Re: [Repeater-Builder] IFR Monitor Repair Charges
John, I don't know. I believe the calibration fees are pretty uniform, but the repair figures I quoted were based on the IFR-1200S. In my one personal experience, IFR fixed three separate problems for $700. The problems I reported were a periodic unlocking of the synthesizer and a regular fluctuation of the frequency error meter of about 27 Hz. Both of these problems were fixed, along with a bad regulator/filter board in the power supply that was found while troubleshooting. Judging from the other postings, I got off easy! 73, Eric Lemmon WB6FLY John Sichert wrote: Eric, Are the repair rates model specific? Thanks John At 01:04 AM 4/27/04, you wrote: I received the following statement from Aeroflex/IFR this morning, regarding their current fees: The current fee for a non-traceable calibration is $250.00 and a NIST calibration is $500.00. The flat-rate repair includes one major repair and a non-traceable calibration for $1,275.00. The flat-rate repair includes one major repair and an NIST calibration for $1,525.00. Please note that if more than one repair is needed, the price will be based on a time and material charge. 73, Eric Lemmon WB6FLY Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] Re: Apcor?
Hi If it's what I think it is .I have one, it is a UHF Corinary monitor radio on medical frequencies..Full Duplex with a duplexer built in. It is capable of transmitting 3 leads of a EKG and voice at the same time. It has a flip up lid to expose a very small control panel, handset with a PTT switch built in, and an antenna. The medical frequencies have a 10 MHZ split that means that the TX and RX are 10 meg apart. The internal duplexer cannot be retuned to a 5 MEG split It is a slick little radioTOY low power tx I think most are 1 or 2 watts and ment to transmit back to a mobile repeater in an ambulance or rescue unit. It is about the same foot print as a laptop computer and about 4.5 to 5.5 inches tall. The business part, internally is a MX350 or MX500 HT I can't remember. I bought a manual for the one that I have, and ordered crystals for the ham bands. I never finished installing them because of the duplexer. I will likely do it some day Who knows I may even tinker with the duplexer. If you need more info let me know. 73 Coy --- In Repeater-Builder@yahoogroups.com, acbross [EMAIL PROTECTED] wrote: Anyone ever heard of a Motorola Apcor radio? A friend has described it as a packset with 10 channels UHF. Can anyone tell me more about it? Art - KC7GF Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Help on Interference
Steve Bosshard wrote: Unless the problem ISN'T two signals occupying the same spectrum, and it's just a matter of one receiver hearing outside its 'channel'. Joe M. 146R325 occupies from 146315 to 146.335 146.310 occupies from 146.300 to 146.320 They SHARE 146.315 to 146.320. Oh Really? If you ASSUME (and you know how I mean that word) that each TX HAS to have 20 kHz of bandwidth, I guess so, but that's not necessary. Only if you have 5 kHz deviation and a 5 kHz of frequency response (or some equivalent combination) will that be true. Most radios, including ham radios, tend to have lower response, and many, especially if set up correctly, will have less than 5 kHz of deviation. In reality, each will have closer to 3 kHz response and 4.5 kHz of deviation. That adds up to about 15 kHz of bandwidth, and ZERO overlapping. IOW: 146R325 occupies from 146.3175 to 146.3325 146.310 occupies from 146.3025 to 146.3175 They SHARE... NOTHING! Now, if your RECEIVER is passing 146.315 to 146.335, yes EXPECT problems, as your OWN RECEIVER is causing the problem. I tend to think that's the problem in this case. Of course, it could be users with TXs that are too wide, too. The front end will make NO difference. Unless you have a VHF Crystal Filter ahead of the receiver input, and I doubt that would make any difference. That must be why people with Micors and MASTR IIs have had fewer problems except for very strong signals or users without properly set up radios. ;- They must be liars. Go narrow band and change IF filters and reduce modulation on BOTH systems, or QSY. Well, if you're answer is either all or nothing, I guess so. BUT, there is such a thing as GRAY areas where it doesn't have to be all of one or none of it. Just because a radio CAN do 7 kHz deviation doesn't follow that it MUST do 7 kHz deviation. Most people gave that mentality up when they left CB. (Only 100% modulation? Crank it up!!!) You CAN limit your NFM deviation (modulation) and frequency response to get adequate rejection without going overboard to SNFM. Of course, this won't matter if your front end is wide as an elephant, which seems to be the case here. Even IF you would go to SNFM, if your front end is passing the RF energy that's contained in the adjacent channel's passband, the problem will still exist. I bet the Micor solves most of, if not all of the problem. Of course, it will have done it via the methods I mentioned above and if the user limits it to 4.0 kHz user audio + 0.5 kHz CTCSS deviation. Of course, it won't matter how wide his TX is, as it's the RX that has the problem, but to be a good neighbor and solve the problem for the users, it should be set up this way. Joe M. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] Help on Interference
Oh Really? If you ASSUME (and you know how I mean that word) that each TX HAS to have 20 kHz of bandwidth, I guess so, but that's not necessary. Only if you have 5 kHz deviation and a 5 kHz of frequency response (or some equivalent combination) will that be true. Most radios, including ham radios, tend to have lower response, and many, especially if set up correctly, will have less than 5 kHz of deviation. In reality, each will have closer to 3 kHz response and 4.5 kHz of deviation. That adds up to about 15 kHz of bandwidth, and ZERO overlapping. IOW: 146R325 occupies from 146.3175 to 146.3325 146.310 occupies from 146.3025 to 146.3175 They SHARE... NOTHING! Now, if your RECEIVER is passing 146.315 to 146.335, yes EXPECT problems, as your OWN RECEIVER is causing the problem. I tend to think that's the problem in this case. Of course, it could be users with TXs that are too wide, too. Reply: Please refer to modulation index and Bessel functions. The frequency response is 300 to 3000 hz emphasized at 3db per octave. Transmitter instantaneous deviation is supposed to be limited to +/- 5 kc deviation from center. Significant sidebands in FM extend beyond the deviation limit, hence emission designator 20K0F3E that equates to about 16 khz occupied plus a guard band on either side. They share part of the same channel (honest - I would not kid about something like this). Has nothing to do with receiver - both transmitters share common ground. Very truly yours, Steve Bosshard AR SK Steve Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Help on Interference
