Re: [Repeater-Builder] Re: Intermod Calculation
Here's the latest: We went up to our site yesterday. We added a lighting arrestor to the receive antenna. We grounded the chassis/rail/cabinet as it was only grounded via the power cord previously. Didn't expect this to fix the paging problem, it just needed to be done. I did find a loose UHF connector on the Wacom. This is a two cavity BP filter on the receive side. I don't know if the loose connector was the problem but it's much cleaner now. We ran in carrier squelch for about an hour and didn't hear much of anything. A dramatic improvement and amazing for our dirty hill. Today there have been a couple of pages bust through the P/L but it's 1,000% better than it was and it's still pretty quite in carrier squelch. Do you think the loose connector and/or grounding could have helped or is this some sort of cruel coincidence? -- Tim :wq On Aug 24, 2010, at 3:48 PM, Walter H wrote: We also had a problem with a 454 pager. Quintron with a 1/4 k amp. Only one in the metro area had a spur, but that one traveled as the PA cage changed temperature. Got a hold of the paging company, and they turned each one off until we saw the spur go away. Final tube had been replaced and not properly neutralized. WalterH --- In Repeater-Builder@yahoogroups.com, Tom W2MN w...@... wrote: We had a pager spur problem with our repeater (no pl). The problem would come and go. We determined it happened mostly with time of day (outside temperature). Sometime it was just a short 1 second event and sometimes it would hold for a bit more (maybe 2 -5 sec). We setup a satellite multimode radio (actually dial in the frequency with widest bandwidth setting) and monitored the repeater input with a tape recorder and vox. We did this to capture the audio so we could listen to characteristics and THE CW CALLSIGN. We captured enough of the callsign that we were able to indentify the whole call (and freq) from the FCC database. With that, we were able to monitor the repeater and the pager for hits. Yes, it did hit some times and not others. The reason was, it was caused by an unstable spur that drifted up and down the ham band with temperature and the amount of pager traffic. It was also hitting other repeaters as it drifted but most of the other repeaters had pl. There was a chain of pagers using the same freq and callsign and we had to figure out which tower it was. We used a beam antenna and chased the spur up/down the band until we were able to get a definite direction. The next step as to visit the site AREA with an HT and just scan the ham repeater input freqs during the likely time of day. Bingo, the spur was loud and clear!. Of course the pager owner was in denial but being a pest for a couple of weeks got the problem removed. They claim it was a spur in the final PA that had been serviced just at the time the problem started. They replaced the PA. Hope this story helps. Tom
Re: [Repeater-Builder] Re: Intermod Calculation
I've seen this before on Wacom BpBr duplexers. Remove the coupling loop from the cavity and re-solder the connectors. Use 2% silver bearing solder if you can find it. On Wed, Aug 25, 2010 at 1:27 PM, Tim Sawyer tisaw...@gmail.com wrote: Here's the latest: We went up to our site yesterday. We added a lighting arrestor to the receive antenna. We grounded the chassis/rail/cabinet as it was only grounded via the power cord previously. Didn't expect this to fix the paging problem, it just needed to be done. I did find a loose UHF connector on the Wacom. This is a two cavity BP filter on the receive side. I don't know if the loose connector was the problem but it's much cleaner now. We ran in carrier squelch for about an hour and didn't hear much of anything. A dramatic improvement and amazing for our dirty hill. Today there have been a couple of pages bust through the P/L but it's 1,000% better than it was and it's still pretty quite in carrier squelch. Do you think the loose connector and/or grounding could have helped or is this some sort of cruel coincidence? -- Tim :wq On Aug 24, 2010, at 3:48 PM, Walter H wrote: We also had a problem with a 454 pager. Quintron with a 1/4 k amp. Only one in the metro area had a spur, but that one traveled as the PA cage changed temperature. Got a hold of the paging company, and they turned each one off until we saw the spur go away. Final tube had been replaced and not properly neutralized. WalterH --- In Repeater-Builder@yahoogroups.comRepeater-Builder%40yahoogroups.com, Tom W2MN w...