Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New file uploaded to Repeater-Builder)
On Dec 27, 2007, at 11:46 AM, Repeater-Builder@yahoogroups.com wrote: Hello, This email message is a notification to let you know that a file has been uploaded to the Files area of the Repeater-Builder group. File: /Simple P25 Repeater / ASTROCapableRepeaterUtilizing2UHFMotorolaMaxtracRadios.pdf Uploaded by : efj44 [EMAIL PROTECTED] Description : Simple P25 Repeater using 2 Motorola Maxtrac Mobiles . You can access this file at the URL: http://groups.yahoo.com/group/Repeater-Builder/files/Simple%20P25%20Repeater%20/ASTROCapableRepeaterUtilizing2UHFMotorolaMaxtracRadios.pdf This has already been done in a number of places with various rigs. The disadvantages are many, but the main one is in that the digital signal is converted to analog and then back to digital, and the resulting double-vocoded audio which has been put through two lossy CODEC's will sound really bad. We have a similar setup here on a VHF machine in Denver. It's copyable, but the audio at the end-user radio will NOT be an accurate representation of what was originally transmitted. Comparing the Amateur P25 system that's double-VOCODed vs. a real P25 repeater is like night and day. There's no such thing as a free lunch -- for P25 (or any other digital real-time audio stream of bits) to sound as good as it can sound, you have to stay digital at the repeater. You should post information on your website or however you communicate with your users that the system's audio will never quite sound right. Otherwise, they may think that P25 always sounds that bad. Other disadvantages are that the repeater won't pass Unit ID's properly, and most of the features of P25 will be lost. Unit to unit calling, etc. Anything included in the data stream beyond the audio is lost. It also won't be ID'ed legally without the assistance of the end-users in that configuration unless you switch back to analog mode for ID's under the watchful eye of an intelligent repeater controller. (Putting MCW through the IMBE VOCODER sounds like the CW is coming from underwater, but it's copyable if you have to go that route.) It's a quick-and-dirty way to set up a P25 capable repeater, but it'd be wise to start shopping for a digital-capable Quantar or similar from any other manufacturer if you want P25. -- Nate Duehr, WY0X [EMAIL PROTECTED]
Re: Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New f...
In a message dated 12/28/2007 4:24:38 A.M. Eastern Standard Time, [EMAIL PROTECTED] writes: The disadvantages are many, but the main one is in that the digital signal is converted to analog and then back to digital, and the resulting double-vocoded audio which has been put through two lossy CODEC's will sound really bad. You cant double vocode using Maxtracs, they have no vocoder to begin with. This is a transparent repeater and will pass IMBE, VSELP, AEGIS and D-Star. Might even be wide enough for 12KB Securenet. What it lacks is error correction so digital errors present on the input will be passed right along. This results in reduced range. This is a good way for Hams to start using their P25 radios immediately while shopping for a Quantar. I am building one right now. Chris N9LLO **See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop000304)
Re: Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New f...
I have 2 Maxtracs Setup that I use for P25 Didgital . Works Well to me . Now it does not ack like a Motorola Quentar or Other P25 Digital Repeaters , But It Works . It just allows you to pass the P25 Digital Pakets from the Radio you are using , and the Other Users Radios Decode it .This Information was put together by a Motorola Tech for Use for HAM Radio . I my Self Mostly work on EF Johnson Radios, So I use alot of P25 EF Johnson Portables and Mobiles . But just wonted to Pass this Info on t **See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop000304)
Re: Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New f...
I have 2 Maxtracs Setup that I use for P25 Didgital . Works Well to me . Now it does not ack like a Motorola Quentar or Other P25 Digital Repeaters , But It Works . It just allows you to pass the P25 Digital Pakets from the Radio you are using , and the Other Users Radios Decode it .This Information was put together by a Motorola Tech for Use for HAM Radio . I my Self Mostly work on EF Johnson Radios, So I use alot of P25 EF Johnson Portables and Mobiles . But just wonted to Pass this Info on to everyone . Just my Thoughts . Steve efj44 **See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop000304)
Re: Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New f...