This is the reason I suggest just adding a helical to the front end of the regency, they really don't have evidence of a grat overlap or overload unless a user has a really wide signal which sounds like it may be the case. In the beginning I was under the assumption it was the output making spurs but it apparently is only a few users causing this rx falsing, if it were me I would invite the spurious user to my machine and let his spurs cause the other bunch falsing and then he will have more evidence to use to advise that user - your radio needs a little help to keep it on frequency. Offer to help him make it better, even though he thinks it is fine now what is fine now worth when it could be better, he will have reports from both sides of the fence that he is the only one making this problem occur - and you may be able to teach him a bit about nice clean signals going farther acting like ammunition compared to throwing watermelons out to sea to kill the prize fish. mch wrote: Steve Bosshard wrote: Unless the problem ISN'T two signals occupying the same spectrum, and it's just a matter of one receiver hearing outside its 'channel'. Joe M. 146R325 occupies from 146315 to 146.335 146.310 occupies from 146.300 to 146.320 They SHARE 146.315 to 146.320. Oh Really? If you ASSUME (and you know how I mean that word) that each TX HAS to have 20 kHz of bandwidth, I guess so, but that's not necessary. Only if you have 5 kHz deviation and a 5 kHz of frequency response (or some equivalent combination) will that be true. Most radios, including ham radios, tend to have lower response, and many, especially if set up correctly, will have less than 5 kHz of deviation. In reality, each will have closer to 3 kHz response and 4.5 kHz of deviation. That adds up to about 15 kHz of bandwidth, and ZERO overlapping. IOW: 146R325 occupies from 146.3175 to 146.3325 146.310 occupies from 146.3025 to 146.3175 They SHARE... NOTHING! Now, if your RECEIVER is passing 146.315 to 146.335, yes EXPECT problems, as your OWN RECEIVER is causing the problem. I tend to think that's the problem in this case. Of course, it could be users with TXs that are too wide, too. The front end will make NO difference. Unless you have a VHF Crystal Filter ahead of the receiver input, and I doubt that would make any difference. That must be why people with Micors and MASTR IIs have had fewer problems except for very strong signals or users without properly set up radios. ;- They must be liars. Go narrow band and change IF filters and reduce modulation on BOTH systems, or QSY. Well, if you're answer is either all or nothing, I guess so. BUT, there is such a thing as GRAY areas where it doesn't have to be all of one or none of it. Just because a radio CAN do 7 kHz deviation doesn't follow that it MUST do 7 kHz deviation. Most people gave that mentality up when they left CB. (Only 100% modulation? Crank it up!!!) You CAN limit your NFM deviation (modulation) and frequency response to get adequate rejection without going overboard to SNFM. Of course, this won't matter if your front end is wide as an elephant, which seems to be the case here. Even IF you would go to SNFM, if your front end is passing the RF energy that's contained in the adjacent channel's passband, the problem will still exist. I bet the Micor solves most of, if not all of the problem. Of course, it will have done it via the methods I mentioned above and if the user limits it to 4.0 kHz user audio + 0.5 kHz CTCSS deviation. Of course, it won't matter how wide his TX is, as it's the RX that has the problem, but to be a good neighbor and solve the problem for the users, it should be set up this way. Joe M. -- 73...Clark Beckman N8PZD Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Help on Interference
At 10:36 PM 4/27/2004 -0400, you wrote: This is the reason I suggest just adding a helical to the front end of the regency, There is nothing magical about helical resonators - John Phillip Sousa Ken -- President and CTO - Arcom Communications Makers of state-of-the-art repeater controllers and accessories. http://www.ah6le.net/arcom/index.html Be sure to see our products at this year's Dayton Hamvention! Repeater Builders spaces 707 through 710 AH6LE/R - IRLP Node 3000 http://www.irlp.net Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Help on Interference
I would agree on the regency being wide as an elephant, but not my Kenwood TS-2000, on a horizontal antenna, getting the user 15 Khz away. That is why I believe it's his transmitter, and the other excessive power. I had another ham 7 miles away transmit on 146.310 with 10 watts and he never touched the reciever here. If he went to 40 watts he would hit and miss slightly, but could never hear what he was saying, and not enough to key up the repeater. So it's a combination of all the above, but more bad transmitter, and excessive power. As for the repeater itself, it does not cause any problems, just the two users. Mathew - Original Message - From: Virden Clark Beckman [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 9:36 PM Subject: Re: [Repeater-Builder] Help on Interference This is the reason I suggest just adding a helical to the front end of the regency, they really don't have evidence of a grat overlap or overload unless a user has a really wide signal which sounds like it may be the case. In the beginning I was under the assumption it was the output making spurs but it apparently is only a few users causing this rx falsing, if it were me I would invite the spurious user to my machine and let his spurs cause the other bunch falsing and then he will have more evidence to use to advise that user - your radio needs a little help to keep it on frequency. Offer to help him make it better, even though he thinks it is fine now what is fine now worth when it could be better, he will have reports from both sides of the fence