@... wrote: We had a pager spur problem with our repeater (no pl). The problem would come and go. We determined it happened mostly with time of day (outside temperature). Sometime it was just a short 1 second event and sometimes it would hold for a bit more (maybe 2 -5 sec). We setup a satellite multimode radio (actually dial in the frequency with widest bandwidth setting) and monitored the repeater input with a tape recorder and vox. We did this to capture the audio so we could listen to characteristics and THE CW CALLSIGN. We captured enough of the callsign that we were able to indentify the whole call (and freq) from the FCC database. With that, we were able to monitor the repeater and the pager for hits. Yes, it did hit some times and not others. The reason was, it was caused by an unstable spur that drifted up and down the ham band with temperature and the amount of pager traffic. It was also hitting other repeaters as it drifted but most of the other repeaters had pl. There was a chain of pagers using the same freq and callsign and we had to figure out which tower it was. We used a beam antenna and chased the spur up/down the band until we were able to get a definite direction. The next step as to visit the site AREA with an HT and just scan the ham repeater input freqs during the likely time of day. Bingo, the spur was loud and clear!. Of course the pager owner was in denial but being a pest for a couple of weeks got the problem removed. They claim it was a spur in the final PA that had been serviced just at the time the problem started. They replaced the PA. Hope this story helps. Tom
Re: [Repeater-Builder] Re: Intermod Calculation
This is a couple of pass cavities, not a duplexer. Do the band pass cavities have the same problem? -- Tim :wq On Aug 25, 2010, at 1:32 PM, DCFluX wrote: I've seen this before on Wacom BpBr duplexers. Remove the coupling loop from the cavity and re-solder the connectors. Use 2% silver bearing solder if you can find it. On Wed, Aug 25, 2010 at 1:27 PM, Tim Sawyer tisaw...@gmail.com wrote: Here's the latest: We went up to our site yesterday. We added a lighting arrestor to the receive antenna. We grounded the chassis/rail/cabinet as it was only grounded via the power cord previously. Didn't expect this to fix the paging problem, it just needed to be done. I did find a loose UHF connector on the Wacom. This is a two cavity BP filter on the receive side. I don't know if the loose connector was the problem but it's much cleaner now. We ran in carrier squelch for about an hour and didn't hear much of anything. A dramatic improvement and amazing for our dirty hill. Today there have been a couple of pages bust through the P/L but it's 1,000% better than it was and it's still pretty quite in carrier squelch. Do you think the loose connector and/or grounding could have helped or is this some sort of cruel coincidence?
Re: [Repeater-Builder] Re: Intermod Calculation
Possibly. Wiggle the connectors while looking at the cavity on a spectrum analyzer and if the peaks and dips change significantly that's probably the problem. The one I had the solder kinda looked like it was sprayed out of one joint at the top of the can, and there was a lot of flux around the joint. On Wed, Aug 25, 2010 at 2:17 PM, Tim Sawyer tisaw...@gmail.com wrote: By the way, the Wacom model number is WP-430-2. -- Tim :wq Begin forwarded message: * * *To: *repeater-buil...@yahoogroups.com *Subject: **Re: [Repeater-Builder] Re: Intermod Calculation* This is a couple of pass cavities, not a duplexer. Do the band pass cavities have the same problem? -- Tim :wq On Aug 25, 2010, at 1:32 PM, DCFluX wrote: I've seen this before on Wacom BpBr duplexers. Remove the coupling loop from the cavity and re-solder the connectors. Use 2% silver bearing solder if you can find it. On Wed, Aug 25, 2010 at 1:27 PM, Tim Sawyer tisaw...@gmail.com wrote: Here's the latest: We went up to our site yesterday. We added a lighting arrestor to the receive antenna. We grounded the chassis/rail/cabinet as it was only grounded via the power cord previously. Didn't expect this to fix the paging problem, it just needed to be done. I did find a loose UHF connector on the Wacom. This is a two cavity BP filter on the receive side. I don't know if the loose connector was the problem but it's much cleaner now. We ran in carrier squelch for about an hour and didn't hear much of anything. A dramatic improvement and amazing for our dirty hill. Today there have been a couple of pages bust through the P/L but it's 1,000% better than it was and it's still pretty quite in carrier squelch. Do you think the loose connector and/or grounding could have helped or is this some sort of cruel coincidence?
