Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Hey I think I'll have mine for Christmas, along with mashed potatoes and Gravy GD ! BTW my initials are MAH reverse HAM !! I guess I am a Ham I am ! Keep on smiling !! Mark Holman AB8RU *** IT Student * Happy Holidays - Original Message - From: mch [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Tuesday, December 21, 2004 1:00 AM Subject: Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters Maybe it's like a Grade A Ham? ;- Joe M. JOHN MACKEY wrote: Hmmm, after 20 years of ham radio, past experience in commercial 2 way currently working as an Chief Engineer in the radio broadcast field and possessing my Extra Amateur and GROL, I don't know what a FCC 1st class licensed ham is!! -- Original Message -- Received: Mon, 20 Dec 2004 10:54:16 PM CST From: kc4ih [EMAIL PROTECTED] with to the repeater frequencies by FCC 1st class licensed hams -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.296 / Virus Database: 265.6.0 - Release Date: 12/17/2004 Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
At 12/20/2004 08:35 PM, you wrote: We have 146.04/.64 repeater on a nearby mountain top. It worked great for years with a range of 100 miles or more. Since the phone company and a pager company installed their high power transmitters near the site of the repeater (within 100 yards) the repeater is virtually useless. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. The equipment that we are using is excellent. The transmitter and receiver on the repeater are both Motorola Micor and were modified with to the repeater frequencies by FCC 1st class licensed hams using Motorola parts. This is not an equipment problem. We are running a set of Wacom cavities which were bought new and are correctly tuned and the antenna is a Phelps-Dodge Stationmaster. When the intermod occurs it is dependant on BOTH pagers transmitting at the same time. If only one pager is transmitting there is no problem. This may at first sound unusual but the pagers are in the 150 mhz band and they are exactly 600 kc apart. These transmitter are both 250 watts or more output. I've dealt with similar problems involving two VHF HB TXs that were 5 MHz apart. They mixed with every 5 MHz split UHF repeater at the site to convert the output to input (A+B-C mix). At first one of the VHF TXs was in another building a few hundred feet away, at that time the interference was just a few dB above the noise floor only present after long periods of dry weather. But then that TX moved into the same building as the other VHF TX our repeaters. That caused it to be present all the time much stronger. I tried DFing the actual source of the interfering signal(s). Sometimes they came from a tower joint, other times it was from an air conditioning unit, then another spot on the tower a minute later. It just came from everywhere. The site manager tried painting all the suspect tower joints (which had no signs of rust or corrosion - this was a fairly new tower) with some sort of metallic paint. This more or less cured the problem for about 2 months, then it came back until it rained or the joints were painted again. The problem finally went away when one of the TXs (a 25 watt paging TX) went off the air. Bottom line is that short of getting one of the TXs involved in the mix to move, there is no good solution. Remoting your TX to another location is probably the best bet. You can always run more power if the alternate location offers less coverage, but you can't make up the difference in RX if you put your RX there instead. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. An odd-split will solve the problem but should only be a last resort, as opposed to going off the air completely. Among other disadvantages, it makes your repeater harder to find by travelers not familiar with your bandplan. Your coordinator may resist the idea, particularly if there are no odd-split repeater pairs currently in your bandplan. However, it's up to the coordinator to accomodate you the best they can given their current activity levels, channel loading your own technical constraints. Refusing to consider odd-splits on the basis of we don't have any don't want them or they're not in the ARRL bandplan is not a valid reason. Bob NO6B Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
We have 146.04/.64 repeater on a nearby mountain top. It worked great for years with a range of 100 miles or more. Since the phone company and a pager company installed their high power transmitters near the site of the repeater (within 100 yards) the repeater is virtually useless. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. The equipment that we are using is excellent. The transmitter and receiver on the repeater are both Motorola Micor and were modified with to the repeater frequencies by FCC 1st class licensed hams using Motorola parts. This is not an equipment problem. We are running a set of Wacom cavities which were bought new and are correctly tuned and the antenna is a Phelps-Dodge Stationmaster. When the intermod occurs it is dependant on BOTH pagers transmitting at the same time. If only one pager is transmitting there is no problem. This may at first sound unusual but the pagers are in the 150 mhz band and they are exactly 600 kc apart. These transmitter are both 250 watts or more output. My theory is that the 600 kc (difference of the 2 pagers) is mixing with the output of the repeater 146.64 and producing the 146.04 signal, the repeater input frequency. We are using sub-audible tone for repeater access and as soon as a station working the repeater drops carrier the repeater drops. The intermod cannot hold up the machine once the tone is removed. This may be happening in the antenna or hardline connectors prior to the cavities. Every test I have run, and there have been many, supports this conclusion. We are not the