that he is the only one making this problem occur - and you may be able to teach him a bit about nice clean signals going farther acting like ammunition compared to throwing watermelons out to sea to kill the prize fish. mch wrote: Steve Bosshard wrote: Unless the problem ISN'T two signals occupying the same spectrum, and it's just a matter of one receiver hearing outside its 'channel'. Joe M. 146R325 occupies from 146315 to 146.335 146.310 occupies from 146.300 to 146.320 They SHARE 146.315 to 146.320. Oh Really? If you ASSUME (and you know how I mean that word) that each TX HAS to have 20 kHz of bandwidth, I guess so, but that's not necessary. Only if you have 5 kHz deviation and a 5 kHz of frequency response (or some equivalent combination) will that be true. Most radios, including ham radios, tend to have lower response, and many, especially if set up correctly, will have less than 5 kHz of deviation. In reality, each will have closer to 3 kHz response and 4.5 kHz of deviation. That adds up to about 15 kHz of bandwidth, and ZERO overlapping. IOW: 146R325 occupies from 146.3175 to 146.3325 146.310 occupies from 146.3025 to 146.3175 They SHARE... NOTHING! Now, if your RECEIVER is passing 146.315 to 146.335, yes EXPECT problems, as your OWN RECEIVER is causing the problem. I tend to think that's the problem in this case. Of course, it could be users with TXs that are too wide, too. The front end will make NO difference. Unless you have a VHF Crystal Filter ahead of the receiver input, and I doubt that would make any difference. That must be why people with Micors and MASTR IIs have had fewer problems except for very strong signals or users without properly set up radios. ;- They must be liars. Go narrow band and change IF filters and reduce modulation on BOTH systems, or QSY. Well, if you're answer is either all or nothing, I guess so. BUT, there is such a thing as GRAY areas where it doesn't have to be all of one or none of it. Just because a radio CAN do 7 kHz deviation doesn't follow that it MUST do 7 kHz deviation. Most people gave that mentality up when they left CB. (Only 100% modulation? Crank it up!!!) You CAN limit your NFM deviation (modulation) and frequency response to get adequate rejection without going overboard to SNFM. Of course, this won't matter if your front end is wide as an elephant, which seems to be the case here. Even IF you would go to SNFM, if your front end is passing the RF energy that's contained in the adjacent channel's passband, the problem will still exist. I bet the Micor solves most of, if not all of the problem. Of course, it will have done it via the methods I mentioned above and if the user limits it to 4.0 kHz user audio + 0.5 kHz CTCSS deviation. Of course, it won't matter how wide his TX is, as it's the RX that has the problem, but to be a good neighbor and solve the problem for the users, it should be set up this way. Joe M. -- 73...Clark Beckman N8PZD 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:
RE: [Repeater-Builder] Duplexer Alignment
There is a rough adjust and a fine adjust. Gregg R. Lengling, W9DHI, Retired Administrator http://www.milwaukeehdtv.org K2/100 S#3075 KX1 S# 57 Politics is the art of appearing candid and completely open, while concealing as much as possible. -States: The Bene Gesserit View -Original Message- From: Mathew Quaife [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 3:26 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Duplexer Alignment Ok, most of that I understand, and I know there is the main tuning rod, then there is the reject high and reject low tuning pots, but there is a third tuning rod on these duplexers, what would be thier function. Mathew - Original Message - From: Gregg Lengling [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 3:14 PM Subject: RE: [Repeater-Builder] Duplexer Alignment You should really be using a return loss bridge and a spectrum analyzer and tracking generatorbut yes I know we can't all afford that equipment. You can fudge by using a signal generator and a receiver, also never never never tune the duplexers under transmitter power. The first thing you need as previously stated is a 3dB pad on the input to your receiver you are going to use as signal strength indicator. You will also need a 50 ohm termination for the unused port of the duplexer during tuning. The pad is similar to those used in cable tv systems...HOWEVER..those pads are 75ohms and you have a 50 ohm system. Step one, Hook your generator to the antenna port and your receiver (with 3dB pad) to either the transmit or receiver port. Terminate the other port (ie: if you are tuning the transmit port, terminate the receiver port). Before you start on the duplexor..hook your signal generator up to your receiver with the 3db pad in line and measure the receiver sensitivity of you receiver (ie: .022uV for 12dB Sinad)this is your reference. In this case we'll say your on the transmit port. The first thing to do is to tune the pass frequency..this is the plunger on each cavity in the transmitter side of the duplexer. Generate just enough signal to start movement of your receiver strength indicator using your transmit frequency. Now tune all the TX cans one at a time for max throughput...max signal strength...you will probably have to continually reduce your output from the generator as you get the unit tuned. Now look at the output level from the generatorhow many dB of insertion loss do you have compared to your receiver performance with the cavities in line. (Assume anywhere from .6 to 1.0 dB per cavity loss)...is this the expected value...if yes the pass is tuned..if not something is wrong. Next you will tune the notches.with everything still connected, now set the generator and receiver to your Notch Frequency (the receiver freq in this case). You can now tune the notches (usually in the little box on top of the coupling loop with a small access hole on the side...use an insulated non-metallic tool). Tune these to attenuate the signal reaching the receiver, one at a time. Now measure the difference between the generator output and the receiver known sensitivity. You should have anywhere between 85 and 100 dB of attenuation. In other words you'll have a huge amount of signal being generated by your signal generator. Now you're done with the transmit side. Now using the same set of instructions but with the frequencies reverseddo