Re: [Repeater-Builder] Re: Intermod Calculation
Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links
RE: [Repeater-Builder] Re: Intermod Calculation
I was just wondering. Sounds like something we had going on here in middle Georgia. Good luck es 73, Mike WM4B _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Saturday, August 21, 2010 12:43 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation I'm in Huntington Beach. -- Tim :wq On Aug 20, 2010, at 8:52 PM, Mike Besemer (WM4B) wrote: Tim, Where are you located? 73, Mike WM4B _ From: mailto:Repeater-Builder@yahoogroups.com Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 11:49 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation No, I never, ever have heard any other audio. But there is time when I don't hear it at all... as if it takes two signals to occur. -- Tim :wq On Aug 20, 2010, at 7:46 PM, MCH wrote: Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com http://www.avg.com/ Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links
RE: [Repeater-Builder] Re: Intermod Calculation
What about hot vs. cold days and sunny vs. cloudy? We'd see our problem on hot days pretty much all the time. Cool and cloudy (or cold) days were quiet. Cool days with full sun usually caused the problem to occur. You could almost set your watch by it. 73, Mike WM4B _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Saturday, August 21, 2010 9:37 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net mailto:mch%40nb.net To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links
Re: [Repeater-Builder] Re: Intermod Calculation
Again, just like a spur. Does it have a 'grungy' sound to it when you hear it on your input? Might also be worth putting the Spectrum Analyzer on your input to see if you can see it drifting through the frequency - or drifting onto it. Joe M. Tim Sawyer wrote: Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links Yahoo! Groups Links Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00
Re: [Repeater-Builder] Re: Intermod Calculation
I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input?
Re: [Repeater-Builder] Re: Intermod Calculation
I'm looking at the pager freq with the SA. The dev looks wide to me. I see about 15 Khz peak to peak. Is that normal? Also I see much bigger spikes. -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Again, just like a spur. Does it have a 'grungy' sound to it when you hear it on your input? Might also be worth putting the Spectrum Analyzer on your input to see if you can see it drifting through the frequency - or drifting onto it. Joe M. Tim Sawyer wrote: Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links Yahoo! Groups Links -- Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00
Re: [Repeater-Builder] Re: Intermod Calculation
Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. Does the repeater run CTCSS on the input? If so, is the behavior the same if CTCSS is off? (CTCSS might clip the signal off at one end or the other, even though the receiver is hearing the whole thing) Can you hear the signal using a completely different receiver on the same frequency at the site? (Preferably one that uses a different first IF frequency, tests to see if it is getting into the IF or if the intermod product is an image rather than the actual receive frequency) Does it happen out of the blue with the repeater inactive, or only when the repeater has been in-use? (Tests to see if the repeater transmitter is part of the mix) Does the paging sound exactly the same, or might you be hearing a link transmitter? (many are on 72 MHz, exactly half your input frequency) Matthew Kaufman Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: repeater-builder-dig...@yahoogroups.com repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Intermod Calculation
Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input?
Re: [Repeater-Builder] Re: Intermod Calculation
Yes the repeater has CTCSS but I turn it off for testing. When on the CTCSS will false but that's not what I'm talking about when I say that the repeater sometimes keys up after the beginning of the page. I'm going to take another repeater which has a different 1st IF up and test with just as you suggest. It's a VXR-5000 with a 1st IF of 21.6 Mhz and a 2nd IF of 455. The current repeater (a Micor) has a 11.7 IF and is single conversion. Yes, it happens out of the blue. I'm confident that the repeater TX is not part of the mix. The paging does sound a bit different. I've been think that's due to the wide dev (15 Khz plus) and that different receivers would hear that differently. I talked to the tech and he told me the system has a satellite feed. He also told me the same feed goes to their transmitter on 929.0375 Mhz. Basically, there is one controller for both the 929.0375 and the 157.74 transmitters. They also have two other transmitters on 929.6375 and 931.6625. -- Tim :wq On Aug 21, 2010, at 9:18 AM, Matthew Kaufman wrote: Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. Does the repeater run CTCSS on the input? If so, is the behavior the same if CTCSS is off? (CTCSS might clip the signal off at one end or the other, even though the receiver is hearing the whole thing) Can you hear the signal using a completely different receiver on the same frequency at the site? (Preferably one that uses a different first IF frequency, tests to see if it is getting into the IF or if the intermod product is an image rather than the actual receive frequency) Does it happen out of the blue with the repeater inactive, or only when the repeater has been in-use? (Tests to see if the repeater transmitter is part of the mix) Does the paging sound exactly the same, or might you be hearing a link transmitter? (many are on 72 MHz, exactly half your input frequency) Matthew Kaufman Yahoo! Groups Links
Re: [Repeater-Builder] Re: Intermod Calculation
I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input?
RE: [Repeater-Builder] Re: Intermod Calculation
The deviation is 15 kHz, or you're seeing 15 kHz of bandwidth on the spectrum analyzer? The latter would be normal, the former wouldn't be. -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Saturday, August 21, 2010 1:33 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input?
