[Repeater-Builder] Re: Pager interference
Hi Mike, Since the pager is multi-channel, we were thinking of the DCI window filter on the pager. Then adding what ever else is needed on our ham receiver. On inverting either of the antennas, no chance. The paging antenna is an 8 bay that is about 40 feet in length. We'd have to drop 60 feet to get any vertical separation. Dwayne Kincaid WD8OYG --- In Repeater-Builder@yahoogroups.com, Mike Morris wa6...@... wrote: The widow filter on the paging transmitter or on your repeater? DCI will do custom designs for special situations, and yours certainly qualifies. If the DCI is going on yours, make sure and plan ahead - I was told about a guy who had to add a DCI box to his system to keep out a new-to-the-site NOAA transmitter and since he wasn't paying for it he made sure to include in the specs that it would not affect anything in 144-148 Mhz rather than just his 2m pair - just in case he had to change frequencies down the road or he wanted to sell it. Another thought - any chance of inverting one of the antennas? (i.e. let the paging antenna sit above the crossmember and you suspend below the crossmember). Just getting your pattern a few feet below his might make enough dBs of difference and avoid the insertion loss of the DCI, and a few feet won't cost you THAT much coverage. One local system had a piece of pipe center-mounted to the tower, with the 440 antenna mounted to the top of it and going up, and the 2m antenna mounted to the bottom of it and going down. A high power 460 repeater was added and ended up on the adjacent tower position. The cure was to exchange the antenna positions - the 2m took the broadside and the 440 was below the pattern. Problem solved. Mike WA6ILQ At 01:33 PM 08/08/10, you wrote: Hi Mike, Excellent information. It's a new pager and it's a two channel system, no cans. We're the ham guys and have been there for about 5 years, but only as guests. Yes, there is a non-interference clause, but we do not want to go that route. We're all on good speaking terms (tower owner, ham group and pager guy) and since we're the guests, we'd like to help solve the problem (rather than just point fingers). The pager transmitter is running 100 watts to a 9 db antenna that points away from our 6db omni. I agree that we're probably getting only 10 to 15 db of isolation at 15 feet (yes, already checked the RB site). Moving either of the antennas is not really an option. It's only 170 feet and we both want the top (in flat-land Maryland). The DCI box on the pager looks like it will give about 40 db to our rx freq and we'll add a notch (40db) and a pass (30 db) to get the total to just over 100. We added the pass and notch last week and it work on all but the weak signals. So we're thinking a little window filter will take care of it. Dwayne Kincaid WD8OYG --- In Repeater-Builder@yahoogroups.com, Mike Morris wa6ilq@ wrote: At 11:38 AM 08/07/10, you wrote: Hi, I've got a new pager issue that has come up on a tower where we have a VHF repeater. It's about 400 watts erp and 15 feet horizontal distance and 4.3 and 4.7 MHz away (it switches). I'm thinking of using one bp/br can that will have the notch wide enough to cover both channels and one pass can on our RX freq. I can also add more pass cans or something like the DCI window filter. The real question is where to these can go and in what order. We have a standard Q-202 duplexer that worked fine before the pager was put in. I'm thinking that the pager cans will go on the RX side of the duplexer, but does it matter if the pass goes on the duplexer side or the RX side of the bp/br can? I'm kinda thinking that it doesn't matter, but want to do it right in case it does. Dwayne Kincaid WD8OYG Is this a situation where the paging transmitter is a new install, or a situation where the paging company consolidated two transmitters, each a single frequency, into one that switches, or a new ham system install? If it's a new paging transmitter install, then 400 watts erp and 15 feet horizontal distance, is too damn close. Your antenna is broadside to its antenna and you have a nice coupling situation. It reminds me of a repeater that was located at an FM broadcast site, and we saw 35 (or so) watts of 90.7 MHz coming DOWN the ham feedline. The ham duplexer was nice and warm... If it's a consolidation I'll bet that the paging transmitter has no pass cavity, or any other filtering - if it ever had any it was probably removed in the consolidation. Digital paging transmitters use square wave modulation and are DIRTY when they have no filtering and local stories have it that the FCC has cited several consolidated transmitter systems. Paging companies are notorious for running overpower. One local situation had a license for 90w and they were
[Repeater-Builder] Re: Pager interference
Hi Mike, Excellent information. It's a new pager and it's a two channel system, no cans. We're the ham guys and have been there for about 5 years, but only as guests. Yes, there is a non-interference clause, but we do not want to go that route. We're all on good speaking terms (tower owner, ham group and pager guy) and since we're the guests, we'd like to help solve the problem (rather than just point fingers). The pager transmitter is running 100 watts to a 9 db antenna that points away from our 6db omni. I agree that we're probably getting only 10 to 15 db of isolation at 15 feet (yes, already checked the RB site). Moving either of the antennas is not really an option. It's only 170 feet and we both want the top (in flat-land Maryland). The DCI box on the pager looks like it will give about 40 db to our rx freq and we'll add a notch (40db) and a pass (30 db) to get the total to just over 100. We added the pass and notch last week and it work on all but the weak signals. So we're thinking a little window filter will take care of it. Dwayne Kincaid WD8OYG --- In Repeater-Builder@yahoogroups.com, Mike Morris wa6...@... wrote: At 11:38 AM 08/07/10, you wrote: Hi, I've got a new pager issue that has come up on a tower where we have a VHF repeater. It's about 400 watts erp and 15 feet horizontal distance and 4.3 and 4.7 MHz away (it switches). I'm thinking of using one bp/br can that will have the notch wide enough to cover both channels and one pass can on our RX freq. I can also add more pass cans or something like the DCI window filter. The real question is where to these can go and in what order. We have a standard Q-202 duplexer that worked fine before the pager was put in. I'm thinking that the pager cans will go on the RX side of the duplexer, but does it matter if the pass goes on the duplexer side or the RX side of the bp/br can? I'm kinda thinking that it doesn't matter, but want to do it right in case it does. Dwayne Kincaid WD8OYG Is this a situation where the paging transmitter is a new install, or a situation where the paging company consolidated two transmitters, each a single frequency, into one that switches, or a new ham system install? If it's a new paging transmitter install, then 400 watts erp and 15 feet horizontal distance, is too damn close. Your antenna is broadside to its antenna and you have a nice coupling situation. It reminds me of a repeater that was located at an FM broadcast site, and we saw 35 (or so) watts of 90.7 MHz coming DOWN the ham feedline. The ham duplexer was nice and warm... If it's a consolidation I'll bet that the paging transmitter has no pass cavity, or any other filtering - if it ever had any it was probably removed in the consolidation. Digital paging transmitters use square wave modulation and are DIRTY when they have no filtering and local stories have it that the FCC has cited several consolidated transmitter systems. Paging companies are notorious for running overpower. One local situation had a license for 90w and they were found to be running 350w. They were cited, changed transmitters, and a year and a half later the interference returned. A no-notice visit from the FCC found then running 500w. Don;t order that DCI box yet - the first thing I'd do is reduce the antenna-to-antenna coupling. If the master site agreement has a no-interference clause perhaps you can get them to relocate an antenna, or go back to the two transmitters with filtering installed. Look at http://www.repeater-builder.com/antenna/separation.html Depending on your antenna gain I'd be very surprised if you are getting even 15db of isolation. Once you have reduced the coupling as best as you can, I'd then re-evaluate the situation by jacking a spectrum analyzer into your antenna and getting some hard numbers, a screen shot (even a digital photo of the CRT) posted here, etc. Then we can help a lot more. Mike WA6ILQ
Re: [Repeater-Builder] Re: Pager interference
