Re: [Repeater-Builder] Re: Duplexer retune / recoax
All this discussion about duplexer tuning and cabling is making me wonder if I should not order a duplexer for the TKR-750 and just use separate TX and RX antennas. Most repeaters, of course, operate on a specific frequency pair but, since mine will be mobile and could be set up anywhere, I'll be selecting whichever frequency pair throughout the 2-meter band that's reserved for repeater use and won't cause any interference with a coordinated repeater wherever I stop. I'll have to be careful about being co-channel with anyone within 120 miles and avoid adjacent frequencies unless I can get the proper separation with the adjacent repeater. By using non-ground plane antennas with magnetic mounts atop the spacious roof of the Sprinter van, there's some flexibility on the spacing between the TX and RX antennas. Is there some rule of thumb for spacing these two antennas (that will be at the same height above ground)? Paul Yonge KC2PBD WQDY219 MIDLAKES REPEATER 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 retune / recoax
That's EXACTLY what the radio world has been needing for decades: bungee coax. We already have lossy coax, and leaky coax. We definitely need stretchy coax. That would make the circle complete. I love it. You should send that suggestion to Andrew or maybe even Belden. Make sure the cable you end up with is double-shielded, silver-tinned, flexible, and rated for outdoor use (no foil and braid mixed together). Ask for patent rights while you're at it. Great idea. Go with it. On a more serious note, if the cables use male N connectors you measure from end to end. The Amphenol crimp-on connectors add 1/2 inch to the length of the center conductor, so if you need a total length of 12 inches, cut the coax for 11 inches. Strip and add the two connectors and you'll be right on 12 inches in length. If you use UHF male connectors, I don't know where you measure from. Bob M. == --- Dave VanHorn [EMAIL PROTECTED] wrote: The length of the jumper cables between the cans has a profound effect upon the insertion loss at the pass frequency, and relatively little effect upon the isolation at the notch frequency. Which brings up a fun question.. How do you know what the right length is, and where do you measure it from? Or is this a cut and try thing? In that case, anyone know sources for bungee coax? :) __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com 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 retune / recoax
At 1/21/2006 04:48, you wrote: If you use UHF male connectors, I don't know where you measure from. I believe it would be the same as for the male Ns (tip to tip). That puts your signal just inside the can, where the loop should be. Bob NO6B 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 retune / recoax
At 1/20/2006 21:27, you wrote: All this discussion about duplexer tuning and cabling is making me wonder if I should not order a duplexer for the TKR-750 and just use separate TX and RX antennas. Most repeaters, of course, operate on a specific frequency pair but, since mine will be mobile and could be set up anywhere, I'll be selecting whichever frequency pair throughout the 2-meter band that's reserved for repeater use and won't cause any interference with a coordinated repeater wherever I stop. I'll have to be careful about being co-channel with anyone within 120 miles and avoid adjacent frequencies unless I can get the proper separation with the adjacent repeater. By using non-ground plane antennas with magnetic mounts atop the spacious roof of the Sprinter van, there's some flexibility on the spacing between the TX and RX antennas. Is there some rule of thumb for spacing these two antennas (that will be at the same height above ground)? I suggest that ask your freq. coordinator to set aside a wide-split pair specifically for portable repeater use. Here in SoCal we have such a pair: 147.585 in, 144.930 out. This split allows for the use of small mobile duplexers normally designed for 5 MHz spacing, which would be much easier to tote around than a full-size 600 kHz spaced 2 meter duplexer. Bob NO6B 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 retune / recoax
Some time back I worked with a 155 Mhz Sinclair Duplexer in the 2M band. I could not get the notches to tune properly, so I added a Type N elbow in one leg of the circuit. This made the coaxial jumper about 1 longer (bungee coax) and solved a problem. I would be much surprised if cables were an issue, unless they had been messed with extensively or modified. Usually a duplexer just sits there and works for years and years, and the cables are usually not moved very much, unless someone monkeys with things. Steve NU5D -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.375 / Virus Database: 267.14.21/235 - Release Date: 1/19/2006 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] [personal reply]
Sorry about that... It was *supposed* to go directly It's been one of them days Kevin Custer wrote: See attached: 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] Spectra Portable Repeater model P1820AX
The local ARES group here has had a Spectra Portable Repeater model P1820AX donated to them. I don't know diddly-squat about them, and haven't laid eyes on it, so does anybody know from the model number if it is VHF or UHF, and what it takes to program it? I suspect from the name that it has at least one, maybe two Spectras inside, and from that it will take a 386, RSS and a RIB, but what RSS? And does anybody have an extra manual lying around? Mike 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] Re: Operating a Spectra-TAC Comparator (Voter) without RX encoders.