the same to the receive side. When both sides are done...go back and check all your measurements again and make sure you didn't screw up. Yes this will not be perfect using this procedure, but I've found you can be within a couple of dB of rejection specs, or as they say good enough for government work until you can beg/borrow/or steal the proper test equipment. Good luck. Gregg R. Lengling, W9DHI, Retired Administrator http://www.milwaukeehdtv.org K2/100 S#3075 KX1 S# 57 Politics is the art of appearing candid and completely open, while concealing as much as possible. -States: The Bene Gesserit View -Original Message- From: Mathew Quaife [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 2:54 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Duplexer Alignment The duplexers are a set of TX/RX duplexers, six of them. When you say a 3db pad, that is something that I am not sure of, is this basically the same thing as a db pad used in CATV systems? All I know is that the duplexers were set up as a Varinotch filter system. Mathew - Original Message - From: Ken Arck [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 2:49 PM Subject: Re: [Repeater-Builder] Duplexer Alignment At 07:40 PM 4/27/2004 -, you wrote: Is there any methods of tuning a set of duplexer without having a Spectrum analyzer. I am in
Re: [Repeater-Builder] Help on Interference
Steve S. Bosshard (NU5D) wrote: Reply: Please refer to modulation index and Bessel functions. The frequency response is 300 to 3000 hz emphasized at 3db per octave. Transmitter instantaneous deviation is supposed to be limited to +/- 5 kc deviation from center. Significant sidebands in FM extend beyond the deviation limit, hence emission designator 20K0F3E that equates to about 16 khz occupied plus a guard band on either side. I'm not going to argue over 1 kHz of bandwidth - especially when you are using a LARGER BASELINE (5 kHz deviation as opposed to 4.5 kHz). Isn't it odd that the extra 500 Hz adds up to 1 kHz (your figure). Again, I'll paraphrase what I said before: just because the TX CAN do +/- 5 kHz doesn't mean it has to be set for +/- 5 kHz. In fact, if you do this in the commercial service, you're pushing your legal limits. (and not following the manufacturer's instructions, in all likelihood). Doing this in the ham band on a 15 kHz channelized subband is ASKING for problems. Yes, there is no legal limit in the ham bands. If you want to go to 7 kHz, it's perfectly legal. But don't be surprised when you get complaints from your 'neighbors'. They share part of the same channel (honest - I would not kid about something like this). Has nothing to do with receiver - both transmitters share common ground. It has NOTHING to do with the receiver? How do you think the interference is being HEARD? You honestly don't think that it's even POSSIBLE that this problem has to do with a receiver that is TOO WIDE? And you further don't believe that a receiver that is too wide will suffer adjacent channel interference problems more than one that is not? If so, I'll leave you to your own version of reality and not continue this discussion with you. Of course the receiver has something to do with it. It's POSSIBLE that it doesn't, and that the problem is TXs that are simply too wide, but considering the manufacturer, I highly suspect that the receiver is a factor. Let's use this logical argument. If a receiver can't be too wide, why should you have to replace anything in one when converting it to SNFM? Same difference. You may have one in this case that doesn't confirm to NFM standards. If so, of course it's going to pick up more adjacent channel energy than it should. Just as an FM receiver (standard FM: +/- 15 kHz deviation) is going to pick up at least two NFM channels on either side of center due the fact that it's wider yet. So, is the answer to lower the TX deviation or frequency response of the adjacent channels? OF COURSE NOT! Because the problem will still be there - even with a dead carrier. The answer is to narrow up the receiver so it conforms to standards, or even lower if possible. Again, just because a standard may be 7 kHz modulation acceptance, there is no reason why you can't drop it down to 6 kHz. Yes, more people with TXs that are too wide will 'chop out' of the passband, but then you fix those TXs to conform to standards. BTW, would it be too much to ask that you set your mail client up to properly quote messages? Joe M. 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] Apcor?
Hmmm, I think I have one of those books ... I just don't remember it bring called an Apcor. Neil - WA6KLA Steve Bosshard wrote: Back in the olden days when Adam 12 and Emergency were on TV, the guys would call Rampart and send a strip back to the ER using a Coronary Observation Radio. The Apcor would use the truck as a vehicular repeater back to the ER. The truck was equipped with a full duplex radio using MED 1 thru MED 10 with MED 9 and 10 reserved for dispatch, and 1 thru 8 for working channels. Med 1 Base was 463.000 and went in 25kc steps except MED 9 and 10, 462.950 and 462.975 respectively. The truck listened on several 458 Mhz. channels and retran on standard med channels. The Apcor worked in tandem with the truck and usually not solo, although some areas it could. Best I recall the 2 headed duplex monster in the truck ran about $21,000 plus the cost of the apcor. Books are probably long gone, Steve 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: Help on Interference
Without directly commenting on the source(s) of problems here, it should be clear that the front end is not the problem. Its the back end, in other words, the low IF, where most of the narrowest filtering occurs. The helical front end is as broad as a barn by comparison, even in the finest GE or Motorola. ::) Laryn K8TVZ --- In Repeater-Builder@yahoogroups.com, Virden Clark Beckman [EMAIL PROTECTED] wrote: This is the reason I suggest just adding a helical to the front end of the regency, they really don't have evidence of a grat overlap or overload unless a user has a really wide signal which sounds like it may be the case 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] Random Repeater Builder Sighting
http://mc4.mohave.edu/mc4/images/lan3/CIMG0017.jpg http://mc4.mohave.edu/modules.php?name=Forumsfile=viewtopict=29 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] Occupied Bandwidth.