The widow filter on the paging transmitter or on your repeater? DCI will do custom designs for special situations, and yours certainly qualifies. If the DCI is going on yours, make sure and plan ahead - I was told about a guy who had to add a DCI box to his system to keep out a new-to-the-site NOAA transmitter and since he wasn't paying for it he made sure to include in the specs that it would not affect anything in 144-148 Mhz rather than just his 2m pair - just in case he had to change frequencies down the road or he wanted to sell it. Another thought - any chance of inverting one of the antennas? (i.e. let the paging antenna sit above the crossmember and you suspend below the crossmember). Just getting your pattern a few feet below his might make enough dBs of difference and avoid the insertion loss of the DCI, and a few feet won't cost you THAT much coverage. One local system had a piece of pipe center-mounted to the tower, with the 440 antenna mounted to the top of it and going up, and the 2m antenna mounted to the bottom of it and going down. A high power 460 repeater was added and ended up on the adjacent tower position. The cure was to exchange the antenna positions - the 2m took the broadside and the 440 was below the pattern. Problem solved. Mike WA6ILQ At 01:33 PM 08/08/10, you wrote: Hi Mike, Excellent information. It's a new pager and it's a two channel system, no cans. We're the ham guys and have been there for about 5 years, but only as guests. Yes, there is a non-interference clause, but we do not want to go that route. We're all on good speaking terms (tower owner, ham group and pager guy) and since we're the guests, we'd like to help solve the problem (rather than just point fingers). The pager transmitter is running 100 watts to a 9 db antenna that points away from our 6db omni. I agree that we're probably getting only 10 to 15 db of isolation at 15 feet (yes, already checked the RB site). Moving either of the antennas is not really an option. It's only 170 feet and we both want the top (in flat-land Maryland). The DCI box on the pager looks like it will give about 40 db to our rx freq and we'll add a notch (40db) and a pass (30 db) to get the total to just over 100. We added the pass and notch last week and it work on all but the weak signals. So we're thinking a little window filter will take care of it. Dwayne Kincaid WD8OYG --- In Repeater-Builder@yahoogroups.com, Mike Morris wa6...@... wrote: At 11:38 AM 08/07/10, you wrote: Hi, I've got a new pager issue that has come up on a tower where we have a VHF repeater. It's about 400 watts erp and 15 feet horizontal distance and 4.3 and 4.7 MHz away (it switches). I'm thinking of using one bp/br can that will have the notch wide enough to cover both channels and one pass can on our RX freq. I can also add more pass cans or something like the DCI window filter. The real question is where to these can go and in what order. We have a standard Q-202 duplexer that worked fine before the pager was put in. I'm thinking that the pager cans will go on the RX side of the duplexer, but does it matter if the pass goes on the duplexer side or the RX side of the bp/br can? I'm kinda thinking that it doesn't matter, but want to do it right in case it does. Dwayne Kincaid WD8OYG Is this a situation where the paging transmitter is a new install, or a situation where the paging company consolidated two transmitters, each a single frequency, into one that switches, or a new ham system install? If it's a new paging transmitter install, then 400 watts erp and 15 feet horizontal distance, is too damn close. Your antenna is broadside to its antenna and you have a nice coupling situation. It reminds me of a repeater that was located at an FM broadcast site, and we saw 35 (or so) watts of 90.7 MHz coming DOWN the ham feedline. The ham duplexer was nice and warm... If it's a consolidation I'll bet that the paging transmitter has no pass cavity, or any other filtering - if it ever had any it was probably removed in the consolidation. Digital paging transmitters use square wave modulation and are DIRTY when they have no filtering and local stories have it that the FCC has cited several consolidated transmitter systems. Paging companies are notorious for running overpower. One local situation had a license for 90w and they were found to be running 350w. They were cited, changed transmitters, and a year and a half later the interference returned. A no-notice visit from the FCC found then running 500w. Don;t order that DCI box yet - the first thing I'd do is reduce the antenna-to-antenna coupling. If the master site agreement has a no-interference clause perhaps you can get them to relocate an antenna, or go back to the two transmitters with filtering installed. Look at http://www.repeater-builder.com/antenna/separation.html
[Repeater-Builder] Re: Pager interference
Thanks for the input. I don't think that is possible (read practical) since it's a two channel pager. The two pager frequencies are about 500 KHz apart. So there is only one PA and one output in the pager box. I may have to call DCI or someone to get a window filter. Dwayne Kincaid --- In Repeater-Builder@yahoogroups.com, Jim in Waco WB5OXQ wb5...@... wrote: You may have to put a can on the pager transmitter. Pagers use square waves which are very rich in harmonics and need to be filtered at the source. This may be the only way to remove the problem. I speak from experience. Jim wb5oxq in Waco - Original Message - From: Dwayne To: Repeater-Builder@yahoogroups.com Sent: Saturday, August 07, 2010 1:38 PM Subject: [Repeater-Builder] Pager interference Hi, I've got a new pager issue that has come up on a tower where we have a VHF repeater. It's about 400 watts erp and 15 feet horizontal distance and 4.3 and 4.7 MHz away (it switches). I'm thinking of using one bp/br can that will have the notch wide enough to cover both channels and one pass can on our RX freq. I can also add more pass cans or something like the DCI window filter. The real question is where to these can go and in what order. We have a standard Q-202 duplexer that worked fine before the pager was put in. I'm thinking that the pager cans will go on the RX side of the duplexer, but does it matter if the pass goes on the duplexer side or the RX side of the bp/br can? I'm kinda thinking that it doesn't matter, but want to do it right in case it does. Dwayne Kincaid WD8OYG -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3056 - Release Date: 08/07/10 01:28:00
[Repeater-Builder] Re: Pager interference
Joe, Its a new pager that switches frequency, just recently put up. Fortunately, we're all on good terms and yes, we're a freebie ham group. So that's why we thought about a window filter for them to get it down 30 or 40 db and we'll do the rest on our end. The original question remains... does the pass go in front of the notch or the notch in front of the pass or does it make a difference. Dwayne Kincaid WD8OYG --- In Repeater-Builder@yahoogroups.com, Joe k1ike_m...@... wrote: Hello Dwayne, I wonder if the paging company has made a change. Did they used to have two separate transmitters, now only have one that switches frequencies? This has been happening at sites since the pager population is dwindling. Paging companies are taking advantage of the multi-frequency capabilities of their transmitters and, for example, putting all their frequencies in one transmitter. They then eliminate the other transmitters to save rent. This is a cost effective thing for them to do. They need to page on all their frequencies because they have pagers out there on different channels and they don't want to replace individual pagers. If this is the case at your site, here is the downside for you. Because one transmitter is doing many frequencies, they have to eliminate any filter cavities they may have had on each individual transmitter. A site can change from no paging interference to tremendous interference overnight. If the original contract for the paging company required filters (some did) or had a non-interfering clause you may have some recourse. If you are a ham freebee like some of my repeaters are, you may just have to live with it. The real fix is probably going to be on the paging transmitter. 73, Joe, K1ike - Original Message - *From:* Dwayne mailto:ldgya...@... *To:* Repeater-Builder@yahoogroups.com mailto:Repeater-Builder@yahoogroups.com *Sent:* Saturday, August 07, 2010 1:38 PM *Subject:* [Repeater-Builder] Pager interference Hi, I've got a new pager issue that has come up on a tower where we have a VHF repeater. It's about 400 watts erp and 15 feet horizontal distance and 4.3 and 4.7 MHz away (it switches). Your email settings: Individual Email|Traditional Change settings via the Web http://groups.yahoo.com/group/Repeater-Builder/join;_ylc=X3oDMTJlNHFkbjJqBF9TAzk3NDc2NTkwBGdycElkAzEwNDE2OARncnBzcElkAzE3MDUwNjMxMDgEc2VjA2Z0cgRzbGsDc3RuZ3MEc3RpbWUDMTI4MTIxNTI0NA-- (Yahoo! ID required) Change settings via email: Switch delivery to Daily Digest mailto:repeater-builder-dig...@yahoogroups.com?subject=email%20delivery:%20Digest | Switch to Fully Featured mailto:repeater-builder-fullfeatu...@yahoogroups.com?subject=change%20delivery%20format:%20Fully%20Featured Visit Your Group http://groups.yahoo.com/group/Repeater-Builder;_ylc=X3oDMTJjcDd1azJhBF9TAzk3NDc2NTkwBGdycElkAzEwNDE2OARncnBzcElkAzE3MDUwNjMxMDgEc2VjA2Z0cgRzbGsDaHBmBHN0aW1lAzEyODEyMTUyNDQ- | Yahoo! Groups Terms of Use http://docs.yahoo.com/info/terms/ | Unsubscribe mailto:repeater-builder-unsubscr...@yahoogroups.com?subject=unsubscribe