Both Kevin and Mike already have copies of the scans I made yesterday. The ComCenterCorp Encoder scan is just the adapter needed to use non motorhead receivers in a Spectra Tac / GE or RCA (yes RCA made a voter) System. I've sent copied direct to you if the email address I found at qrz.com is right. Enjoy, skipp N9WYS [EMAIL PROTECTED] wrote: If I can speak up at this point - I am currently in the process of adding Spectra TAC receivers to a repeater system I administer. I'd really like to take a look at those mod sheets that both Skipp and Dan refer to, especially if it will improve receiver operation and voting. Thanks in advance! Mark - N9WYS 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 retune / recoax
Paul, There are many useful programs available for calculating duplexer isolation and antenna separation. I happen to like CommShop for Windows, but I know that it (like all of the other programs) makes some assumptions in the calculations. I plugged in 25 watts for TX power, 144.000/144.600 for frequencies, and 0.3 uV for RX sensitivity. CommShop determined that the necessary isolation was about 86 dB. It also calculated that this isolation could be achieved with a vertical antenna separation of 183 feet or a horizontal antenna separation of 15,058 feet- about 2.8 miles. Needless to say, a 600 kHz split at 2m does not lend itself to separate antennas! In my area of California, the 2m coordinator (TASMA) has set aside a wide-spaced pair exclusively for portable/mobile repeater operation. The 2.655 MHz split allowed me to assemble a complete repeater in a portable case of about one cubic foot, using a Celwave 5085-1 compact duplexer. The radio is a 10-watt full-duplex Motorola R1225 transceiver, which has an internal controller and Morse ID-er. When I finish converting the prototype into the final product, I'll post some pictures. I strongly suggest that you petition your local two-meter coordinating body to establish a wide-spaced pair for short-term portable and mobile operation. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Paul Yonge Sent: Friday, January 20, 2006 9:27 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Duplexer retune / recoax All this discussion about duplexer tuning and cabling is making me wonder if I should not order a duplexer for the TKR-750 and just use separate TX and RX antennas. Most repeaters, of course, operate on a specific frequency pair but, since mine will be mobile and could be set up anywhere, I'll be selecting whichever frequency pair throughout the 2-meter band that's reserved for repeater use and won't cause any interference with a coordinated repeater wherever I stop. I'll have to be careful about being co-channel with anyone within 120 miles and avoid adjacent frequencies unless I can get the proper separation with the adjacent repeater. By using non-ground plane antennas with magnetic mounts atop the spacious roof of the Sprinter van, there's some flexibility on the spacing between the TX and RX antennas. Is there some rule of thumb for spacing these two antennas (that will be at the same height above ground)? Paul Yonge KC2PBD WQDY219 MIDLAKES REPEATER 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] odd split repeaters
Eric Lemmon [EMAIL PROTECTED] wrote: In my area of California, the 2m coordinator (TASMA) has set aside a wide-spaced pair exclusively for portable/mobile repeater operation. There are/were wide split repeater pairs in the originl ARRL 2M band plan. Before I learned how to deal with the coordination bs (narcc), I fired one up using a 1MHz split. Worked very well for a number of years. We found a 600KHz split and later moved. Based on the initial response, you would have thought it was a national crime to put up an odd split repeater. We received a lot of crap from various local sources even though the repeater was a very smart operation. Eventually people got over the upstart club repeater and we became just another group on the band. I strongly suggest that you petition your local two-meter coordinating body to establish a wide-spaced pair for short-term portable and mobile operation. 73, Eric Lemmon WB6FLY Don't hold your breath when dealing with some coordination groups... use the various band plans as a guide, do serious frequency monitoring and pick some smart choices of equipment, location and operation. you can do it cheres, skipp 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 retune / recoax