Re: [Repeater-Builder] Re: Intermod Calculation
Tim, Digital paging (mostly POCSAG coding these days) is FSK and will easily occupy 15KHz of bandwidth. On a Service Monitor deviation screen you will see a square wave pattern that looks like it is overdeviated unless you are very close to the transmitter in question. Read on and you will see why a deviation measurement is of little use. On a Spectrum Analyser you will see a single spike that jumps back and forth between a freq higher than the channel center and a freq lower than the channel center. The typical digital paging transmitter settings are +4KHz above the assigned freq and - 4KHz below the assigned freq. If the system uses multiple transmitters the + and - settings may be asymmetrical to allow for slight offsets between transmitters. As demodulated at the paging receiver the signal is a 1200 baud pattern of square waves. Newer systems such as FLEX may have two levels of + and - with settings of say +4K +2K -2K and -4K. If the problem is the digital paging transmitter you need to determine how close the transmitter is to your installation. Paging receivers represent a compromised antenna system and most paging transmitters compensate for the shortcomings of the receiver by sending at very high power levels. If the paging transmitter is close to you, it might be meeting spec but the low level grundge could be causing you problems. Milt N3LTQ Quoting Tim Sawyer tisaw...@gmail.com: I'm looking at the pager freq with the SA. The dev looks wide to me. I see about 15 Khz peak to peak. Is that normal? Also I see much bigger spikes. -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Again, just like a spur. Does it have a 'grungy' sound to it when you hear it on your input? Might also be worth putting the Spectrum Analyzer on your input to see if you can see it drifting through the frequency - or drifting onto it. Joe M. Tim Sawyer wrote: Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way
Re: [Repeater-Builder] Re: Intermod Calculation
Before you said 15 kHz P-P (IOW bandwidth). Now you're saying 15 kHz deviation. 15 kHz deviation would be way too high. Joe M. Tim Sawyer wrote: I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input? Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00
Re: [Repeater-Builder] Re: Intermod Calculation
The deviation is 15 Khz. -- Tim :wq On Aug 21, 2010, at 10:52 AM, Jeff DePolo wrote: The deviation is 15 kHz, or you're seeing 15 kHz of bandwidth on the spectrum analyzer? The latter would be normal, the former wouldn't be. -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Saturday, August 21, 2010 1:33 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input?
Re: [Repeater-Builder] Re: Intermod Calculation
My service monitor (HP 8924C) has both a deviation meter and an oscilloscope to display the demodulated audio. Both the numbers on the dev meter and the peak to peak on the scope read about 15 Khz. I see another paging system (152.84) that shows the same 15 Khz dev, and a bunch of other ones that show 5 Khz dev. -- Tim :wq On Aug 21, 2010, at 12:18 PM, MCH wrote: Before you said 15 kHz P-P (IOW bandwidth). Now you're saying 15 kHz deviation. 15 kHz deviation would be way too high. Joe M. Tim Sawyer wrote: I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input? -- Internal Virus Database is out of date. Checked by AVG - www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00
Re: [Repeater-Builder] Re: Intermod Calculation
I have noticed the carrier appears to jump between +4 and -4 Khz of center. The transmitter is about 75 yards from me. It's running 225 watts according to the tech. The interference is pretty strong. It competes with my base station on low power. I'm 25 miles from the repeater. -- Tim :wq On Aug 21, 2010, at 11:25 AM, men...@pa.net wrote: Tim, Digital paging (mostly POCSAG coding these days) is FSK and will easily occupy 15KHz of bandwidth. On a Service Monitor deviation screen you will see a square wave pattern that looks like it is overdeviated unless you are very close to the transmitter in question. Read on and you will see why a deviation measurement is of little use. On a Spectrum Analyser you will see a single spike that jumps back and forth between a freq higher than the channel center and a freq lower than the channel center. The typical digital paging transmitter settings are +4KHz above the assigned freq and - 4KHz below the assigned freq. If the system uses multiple transmitters the + and - settings may be asymmetrical to allow for slight offsets between transmitters. As demodulated at the paging receiver the signal is a 1200 baud pattern of square waves. Newer systems such as FLEX may have two levels of + and - with settings of say +4K +2K -2K and -4K. If the problem is the digital paging transmitter you need to determine how close the transmitter is to your installation. Paging receivers represent a compromised antenna system and most paging transmitters compensate for the shortcomings of the receiver by sending at very high power levels. If the paging transmitter is close to you, it might be meeting spec but the low level grundge could be causing you problems. Milt N3LTQ Quoting Tim Sawyer tisaw...