On Dec 28, 2007, at 3:01 AM, [EMAIL PROTECTED] wrote: In a message dated 12/28/2007 4:24:38 A.M. Eastern Standard Time, [EMAIL PROTECTED] writes: The disadvantages are many, but the main one is in that the digital signal is converted to analog and then back to digital, and the resulting double-vocoded audio which has been put through two lossy CODEC's will sound really bad. You cant double vocode using Maxtracs, they have no vocoder to begin with. This is a transparent repeater and will pass IMBE, VSELP, AEGIS and D-Star. Might even be wide enough for 12KB Securenet. What it lacks is error correction so digital errors present on the input will be passed right along. This results in reduced range. This is a good way for Hams to start using their P25 radios immediately while shopping for a Quantar. I am building one right now. Chris N9LLO Oh, so this is just taking discriminator audio and passing it to another exciter with no filtering? The drawing labels don't make that clear, but not sure why you'd need Maxtrac rigs to do this. Virtually any rig would do it. A lot of the repeaters built for 100% duty- cycle at high power levels that folks are already doing will do it, if modified appropriately. The disadvantage to this type of setup, is exactly what you mention -- no bit-regeneration. Garbage in, garbage out -- probably with some unintended additional bit errors added by audio shaping inside the rig if its all not completely bypassed. Also has the disadvantage of being able to accept ultra-wide signals and re-transmit them, even if coordinated for a much smaller occupied bandwidth, if a hard limiter isn't inserted between the receiver and transmitter in the audio path. Are you finding reasonable pricing on P25 radios in your area, Chris? They're really not that reasonable out here, yet. I expect a lot of P25 Phase I rigs will drop out of Public Safety service if/when Phase II starts getting widely deployed. (That will be a while yet...) There's been some minor discussion between the RF-heads around here and some of the bit-jockeys (heh heh... just joking with the nicknames) about building bit-regeneration devices to put in solid old repeaters, but the problems seem to lie in detection of the raised- cosign modulation type. It's not simple, except perhaps for DSP engineers who are too busy building real products for their day jobs to dive into writing the code needed to detect the P25 analog waveform and convert it back to a bitstream. Then you have to go the other direction and create that same raised- cosign waveform in the exciter for transmit. All pretty heavy duty coding, even for good DSP engineers, unfortunately. Seems very do-able to create a real blob that would drop into certain repeater-quality RF platforms to do this, but way beyond my capabilities... and everyone I've talked to so far about it. It's similar but harder engineering than say, the old 9600 bps bit- regenerative repeaters when Packet was popular. The modulation for that was a quadrature signal (if I remember correctly) and much easier to detect, even in discreet component electronics. This waveform that P25 uses appears to be quite a different beast altogether. -- Nate Duehr, WY0X [EMAIL PROTECTED]
Re: Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New f...
This is only a Quick setup. I would prefer a real P25 Digital Repeater , But this Setup Works . You can go to Ebay and Get Motorola Astro Sabers or a XTS-3000 And Others . But you haft to get one that is IMBE P25 . VSLEP Is not Allowd on Ham Bands . IMBE Is Allowd for Ham Use . And it sounds Better than DSTAR AMBE . Steve efj44 **See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop000304)
Re: Cheap P25 repeater using mobile rigs (was: Re: [Repeater-Builder] New f...
p.s. Yes, I'm fishing a bit with this message. I stood around and looked stupid while a local good digital engineer (and RF guy) and another good RF engineer discussed this idea once, and they both expressed interest but no time to work on it right now. Anyone who knows how to go about this level of DSP engineering to get to the raw bit level from a common FM discriminator (receiver) without resorting to buying the IMBE chipset (and I suppose it goes without saying that it'd have to be someone who also isn't under an NDA because they already work on such things) -- I'd be willing to put you in touch with both of them, put up a website, deal with the general public inquiries, or whatever administrivia would keep the world off your back while y'all are working on something that nifty. (I'm guessing I won't find any takers -- unless someone feels like doing a lot of hard work for free... but what the heck, it doesn't hurt to ask.) On Dec 28, 2007, at 4:31 AM, Nate Duehr wrote: On Dec 28, 2007, at 3:01 AM, [EMAIL PROTECTED] wrote: In a message dated 12/28/2007 4:24:38 A.M. Eastern Standard Time, [EMAIL PROTECTED] writes: The disadvantages are many, but the main one is in that the digital signal is converted to analog and then back to digital, and the resulting double-vocoded audio which has been put through two lossy CODEC's will sound really bad. You cant double vocode using Maxtracs, they have no vocoder to begin with. This is a transparent repeater and will pass IMBE, VSELP, AEGIS and D-Star. Might even be wide enough for 12KB Securenet. What it lacks is error correction so digital errors present on the input will be passed right along. This results in reduced range. This is a good way for Hams to start using their P25 radios immediately while shopping for a Quantar. I am building one right now. Chris N9LLO