only 2 meter repeater that has fallen victim of this problem and in every case we have found two pager transmitters situated 600 kc apart near the repeater. Most of the other machines have been taken off the air, others just put up with it. No one has been able to solve the problem and many technicians have studied it. Moving the repeater far enough away is not an option since the peak of the mountain is so small. Also we are using an existing tower which we would not have access to at other locations. The searches I have done on Google has turned up the stock answer of helical resonators which would apply to 2 meter radios but not repeaters. If you are familiar with the Micor equipment you know that the receiver has excellent helical resonators built in. Tonight I have considered the possibility of splitting the receiver and the transmitter of the repeater and linking the rx signal by a 220 mhz link. I am hoping that by reducing the level of the 146.64 signal by 50-60 db would alleviate the problem. Maybe not, but I'm out of ideas. This split would be only about 100 yards but could that be sufficient to relieve the problem? Have any of you ever had this problem and solved it? Any input (pun intended) on this matter would be appreciated. Ken Sturgill, KC4IH Marion VA please reply to ([EMAIL PROTECTED]) Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
-- Original Message -- Received: Mon, 20 Dec 2004 10:54:16 PM CST From: kc4ih [EMAIL PROTECTED] SNIP virtually useless. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. In my area I had to eventually say the hell with the repeater coordinator! and put up a 2 meter repeater with a non-600 split to deal with the problem I had. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Ken the problem is not your equipment but simply a problem with the commercial pagers. Paging Xmiters are know for there sloppy transmissions. If you have access to a spectrum analyzer that is well calibrated go to the site and check their transmissions for bandwidth and see if they are within regs. If they are, and if your repeater is used for Civil Defense purposes I would file a notice of interferance against them with the FCC Field Office. If all that fails then screw the repeater co-ordinator and change your split. Mike/K1EG - Original Message - From: kc4ih [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Sent: Monday, December 20, 2004 10:35 PM Subject: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters We have 146.04/.64 repeater on a nearby mountain top. It worked great for years with a range of 100 miles or more. Since the phone company and a pager company installed their high power transmitters near the site of the repeater (within 100 yards) the repeater is virtually useless. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. The equipment that we are using is excellent. The transmitter and receiver on the repeater are both Motorola Micor and were modified with to the repeater frequencies by FCC 1st class licensed hams using Motorola parts. This is not an equipment problem. We are running a set of Wacom cavities which were bought new and are correctly tuned and the antenna is a Phelps-Dodge Stationmaster. When the intermod occurs it is dependant on BOTH pagers transmitting at the same time. If only one pager is transmitting there is no problem. This may at first sound unusual but the pagers are in the 150 mhz band and they are exactly 600 kc apart. These transmitter are both 250 watts or more output. My theory is that the 600 kc (difference of the 2 pagers) is mixing with the output of the repeater 146.64 and producing the 146.04 signal, the repeater input frequency. We are using sub-audible tone for repeater access and as soon as a station working the repeater drops carrier the repeater drops. The intermod cannot hold up the machine once the tone is removed. This may be happening in the antenna or hardline connectors prior to the cavities. Every test I have run, and there have been many, supports this conclusion. We are not the only 2 meter repeater that has fallen victim of this problem and in every case we have found two pager transmitters situated 600 kc apart near the repeater. Most of the other machines have been taken off the air, others just put up with it. No one has been able to solve the problem and many technicians have studied it. Moving the repeater far enough away is not an option since the peak of the mountain is so small. Also we are using an existing tower which we would not have access to at other locations. The searches I have done on Google has turned up the stock answer of helical resonators which would apply to 2 meter radios but not repeaters. If you are familiar with the Micor equipment you know that the receiver has excellent helical resonators built in. Tonight I have considered the possibility of splitting the receiver and the transmitter of the repeater and linking the rx signal by a 220 mhz link. I am hoping that by reducing the level of the 146.64 signal by 50-60 db would alleviate the problem. Maybe not, but I'm out of ideas. This split would be only about 100 yards but could that be sufficient to relieve the problem? Have any of you ever had this problem and solved it? Any input (pun intended) on this matter would be appreciated. Ken Sturgill, KC4IH Marion VA please reply to ([EMAIL PROTECTED]) Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Hmmm, after 20 years of ham radio, past experience in commercial 2 way currently working as an Chief Engineer in the radio broadcast field and possessing my Extra Amateur and GROL, I don't know what a FCC 1st class licensed ham is!! -- Original Message -- Received: Mon, 20 Dec 2004 10:54:16 PM CST From: kc4ih [EMAIL PROTECTED] with to the repeater frequencies by FCC 1st class licensed hams Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