@gmail.com: I'm looking at the pager freq with the SA. The dev looks wide to me. I see about 15 Khz peak to peak. Is that normal? Also I see much bigger spikes. -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Again, just like a spur. Does it have a 'grungy' sound to it when you hear it on your input? Might also be worth putting the Spectrum Analyzer on your input to see if you can see it drifting through the frequency - or drifting onto it. Joe M. Tim Sawyer wrote: Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater
Re: [Repeater-Builder] Re: Intermod Calculation
There is something wrong with your SM, then, as it should not show a deviation of 15 kHz on a signal that is 15 kHz P-P unless it's only deviating in one direction from the carrier. The +/- 4 kHz sounds about right. But, it should be centered around the carrier frequency of 157.740 (Or, on 157.736 and 157.744). It would also equate to a P-P of about 8 kHz as there is nothing but a shifted carrier involved. Regardless, I suspect none of this relates to your problem. If it's only 75 yards from you, I bet it's a very weak spur. It's likely down far enough that it's legal, too. If that is the case, the only thing that will solve it is putting a filter on its TX to notch your repeater RX frequency (good luck getting that to happen if it's not on the same site - and often if it is on the same site). Joe M. Tim Sawyer wrote: My service monitor (HP 8924C) has both a deviation meter and an oscilloscope to display the demodulated audio. Both the numbers on the dev meter and the peak to peak on the scope read about 15 Khz. I see another paging system (152.84) that shows the same 15 Khz dev, and a bunch of other ones that show 5 Khz dev. -- Tim :wq On Aug 21, 2010, at 12:18 PM, MCH wrote: Before you said 15 kHz P-P (IOW bandwidth). Now you're saying 15 kHz deviation. 15 kHz deviation would be way too high. Joe M. Tim Sawyer wrote: I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input? -- Internal Virus Database is out of date. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: repeater-builder-dig...@yahoogroups.com repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Intermod Calculation
You might be able to get the paging company to swap out the transmitter or at least the PA. That may solve the problem, too. Or, if you can show them the interference, and they are sympathetic, they may fix it. One bright side: Paging companies are going the way of the dinosaur, so it may not be on the air much longer. There used to be a couple dozen paging companies in my area. Now there are 5 or 6 left - mostly on UHF/900. Joe M. Tim Sawyer wrote: I have noticed the carrier appears to jump between +4 and -4 Khz of center. The transmitter is about 75 yards from me. It's running 225 watts according to the tech. The interference is pretty strong. It competes with my base station on low power. I'm 25 miles from the repeater. -- Tim :wq On Aug 21, 2010, at 11:25 AM, men...@pa.net mailto:men...@pa.net wrote: Tim, Digital paging (mostly POCSAG coding these days) is FSK and will easily occupy 15KHz of bandwidth. On a Service Monitor deviation screen you will see a square wave pattern that looks like it is overdeviated unless you are very close to the transmitter in question. Read on and you will see why a deviation measurement is of little use. On a Spectrum Analyser you will see a single spike that jumps back and forth between a freq higher than the channel center and a freq lower than the channel center. The typical digital paging transmitter settings are +4KHz above the assigned freq and - 4KHz below the assigned freq. If the system uses multiple transmitters the + and - settings may be asymmetrical to allow for slight offsets between transmitters. As demodulated at the paging receiver the signal is a 1200 baud pattern of square waves. Newer systems such as FLEX may have two levels of + and - with settings of say +4K +2K -2K and -4K. If the problem is the digital paging transmitter you need to determine how close the transmitter is to your installation. Paging receivers represent a compromised antenna system and most paging transmitters compensate for the shortcomings of the receiver by sending at very high power levels. If the paging transmitter is close to you, it might be meeting spec but the low level grundge could be causing you problems. Milt N3LTQ Quoting Tim Sawyer tisaw...