Oh, so this is just taking discriminator audio and passing it to another exciter with no filtering? The drawing labels don't make that clear, but not sure why you'd need Maxtrac rigs to do this. Virtually any rig would do it. A lot of the repeaters built for 100% duty- cycle at high power levels that folks are already doing will do it, if modified appropriately. The disadvantage to this type of setup, is exactly what you mention -- no bit-regeneration. Garbage in, garbage out -- probably with some unintended additional bit errors added by audio shaping inside the rig if its all not completely bypassed. Also has the disadvantage of being able to accept ultra-wide signals and re-transmit them, even if coordinated for a much smaller occupied bandwidth, if a hard limiter isn't inserted between the receiver and transmitter in the audio path. Are you finding reasonable pricing on P25 radios in your area, Chris? They're really not that reasonable out here, yet. I expect a lot of P25 Phase I rigs will drop out of Public Safety service if/when Phase II starts getting widely deployed. (That will be a while yet...) There's been some minor discussion between the RF-heads around here and some of the bit-jockeys (heh heh... just joking with the nicknames) about building bit-regeneration devices to put in solid old repeaters, but the problems seem to lie in detection of the raised- cosign modulation type. It's not simple, except perhaps for DSP engineers who are too busy building real products for their day jobs to dive into writing the code needed to detect the P25 analog waveform and convert it back to a bitstream. Then you have to go the other direction and create that same raised- cosign waveform in the exciter for transmit. All pretty heavy duty coding, even for good DSP engineers, unfortunately. Seems very do-able to create a real blob that would drop into certain repeater-quality RF platforms to do this, but way beyond my capabilities... and everyone I've talked to so far about it. It's similar but harder engineering than say, the old 9600 bps bit- regenerative repeaters when Packet was popular. The modulation for that was a quadrature signal (if I remember correctly) and much easier to detect, even in discreet component electronics. This waveform that P25 uses appears to be quite a different beast altogether. -- Nate Duehr, WY0X [EMAIL PROTECTED] Yahoo! Groups Links -- Nate Duehr [EMAIL PROTECTED]
[Repeater-Builder] GLB Preselector
Anyone know the device number of the gaasfet (or whatever type it is) in the P-145 model? Inherited one with -12 db gain. Looks easy enough to fix. Thanks, Dwayne Kincaid WD8OYG
[Repeater-Builder] Re: UHF duplexers and preamps
Hi Guys, Thanks for the replies on this, my curiousity about the pre amp is based on my limited knowledge that you can't improve what you can't already hear so I wasn't too sure how much benefit they actually give. We are lucky in as much as our site has no other users and the nearest UHF site is about 1/2 mile away with 410Mhz Tetra and TV. I had a quick look on the Angle linear site for pre amps and notice they sell complete duplexers as well, the spec looks excellent but I'm sure it comes at a price! On this side of the pond there doesn't seem to be much of a second hand market for commercial kit, for new stuff we've got Procom, their website lists http://www.profilant.net/uk/filter/13061800 which seems to BPBR and has more than adequate power handling, UK repeaters are limited to a measly 25W ERP! I'll make some enquiries about the Procom and meantime our groups technical guy has decided to buy one of those Ebay items to see if it performs as stated with no intention of using it on our repeater :) Cheers Paul --- In Repeater-Builder@yahoogroups.com, Ken Arck [EMAIL PROTECTED] wrote: ---Hi Paul. First of all, the type of duplexer you're looking at is a notch only type. Secondly, I find their claim of 75 dB isolation and 1 dB insertion loss pretty comical. I'd go so far as to say that claim is total BS. Even at your spacing of 7.5 mHz, I don't see how the performance is anywhere near as good as they claim. You ca' not fight the law of physics as Scotty would say. A notch-only type duplexer is usually adequate for lower power repeaters in a low RF environment. I would certainly NEVER use one at a radio site where other radios/repeaters reside as they do not offer adequate out-of-band rejection nor even adequate in-band rejection. To further complicate things, adding a preamp would probably be a complete disaster without adding additional filtering. I do agree with Jed that AngleLinear makes most excellent preamps with just the right amount of gain for a repeater preamp, whereas ones such as ARR have WY too much gain. The purpose of a preamp in a repeater (assuming your receiver is worth a damn in the first place) is to overcome the loss of the duplexer and feedline. Too much gain opens the door to all sorts of issues, not the least of which are desense and front-end overloading. And again, using one with the typical mobile duplexer will probably cause problems anyway. You can find good deals on used band-pass/band-reject UHF duplexers, usually quite easily. My advice is to buy one of those and forget about the mobile type. Ken
Re: [Repeater-Builder] GLB Preselector