The length of the jumper cables between the cans has a profound effect upon the insertion loss at the pass frequency, and relatively little effect upon the isolation at the notch frequency. 73, Eric Lemmon WB6FLY Eric, I'm curious why you say this, as it contradicts what I would believe to be the case in theory. At the pass frequency, the Z should be very close to 50+j0, so having the wrong cable length won't affect the insertion loss between each of the pairs (or three, for a 6-pack) of cavities on either side of the duplexer. In contrast, for proper reject notch performance, there has to be correct phasing between cavities. The notches are effectively shorts at the notch frequency, and if they are not repeated at 1/2 wavelength intervals between cavities, they will tend to not align when cavities are cascaded due to transmission line transformer effects (ever try tuning a duplexer and the notches act like they're chasing each other and you can't get them to fall into place?). Likewise, between the antenna T and the first cavity on each side, having the wrong cable length will cause the notch short to not be properly transformed to an open at the tee (via the odd 1/4 wave section between the tee and the first can of the opposing side of the duplexer). This will make the insertion loss appear to go up when looking from Tx input to antenna or antenna to Rx output, and also throw off the pass Z since the opposing side of the duplexer is no longer invisible as it should be. Regarding the question posed by others for finding cable lengths and tuning methods: For experimentation purposes, a line stretcher is the easiest way to find optimum cable lengths when re-cabling a duplexer. However, you can usually just scale the lengths of the original harness to the new operating frequencies using simple ratios of the old and new frequencies; an error of 1/4 or so isn't going to make a noticible difference on VHF, and may even be tolerable on UHF. The other option is that if you have a duplexer that was, say, originally on 160 MHz and you want to move it down to 2m is to add elbow adapters to extend the length of the cables. Even if you don't leave them in on a permanent basis, it gives you a good approximation of how much the cables need to be lengthened by. As far as tuning duplexers, many manufacturers' tuning instructions give a simple how-to using just a spectrum analyzer and tracking generator. While this might get you close, the passband performance is almost guaranteed to not be properly optimized. At the factory, duplexers and filter cavities are tuned on a network analyzer so both reflection (return loss) and transmission (passband insertion loss and reject notch depth) can be measured and optimized concurrently. When looking at insertion loss only, pass/reject duplexers appear to have a relatively broad pass response, but in reality, if you look at return loss, the pass is really quite sharp. If you don't have a network analyzer, a return loss bridge is a great, and relatively inexpensive, piece of equipment to have to give you the ability to measure return loss using a typical spectrum analyzer/tracking generator in a service monitor. You do need good termination loads to go with it - most run-of-the-mill high-power dummy loads don't have enough return loss to yield accurate results. Spend a few bucks and get precision terminations to screw directly onto the port(s) without patch cables, and measure them with the return loss bridge to make sure they're good (30 dB should be the bare minimum). There are lots of good loads floating around on the surplus market - I see new Narda 370's show up at hamfests and Ebay regularly in the $10 range and they usually do better than 35 dB up through UHF. I don't lug my network analyzer out to sites, but I do keep the return loss bridge in the truck in case I have to do a quick-n-dirty retune on-site when I can't afford the downtime of transporting and tuning back at the shop. --- 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 retune / recoax