Re: [Repeater-Builder] Re: Pager Interference Revisited
The biggest problem is that testing the cable system in one area only gives you info from that area node to the active amps up to the point where you are connected. Any downstream amps won't show up. And there could be a LOT of nodes in a cable system. Chuck WB2EDV - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 11:01 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited You're reading my mind, Gary! 73, Mike WM4B -- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Gary Schafer Sent: Saturday, April 24, 2010 10:59 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Just for grins, find a place (house) to hook your spectrum analyzer up to the local cable system and see if it is on there. 73 Gary K4FMX -- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike Besemer (WM4B) Sent: Saturday, April 24, 2010 6:15 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Problem is Milt, the darn signal level varies like crazy from day to day and location to location. I can be in a certain spot and receive the signal very well, drive until it disappears, and then have it reappear at a high level as I continue on. Obviously elevation and blockage has a lot to do with that, but it actually does that to the point of being ridiculous. almost like it moves. I have been wondering if one of the pole-mounted CATV amps is going crazy and the stuff is squirting out of the CATV system every place it leaks. Sure wish we'd get a trace of audio (besides the pager) on the darn thing. This is gonna drive us nuts before we're done. I'm hearing the stupid thing in my sleep! 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 5:27 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited OK, this is probably not going to be an easy one. I have seen several instances of mast-mounted TV preamps oscillating and acting as miniature transmitters capable of sweeping over wide swaths of spectrum as the temperature changes. They usually exhibit a raw AC buzz on the signal. They are almost never active when the weather is cold, only coming active as the ambient temperature rises. Usually were fed with twin lead. Your description of the audio seems to put that possibility pretty far down the list. At this point I would probably want to look at the incoming signals on the repeater with a spectrum analyser and see if you can quantify the level of the incoming interference signals. If the interference level is high enough you should be able to hear it and maybe track it with a service monitor that can be run off of 12v in a mobile. Since you can call a number on one of the transmitters you can control things a bit. Good luck hunting. Milt - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 4:42 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Milt, Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything els There is an abundance of TV stations, DTV, translators, AM, FM. you name it. The paging signals are both, depending on which site it's coming from. I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 4:19 PM To: Repeater-Builder
[Repeater-Builder] Re: Pager Interference Revisited
--- In Repeater-Builder@yahoogroups.com, Kris Kirby k...@... wrote: On Sat, 24 Apr 2010, Mike Besemer (WM4B) wrote: The issue disappeared over the winter months. If it's a hot, sunny day you can be sure the problem will be present. A hot, cloudy day is also a fairly good bet. Also, a cooler, sunny day will bring it out. Cool and cloudy or cold and sunny do not allow the problem to manifest. The issue has been present during and after several days of rain, so that seems to eliminate the 'rusty bolt' syndrome. I tend to believe it's an amplifier mounted on a pole or tower someplace that's going spurious with heat, but that is just a theory. Beam headings tend to point to the paging transmitters rather than the possible mixing source, which is baffling me as well. Does the paging transmitter have a circulator, or a bandpass cavity between it and the antenna? Does it stay on one frequency or hop around? -- Kris Kirby, KE4AHR Disinformation Analyst I'm told that they do Kris, although I've never been inside any of the sites to see for myself. Given the amount of effort that the pager operator has put in to this effort, I'm inclinded to take him at his word. Even if they did not, I'm having a hard time believe that 3 transmitters in 3 different locations would produce the same issue. (Of course, stranger things have happened.) The transmitters all stay on 462.775. Mike
RE: [Repeater-Builder] Re: Pager Interference Revisited
So has anyone conducted tests to determine if it is a mixing problem ? sig gen and proximity ? To: Repeater-Builder@yahoogroups.com From: mwbese...@cox.net Date: Sat, 24 Apr 2010 17:28:41 + Subject: [Repeater-Builder] Re: Pager Interference Revisited --- In Repeater-Builder@yahoogroups.com, Kris Kirby k...@... wrote: On Sat, 24 Apr 2010, Mike Besemer (WM4B) wrote: The issue disappeared over the winter months. If it's a hot, sunny day you can be sure the problem will be present. A hot, cloudy day is also a fairly good bet. Also, a cooler, sunny day will bring it out. Cool and cloudy or cold and sunny do not allow the problem to manifest. The issue has been present during and after several days of rain, so that seems to eliminate the 'rusty bolt' syndrome. I tend to believe it's an amplifier mounted on a pole or tower someplace that's going spurious with heat, but that is just a theory. Beam headings tend to point to the paging transmitters rather than the possible mixing source, which is baffling me as well. Does the paging transmitter have a circulator, or a bandpass cavity between it and the antenna? Does it stay on one frequency or hop around? -- Kris Kirby, KE4AHR Disinformation Analyst I'm told that they do Kris, although I've never been inside any of the sites to see for myself. Given the amount of effort that the pager operator has put in to this effort, I'm inclinded to take him at his word. Even if they did not, I'm having a hard time believe that 3 transmitters in 3 different locations would produce the same issue. (Of course, stranger things have happened.) The transmitters all stay on 462.775. Mike _ Browse profiles for FREE! Meet local singles online. http://clk.atdmt.com/NMN/go/150855801/direct/01/
RE: [Repeater-Builder] Re: Pager Interference Revisited
Elaborate please Barry. you lost me. Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Barry Sent: Saturday, April 24, 2010 2:36 PM To: repeater-builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited So has anyone conducted tests to determine if it is a mixing problem ? sig gen and proximity ? _ To: Repeater-Builder@yahoogroups.com From: mwbese...@cox.net Date: Sat, 24 Apr 2010 17:28:41 + Subject: [Repeater-Builder] Re: Pager Interference Revisited --- In Repeater-Builder@yahoogroups.com, Kris Kirby k...@... wrote: On Sat, 24 Apr 2010, Mike Besemer (WM4B) wrote: The issue disappeared over the winter months. If it's a hot, sunny day you can be sure the problem will be present. A hot, cloudy day is also a fairly good bet. Also, a cooler, sunny day will bring it out. Cool and cloudy or cold and sunny do not allow the problem to manifest. The issue has been present during and after several days of rain, so that seems to eliminate the 'rusty bolt' syndrome. I tend to believe it's an amplifier mounted on a pole or tower someplace that's going spurious with heat, but that is just a theory. Beam headings tend to point to the paging transmitters rather than the possible mixing source, which is baffling me as well. Does the paging transmitter have a circulator, or a bandpass cavity between it and the antenna? Does it stay on one frequency or hop around? -- Kris Kirby, KE4AHR Disinformation Analyst I'm told that they do Kris, although I've never been inside any of the sites to see for myself. Given the amount of effort that the pager operator has put in to this effort, I'm inclinded to take him at his word. Even if they did not, I'm having a hard time believe that 3 transmitters in 3 different locations would produce the same issue. (Of course, stranger things have happened.) The transmitters all stay on 462.775. Mike _ Meet local singles online. Browse http://clk.atdmt.com/NMN/go/150855801/direct/01/ profiles for FREE!