I'm assuming you mean preselector - preamp. At that frequency, they were usually made with a bipolar transistor, unless it was custom made; then it could be a GaAs device. It is a MRF-901 (or equivalent) if it is bipolar. Many times only 901 appeared on the device, if it wasn't ever changed. Looking at the components around it, one should be able to tell if it's a FET or a regular transistor. I never owned one with a FET device, so I don't know what that would be. Kevin ldgelectronics wrote: Anyone know the device number of the gaasfet (or whatever type it is) in the P-145 model? Inherited one with -12 db gain. Looks easy enough to fix. Thanks, Dwayne Kincaid WD8OYG
Re: [Repeater-Builder] GLB Preselector
At 03:49 AM 12/28/07, you wrote: Anyone know the device number of the gaasfet (or whatever type it is) in the P-145 model? Inherited one with -12 db gain. Looks easy enough to fix. Thanks, Dwayne Kincaid WD8OYG I fixed one years ago with a Siliconix U-310, but I have no doubt that there are better devices out there today. Mike WA6ILQ
Re: [Repeater-Builder] GLB Preselector
I have a GLB Model P-147.49 that was custom made for me years ago. It use an MRF901 device. 73, Joe, K1ike ldgelectronics wrote: Anyone know the device number of the gaasfet (or whatever type it is) in the P-145 model? Inherited one with -12 db gain. Looks easy enough to fix. Thanks, Dwayne Kincaid WD8OYG
[Repeater-Builder] Mitrek Transmitter Tuning
Repeater-Builder Guru's, I am trying to tune up the transmitter on one of my Mitrek's and am having no luck and alot of frusteration. I have the motorola manual and the cheat sheets here: http://www.repeater-builder.com/mitrek/pix/mitrek-tx-tuning.gif The question is, what do I need to measure when they say, Meter position 3 (Which I understand is pin 3 on the test socket) but what do I need to measure with my multi-meter? Milli-volts? Milli-amps? Micro-amps? Do I simply put my negative terminal for my multi-meter to ground, and the other test lead to the appropriate pin? Or does my negative terminal need to be in one of the test sockets? Also, I have Mitrek Model HUE1159BPR radio, which is for 470-512. I am trying to run it on 462/467, is that too far out of range for this radio? Any word of advice would be greatly appreciated. Regards, Richard Bessey KE7IOD
[Repeater-Builder] Manual
Anyone know where I can obtain the manual for GE LBI #4100 ? It is not found in: The 'Mastr' Index of GE LBI's
[Repeater-Builder] Re: National Radio Quiet Zone
I have known Wes for about 15 yrs. He's a good dude!! Mike Perryman [EMAIL PROTECTED] 7839 Ashton Avenue Manassas, Virginia 20109-2883 Download Outlook Contact Info 703.392.9090 General Office 703.392.9559 Facsimile 202.332.0110 Washington, D.C. Line www.CavellMertz.com www.FCCInfo.com
Re: [Repeater-Builder] Mitrek Transmitter Tuning
Almost all Motorola radios use a 50 micro-amp DC meter. Sometimes the negative end goes to ground, sometimes the positive end. The metering test set will have a meter reversal switch on it to flip the leads. You can use almost any 50uA meter. Most of the time you're just peaking various stages, however when measuring the PA current, the meter is often connected across a low-value resistor, so neither end is grounded. Schematics for some popular Motorola test sets are also on repeater-builder, in the Motorola area, Test Set section. Depending on the model, the appropriate metering socket pins are selected and fed to the meter. Someone else will have to comment on operating the unit out-of-band. Bob M. == --- Richard Bessey [EMAIL PROTECTED] wrote: Repeater-Builder Guru's, I am trying to tune up the transmitter on one of my Mitrek's and am having no luck and alot of frusteration. I have the motorola manual and the cheat sheets here: http://www.repeater-builder.com/mitrek/pix/mitrek-tx-tuning.gif The question is, what do I need to measure when they say, Meter position 3 (Which I understand is pin 3 on the test socket) but what do I need to measure with my multi-meter? Milli-volts? Milli-amps? Micro-amps? Do I simply put my negative terminal for my multi-meter to ground, and the other test lead to the appropriate pin? Or does my negative terminal need to be in one of the test sockets? Also, I have Mitrek Model HUE1159BPR radio, which is for 470-512. I am trying to run it on 462/467, is that too far out of range for this radio? Any word of advice would be greatly appreciated. Regards, Richard Bessey KE7IOD Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping
[Repeater-Builder] Re: R1225 repeater
Just ordered the Service Manual per Eric's information (thank you Eric) and the part number works mucho fine. The price today is $14.40 per copy plus any tax and ground shipping. cheers, skipp Eric Lemmon [EMAIL PROTECTED] wrote: Mark, You should order a copy of the R1225 service manual 6880905Z53 from Motorola Parts while it is still in print. It costs about $13, less than 1/3 the cost to make a color copy of it. The receiver front end has back-to-back diodes to provide some protection against high voltages, but a lightning strike or a misconnection to a transmitter can certainly fry them. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of n9wys Sent: Thursday, December 27, 2007 2:12 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] R1225 repeater A while back I posted an inquiry regarding an R1225 repeater I was looking at for another. it was deaf as a fence post. Well, today I had a chance to finally open this thing up and get a look-see. (This took so long because I've been ridding myself of a number of kidney stones.) Anyway, the front end of the receiver is burnt to a crisp - my best guess is that it got hit with strong incoming RF that was not blocked by a mis-tuned duplexer. or the owner hooked the duplexer up backward. (I think this was discussed previously.) Anyway, in order to get this thing going, I am in need of the receive board layout diagram and a parts list. With the radio oriented so the RX antenna connection is at the lower left, the components that are toasted are just above the antenna connection. (They all look like SMC capacitors, but without the board layout and parts list, I can't be certain - nor can I determine proper replacement values.) If anyone can help, I'd be much obliged! Thanks in advance! Mark - N9WYS