Jeff DePolo wrote: In contrast, for proper reject notch performance, there has to be correct phasing between cavities. The notches are effectively shorts at the notch frequency, and if they are not repeated at 1/2 wavelength intervals between cavities, they will tend to not align when cavities are cascaded due to transmission line transformer effects (ever try tuning a duplexer and the notches act like they're chasing each other and you can't get them to fall into place). This effect can easily be seen on the Motorola T-1504 BpBr duplexer. If your cabling isn't right, the pass insertion loss is correct, but the notches will not align on top of one another and optimum notch depths aren't achieved. The effects at VHF are not usually as bad because it's rare that the cable lengths are off at a percentage that shows this profoundly. YMMV of course... Kevin 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] CSC CWID-51B Rev D
CSC will porgram a prom for you for about $35.00. Contact them. Search on Google. Dave WB2FTX kb0jyl1 wrote: I am sure this has been asked a thousand times all ready, so please excuse me for doing it again as new memeber of your group. I am looking for programing and wireing information for this cw id'er. It will go on my VHF Engineering 220 repeater if I can make it work. Any help is appreciated. Thank you Steve KB0JYL Topeka 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] Mocom 70
Hello I need a manual for a UHF Mocom 70. Mine dissappeared. Any help is appreciated. [EMAIL PROTECTED]Dave N8DNZ 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] Repeater-Builder net anyone??
Hi Gang I know this was done a while ago, Is anyone interested in a repeater discusson net over IRLP or Echolink? might be able to use one of the IRLP reflectors that bridge echolink and IRLP together Thanks Scott Ka9sln IRLP 8380 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] Mocom 70
By your description, the following manuals by part number, are appropriate: 68-81011E30 68-81012E60 68-81023E55 Also which version do you have ... the varactor multiplier in the transmitter (early) or the microstrip version (late) Neil - WA6KLA dph96266 wrote: Hello I need a manual for a UHF Mocom 70. Mine dissappeared. Any help is appreciated. [EMAIL PROTECTED]Dave N8DNZ 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] Re: Repeater-Builder net anyone??
--- In Repeater-Builder@yahoogroups.com, [EMAIL PROTECTED] wrote: Hi Gang I know this was done a while ago, Is anyone interested in a repeater discusson net over IRLP or Echolink? might be able to use one of the IRLP reflectors that bridge echolink and IRLP together Thanks Scott Ka9sln IRLP 8380 Sounds good here, Dave VanHorn KC6ETE IRLP 4161 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] Re: Duplexer retune / recoax
I would be much surprised if cables were an issue, unless they had been messed with extensively or modified. Usually a duplexer just sits there and works for years and years, and the cables are usually not moved very much, unless someone monkeys with things. True, or it was not right to start with. In my case, I have this 2M repeater with no real history behind it. I don't know if the cans were commercial ones pulled into the ham band, or ham cans to start with.. I have no idea if they were fixed by someone before they got to me. (Fixed, as in 'fixed like a cat') So, I am of the mind to check everything when we go up there for the rebuild. 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] Repeater-Builder net anyone??