RE: [Repeater-Builder] Re: Pager Interference Revisited
Portable sig gen into the repeater site and swing it about the place in various locations , sort of a revrse hammer to the power poles if it is coax introduced you quickly confirm your suspicions but if its ac introduced or grounding or some other oddity it usually helps to eliminate the rf feed I have seen some odd stuff introduced via the oddest things into commercial sites so discount nothing and the best of luck Have to go service now as its 4:30 am Lest We Forget _ Need a new place to live? Find it on Domain.com.au http://clk.atdmt.com/NMN/go/157631292/direct/01/
RE: [Repeater-Builder] Re: Pager Interference Revisited
Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Barry Sent: Saturday, April 24, 2010 2:44 PM To: repeater-builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Portable sig gen into the repeater site and swing it about the place in various locations , sort of a revrse hammer to the power poles if it is coax introduced you quickly confirm your suspicions but if its ac introduced or grounding or some other oddity it usually helps to eliminate the rf feed I have seen some odd stuff introduced via the oddest things into commercial sites so discount nothing and the best of luck Have to go service now as its 4:30 am Lest We Forget _ Find it on Domain.com.au Need a http://clk.atdmt.com/NMN/go/157631292/direct/01/ new place to live?
Re: [Repeater-Builder] Re: Pager Interference Revisited
How close is Robins AFB? Maybe? Chuck WB2EDV - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 2:48 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B
RE: [Repeater-Builder] Re: Pager Interference Revisited
I don't think so, Chuck. I work on Robins and traverse it pretty much from end-to-end daily. I also have to traverse it quite a ways just to get off of it to go foxhunt this beast. Generally the signals on-base are weak to non-existent. It's bloody amazing how much RF crap is in the air. Using a Google Earth application I can see zillions of sites within earshot. The mixing possibilities are endless! I'm somewhat surprise that we've never heard any audio mixing in with it. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Saturday, April 24, 2010 3:16 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited How close is Robins AFB? Maybe? Chuck WB2EDV - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 2:48 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B
e: [Repeater-Builder] Re: Pager Interference Revisited
Mike, Does the interfering signal come and go or is it constant? Does it have any AC component; ie buzz or hum at 60Hz, 120Hz, etc., or any raw buzzing noise? Are there any broiadcast TV stations in the area, DTV or LP translators? Is the UHF pager signal analog, digital or both? What test equipmet do you ahve available? Is the repeater in a poplulated area or remote? Milt N3LTQ - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 3:36 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited I don't think so, Chuck. I work on Robins and traverse it pretty much from end-to-end daily. I also have to traverse it quite a ways just to get off of it to go foxhunt this beast. Generally the signals on-base are weak to non-existent. It's bloody amazing how much RF crap is in the air. Using a Google Earth application I can see zillions of sites within earshot. The mixing possibilities are endless! I'm somewhat surprise that we've never heard any audio mixing in with it. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Saturday, April 24, 2010 3:16 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited How close is Robins AFB? Maybe? Chuck WB2EDV - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 2:48 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B
RE: [Repeater-Builder] Re: Pager Interference Revisited
Milt, Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything else. There is an abundance of TV stations, DTV, translators, AM, FM. you name it. The paging signals are both, depending on which site it's coming from. I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 4:19 PM To: Repeater-Builder@yahoogroups.com Subject: e: [Repeater-Builder] Re: Pager Interference Revisited Mike, Does the interfering signal come and go or is it constant? Does it have any AC component; ie buzz or hum at 60Hz, 120Hz, etc., or any raw buzzing noise? Are there any broiadcast TV stations in the area, DTV or LP translators? Is the UHF pager signal analog, digital or both? What test equipmet do you ahve available? Is the repeater in a poplulated area or remote? Milt N3LTQ - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 3:36 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited I don't think so, Chuck. I work on Robins and traverse it pretty much from end-to-end daily. I also have to traverse it quite a ways just to get off of it to go foxhunt this beast. Generally the signals on-base are weak to non-existent. It's bloody amazing how much RF crap is in the air. Using a Google Earth application I can see zillions of sites within earshot. The mixing possibilities are endless! I'm somewhat surprise that we've never heard any audio mixing in with it. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Saturday, April 24, 2010 3:16 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited How close is Robins AFB? Maybe? Chuck WB2EDV - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 2:48 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B
Re: [Repeater-Builder] Re: Pager Interference Revisited
How do the paging signals get to the three transmitters? Wireline? 72 MHz link? 930 MHz link? Matthew Kaufman
RE: [Repeater-Builder] Re: Pager Interference Revisited
1 is wireline, two are satellite. From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Matthew Kaufman Sent: Saturday, April 24, 2010 4:44 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited How do the paging signals get to the three transmitters? Wireline? 72 MHz link? 930 MHz link? Matthew Kaufman
Re: [Repeater-Builder] Re: Pager Interference Revisited
Yes, but odds are good you are dealing with three different problems - similar mechanisms but different participants. Unless of course you can hear it at all three sites on the same frequency. On 4/24/2010 1:48 PM, Mike Besemer (WM4B) wrote: Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport)
Re: [Repeater-Builder] Re: Pager Interference Revisited
Mike, I'm coming to this late, but I have comments and questions. What type of hardware are the paging transmitters? What are the repeaters in question, and what type of duplexers, feedline, and antennas are used? On 4/24/2010 3:42 PM, Mike Besemer (WM4B) wrote: Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. In another message you implied it sweeps across multiple repeater inputs. It also comes and goes with heat and sun... we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. We saw the same thing with Radio Shack and Winegard active TV antennas on RVs. The problem was a high band pager and our UHF radio inputs. Nothing remarkable about the audio... sounds like clean, clear paging tones. Never heard anything else. This implies a first order contribution to a mix or spur. If the second or third harmonic of the pager was involved, the deviation would be a suitable multiple and should sound distorted. Might be good to ask him what transmit dev. he runs, or measure it. There is an abundance of TV stations, DTV, translators, AM, FM... you name it. Yeah but this sounds like something flying. If mixes sweep across your input one contributor is almost always an amplifier that is oscillating. The two frequencies you mention would require a channel 37 station and those don't exist in the US. The paging signals are both, depending on which site it's coming from. Eh? what do you mean here? I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. Is the paging system key down, or is it transmit on demand? Can you hear the interference far from your site (several miles?) The ability to DF it sort of implies this. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) What kind of sites are the paging transmitters on? Rental tower, water tank, building? -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport)
Re: [Repeater-Builder] Re: Pager Interference Revisited