CARSON'S RULE BANDWIDTH = 2 X (PEAK DEVIATION + HIGHEST MODULATING FREQUENCY) Most 2M off the shelf radios I have seen lately in wide band FM hit at least +/- 5kc peak deviation, and 6 to 6 ½ is not at all uncommon. Measurements using HP8921 or IFR COM120B. I have not run a swept transmit audio response test using an audio sweep generator into the mic input @ 60% full system deviation, but I suspect it would not come to a dead stop at 3 kc of audio response. Hence the 16 khz or more of occupied band width. Now add a little bit for slightly off frequency operation, and a little over modulation and you really crowd the channel bandwidth. Add to that a little excessive high pass in the post limiting audio filter and the bandwidth again increases. The selectivity of a VHF FM radio is largely determined by the IF section, and crystal filters. The front end helical resonators or tuned lines from the old days, are going to be more than 200 kc wide at 3 db points. Even a couple of band pass cavities in front of the receiver will be very large in bandwidth compared to the overlap of the two repeater input frequencies. Using a MastrIII or MSF5000 would have better front end performance, but adjacent channel rejection (when the adjacent channel shares part of the desired channel) is not going to be very good. Going to a Micor or M2 or adding a helical preselector will help, but mostly by adding insertion loss and not in bandwidth shrinkage. At best, changing the IF filters might narrow the response, or offsetting the mixer frequency on the receiver, or mistuning the IF away from the neighboring input might help, at the expense of degrading performance on the desired operating frequency. Introducing loss in the front end may also help. I wonder how a signal generator at the input of the repeater generating on the offending frequency would act? If a -80 dbm. Signal at the antenna port modulated at 1 Kc tone with 4 or 5 kc of deviation bothers the repeater then it will be difficult to ask your neighbor to turn things down. Anyhow, best luck with the project and let me know how it turns out, Steve Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ attachment: winmail.dat
RE: [Repeater-Builder] Apcor?
Seemed like Pioneer also made a coronary observation radio using GE MPE parts and pieces. Ssb 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] Occupied Bandwidth.
Steve S. Bosshard (NU5D) wrote: CARSON'S RULE BANDWIDTH = 2 X (PEAK DEVIATION + HIGHEST MODULATING FREQUENCY) Thank you for quoting what I've been saying the past two posts. Most 2M off the shelf radios I have seen lately in wide band FM hit at least +/- 5kc peak deviation, and 6 to 6 ½ is not at all uncommon. Measurements using HP8921 or IFR COM120B. I have not run a swept transmit audio response test using an audio sweep generator into the mic input @ 60% full system deviation, but I suspect it would not come to a dead stop at 3 kc of audio response. Yes, I agree that most off the shelf radios are not properly set up. BUT, what does that have to do with a PROPERLY set up system? You don't solve this problem by saying that 20 kHz bandwidth is OK because that's what we are seeing as a spoon-fed limit. The minute you do that, you will then see 25 kHz BW radios being made. Where do you stop? The ONLY answer is to educate these so-called *trained* radio technicians (licensed hams). If they can't solve the problem, they should at least be taught to be able to identify a problem and take it to someone who CAN fix it. Of course, on this list we are for the most part preaching to the choir. It's the non-technical hams that need it. But the point is that you NEVER cater to the lowest common denominator, you would would never have gone below 60 kHz spacing that you had in the 60s or early 70s. If you see a problem, and can show that the TX is not properly aligned (be it user OR repeater), you tell the operator that and let them decide how to solve it (either by doing it themselves, or having it aligned by someone with the proper equipment, or discontinuing use). I recently got an FT-736R. Nice radio, but it has no provision for limiting the deviation to any calibrated settings. This is a manufacturing flaw, IMHO. There should be a way to set the deviation other than a vague meter setting. But, I got it for SSB/CW anyway, so I'll use it there and not on FM (except perhaps on 440 where it won't matter as much). Going to a Micor or M2 or adding a helical preselector will help, but mostly by adding insertion loss and not in bandwidth shrinkage. You're not going to see that much insertion loss in a preselector! But, I also agree that you're not going to solve that much with one, either. At best, changing the IF filters might narrow the response, Great idea! I wish I'd said that. OH WAIT! I DID! (in my last post) 8-O I'm surprised about the 180 turn you did from saying Has nothing to do with receiver to the above comments. :-) Joe M. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] IFR Monitor Repair Charges
I have a IFR 1200 that the power supply seems to have gone out.. anyone know someone that can repair this. thanks --- Tommie Taylor Lampasas Skywarn Weather Repeater 145.330- 162.2T (SWLynx) / 444.875+ 88.5 (Echolink) http://www.a1cmugs.com WEEKLY CENTRAL TEXAS STORM SPOTTERS Net TUESDAY EVENINGS AT 7PMCST ON REPEATER ABOVE AND ECHOLINK VoiceOverIP NODE#28689/28821 - Original Message - From: Steve S. Bosshard (NU5D) [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 6:43 AM Subject: RE: [Repeater-Builder] IFR Monitor Repair Charges Same deal with large LMR factory depot - flat rate for one problem - more problems MORE $$$s. Steve 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] Help on Interference