@gmail.com mailto:tisawyer%40gmail.com: I'm looking at the pager freq with the SA. The dev looks wide to me. I see about 15 Khz peak to peak. Is that normal? Also I see much bigger spikes. -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Again, just like a spur. Does it have a 'grungy' sound to it when you hear it on your input? Might also be worth putting the Spectrum Analyzer on your input to see if you can see it drifting through the frequency - or drifting onto it. Joe M. Tim Sawyer wrote: Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net mailto:mch%40nb.net To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed
Re: [Repeater-Builder] Re: Intermod Calculation
The meter reads P-P just like the scope. I generally set dev with the meter and confirm it on the scope. But your right, this really doesn't matter. I was just making sure they didn't have the dev out of wack and from what I gather here they don't. We're going up Tuesday with another repeater and the 8924c to check it out. I'll be looking to see what comes down the antenna. If there are no big signals that shouldn't be there, and we can see/hear the paging on channel, and I there is no activity on 151.14 (actually 151.145 is San Bernardino County) or 170.94 (ULS FCC DB shows nothing) then I'll assume it's a spur. I have talked to the tech and he was friendly. I'm going to contact him again and see if he will come up the hill with us and inspect his transmitter. -- Tim :wq On Aug 21, 2010, at 12:59 PM, MCH wrote: There is something wrong with your SM, then, as it should not show a deviation of 15 kHz on a signal that is 15 kHz P-P unless it's only deviating in one direction from the carrier. The +/- 4 kHz sounds about right. But, it should be centered around the carrier frequency of 157.740 (Or, on 157.736 and 157.744). It would also equate to a P-P of about 8 kHz as there is nothing but a shifted carrier involved. Regardless, I suspect none of this relates to your problem. If it's only 75 yards from you, I bet it's a very weak spur. It's likely down far enough that it's legal, too. If that is the case, the only thing that will solve it is putting a filter on its TX to notch your repeater RX frequency (good luck getting that to happen if it's not on the same site - and often if it is on the same site). Joe M. Tim Sawyer wrote: My service monitor (HP 8924C) has both a deviation meter and an oscilloscope to display the demodulated audio. Both the numbers on the dev meter and the peak to peak on the scope read about 15 Khz. I see another paging system (152.84) that shows the same 15 Khz dev, and a bunch of other ones that show 5 Khz dev. -- Tim :wq On Aug 21, 2010, at 12:18 PM, MCH wrote: Before you said 15 kHz P-P (IOW bandwidth). Now you're saying 15 kHz deviation. 15 kHz deviation would be way too high. Joe M. Tim Sawyer wrote: I haven't noticed a hum. There's more of a scream on it. It's POCSAG. Is that analog? The dev is basically 15 Khz but there is, what I going to call splatter that is like 30 Khz. -- Tim :wq On Aug 21, 2010, at 10:14 AM, MCH wrote: Many times (but not all), there will be a grungy sound with the spur. Think of a very loud 60 cycle hum. And 15 kHz is higher than normal. I think the typical shift is 5 kHz (+/- 2.5 kHz) if we are talking about digital paging. Analog might be 15 kHz, as the bandwidth limit would be 16 kHz. Joe M. Tim Sawyer wrote: I'm not sure what you mean by grungy. What are you getting at? -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Does it have a 'grungy' sound to it when you hear it on your input? -- Internal Virus Database is out of date. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.783 / Virus Database: 271.1.1/2746 - Release Date: 03/14/10 03:33:00 Yahoo! Groups Links
Re: [Repeater-Builder] Re: Intermod Calculation
Apparently, from what the tech said, this one is slated to go off the air in coming months, too. But I can't wait that long as our repeater is basically useless at this point. And you never know, it might take them longer than that to actually kill it. -- Tim :wq On Aug 21, 2010, at 1:02 PM, MCH wrote: One bright side: Paging companies are going the way of the dinosaur, so it may not be on the air much longer. There used to be a couple dozen paging companies in my area. Now there are 5 or 6 left - mostly on UHF/900.