OK, this is probably not going to be an easy one. I have seen several instances of mast-mounted TV preamps oscillating and acting as miniature transmitters capable of sweeping over wide swaths of spectrum as the temperature changes. They usually exhibit a raw AC buzz on the signal. They are almost never active when the weather is cold, only coming active as the ambient temperature rises. Usually were fed with twin lead. Your description of the audio seems to put that possibility pretty far down the list. At this point I would probably want to look at the incoming signals on the repeater with a spectrum analyser and see if you can quantify the level of the incoming interference signals. If the interference level is high enough you should be able to hear it and maybe track it with a service monitor that can be run off of 12v in a mobile. Since you can call a number on one of the transmitters you can control things a bit. Good luck hunting. Milt - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 4:42 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Milt, Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything els There is an abundance of TV stations, DTV, translators, AM, FM. you name it. The paging signals are both, depending on which site it's coming from. I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 4:19 PM To: Repeater-Builder@yahoogroups.com Subject: e: [Repeater-Builder] Re: Pager Interference Revisited Mike, Does the interfering signal come and go or is it constant? Does it have any AC component; ie buzz or hum at 60Hz, 120Hz, etc., or any raw buzzing noise? Are there any broiadcast TV stations in the area, DTV or LP translators? Is the UHF pager signal analog, digital or both? What test equipmet do you ahve available? Is the repeater in a poplulated area or remote? Milt N3LTQ - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 3:36 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited I don't think so, Chuck. I work on Robins and traverse it pretty much from end-to-end daily. I also have to traverse it quite a ways just to get off of it to go foxhunt this beast. Generally the signals on-base are weak to non-existent. It's bloody amazing how much RF crap is in the air. Using a Google Earth application I can see zillions of sites within earshot. The mixing possibilities are endless! I'm somewhat surprise that we've never heard any audio mixing in with it. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Saturday, April 24, 2010 3:16 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited How close is Robins AFB? Maybe? Chuck WB2EDV - Original Message - From: Mike Besemer (WM4B) To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 2:48 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Given that the interference is in three different repeaters over about 40 air-miles, I have not done that. I've THOUGHT about it, but it didn't make sense, give the circumstances. 73, Mike WM4B
RE: [Repeater-Builder] Re: Pager Interference Revisited
Not sure about the paging systems. The repeaters themselves are a variety of systems and their architecture really doesn't matter since the interference can be heard on the input frequency with a string and a tin can. That being said, I know that 2 of them (mine) are using DB-224s, 7/8 hardline and WACOM cans. Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Oz-in-DFW Sent: Saturday, April 24, 2010 5:17 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited Mike, I'm coming to this late, but I have comments and questions. What type of hardware are the paging transmitters? What are the repeaters in question, and what type of duplexers, feedline, and antennas are used? On 4/24/2010 3:42 PM, Mike Besemer (WM4B) wrote: Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. In another message you implied it sweeps across multiple repeater inputs. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. We saw the same thing with Radio Shack and Winegard active TV antennas on RVs. The problem was a high band pager and our UHF radio inputs. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything else. This implies a first order contribution to a mix or spur. If the second or third harmonic of the pager was involved, the deviation would be a suitable multiple and should sound distorted. Might be good to ask him what transmit dev. he runs, or measure it. There is an abundance of TV stations, DTV, translators, AM, FM. you name it. Yeah but this sounds like something flying. If mixes sweep across your input one contributor is almost always an amplifier that is oscillating. The two frequencies you mention would require a channel 37 station and those don't exist in the US. The paging signals are both, depending on which site it's coming from. Eh? what do you mean here? I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. Is the paging system key down, or is it transmit on demand? Can you hear the interference far from your site (several miles?) The ability to DF it sort of implies this. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) What kind of sites are the paging transmitters on? Rental tower, water tank, building? -- mailto:o...@ozindfw.net Oz POB 93167 Southlake, TX 76092 (Near DFW Airport)
RE: [Repeater-Builder] Re: Pager Interference Revisited
Problem is Milt, the darn signal level varies like crazy from day to day and location to location. I can be in a certain spot and receive the signal very well, drive until it disappears, and then have it reappear at a high level as I continue on. Obviously elevation and blockage has a lot to do with that, but it actually does that to the point of being ridiculous. almost like it moves. I have been wondering if one of the pole-mounted CATV amps is going crazy and the stuff is squirting out of the CATV system every place it leaks. Sure wish we'd get a trace of audio (besides the pager) on the darn thing. This is gonna drive us nuts before we're done. I'm hearing the stupid thing in my sleep! 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 5:27 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited OK, this is probably not going to be an easy one. I have seen several instances of mast-mounted TV preamps oscillating and acting as miniature transmitters capable of sweeping over wide swaths of spectrum as the temperature changes. They usually exhibit a raw AC buzz on the signal. They are almost never active when the weather is cold, only coming active as the ambient temperature rises. Usually were fed with twin lead. Your description of the audio seems to put that possibility pretty far down the list. At this point I would probably want to look at the incoming signals on the repeater with a spectrum analyser and see if you can quantify the level of the incoming interference signals. If the interference level is high enough you should be able to hear it and maybe track it with a service monitor that can be run off of 12v in a mobile. Since you can call a number on one of the transmitters you can control things a bit. Good luck hunting. Milt - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 4:42 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Milt, Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything els There is an abundance of TV stations, DTV, translators, AM, FM. you name it. The paging signals are both, depending on which site it's coming from. I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 4:19 PM To: Repeater-Builder@yahoogroups.com Subject: e: [Repeater-Builder] Re: Pager Interference Revisited Mike, Does the interfering signal come and go or is it constant? Does it have any AC component; ie buzz or hum at 60Hz, 120Hz, etc., or any raw buzzing noise? Are there any broiadcast TV stations in the area, DTV or LP translators? Is the UHF pager signal analog, digital or both? What test equipmet do you ahve available? Is the repeater in a poplulated area or remote? Milt N3LTQ - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 3:36 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited I don't think so, Chuck. I work on Robins and traverse it pretty much from end-to-end daily. I also have to traverse it quite a ways just to get off of it to go foxhunt this beast. Generally the signals on-base are weak to non-existent. It's bloody amazing how much RF crap is in the air. Using a Google Earth application I can see zillions of sites within earshot. The mixing possibilities are endless! I'm somewhat surprise that we've never heard any audio mixing in with it. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Saturday, April 24, 2010 3:16 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited How close is Robins AFB? Maybe? Chuck WB2EDV - Original
[Repeater-Builder] Re: Pager Interference Revisited