In a somewhat similar but distant situation a number of years ago, I use a service monitor in the generate mode to test a repeater that was about 9 miles away. Neil - WA6KLA Rogers, Ron wrote: Remind the fellow using 100 watts to talk to a repeater that he could be in violation of Part 97 rules on using minimal power. We had a similar situation and interference to our one 2 meter repeater on the mountain and we had to remind the guy of the Laws of Radio Physics, power, distance, and Part 97 !! Ron WW8RR -Original Message- From: Mathew Quaife [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 3:46 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Help on Interference Well I narrowed down parts of the problem, the first being the wide as a 2x4 Regency receiver, which is going to be changed out, and the other is a local ham using 100 watts to talk to this machine, when in it really only needs about 7 watts to hit it full quieting with minimal antenna height. My repeater actually is just gettting underway, new coordination. So each day is a new adventure for me. Having not played with FM and etcfor about 15 years, still trying to remember, kinda hard to get all the cobwebs out of the brain. Thanks. Mathew - Original Message - From: Virden Clark Beckman [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 2:26 PM Subject: Re: [Repeater-Builder] Help on Interference Try using the math on the IF of your rx to see what is making them mix on your freq, how long have the 2 machines been co-existing on-the-air? If it were one or 2 users you would know it rather than the entire time the machine is active, can you see how clean the signal is from that machine, I doubt if 50 miles is gonna make trouble unless the have some really wide spurs and then every open rx is gonna see some falsing. w9mwq wrote: I have a repeater with an antenna up about 60 feet in the air, Frequency of 146.925/146.325 minus offset. Receiever sensitity is .25 micorovolt at 12DB, seems to be purring along just fine. IFR show the receive to be on frequency. Here's the problem, there is a repeater about 50 air miles away, on the pair of 146.910/146.31o minus offset. There repeater is getting into my receiver, causing the repeater to key up. There is no pl on my repeater at this time. They sound like they are on sideband when they come in. I can goto the 91 machine, hear them talking, when they quit, the interference quits. I took my IFR and inserted a tone on 146.310 into my receiver, it took 15 microvolts to open the squelch of my receiver. Is it my receiver, which is a Regency receiver, or is it the person transmitting on the other machine. I could see if it was the 91 machine if all it was doing was killing my receive, but it's actually keying up the repeater. SO my guess would be it would have to be the person talking on the 91 repeater. I hope I explained this right. Any suggestions. Thanks. Mathew -- 73...Clark Beckman N8PZD Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Duplexer Alignment
Hello, Vari-notch is a TX-RX Company trade name. Neil - WA6KLA Ken Arck wrote: At 02:54 PM 4/27/2004 -0500, you wrote: The duplexers are a set of TX/RX duplexers, six of them. When you say a 3db pad, that is something that I am not sure of, is this basically the same thing as a db pad used in CATV systems? ---Yes they are the same CONCEPT, but CATV ones would be 72 (75?) ohm. You, of course, need 50 ohm ones. The idea behind using them is to present an accurate 50 ohm load on the duplexer ports, because a change of load affects the tuning. If you don't have any, I'd suggest begging or borrowing some from a buddy :-) All I know is that the duplexers were set up as a Varinotch filter system. ---If I'm not mistaken, that's a notch type duplexer. Aside from visiting TX/RX's website (to see if you can locate tuning instructions), you might want to check out this link as well: http://www.repeater-builder.com/rbtip/notchduptuning.html Ken -- President and CTO - Arcom Communications Makers of state-of-the-art repeater controllers and accessories. http://www.ah6le.net/arcom/index.html Be sure to see our products at this year's Dayton Hamvention! Repeater Builders spaces 707 through 710 AH6LE/R - IRLP Node 3000 http://www.irlp.net 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] Help on Interference
Ahem ... The was a regional ham radio swapmeet in the Salem, Oregon area recently. One fellow was selling high-band brown handle GE Mastr II's for $5.00 each. I feel bad about not buying all of them so I could say in the future Here, use this!!! instead of reading about the Regency, Spectrum and Wilson repeater attempts out there. What is said about hindsight? Neil Mathew Quaife wrote: Objective to changing the reciever is to sperate it from the transmitter, when I first started this project, the regency repeaters were at hand, but as I play with more and more, find that they need a little help. I'm just waiting on the new receivers to get here. I'm sure the GE century has got to be somewhat better than the Regency. A preamp would be nice, but hopefully I can get by without it. Plans are to later on put in two voters to cover a few parts of the county that will be troublesome. Mathew - Original Message - From: Virden Clark Beckman [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 3:02 PM Subject: Re: [Repeater-Builder] Help on Interference Rather than re-invent the wheel why not try carving the helical from a dead old high band rx tray and add to the front of yours to make it a bit narrower than it is barefoot, if you can find a mastr2 with 5 helicals you could ad a pre-amp and convert the near hits to misses. Mathew Quaife wrote: Well I narrowed down parts of the problem, the first being the wide as a 2x4 Regency receiver, which is going to be changed out, and the other is a local ham using 100 watts to talk to this machine, when in it really only needs about 7 watts to hit it full quieting with minimal antenna height. My repeater actually is just gettting underway, new coordination. So each day is a new adventure for me. Having not played with FM and etcfor about 15 years, still trying to remember, kinda hard to get all the cobwebs out of the brain. Thanks. Mathew - Original Message - From: Virden Clark Beckman [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 2:26 PM Subject: Re: [Repeater-Builder] Help on Interference Try using the math on the IF of your rx to see what is making them mix on your freq, how long have the 2 machines been co-existing on-the-air? If it were one or 2 users you would know it rather than the entire time the machine is active, can you see how clean the signal is from that machine, I doubt if 50 miles is gonna make trouble unless the have some really wide spurs and then every open rx is gonna see some falsing. -- 73...Clark Beckman N8PZD Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Help on Interference
At 4/27/2004 07:36 PM, Virden Clark Beckman [EMAIL PROTECTED] wrote: This is the reason I suggest just adding a helical to the front end of the regency, they really don't have evidence of a grat overlap or overload unless a user has a really wide signal which sounds like it may be the case. Looks like you didn't read my previous posting. Once again: Front-end cavity or helical RF filters will NOT help adjacent-channel interference problems. Please do not suggest to others that they could; you will only waste their time money. 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] Occupied Bandwidth.