Re: [Repeater-Builder] Mitrek Transmitter Tuning
At 05:10 PM 12/27/07, you wrote: Repeater-Builder Guru's, I am trying to tune up the transmitter on one of my Mitrek's and am having no luck and alot of frusteration. And I guarantee you will ruin the PA deck (all it takes is one click) unless you read the caution in my interfacing article about C800L and how to tune it. I have the motorola manual and the cheat sheets here: http://www.repeater-builder.com/mitrek/pix/mitrek-tx-tuning.gif The question is, what do I need to measure when they say, Meter position 3 (Which I understand is pin 3 on the test socket) On the lower numbered positions, yes, but not always. Some times it is a sequence of 21345 rather then 12345. The higher numbered ones get strange, and on the transmitter they float both ends to measure PA deck current. It can be a real pain to try and hold both probes in socket pins and tune an adjustment, and then swing a locknut on the peak. 90% of the time the adjustment creeps just a hair as the locknut binds. but what do I need to measure with my multi-meter? Milli-volts? Milli-amps? Micro-amps? 50 ua full scale. And don't even think of trying to use a DVM to tune a radio. You really need a needle type meter to see the peaks and dips. Do I simply put my negative terminal for my multi-meter to ground, and the other test lead to the appropriate pin? Or does my negative terminal need to be in one of the test sockets? Look in the Test Set article on Repeater-builder (click on Motorola then test sets). You will find schematics of the test set and the cables. If you are going to do more than one radio then buy a greyface or silverface test set on ebay, you will thank yourself, especially when you are trying to hold two probes, a screwdriver and an open-end wrench. A friend one took a photo of me with a screwdriver in one hand, a wrench in the other, a test probe in my teeth, while keeping my eyes on a VOM, and his parrot on my shoulder looking down on it all. Not to be blunt - but if you can't afford a old Moto Test Set and a Motrac/Motran/Mocom/Mitrek cable, at least buy an old Simpson 260 or a Tripplet 630 and build a box with a test plug (you can gut a sealed relay that has the right plug) and a rotary switch to drive the meter. I went the cheap way in my early days and bought old 50ua meters for $5 to $10ea and burned up two of them by going across the wrong points on the test jacks. Also, I have Mitrek Model HUE1159BPR radio, which is for 470-512. I am trying to run it on 462/467, is that too far out of range for this radio? Only had three high range radios and used em all for parts or trading stock, so can't help you much. But figuring that a 450 radio will have acceptable receive performance down to at least 438.5, occasionally to 435, you should be OK. Transmitters stretch farther than receivers. Any word of advice would be greatly appreciated. See above. Let us know how it works out. Regards, Richard Bessey KE7IOD Mike WA6ILQ
[Repeater-Builder] Re: GLB Preselector
Thanks, This one had different marking, but could have been changed. I'll put a 901 in it and see how it does. Dwayne --- In Repeater-Builder@yahoogroups.com, Joe [EMAIL PROTECTED] wrote: I have a GLB Model P-147.49 that was custom made for me years ago. It use an MRF901 device. 73, Joe, K1ike ldgelectronics wrote: Anyone know the device number of the gaasfet (or whatever type it is) in the P-145 model? Inherited one with -12 db gain. Looks easy enough to fix. Thanks, Dwayne Kincaid WD8OYG
[Repeater-Builder] RLC-Mot and Optocoupler for COR - Not Working Correctly.
Hi All, Hope you had a good Christmas, and looking forward to the New Year. Anyway my question. I have a RLC-MOT installed in my Mitrek 10mtr RX, and have also fitted a optocouple to isolate the radio from the controller (RLC-2A) I have used the circuit from the Mitrek pages in Repeater-Builder which includes a NPN transistor to switch the + output from the RLC-MOT, to a low on the controller. However the problem I have is that when it is connected using a 3.3K or 4.7K resistor in series on the base it does not work, it keeps it low (RLC-MOT) and I get no switching. Take the wire off the base resistor and I have 6v on the output of the RLC-MOT. Now I have got it to work by putting a 1N914 diode before the base resistor, but I only have 2v on the line from the RLC-MOT, which I think is strange??? So now I have the following. Pin 4 (earth) and pin 5 of the optocoupler are the COR from controller. Pin 1 anode of opto. This has a 1.2k to 12v Pin 2 cathode of opto. This is connected to the collector of the 2N Emiter is connected to earth or ground Base is connected to the 5v output of the RLC-MOT through a 1N914 diode and a 3.3k resistor. And that is it. This is taken from page 31 of Mike Morries's information sheet on Interfacing the Motorola Mitrek Mobile Radio to a Repeater Controller (A very well written and helpful guide - Highly recommended) Any assistance would be gratefully received, if not I will go with what I have. Regards Kevin. Get Skype and call me for free. sparc_nz Description: Binary data
[Repeater-Builder] Anybody have a FM Magazine collection?
