problem on highband (3rd harmonic ends up on UHF). A real low-pass filter is what you should use. --- Jeff - Jeff DePolo WN3A Broadcast and Communications Consultant -Original Message- From: skipp025 [mailto:[EMAIL PROTECTED] Sent: Monday, November 03, 2003 1:38 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Tuning of DB4613-1A Circulator Hi Jim, As Eric mentioned in a reply post, Decibel has much information on line. One thing to know is that circulator tuning adjustments are slightly different for large vs small power levels. It's probably ok to do an initial ballpark tune using lower power, but the actual final tune should be done at the system normal/full power level. Circulators should also be followed by some form of harmonic filtering. In many cases, a band pass duplexer cavity or low pass filter are used. A circulator followed by a notch-notch or notch-pass duplexer is not a very good practice. In some applications, the results might be worse than running without a circulator. cheers skipp Jim Cicirello [EMAIL PROTECTED] wrote: Can anyone help me with the tuning instructions for the Decibel Circulator listed above. It has an adjustment on the input, output and one towards the attached dummy load. I can tune it, but I am loosing 3 DB of power. On of the few articles I can find shows a loss of 0.4dB. Any help appreciated. 73 JIm KA2AJH Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