At the risk of mentioning something that's been mentioned and/or checked by you before... I believe you said that linking to the sites is not terrestrial RF but wireline and satellite. Be sure that there isn't some RF linking that's been fogotten by someone not very familiar with the entire system. I've seen 72 mc. link transmitters transmit spurs just like any defective transmitter can. The way this spur wanders around sure sounds like a dirty transmitter. Puzzling thing is that you've said that the bearings to the spurs while DFing wander all over the place. I would doubt there's more than one spur generator, so, point is, make sure your DFing person is an experienced Foxhunter and knows how to handle multipath, one of the biggest *spoilers* for any Foxhunter. You said you sat near one of the sites but the interfering signal was weak, or non-existent. Have you done the same at the other two sites? Good luck finding this beast! Laryn K8TVZ
RE: [Repeater-Builder] Re: Pager Interference Revisited
Laryn, I don't 'think' there are any forgotten links, but I'll certainly ask the question when I speak to the owner again. He's very open about his systems and I believe he's very involved, but like any of us who is getting older, it's possible he forgot something. I agree about the spur sounding like a dirty transmitter. that was my first thought when we heard it and it took a lot of convincing for me to believe that the pager transmitters were clean. That being said, it's still very possible (and likely) that it's mixing with something that is extremely cruddy and unstable. I can't imagine anything different. I also agree with your comment about multipath. I also think there is only one problem source. I've done quite a bit of foxhunting in the past, but will admit that I'm rusty and also that I've never hunted in this area. It also seems like every place I want to go to take a shot, there's a darn chain link fence that's either funneling or reflecting the signals. Nothing is easy anymore! I've not been to any of the other sites while this is going on. The issue with 145.43 was only made known to me after-the-fact and the operator of that system and I have had several disagreements in the past, so I've just let that sleeping dog lie. The 145.11 in Cochran only experiences the problem on occasion (as opposed to just about any warm/sunny day for the 146.85) and it takes me about 40 minutes to drive to there from either work or home, so I haven't made a huge effort to do so. Last time we hooked up the spectrum analyzer to the repeater antenna, what we were seeing was very daunting. I need to go back through the many pages of notes and emails from last year to see if there's anything that I might have overlooked at the time. At this point, I'd like to find the offending device and beat it to pieces with a baseball bat! 73, Mike WM4B _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of larynl2 Sent: Saturday, April 24, 2010 9:04 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Pager Interference Revisited At the risk of mentioning something that's been mentioned and/or checked by you before... I believe you said that linking to the sites is not terrestrial RF but wireline and satellite. Be sure that there isn't some RF linking that's been fogotten by someone not very familiar with the entire system. I've seen 72 mc. link transmitters transmit spurs just like any defective transmitter can. The way this spur wanders around sure sounds like a dirty transmitter. Puzzling thing is that you've said that the bearings to the spurs while DFing wander all over the place. I would doubt there's more than one spur generator, so, point is, make sure your DFing person is an experienced Foxhunter and knows how to handle multipath, one of the biggest *spoilers* for any Foxhunter. You said you sat near one of the sites but the interfering signal was weak, or non-existent. Have you done the same at the other two sites? Good luck finding this beast! Laryn K8TVZ
RE: [Repeater-Builder] Re: Pager Interference Revisited
As mentioned finding the trigger both with and without the antenna would assist with a solution , it could be very simple but you need to establish possible triggers and monitor accordingly with the Spec unit _ If It Exists, You'll Find it on SEEK. Australia's #1 job site http://clk.atdmt.com/NMN/go/157639755/direct/01/
[Repeater-Builder] Re: Pager Interference Revisited
What Coax or hardline and antenna's are in use for both rpt's ? What happens when another RX is used at the site? Maybe a IF issue with the Ham rpt's and 72 mhz some thoughts. Ryan n3ssl
RE: [Repeater-Builder] Re: Pager Interference Revisited
No guys. The signals on the INPUT are heard in many places around town. If the signals are on the INPUT it ain't the ham equipment. Aside from that, I've already stated that the hardline is 7/8 and the antennas are DB-224. WM4B _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of n3ssl Sent: Saturday, April 24, 2010 10:12 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Pager Interference Revisited What Coax or hardline and antenna's are in use for both rpt's ? What happens when another RX is used at the site? Maybe a IF issue with the Ham rpt's and 72 mhz some thoughts. Ryan n3ssl
RE: [Repeater-Builder] Re: Pager Interference Revisited
Just for grins, find a place (house) to hook your spectrum analyzer up to the local cable system and see if it is on there. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike Besemer (WM4B) Sent: Saturday, April 24, 2010 6:15 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Problem is Milt, the darn signal level varies like crazy from day to day and location to location. I can be in a certain spot and receive the signal very well, drive until it disappears, and then have it reappear at a high level as I continue on. Obviously elevation and blockage has a lot to do with that, but it actually does that to the point of being ridiculous. almost like it moves. I have been wondering if one of the pole-mounted CATV amps is going crazy and the stuff is squirting out of the CATV system every place it leaks. Sure wish we'd get a trace of audio (besides the pager) on the darn thing. This is gonna drive us nuts before we're done. I'm hearing the stupid thing in my sleep! 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 5:27 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited OK, this is probably not going to be an easy one. I have seen several instances of mast-mounted TV preamps oscillating and acting as miniature transmitters capable of sweeping over wide swaths of spectrum as the temperature changes. They usually exhibit a raw AC buzz on the signal. They are almost never active when the weather is cold, only coming active as the ambient temperature rises. Usually were fed with twin lead. Your description of the audio seems to put that possibility pretty far down the list. At this point I would probably want to look at the incoming signals on the repeater with a spectrum analyser and see if you can quantify the level of the incoming interference signals. If the interference level is high enough you should be able to hear it and maybe track it with a service monitor that can be run off of 12v in a mobile. Since you can call a number on one of the transmitters you can control things a bit. Good luck hunting. Milt - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 4:42 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Milt, Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything els There is an abundance of TV stations, DTV, translators, AM, FM. you name it. The paging signals are both, depending on which site it's coming from. I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 4:19 PM To: Repeater-Builder@yahoogroups.com Subject: e: [Repeater-Builder] Re: Pager Interference Revisited Mike, Does the interfering signal come and go or is it constant? Does it have any AC component; ie buzz or hum at 60Hz, 120Hz, etc., or any raw buzzing noise? Are there any broiadcast TV stations in the area, DTV or LP translators? Is the UHF pager signal analog, digital or both? What test equipmet do you ahve available? Is the repeater in a poplulated area or remote? Milt N3LTQ - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 24, 2010 3:36 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited I don't think so, Chuck. I work on Robins and traverse it pretty much from end-to-end daily. I also have to traverse it quite a ways just to get off of it to go foxhunt this beast. Generally the signals on-base are weak to non-existent. It's bloody amazing how much RF crap is in the air. Using a Google Earth application I can see zillions of sites within earshot. The mixing possibilities are endless! I'm
RE: [Repeater-Builder] Re: Pager Interference Revisited