Re: [Repeater-Builder] Re: Intermod Calculation
How long has the pager been in operation? If it has been there for a long time either something changed in the pager setup or something changed on your end. What you have is a case of RF overload. No other frequencies are involved, not even your own transmitter. 225 watts RF + how much antenna gain on the pager end or is that the total ERP of the pager? What is the difference in vertical height between the pager transmit antenna and your repeater antenna? What sort of filtering are you using? Duplexer? Dual antennas? The HP8924 in the Spectrum Analyser mode will show you the transmitted frequency shifting between the upper and lower limits. The deviation measurement will be useless since you are not measuring deviation of an analog signal. Setting up a digital paging transmitter usually involves activating a test mode which will place the unmodulated TX signal at the the limits. The adjustment is made to set the amount of shift from the center channel according to the enginnering for the system. When the incoming signal from the paging terminal is received it causes the transmitter to shift to one of the two limits which can be thought of as a 1 or a 0. Ironically the systems I saw usually used AFSK on the link from the paging terminal (modem to modem). If there is more than one transmitter involved measuring off the air cannot give you an accurate deviation measurement since any hetrodyne between the two or more carriers will also be seen by the service monitor and will distort the measurement. Milt N3LTQ Quoting Tim Sawyer tisaw...@gmail.com: I have noticed the carrier appears to jump between +4 and -4 Khz of center. The transmitter is about 75 yards from me. It's running 225 watts according to the tech. The interference is pretty strong. It competes with my base station on low power. I'm 25 miles from the repeater. -- Tim :wq On Aug 21, 2010, at 11:25 AM, men...@pa.net wrote: Tim, Digital paging (mostly POCSAG coding these days) is FSK and will easily occupy 15KHz of bandwidth. On a Service Monitor deviation screen you will see a square wave pattern that looks like it is overdeviated unless you are very close to the transmitter in question. Read on and you will see why a deviation measurement is of little use. On a Spectrum Analyser you will see a single spike that jumps back and forth between a freq higher than the channel center and a freq lower than the channel center. The typical digital paging transmitter settings are +4KHz above the assigned freq and - 4KHz below the assigned freq. If the system uses multiple transmitters the + and - settings may be asymmetrical to allow for slight offsets between transmitters. As demodulated at the paging receiver the signal is a 1200 baud pattern of square waves. Newer systems such as FLEX may have two levels of + and - with settings of say +4K +2K -2K and -4K. If the problem is the digital paging transmitter you need to determine how close the transmitter is to your installation. Paging receivers represent a compromised antenna system and most paging transmitters compensate for the shortcomings of the receiver by sending at very high power levels. If the paging transmitter is close to you, it might be meeting spec but the low level grundge could be causing you problems. Milt N3LTQ Quoting Tim Sawyer tisaw...@gmail.com: I'm looking at the pager freq with the SA. The dev looks wide to me. I see about 15 Khz peak to peak. Is that normal? Also I see much bigger spikes. -- Tim :wq On Aug 21, 2010, at 6:59 AM, MCH wrote: Again, just like a spur. Does it have a 'grungy' sound to it when you hear it on your input? Might also be worth putting the Spectrum Analyzer on your input to see if you can see it drifting through the frequency - or drifting onto it. Joe M. Tim Sawyer wrote: Another tidbit about this problem is that it's clean in the mornings. The paging transmitter can be going off like crazy and the repeater will be totally clean in carrier squelch. As the day progresses it gets worse. -- Tim :wq On Aug 20, 2010, at 7:51 PM, Chuck Kelsey wrote: I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq
Re: [Repeater-Builder] Re: Intermod Calculation
If that was the issue I'd think every other two meter repeater on the hill (and there are many) would have the my same problem. But they don't. -- Tim :wq On Aug 21, 2010, at 7:27 PM, larynl2 wrote: --- In Repeater-Builder@yahoogroups.com, Tim Sawyer tisaw...@... wrote: Basically, there is one controller for both the 929.0375 and the 157.74 transmitters. They also have two other transmitters on 929.6375 and 931.6625. Are the 929.0375 and 929.6375 transmitters at the same site as your repeater? I'm seeing 600 kc. difference there... Laryn K8TVZ
Re: [Repeater-Builder] Re: Intermod Calculation
On Aug 21, 2010, at 6:38 PM, men...@pa.net wrote: How long has the pager been in operation? If it has been there for a long time either something changed in the pager setup or something changed on your end. We've been having many problems at the site (including a broken tower cross arm, now fixed) for a while now and lots of things have been changing. I'm aware that it could be our problem as likely as theirs. We've been up there for 30 years, don't know how long they have been there, certianly longer than this problem. What you have is a case of RF overload. No other frequencies are involved, not even your own transmitter. I'm thinking spurious pager TX , not our RX overload at this point. But I'm going to go have a look at things. 225 watts RF + how much antenna gain on the pager end or is that the total ERP of the pager? That's power out of the transmitter. I think they are allowed 999 watts ERP but I don't know what theirs is. What is the difference in vertical height between the pager transmit antenna and your repeater antenna? Our antenna is a little higher and about 75 yards away. What sort of filtering are you using? Duplexer? Dual antennas? Split TX/RX antennas about 40 feet apart with near straight vertical separation. Six cavity BP/BR duplexer plus two bottle Wacom filter on the RX. TX has a 3 pole circulator and low pass filter. The HP8924 in the Spectrum Analyser mode will show you the transmitted frequency shifting between the upper and lower limits. The deviation measurement will be useless since you are not measuring deviation of an analog signal. Setting up a digital paging transmitter usually involves activating a test mode which will place the unmodulated TX signal at the the limits. The adjustment is made to set the amount of shift from the center channel according to the enginnering for the system. When the incoming signal from the paging terminal is received it causes the transmitter to shift to one of the two limits which can be thought of as a 1 or a 0. Ironically the systems I saw usually used AFSK on the link from the paging terminal (modem to modem). Yea, ok. I'm not that familiar with what these paging systems look like on the SA. It looked odd to me. But the consensus here seems to be that dev is ok. I did see another paging system with this same looking modulation. If there is more than one transmitter involved measuring off the air cannot give you an accurate deviation measurement since any hetrodyne between the two or more carriers will also be seen by the service monitor and will distort the measurement. They do have more than 1 transmitter. I can't tell for sure if I can hear more than one. It's possible.