While answering KE7IODs question on tuning a radio I realized that having a scan of the old Build Yourself A Moto Test Set article would be, to use a Martha Stewart term, A Good Thing. So is there anybody out here that has a FMM collection and a scanner? Or the critical issue and a xerox machine? Mike
[Repeater-Builder] Re: Stop the Madness
I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ
RE: [Repeater-Builder] Re: Stop the Madness
Doug, Two repeaters operating on the same frequency pair but with different PL tones is essentially a community repeater that will have the same disadvantages. A community repeater is fine for infrequent users in the agricultural, delivery, and towing services, for example. The chances for collisions are rare enough that the users simply wait several seconds and try again. When such a community repeater is tied up for long periods by ragchewers, the other users quickly become annoyed. Each group claims ownership of the frequency, and how dare those windbags keep me from using my machine! Just a few hotheads in this scenario can create chaos. In my area of California's Central Coast, most areas are served by at least two 2m repeaters. This is done not just for better coverage of mountainous terrain, but also to keep a repeater open for general public use while the other repeater is tied up with ARES activity during emergencies or exercises. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Doug Dickinson Sent: Friday, December 28, 2007 10:20 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Stop the Madness I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ
Re: [Repeater-Builder] Re: Stop the Madness
On Dec 28, 2007, at 11:19 AM, Doug Dickinson wrote: I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. No one here objects to this -- it happens all the time. It's called a co-channel repeater coordination. It also works just fine on Shared Non-Protected pairs, if your area has such pairs. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. The criteria for a co-channel coordination in most areas (check with your own coordinators) is measured in DISTANCE between two co- channeled repeaters for a normal coordination. The distance criteria includes an attempt to keep the overlap coverage areas of two co-channeled machines from being too large, which also limits the area where mobile stations transmitting into one system will be heard by the other. CTCSS or not, mobiles in the overlap coverage area are going to be using one system and interfering with the other, and coordination is an attempt to mitigate mutual interference. Repeater owner/operators in most areas can allow the distance criteria to be lowered or removed altogether if a desire to do so is sent in writing to the coordinators. Coordination rules are typically set up (and agreed to by the local repeater operators) to provide high levels of protection from interference. If repeater owner/operators (BOTH of them) wish to raise their personal tolerances for interference and problems, they certainly are allowed to do so by most coordination bodies. All they have to do is to send a note, and the coordinator will happily dump two or three other repeater owners who also claim they don't care about interference, right on top of their coordinated frequency. If that's what they truly want. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. In reality, the two repeaters won't have the same coverage and sooner or later a user who doesn't have a clue and is only in the coverage pattern of ONE of the repeaters, will cause unintentional QRM ... Which will either be a big problem for lots of people, or it won't, all depending on how the owner/operators of the systems react, whether or not the end-user is teachable, and various multitudes of other factors. -- Nate Duehr, WY0X [EMAIL PROTECTED]
Re: [Repeater-Builder] Anybody have a FM Magazine collection?
I'm all for that. We're using less than 10 of a 200 gig RAID array on the server. If anybody has copies of FMM or of rpt I'll be happy to get them scanned and on the server. Mike WA6ILQ At 09:48 AM 12/28/07, you wrote: What would also be interesting to have as scanned files on a CD or available on-line would be the old copies of rpt Magazine. Lots of great articles from back in the days when Repeaters were just getting popular in Ham Radio. I only have a couple of issues left after all these years. LJ -Original Message- From: Mike Morris WA6ILQ Sent: Dec 28, 2007 9:37 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Anybody have a FM Magazine collection? While answering KE7IODs question on tuning a radio I realized that having a scan of the old Build Yourself A Moto Test Set article would be, to use a Martha Stewart term, A Good Thing. So is there anybody out here that has a FMM collection and a scanner? Or the critical issue and a xerox machine? Mike
RE: [Repeater-Builder] Re: R1225 repeater
Thanks Skipp and Eric... I broke down today and ordered the manual myself. Again, thanks! Mark - N9WYS -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of skipp025 Just ordered the Service Manual per Eric's information (thank you Eric) and the part number works mucho fine. The price today is $14.40 per copy plus any tax and ground shipping. cheers, skipp Eric Lemmon [EMAIL PROTECTED] wrote: Mark, You should order a copy of the R1225 service manual 6880905Z53 from Motorola Parts while it is still in print. It costs about $13, less than 1/3 the cost to make a color copy of it. The receiver front end has back-to-back diodes to provide some protection against high voltages, but a lightning strike or a misconnection to a transmitter can certainly fry them. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com On Behalf Of n9wys A while back I posted an inquiry regarding an R1225 repeater I was looking at for another. it was deaf as a fence post. Well, today I had a chance to finally open this thing up and get a look-see. (This took so long because I've been ridding myself of a number of kidney stones.) Anyway, the front end of the receiver is burnt to a crisp - my best guess is that it got hit with strong incoming RF that was not blocked by a mis-tuned duplexer. or the owner hooked the duplexer up backward. (I think this was discussed previously.) Anyway, in order to get this thing going, I am in need of the receive board layout diagram and a parts list. With the radio oriented so the RX antenna connection is at the lower left, the components that are toasted are just above the antenna connection. (They all look like SMC capacitors, but without the board layout and parts list, I can't be certain - nor can I determine proper replacement values.) If anyone can help, I'd be much obliged! Thanks in advance! Mark - N9WYS
[Repeater-Builder] Re: Stop the Madness
---your not talking about two repeaters in differant towns with the same frequency and differant pl's? I believe your talking about about 2-repeaters in the same town? Cause I do know that frequency coordinators do set the same frequencies on repeaters within a 200 mile radius, which does cause interferance with the other repeater. . . . In Repeater-Builder@yahoogroups.com, Doug Dickinson [EMAIL PROTECTED] wrote: I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ
Re: [Repeater-Builder] Anybody have a FM Magazine collection?