You're reading my mind, Gary! 73, Mike WM4B _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Gary Schafer Sent: Saturday, April 24, 2010 10:59 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Just for grins, find a place (house) to hook your spectrum analyzer up to the local cable system and see if it is on there. 73 Gary K4FMX _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Mike Besemer (WM4B) Sent: Saturday, April 24, 2010 6:15 PM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Problem is Milt, the darn signal level varies like crazy from day to day and location to location. I can be in a certain spot and receive the signal very well, drive until it disappears, and then have it reappear at a high level as I continue on. Obviously elevation and blockage has a lot to do with that, but it actually does that to the point of being ridiculous. almost like it moves. I have been wondering if one of the pole-mounted CATV amps is going crazy and the stuff is squirting out of the CATV system every place it leaks. Sure wish we'd get a trace of audio (besides the pager) on the darn thing. This is gonna drive us nuts before we're done. I'm hearing the stupid thing in my sleep! 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 5:27 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Pager Interference Revisited OK, this is probably not going to be an easy one. I have seen several instances of mast-mounted TV preamps oscillating and acting as miniature transmitters capable of sweeping over wide swaths of spectrum as the temperature changes. They usually exhibit a raw AC buzz on the signal. They are almost never active when the weather is cold, only coming active as the ambient temperature rises. Usually were fed with twin lead. Your description of the audio seems to put that possibility pretty far down the list. At this point I would probably want to look at the incoming signals on the repeater with a spectrum analyser and see if you can quantify the level of the incoming interference signals. If the interference level is high enough you should be able to hear it and maybe track it with a service monitor that can be run off of 12v in a mobile. Since you can call a number on one of the transmitters you can control things a bit. Good luck hunting. Milt - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@ mailto:Repeater-Builder@yahoogroups.com yahoogroups.com Sent: Saturday, April 24, 2010 4:42 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited Milt, Not sure what you mean by 'come and go'. It's there when the pager transmitter is up, gone when it's not. It also comes and goes with heat and sun. we may have days with no interference if it's cool and cloudy or just plain cold. Rain makes no difference. Nothing remarkable about the audio. sounds like clean, clear paging tones. Never heard anything els There is an abundance of TV stations, DTV, translators, AM, FM. you name it. The paging signals are both, depending on which site it's coming from. I can get my hands on pretty much anything I need. Spectrum analyzer is no problem. I have a good 'connection'. Did some hunting with a spectrum analyzer last year to no avail, but now that I have the ability to call the system and have it send out a page we have a little better advantage. I'd call the area 'populated', but not 'urban'. Mostly housing around the site, but plenty of industry (and towers) visible from the top of the water tank. (We are, by the way, the only user on the tank.) From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Milt Sent: Saturday, April 24, 2010 4:19 PM To: Repeater-Builder@yahoogroups.com Subject: e: [Repeater-Builder] Re: Pager Interference Revisited Mike, Does the interfering signal come and go or is it constant? Does it have any AC component; ie buzz or hum at 60Hz, 120Hz, etc., or any raw buzzing noise? Are there any broiadcast TV stations in the area, DTV or LP translators? Is the UHF pager signal analog, digital or both? What test equipmet do you ahve available? Is the repeater in a poplulated area or remote? Milt N3LTQ - Original Message - From: Mike Besemer (WM4B) mailto:mwbese...@cox.net To: Repeater-Builder@ mailto:Repeater-Builder@yahoogroups.com yahoogroups.com Sent: Saturday, April 24, 2010 3:36 PM Subject: RE: [Repeater-Builder] Re: Pager Interference Revisited I don't think so
[Repeater-Builder] Re: Pager Interference to 2-meter VHF Public Service Band
If I have followed the thread correctly, this interference happens from either of the paging transmitters, not just one or the other. I would suggest you check to see if there is a TV linear translator very nearby it could be the source. --- In Repeater-Builder@yahoogroups.com, Mike Besemer \(WM4B\) mwbese...@... wrote: Joe, The problem isn't traffic dependant (10 am being a busy time), as I monitor on and off all day and there is PLENTY of traffic all day long. It seems to have more to do with temperature. You can clearly hear the signals come on and fade off frequency. It's also easy to hear which transmitter is sending the pages. I have two dual band radios in my vehicle. Typically one is on the repeater output, one on the input, one of VHF paging and one on UHF paging. It's also been confirmed by having the owner send test bursts by specific transmitters. The other two UHF frequencies are also paging transmitters. Good thoughts about the transmitter self-oscillating when unkeyed... that's another road we can go down. Speaking of going down roads. what I really need is more help! Several of our club members are engaged in assisting, but what I really need is a dedicated team of folks. Having to work for a living is taking a serious bite out my tracking time! 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Joe Sent: Wednesday, October 28, 2009 11:51 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Pager Interference to 2-meter VHF Public Service Band Hello Mike. The first clue is that the signal is moving up and down the 2 meter band. This would tell me that something not frequency controlled is causing the interference. Not frequency controlled would mean that the transmitter is not crystal or GPS locked to a specific frequency. Now, something that is frequency controlled may be involved with the IMD mix, but the signal that is free running is possibly causing an IMD mix to drift. I have seen this happen in a PA when it was NOT transmitting. We had a case of a paging transmitter PA that would go into self oscillation when it was not keyed by the exciter. The PA had power to it at all times and it would create interference when it was idle. Some random thoughts: Your paging company signal may be mixing with it, but they may not be the culprit. 10AM can be busy time for a paging company, so the fact that it happens around that time would not be unusual. How do you know the data is from a specific paging company? Did you listen to their signal and the interference at the same time? Is it exactly the same? He says that he has remote control of the transmitters. What happens when he shuts them both off? As someone else pointed out, does he have a link frequency that he ties the sites together with? The link transmitter may be causing the interference, or be part of the RF mix. An IMD program will be useless to figure the IMD of a drifting transmitter that is part of a mix. You said 462.850 and 462.925 are also involved. What is on those frequencies? Who is on these frequencies and how are they involved? A lightning hit may have caused this all to happen. In my last job I troubleshooted lots of interference. You really need to take an antenna and directional find the source of the interference. It is time consuming, but will lead you to the physical source of the interference. Don't be fooled that it is positively the paging companies fault, as it may just be a mix in some other service PA. The last one I found was interference on a 53.85 Mhz repeater. At first, the culprit seemed to be the NOAA weather station on 162.55Mhz. NOAA weather audio was coming through the repeater crystal clear. It turned out to be a telemetry station PA that was mixing 4 X 53.85 - 162.55 = 52.85Mhz. The mix was exactly on the input! The telemetry station was owned by the water company that allowed us on the site, so we ended up moving the repeater to 53.71Mhz. We could have pushed the water company to fix their equipment, but probably would have been asked to leave the site. Sometimes diplomacy rules. I worked for paging companies for quite awhile and know that they get a bad rap, probably rightfully so for the most part. This sounds like the paging company is willing to work with you. My gut feeling is that you are going to find something else causing the problem. Again, diplomacy rules. 73, Joe, K1ike Mike wrote: A couple of weeks ago, our repeater system started to experience interference from a paging system. The repeater is on 146.850 (-600 KHz), with the antenna system about 120 feet up a water tower. T
[Repeater-Builder] Re: Pager Interference.........