Re: [Repeater-Builder] Re: Intermod Calculation
Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00
Re: [Repeater-Builder] Re: Intermod Calculation
It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00
Re: [Repeater-Builder] Re: Intermod Calculation
Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: repeater-builder-dig...@yahoogroups.com repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Intermod Calculation
I agree, if you don't hear anything else in the mix, and it pretty much happens for the full length of the page, it's likely a spur on the paging transmitter, at least that's what I'd be looking at. Chuck WB2EDV - Original Message - From: MCH m...@nb.net To: Repeater-Builder@yahoogroups.com Sent: Friday, August 20, 2010 10:46 PM Subject: Re: [Repeater-Builder] Re: Intermod Calculation Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: repeater-builder-dig...@yahoogroups.com repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Re: Intermod Calculation
No, I never, ever have heard any other audio. But there is time when I don't hear it at all... as if it takes two signals to occur. -- Tim :wq On Aug 20, 2010, at 7:46 PM, MCH wrote: Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links
RE: [Repeater-Builder] Re: Intermod Calculation
Tim, Where are you located? 73, Mike WM4B _ From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 11:49 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation No, I never, ever have heard any other audio. But there is time when I don't hear it at all... as if it takes two signals to occur. -- Tim :wq On Aug 20, 2010, at 7:46 PM, MCH wrote: Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links
Re: [Repeater-Builder] Re: Intermod Calculation
I'm in Huntington Beach. -- Tim :wq On Aug 20, 2010, at 8:52 PM, Mike Besemer (WM4B) wrote: Tim, Where are you located? 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 11:49 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Re: Intermod Calculation No, I never, ever have heard any other audio. But there is time when I don't hear it at all... as if it takes two signals to occur. -- Tim :wq On Aug 20, 2010, at 7:46 PM, MCH wrote: Could be a spur. Can you hear any other audio with the page? (ever) Joe M. Tim Sawyer wrote: It seems to pick up most of the page. Occasionally the beginning is missing or it will get just the very end. It always seems to drop at the same time as the page. -- Tim :wq On Aug 20, 2010, at 4:38 PM, Chuck Kelsey wrote: Does the entire page happen, or does it abruptly stop part way through some of the time? Partial page would indicate to me that another transmitter is in the mix and dropping before the pager does. However, I had a situation where there were four paging sites scattered in the county on the same frequency and one of the transmitters was spurious and getting into my receiver. In that case, I always heard the entire page, but only when that particular transmitter came up. Chuck WB2EDV - Original Message - From: Tim - WD6AWP tisaw...@gmail.com mailto:tisawyer%40gmail.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, August 20, 2010 7:27 PM Subject: [Repeater-Builder] Re: Intermod Calculation It occurs whether or not the repeater transmitter is keyed. --- In Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com, Jeff DePolo j...@... wrote: Before we get into the math, an important question that needs to be answered is whether or not this mix occurs when your repeater transmitter is unkeyed. --- Jeff WN3A -Original Message- From: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com [mailto:Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com] On Behalf Of Tim Sawyer Sent: Friday, August 20, 2010 6:36 PM To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: [Repeater-Builder] Intermod Calculation I have paging intermod from 157.740 Mhz. My receiver is on 144.540 Mhz. I'm 100% sure there is another transmitter involved in the mix because sometimes the pager is transmitting and I have no interference. I have an intermod calculator program but it wants all the known transmitters and the target receiver. But I need to solve for an unknown transmitter. Is there a way to calculate the other possible soruce(s)? -- Tim :wq Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com http://www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3084 - Release Date: 08/20/10 14:35:00 Yahoo! Groups Links