Hell yeah! I tried to do this a while back, but we tried over HF. I think IRLP, or echolink, or both would be a good idea. Thoughts? Thanks, Jed -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Saturday, January 21, 2006 2:39 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Repeater-Builder net anyone?? Hi Gang I know this was done a while ago, Is anyone interested in a repeater discusson net over IRLP or Echolink? might be able to use one of the IRLP reflectors that bridge echolink and IRLP together Thanks Scott Ka9sln IRLP 8380 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] Re: Duplexer retune / recoax
I love it. You should send that suggestion to Andrew or maybe even Belden. Make sure the cable you end up with is double-shielded, silver-tinned, flexible, and rated for outdoor use (no foil and braid mixed together). Ask for patent rights while you're at it. In theory, it should be possible. A compressible center conductor that shrinks in proportion to the outer conductor diameter. But, I'll leave that for others to ponder. On a more serious note, if the cables use male N connectors you measure from end to end. The Amphenol crimp-on connectors add 1/2 inch to the length of the center conductor, so if you need a total length of 12 inches, cut the coax for 11 inches. Strip and add the two connectors and you'll be right on 12 inches in length. If you use UHF male connectors, I don't know where you measure from. Well, our cans are UHF connectors. Isn't that hilarious? UHF connectors really good for HF, on VHF cans. The radios are all N, and my preamps are BNC or SMA. Life's like that some days. If I had a choice, I'd change the cans to N, and the amps as well, but at the moment that's what I've got. At least I worked out how to put cheap crimp-on N connectors on the FSJ1-50 jumpers along with the UHF connectors. Hopefully I can make up for the icky connectors in the nice jumper cables. This measurement thing is something that always bugs me in antenna designs too. When you're talking about an HF beam, little things don't matter, but when you're talking VHF or UHF, I do think it's important to show WHERE you're taking the measurements from. 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] Re: Duplexer retune / recoax
You can't simply cut the jumper cables to a certain fraction of the wavelength, because the coupling loops inside the cans are part of the total length. That's what I figured. It takes a network analyzer to determine the optimum length, and most folks simply don't feel that it's necessary to go to that extreme. Have SA and tracking generator, but not network analyzer. Could I emulate this by tuning with an HT as a signal source, and looking for minimum reflection? I have 500mW bird slugs. I know people say that you can't tune them with power applied, but there has to be a damage threshold, otherwise you couldn't tune them at all! He uses a network analyzer to measure the insertion loss between two cans at a time, and then he will try a longer or a shorter jumper until he finds the optimum. I'm trying to picture the setup here, and where he's measuring. When I am doing the pass frequency, I have the SA at the antenna terminal, and the tracking generator at the other end of the appropriate can pair, with the unused one terminated. Needless to say, he soon has a list of sweet lengths to start with for each frequency, so it normally takes only a few tries to get it on the nose. It is still a cut and try approach, but it works. Hmm. Assuming that my measurements show that we aren't getting what we should, I guess I could make a guess in the appropriate direction, and see what happens. The nice thing about doing the UHF connectors with FSJ1-50 is that they are easy to take off again. I have plenty of cable, so I'm not worried about expending that, and the connectors are silver/teflon. The typical spectrum analyzer works in transmission mode, and doesn't have the extreme reflection sensitivity needed to properly tune for bandpass. A good spectrum analyzer with a return-loss bridge can probably be used in place of a network analyzer for this task. Hmm. I know what you mean here. I did return loss measurements on telco equipment with a bridge that I built, but I'd be nervous making one up for VHF work. 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 retune / recoax