Have seen this several times where a transmitter went spurious. The worst have been Johnsons. It's often temperature related, at least the frequency of the spur. A spectrum analyzer and a directional antenna are your best tools. A portable scanner is also very handy. In one case we tracked down it was a small two watt telemetry transmitter, not a pager, trashing a UHF repeater ten miles away when the temperature was between 40 and 50 degrees. We found their spur was there any time their transmitter was up but only on the repeater input at certain temperatures. This particular transmitter was owned by a pipeline outfit. When we finally were able to contact them their tech was quite knowledgeable and replaced the offending transmitter. And they thanked us for bringing the problem to their attention. With other entities sometimes we have not been so fortunate. Often when an offending transmitter was identified we got denials of responsibility from the owners but persistence and pressure from authorities have generally paid off. Good luck, Al, K9SI
[Repeater-Builder] Re: Pager Interference.........
We had a wandering spur passing through the Game and Fish statewide frequency at 151 MHz. The maintenance engineer had to put the spec-a on the IF section of the affected receiver [MastrII] to actually see it. One he saw it, he demodded the signal and it was a local paging outfit on 454 MHz. The paging company engineer turned off the transmitters one by one [simulcast system], until the interference went away. When they went out there, the PA tube had been recently replaced, and the technician hadn't properly neutralized it [Quintron?]. Seems to be kind of a lost art. Another time, we had a 462 MHz pager that was EXACTLY half-way between our input and output on 460/465. Whenever we were on the air simultaneously, we got hit hard. It ended up being in his transmitter, and a dual-isolator on his end cured the problem. but he really disliked the loss of ERP. Thank heavens that company folded. WalterH --- In Repeater-Builder@yahoogroups.com, Al Wolfe k...@... wrote: Have seen this several times where a transmitter went spurious. The worst have been Johnsons. It's often temperature related, at least the frequency of the spur. A spectrum analyzer and a directional antenna are your best tools. A portable scanner is also very handy. In one case we tracked down it was a small two watt telemetry transmitter, not a pager, trashing a UHF repeater ten miles away when the temperature was between 40 and 50 degrees. We found their spur was there any time their transmitter was up but only on the repeater input at certain temperatures. This particular transmitter was owned by a pipeline outfit. When we finally were able to contact them their tech was quite knowledgeable and replaced the offending transmitter. And they thanked us for bringing the problem to their attention. With other entities sometimes we have not been so fortunate. Often when an offending transmitter was identified we got denials of responsibility from the owners but persistence and pressure from authorities have generally paid off. Good luck, Al, K9SI
RE: [Repeater-Builder] Re: Pager Interference.........
Hi Walter, If the paging operator is bitching about .6db of loss from an isolator. ft it were my site I would have made him add a band pass can as well or he could go find another site to trash. Most likely we would have made the operator run through the site combiner and then he would really have bitched since it would have been around 2db of loss. Mike Mullarkey K7PFJ _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of ka1jfy Sent: Thursday, October 29, 2009 10:47 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Pager Interference. We had a wandering spur passing through the Game and Fish statewide frequency at 151 MHz. The maintenance engineer had to put the spec-a on the IF section of the affected receiver [MastrII] to actually see it. One he saw it, he demodded the signal and it was a local paging outfit on 454 MHz. The paging company engineer turned off the transmitters one by one [simulcast system], until the interference went away. When they went out there, the PA tube had been recently replaced, and the technician hadn't properly neutralized it [Quintron?]. Seems to be kind of a lost art. Another time, we had a 462 MHz pager that was EXACTLY half-way between our input and output on 460/465. Whenever we were on the air simultaneously, we got hit hard. It ended up being in his transmitter, and a dual-isolator on his end cured the problem. but he really disliked the loss of ERP. Thank heavens that company folded. WalterH --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, Al Wolfe k...@... wrote: Have seen this several times where a transmitter went spurious. The worst have been Johnsons. It's often temperature related, at least the frequency of the spur. A spectrum analyzer and a directional antenna are your best tools. A portable scanner is also very handy. In one case we tracked down it was a small two watt telemetry transmitter, not a pager, trashing a UHF repeater ten miles away when the temperature was between 40 and 50 degrees. We found their spur was there any time their transmitter was up but only on the repeater input at certain temperatures. This particular transmitter was owned by a pipeline outfit. When we finally were able to contact them their tech was quite knowledgeable and replaced the offending transmitter. And they thanked us for bringing the problem to their attention. With other entities sometimes we have not been so fortunate. Often when an offending transmitter was identified we got denials of responsibility from the owners but persistence and pressure from authorities have generally paid off. Good luck, Al, K9SI No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.423 / Virus Database: 270.14.38/2467 - Release Date: 10/29/09 07:38:00
[Repeater-Builder] Re: Pager Interference to 2-meter VHF Public Service Band
We had a similar problem here years ago, caused by a city fire dispatch transmitter 30 miles away. It had a spur that we could follow around in frequency too. Our repeater is on 2M and their transmitter was on 154.37, if I remember. Their transmitter was the entire cause of the problem; no mixing was involved. I'd carefully check that, in fact, the suspect transmitters were disabled for the tests you mentioned. The linking scheme to them is also suspect as suggested. Are you hearing any other audio in the spur? If not I think it's a dirty transmitter; no mixing or intermod involved. Laryn K8TVZ