Hi Mike, Have an FM Repeater collection(think it is complete). Back in the 60's, but do not have a way to scan them. Enjoyed them very much. Wonder what happened to Ken Sessions Michael J.Van Den Branden. Sad to see it disapear. Wesley AB8KD
Re: [Repeater-Builder] Re: Stop the Madness
we have had repeaters on the air in the past and Motorola has put a repeater in town with the same Freg. time and time again. It is a common thing just happen last year to a repeater we have in TN. new repeater 20 miles away same Freg. don't get mad over it, just the way it is. John - Original Message - From: Randy To: Repeater-Builder@yahoogroups.com Sent: Friday, December 28, 2007 4:50 PM Subject: [Repeater-Builder] Re: Stop the Madness ---your not talking about two repeaters in differant towns with the same frequency and differant pl's? I believe your talking about about 2-repeaters in the same town? Cause I do know that frequency coordinators do set the same frequencies on repeaters within a 200 mile radius, which does cause interferance with the other repeater. . . . In Repeater-Builder@yahoogroups.com, Doug Dickinson [EMAIL PROTECTED] wrote: I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ
RE: [Repeater-Builder] Re: Stop the Madness
If your goal in building a repeater is the experience and education it brings, and the chance to see how users react to your particular philosophy, could you live with having it on the air every other day to get a coordination 10 years sooner? I think that would work for most hams. If you share a frequency by assigning exclusive times for operation, there's no interference issue. If you try to leave overlapping repeaters on the air at the same time, many users will come on with the wrong tone programmed and inadvertently bring up the wrong machine, users will need two memories per frequency to differentiate tones, and there will be lots of other compromises. I would enjoy the friendly competition that might result from having another repeater sharing a frequency pair. It would probably be smart to partner with someone with similar views on repeaters. (If a minimalist who didn't like talking controllers or courtesy beeps was paired with a guy running an ACC in full game-arcade mode, the arrangement wouldn't satisfy either user base.) 73, Paul, AE4KR _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Doug Dickinson Sent: Friday, December 28, 2007 10:20 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Stop the Madness I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ
Re: [Repeater-Builder] Re: Stop the Madness
Our club operates two repeaters on the same channel using two different tones, and all works fine. In our case, we wanted to have instant backup in case one repeater went down (one is solar powered) and all the user had to do was switch tone frequencies and use the other repeater. They are not located in the same spot, so some advantage can be had by using the repeater which shows the best path to a user location. Short squelch tails and distinctive courtesy tones make it easy to identify which repeater is being used, and both repeaters transmit CTCSS tones while a user is key down on the input. More info is available at the club site if anyone is interested: www.sbarcnm.org 73 - Jim W5ZIT --- Doug Dickinson [EMAIL PROTECTED] wrote: I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping
Re: [Repeater-Builder] Re: GLB Preselector
Here is a few photos of what mine looks like. The circuit board is labeled on the top P40-500. 73, Joe, K1ike ldgelectronics wrote: Thanks, This one had different marking, but could have been changed. I'll put a 901 in it and see how it does. Dwayne .
[Repeater-Builder] TX RX Systems Model Number Nomenclature
Anyone know where I can find the model number decoding matrix for the TX RX product lines? I have been through there web site and they dont seem to offer much info on this subject? If you have any idea where I can find this info please email me at my address on qrz.com as I do not get emails from this group or check here often - TIA.dan n2aym
[Repeater-Builder] re-quiet zone-how we deal with it
living and working at ground zero so to speak has advantages and disadvantages. we dont have to deal with pagers and alot of other interference that alot of you deal with. on the other hand cell phone service in this county is poor at best. most all repeater owners as well as local hams have a working relationship with wes. once we get a freq. from sera we have to get it cordinated by his group. it is all but impossible to meet their limits in close so a repeater owner has to sign a paper saying that he would shut down the repeater when asked to do so. that does not happen often, but is the only way to have a repeater. around the area we have 6 meter, 2 meter, 220 and a 440 machine. it might be real hard to get a machine above 440 here. we have a radio club here and about 100 tickets in our county but as everywhere else about only 15 percent or so active. if any of you ever come near Greenbank stop in and say hello and visit the tour center. we have a group of hams that work here as well and we would be happy to meet ya all !! pat schaffner-kc8cse pocahontas co. wv
[Repeater-Builder] Musty Book Magazine collection
Re: Musty Book Magazine collection I love old Ham Radio Books and Magazines more than most people but those old magazines cover some pretty musty technology and equipment. The sad part about the FM-Repeater subject is how little new information is available in book form. If you're going for some vintage FM Repeater information... a copy of the ARRL - FM Repeaters and the VHF Handbook are well worth the money. More build-it yourself information about vintage repeater and vhf/uhf equipment in those books than many other locations. And the two mentioned books seem to often be selling dirt cheap on ebay. cheers, s. *[beats a copy of Watch Wayne Run any day] Have an FM Repeater collection(think it is complete). Back in the 60's, but do not have a way to scan them. Enjoyed them very much. Wonder what happened to Ken Sessions Michael J.Van Den Branden. Sad to see it disapear.
Re: [Repeater-Builder] Mitrek Transmitter Tuning
I have a meter that I removed from a Mitrek based paging transmitter that I used to tune Mitrek mobiles when I built repeaters out of them. It has the plugs on the ends of the wires for the receiver and transmitter as well as the function and meter reverse switch on it would sell it if anyone interested email me off of the list. I am good in QRZ. WB5OXQ
[Repeater-Builder] RLC-Mot and Optocoupler for COR - Not Working Correctly.