Jeff, I'll be the first to admit that reality often contradicts theory. However, both EMR and TX-RX have published application notes which support my statement. Some time ago, I tried to tune up a Sinclair Q-202G BpBr duplexer for a Ham, which simply involved moving from one 2m pair to another pair only 120 kHz away. The label on the duplexer showed that it was originally made for a 600 kHz split in the 2m band, but I was unable to get the insertion loss below 3.0 dB, even though each cavity had the correct 0.8 dB insertion loss. The combined notch attenuation was about 87 dB, but the pass loss was far too high. After studying the duplexer for a while, I wondered why the cable harness seemed to be pretty decrepit for a fairly-new duplexer. On a hunch, I dug out the harness info I got from Sinclair and discovered that the previous owner had put a high-split harness on this duplexer before selling it to the Ham, keeping the original low split harness for himself. Once a new low-split harness was purchased directly from Sinclair (about $125, as I recall) and installed, the duplexer tuned up with the expected pass loss of about 1.6 dB. The notch attenuation was within a dB of the previous value, using the incorrect harness. As I recall, the low-split Sinclair harness had jumpers that were about 2 longer than the high-split jumpers. Even though theory may dictate otherwise, this particular incident with this duplexer proved to me that incorrect jumper lengths between cans may have a profound effect upon pass attenuation, and almost no effect upon notch depth. YMMV. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo Sent: Saturday, January 21, 2006 9:16 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Duplexer retune / recoax The length of the jumper cables between the cans has a profound effect upon the insertion loss at the pass frequency, and relatively little effect upon the isolation at the notch frequency. 73, Eric Lemmon WB6FLY Eric, I'm curious why you say this, as it contradicts what I would believe to be the case in theory... The remainder of Jeff's scholarly letter is snipped for brevity 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] Re: Duplexer retune / recoax
--- In Repe As I recall, the low-split Sinclair harness had jumpers that were about 2 longer than the high-split jumpers. Even though theory may dictate otherwise, this particular incident with this duplexer proved to me that incorrect jumper lengths between cans may have a profound effect upon pass attenuation, and almost no effect upon notch depth. YMMV. Could be that the notch depth was obscured by the noise floor of the analyzer, coax leakage, or other factors, and you just couldn't see the change. When tuning a set for the local club, I had the rejects down to where I couldn't see the bottoms with my tracking generator at 11dBm and noise floor at -70 IIRC, and I had to use an HT for signal source and tune the notches that way. Scary thought when a bit too much input would permanently smoke my analyzer. But, if you're getting enough notch, then it's enough :) 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] Re: Repeater-Builder net anyone??
That sounds like a good idea AC0Y Echolink node# 86525 --- In Repeater-Builder@yahoogroups.com, [EMAIL PROTECTED] wrote: Hi Gang I know this was done a while ago, Is anyone interested in a repeater discusson net over IRLP or Echolink? might be able to use one of the IRLP reflectors that bridge echolink and IRLP together Thanks Scott Ka9sln IRLP 8380 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] Mocom 70
Wow Thanks for such a fast response. I really don't know what I inherited here, just went to the file and the folder was missing. Is there a easy way of identifying the characteristics between the varactor and the micro strip? I have worked on the later versions and don't believe I have ever seen the varactor versions. In fact the last Mocom 70 was on a motorcycle, years ago. When I am able to put my hands on the repeater I will be able to talk more intelligently about model # and series. Thanks for the response I will get back to you with the dataDaveNeil McKie [EMAIL PROTECTED] wrote: By your description, the following manuals by part number, are appropriate: 68-81011E3068-81012E60 68-81023E55 Also which version do you have ... the varactor multiplier in the transmitter (early) or the microstrip version (late) Neil - WA6KLA dph96266 wrote: Hello I need a manual for a UHF Mocom 70. Mine dissappeared. Any help is appreciated. [EMAIL PROTECTED] Dave N8DNZYahoo! 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 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] Re: Duplexer retune / recoax
Dave, That's when a good network analyzer's dynamic range really is important. With a DR in excess of 125 dB, the noise floor is not a factor even if you're tuning a six-cavity duplexer with 8 or 10 cans- and there is still the capability to increase the stimulus power. Once I got used to using my VNA, my spectrum analyzer was relegated to other tasks. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Dave VanHorn Sent: Saturday, January 21, 2006 5:47 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Duplexer retune / recoax Could be that the notch depth was obscured by the noise floor of the analyzer, coax leakage, or other factors, and you just couldn't see the change... snip 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 retune / recoax