At 4/28/2004 12:34 AM, you wrote: Steve S. Bosshard (NU5D) wrote: CARSON'S RULE BANDWIDTH = 2 X (PEAK DEVIATION + HIGHEST MODULATING FREQUENCY) Thank you for quoting what I've been saying the past two posts. Here's a question: just what amount of the transmitter's TPO is Carson's Rule bandwidth? -20 dBc? -26 dBc? -30 dBc? I've seen all 3 in various definitions. If you use the Bessel functions to calculate bandwidth for worst-case single-tone emissions, using 3 kHz tone @ 5 kHz deviation, the 3rd sideband (J3) @ +/- 9 kHz is only 21.85 dB down from the unmodulated carrier. Fortunately, voice emission PSDs are spread fairly evenly across the entire 300 to 3000 Hz modulation band (thanks to pre-emphasis, otherwise the PSD would be sloped toward the low end, yes we're talking FM not PM Bob don't go there!!), in addition there may be an assumption in Carson's Rule that the upper modulation limit is down by 3 dB due to conventional analog low-pass filtering, so a 3 kHz tone would only deviate the TX 3.54 kHz, not 5 kHz. Using 3.54 kHz deviation 3 kHz modulating freq. gives a modulation index of 1.178, corresponding J3 at -30.1 dB J2 (+/- 6 kHz sideband) at -16.2 dB. That's more like it! Using linear interpolation (don't know if that's legit here, but I'm just ranting at this point), +/- 7.5 kHz would be at -23.15 dB. As a (in)sanity check, let's try 2 kHz tone modulation. Let's say the post-limiter filter doesn't kick in yet, so we have full 5 kHz deviation corresponding modulation index of 2.5: J3 (the sidebands at +/- 6 kHz) are 13.3 dB down from the unmodulated carrier, J4 (+/- 8 kHz) are at -22.64 dB. So my guess is that Carson's Rule specifies the 22 to 23 dB bandwidth of a conventional NBFM voice TX. Am I close? 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] Duplexer Alignment
Gregg, Very well written. Thank you for your effort here. Hopefully your comments will be noted for future reference by others on this list. 73, Neil McKie - WA6KLA Gregg Lengling wrote: You should really be using a return loss bridge and a spectrum analyzer and tracking generatorbut yes I know we can't all afford that equipment. You can fudge by using a signal generator and a receiver, also never never never tune the duplexers under transmitter power. The first thing you need as previously stated is a 3dB pad on the input to your receiver you are going to use as signal strength indicator. You will also need a 50 ohm termination for the unused port of the duplexer during tuning. The pad is similar to those used in cable tv systems...HOWEVER..those pads are 75ohms and you have a 50 ohm system. Step one, Hook your generator to the antenna port and your receiver (with 3dB pad) to either the transmit or receiver port. Terminate the other port (ie: if you are tuning the transmit port, terminate the receiver port). Before you start on the duplexor..hook your signal generator up to your receiver with the 3db pad in line and measure the receiver sensitivity of you receiver (ie: .022uV for 12dB Sinad)this is your reference. In this case we'll say your on the transmit port. The first thing to do is to tune the pass frequency..this is the plunger on each cavity in the transmitter side of the duplexer. Generate just enough signal to start movement of your receiver strength indicator using your transmit frequency. Now tune all the TX cans one at a time for max throughput...max signal strength...you will probably have to continually reduce your output from the generator as you get the unit tuned. Now look at the output level from the generatorhow many dB of insertion loss do you have compared to your receiver performance with the cavities in line. (Assume anywhere from .6 to 1.0 dB per cavity loss)...is this the expected value...if yes the pass is tuned..if not something is wrong. Next you will tune the notches.with everything still connected, now set the generator and receiver to your Notch Frequency (the receiver freq in this case). You can now tune the notches (usually in the little box on top of the coupling loop with a small access hole on the side...use an insulated non-metallic tool). Tune these to attenuate the signal reaching the receiver, one at a time. Now measure the difference between the generator output and the receiver known sensitivity. You should have anywhere between 85 and 100 dB of attenuation. In other words you'll have a huge amount of signal being generated by your signal generator. Now you're done with the transmit side. Now using the same set of instructions but with the frequencies reverseddo the same to the receive side. When both sides are done...go back and check all your measurements again and make sure you didn't screw up. Yes this will not be perfect using this procedure, but I've found you can be within a couple of dB of rejection specs, or as they say good enough for government work until you can beg/borrow/or steal the proper test equipment. Good luck. Gregg R. Lengling, W9DHI, Retired Administrator http://www.milwaukeehdtv.org K2/100 S#3075 KX1 S# 57 Politics is the art of appearing candid and completely open, while concealing as much as possible. -States: The Bene Gesserit View -Original Message- From: Mathew Quaife [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 2:54 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Duplexer Alignment The duplexers are a set of TX/RX duplexers, six of them. When you