I Am not sure which diagram you are looking at but when I connect a opto to A transistor, the base of the output transistor (I.e. 2n)connects to the Emitter or collector (depending how you wish the output transistor to work ) Of the opto transistor.Over here I set them up all the time to switch TX on Different radios and we use a 4n28 with a bc548 or bc558 as a output Sometimes they drive a relay off the BC with no problems.In most optos the Anode and cathode (input side)of the opto are connections to the led that Provides the light inside the opto to drive/switch the small current Transistor on the other side of the opto(Output side) On a transistor the base is the low current input that switches the the Collector and emitter which are connected to the higher current loads Thank You, Ian Wells, Kerinvale Comaudio, 361 Camboon Road.Biloela.4715 www.kerinvalecomaudio.com.au
Re: [Repeater-Builder] Anybody have a FM Magazine collection?
At 02:00 PM 12/28/07, you wrote: Hi Mike, Have an FM Repeater collection(think it is complete). Back in the 60's, but do not have a way to scan them. Enjoyed them very much. Wonder what happened to Ken Sessions Michael J.Van Den Branden. Sad to see it disapear. Wesley AB8KD Mike Van Den Branded WA8UTB is still in the QRZ callbook system in CHATHAM MI 49816 Ken Sessions K6MVH (aka Modulated Vibrator Hash) ... dunno. The callsign is now the Los Angeles Repeater Association... in Sun City Arizona... If Ken is still alive I'd like to hear from him. If anybody is in the Chatham Michigan area, wouldn't mind doing a phone book lookup, and contact Mike please invite him to this mailing list. Or at lease get a mailing address for him. Mike WA6ILQ
Re: [Repeater-Builder] TX RX Systems Model Number Nomenclature
At 06:55 PM 12/28/07, you wrote: Anyone know where I can find the model number decoding matrix for the TX RX product lines? I have been through there web site and they dont seem to offer much info on this subject? If you have any idea where I can find this info please email me at my address on qrz.com as I do not get emails from this group or check here often - TIA.dan n2aym Look at the Antenna Systems page at www.repeater-builder.com Mike WA6ILQ
[Repeater-Builder] Re: Mitrek Transmitter Tuning
The accual meter circuit IS one volt full scale at 50uA. The Motorola test sets all used a 19K (give or take) resistor in series with the 50uA meter. That = 20K resistance. Measurements are refered to the 0 to 50 scale. Richard Bessey [EMAIL PROTECTED] wrote: The question is, what do I need to measure when they say, Meter position 3 (Which I understand is pin 3 on the test socket) but what do I need to measure with my multi-meter? Milli-volts? Milli-amps? Micro-amps?
[Repeater-Builder] Re: Anybody have a FM Magazine collection?
--- In Repeater-Builder@yahoogroups.com, Mike Morris WA6ILQ [EMAIL PROTECTED] wrote: At 02:00 PM 12/28/07, you wrote: Hi Mike, Have an FM Repeater collection(think it is complete). Back in the 60's, but do not have a way to scan them. Enjoyed them very much. Wonder what happened to Ken Sessions Michael J.Van Den Branden. Sad to see it disapear. Wesley AB8KD Mike Van Den Branded WA8UTB is still in the QRZ callbook system in CHATHAM MI 49816 Ken Sessions K6MVH (aka Modulated Vibrator Hash) ... dunno. The callsign is now the Los Angeles Repeater Association... in Sun City Arizona... If Ken is still alive I'd like to hear from him. According the K6VGP and WA6ITF Ken died about a decade ago. They have been in contact with his son who is looking for memorabilia of his dad such as copies of the Chronicles and/or any tapes that might exist of Ken's a Newsbeat broadcasts. The chronicles of 76 from Neil's collection were scanned by Dave N7AF and are available here: http://www.palisadesarc.com/downloads/ChroniclesPDF/ I have quite a few copies of FM Mag and a few RPT mags you are welcome to borrow for scanning. Unfortunately I don't have a scanner. 73's Skip WB6YMH If anybody is in the Chatham Michigan area, wouldn't mind doing a phone book lookup, and contact Mike please invite him to this mailing list. Or at lease get a mailing address for him. Mike WA6ILQ
[Repeater-Builder] Re: Repeater conversion
Thankyou Eric for this information. Would anyone know where I can find the LBI-4100 ??? I have already searched The 'Mastr' Index of GE LBI's, The 4100 is not listed. . . . In Repeater-Builder@yahoogroups.com, Eric Lemmon [EMAIL PROTECTED] wrote: Randy, There's nothing to convert; the 4EF4A3 Mastr Progress Line power amplifier is already designed to cover the 6m (50-54 MHz) band. My data identifies this unit as a continuous-duty amplifier that is rated at 150-300 watts, using a 4CX250B tube. It's a real workhorse. It will require careful tuning per the instructions found in LBI-4100, of course, but I don't think any modifications are needed. However, that statement applies only to the power amplifier; the other RF components of a 6m repeater, depending upon their model numbers, may require some modification for peak performance in the 6m band. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Randy Sent: Wednesday, December 26, 2007 10:51 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Repeater conversion I have access to a GE Power Amp Model# 4EF4A3 The freq is 42-54 MHz Can this repeater be converted to 6m (easily)? I also have the Duplexer.