Once a new low-split harness was purchased directly from Sinclair (about $125, as I recall) and installed, the duplexer tuned up with the expected pass loss of about 1.6 dB. The notch attenuation was within a dB of the previous value, using the incorrect harness. Well, my guess is that the high insertion loss you saw was not due to the incorrect cable lengths *between* adjacent cavities, but rather between the first cavity on each side and the tee. With that length being wrong, the two sides of the duplexer are not fully decoupled, i.e. the reject notch on one side isn't being echoed exactly 1/4 wave away back at the tee. I'd bet that if you only increased the lengths of the cables between the first cavities and the tee that the measured performance would have been comparable to replacing the entire harness. --- 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 retune / recoax
Eric, Can you provide links to these? Chuck WB2EDV Eric Lemmon wrote: Jeff, I'll be the first to admit that reality often contradicts theory. However, both EMR and TX-RX have published application notes which support my statement. 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 retune / recoax
Jeff, That's quite possible, but I did not check it because the Sinclair harness was completely made up of Delta connectors crimped onto RG-214/U cable. The harness came preassembled as one long piece of coax with five N-male tees crimped into place, with N-male connectors on the ends going to the transmitter and receiver. I do remember that the cables between the antenna tee and the first cavities were about the same distance longer as the between-cavity jumpers were longer, for the low-split. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jeff DePolo Sent: Saturday, January 21, 2006 6:21 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Duplexer retune / recoax Well, my guess is that the high insertion loss you saw was not due to the incorrect cable lengths *between* adjacent cavities, but rather between the first cavity on each side and the tee. With that length being wrong, the two sides of the duplexer are not fully decoupled, i.e. the reject notch on one side isn't being echoed exactly 1/4 wave away back at the tee. I'd bet that if you only increased the lengths of the cables between the first cavities and the tee that the measured performance would have been comparable to replacing the entire harness. --- 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 retune / recoax
Thanks for the links. I've seen them all previously. I do not see where any of them indicate that the interconnect cables affect the bandpass loss. Where did you find this? Maybe I missed it somewhere. Chuck WB2EDV Eric Lemmon wrote: Chuck, I don't know if the papers I have were ever published in electronic form. Here are some links to get you started, but possibly not the exact notes I referred to, since a great deal of time has passed since their original publication. http://www.emr.com/images/tech_papers/Duplexer_Manual.pdf http://www.emr.com/images/tech_papers/The_Fifty_Ohm_Enigma2.pdf http://www.emr.com/images/tech_papers/tech_cover/antenna_duplexors(15-26).pd f http://www.emr.com/images/tech_papers/tech_cover/cavity_resonators(54-67).pd f http://www.rfsolutions.com/duplex.htm http://tinyurl.com/bvt7t http://www.seits.org/duplexer/duplexer.pdf 73, Eric Lemmon WB6FLY -Original Message- Subject: Re: [Repeater-Builder] Re: Duplexer retune / recoax From: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com To: Repeater-Builder@yahoogroups.com Eric, Can you provide links to these? Chuck WB2EDV 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] Azden PCS-4000
Anyone know much about this radio..moreover, anyone know what battery it takes.. the battery was removed by a previous owner, wanting to use it as a link radio, but w/o the battery, it won't hold a memory Thank You for your time, Glen Briggs - KBØRPJ Grundy County Amateur Radio Emergency Services Coordinator http://grundy.ares-mo.org/ - North Central Missouri Amateur Radio Club --- This message has passed an anti-virus scan using the avast! anti-virus system, database: 0603-4, 01/20/2006 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] Re: Duplexer retune / recoax
That's when a good network analyzer's dynamic range really is important. With a DR in excess of 125 dB, the noise floor is not a factor even if you're tuning a six-cavity duplexer with 8 or 10 cans- and there is still the capability to increase the stimulus power. Once I got used to using my VNA, my spectrum analyzer was relegated to other tasks. Well, until I find one that's a good deal at dayton... 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 retune / recoax
At 1/21/2006 18:18, you wrote: Dave, That's when a good network analyzer's dynamic range really is important. With a DR in excess of 125 dB, the noise floor is not a factor even if you're tuning a six-cavity duplexer with 8 or 10 cans- and there is still the capability to increase the stimulus power. Once I got used to using my VNA, my spectrum analyzer was relegated to other tasks. 73, Eric Lemmon WB6FLY I always thought of the HP8510C as a good network analyzer (you'd think so with the $100,000 price tag), yet it barely makes it to 100 dB. Bob NO6B 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/