say a 3db pad, that is something that I am not sure of, is this basically the same thing as a db pad used in CATV systems? All I know is that the duplexers were set up as a Varinotch filter system. Mathew - Original Message - From: Ken Arck [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, April 27, 2004 2:49 PM Subject: Re: [Repeater-Builder] Duplexer Alignment At 07:40 PM 4/27/2004 -, you wrote: Is there any methods of tuning a set of duplexer without having a Spectrum analyzer. I am in the learning stages again. I have an IFR-500a, so I can generate a signal into them. I know this would work somewhat for the receive, but what does one do for the transmit. ---Why wouldn't it work for transmit? As a matter of fact, it would work just fine by both the receive AND transmit sides of the duplexer. RF is RF, regardless if its -100 Dbm or +10 Dbm, right? Depending on what kind of duplexer is it (BP/BR or just BR) determines the tuning procedure. You might want to check the website to see if yours is listed. One thing though - It's a good idea to use a 3 db pad on the receiver you're using for tuning, since you have no guarantee it
RE: [Repeater-Builder] 1 5/8 HARDLINE
Dave, Get up with me off-line, and I can fix you up for the shipping. I have tons of the stuff... Mike -Original Message- From: David Schornak [mailto:[EMAIL PROTECTED] Sent: Wednesday, April 28, 2004 3:00 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] 1 5/8 HARDLINE does anyone here now where I can get 6 pieces of 1 5/8 hard-line about 5' long or thirty feet cheap I want to build a 6m duplexer. David N1IB 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] 1 5/8 HARDLINE
I've got 6 pcs 6 foot long of 3 1/2 inch if that would help Dave / NØATH - Original Message - From: David Schornak [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Wednesday, April 28, 2004 2:00 PM Subject: [Repeater-Builder] 1 5/8 HARDLINE does anyone here now where I can get 6 pieces of 1 5/8 hard-line about 5' long or thirty feet cheap I want to build a 6m duplexer. David N1IB 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] Help on Interference
So very true. Neil - WA6KLA Ronald Schiller wrote: Hi Guys, Any of you ever hear of Modulation Acceptance? Test the receiver and find out. No receiver made has a linear Pass Band and sometimes by running the if cans to the second resonant point, you can find a more linear point. Another trick is to change the 2nd conversion xtal above or below the if. Bottom line is test the Receiver. Clean up the mixers, Birdies out of the oscillator will kill you. Ron wa6unm -Original Message- From: Steve S. Bosshard (NU5D) [mailto:[EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 7:34 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Help on Interference Oh Really? If you ASSUME (and you know how I mean that word) that each TX HAS to have 20 kHz of bandwidth, I guess so, but that's not necessary. Only if you have 5 kHz deviation and a 5 kHz of frequency response (or some equivalent combination) will that be true. Most radios, including ham radios, tend to have lower response, and many, especially if set up correctly, will have less than 5 kHz of deviation. In reality, each will have closer to 3 kHz response and 4.5 kHz of deviation. That adds up to about 15 kHz of bandwidth, and ZERO overlapping. IOW: 146R325 occupies from 146.3175 to 146.3325 146.310 occupies from 146.3025 to 146.3175 They SHARE... NOTHING! Now, if your RECEIVER is passing 146.315 to 146.335, yes EXPECT problems, as your OWN RECEIVER is causing the problem. I tend to think that's the problem in this case. Of course, it could be users with TXs that are too wide, too. Reply: Please refer to modulation index and Bessel functions. The frequency response is 300 to 3000 hz emphasized at 3db per octave. Transmitter instantaneous deviation is supposed to be limited to +/- 5 kc deviation from center. Significant sidebands in FM extend beyond the deviation limit, hence emission designator 20K0F3E that equates to about 16 khz occupied plus a guard band on either side. They share part of the same channel (honest - I would not kid about something like this). Has nothing to do with receiver - both transmitters share common ground. Very truly yours, Steve Bosshard AR SK Steve Yahoo! Groups Links Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Help on Interference
In fact, you'll actually be exceeding limits because that +/-5 Khz is TOTAL deviation-including CTCSS/DCS/whatever! And since the spec for CTCSS/DCS is +/-500 to 800 hz, and the spec for LTR signalling is +/-1Khz, voice deviation cannot exceed +/-4.5 Khz (4Khz for LTR). And the equipment is designed for that. So all you hams out there need to keep your voice deviation down to no more than that! There does not seem to be a voice bandwidth for hams on the two meter band. Atleast not as narrow as 5 kc deviation. It is a known fact that it is difficult to seperate stations by 15 khz and not have problems with close stations. Not sure how much deviation other receivers will take but the Mastr ll specifices an acceptance of +- 7Khz. This makes the receiver somewhat wide for 15 khz spacing. Some of the worse offenders I have seen are the Icom 706 rigs. Seems that if most set it for the low bands in ssb when switched to VHF FM the thing is very much overdeviated. 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/