And pray you don't cause interference with any other repeaters. Joe M. [EMAIL PROTECTED] wrote: If all that fails then screw the repeater co-ordinator and change your split. -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.296 / Virus Database: 265.6.0 - Release Date: 12/17/2004 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Ken, Please advise exactly what frequencies these pager transmitters are operating on. There are a number of possibilities for intermod, but knowing the offending frequencies is crucial to a solution. Less than a mile from my home station, there is a hilltop site at which two high-power (3,500 watts ERP) paging transmitters operate. One is at 152.480 MHz and the other is at 157.740 MHz. A classic third-order intermodulation (2A-B) occurs when both are keyed up, resulting in a product at 147.220 MHz, which nearly clobbers my reception of the K6SYV repeater at 147.210 MHz. This is receive IM, where the mixing occurs in my own receiver due to a wide bandwidth in the front end. I cured this by changing to a Motorola CDM1550 radio, which has a very tight front end that tracks the desired receive frequency. You did not state whether the interference is on your repeater's input or output, and corrective action will be different for the two. Moreover, without having all of the pertinent information, it is almost impossible to consider a solution. Please provide a complete description of the symptoms. Part of the problem (but not necessarily the prime cause) may be due to insufficient selectivity in the front end of your repeater. The majority of bandpass/bandreject duplexers have practically no bandpass action; their operation depends primarily upon the notch action. A lot of undesirable signal can sail right through the receive side of such duplexers, ready to overload the RF input stage. In such cases, the solution is to add two or three bandpass cavities between the duplexer and the receiver. But, please provide the necessary information so that others who read this list can study the problem and recommend solutions. Who knows, the solution may be the responsibility of one or both pager operators. 73, Eric Lemmon WB6FLY kc4ih wrote: We have 146.04/.64 repeater on a nearby mountain top. It worked great for years with a range of 100 miles or more. Since the phone company and a pager company installed their high power transmitters near the site of the repeater (within 100 yards) the repeater is virtually useless. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. The equipment that we are using is excellent. The transmitter and receiver on the repeater are both Motorola Micor and were modified with to the repeater frequencies by FCC 1st class licensed hams using Motorola parts. This is not an equipment problem. We are running a set of Wacom cavities which were bought new and are correctly tuned and the antenna is a Phelps-Dodge Stationmaster. When the intermod occurs it is dependant on BOTH pagers transmitting at the same time. If only one pager is transmitting there is no problem. This may at first sound unusual but the pagers are in the 150 mhz band and they are exactly 600 kc apart. These transmitter are both 250 watts or more output. My theory is that the 600 kc (difference of the 2 pagers) is mixing with the output of the repeater 146.64 and producing the 146.04 signal, the repeater input frequency. We are using sub-audible tone for repeater access and as soon as a station working the repeater drops carrier the repeater drops. The intermod cannot hold up the machine once the tone is removed. This may be happening in the antenna or hardline connectors prior to the cavities. Every test I have run, and there have been many, supports this conclusion. We are not the only 2 meter repeater that has fallen victim of this problem and in every case we have found two pager transmitters situated 600 kc apart near the repeater. Most of the other machines have been taken off the air, others just put up with it. No one has been able to solve the problem and many technicians have studied it. Moving the repeater far enough away is not an option since the peak of the mountain is so small. Also we are using an existing tower which we would not have access to at other locations. The searches I have done on Google has turned up the stock answer of helical resonators which would apply to 2 meter radios but not repeaters. If you are familiar with the Micor equipment you know that the receiver has excellent helical resonators built in. Tonight I have considered the possibility of splitting the receiver and the transmitter of the repeater and linking the rx signal by a 220 mhz link. I am hoping that by reducing the level of the 146.64 signal by 50-60 db would alleviate the problem. Maybe not, but I'm out of ideas. This split would be only about 100 yards but could that be sufficient to relieve the problem? Have any of you ever had this problem and solved it? Any input (pun intended) on this matter would be appreciated.
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Maybe it's like a Grade A Ham? ;- Joe M. JOHN MACKEY wrote: Hmmm, after 20 years of ham radio, past experience in commercial 2 way currently working as an Chief Engineer in the radio broadcast field and possessing my Extra Amateur and GROL, I don't know what a FCC 1st class licensed ham is!! -- Original Message -- Received: Mon, 20 Dec 2004 10:54:16 PM CST From: kc4ih [EMAIL PROTECTED] with to the repeater frequencies by FCC 1st class licensed hams -- No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.0.296 / Virus Database: 265.6.0 - Release Date: 12/17/2004 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Excellent reply, Eric. I worked for several paging companies for about 10 years. Although several problems I found in the past were caused by the paging company, just as many were found to be shortcomings in the repeater equipment or faulty hardware on the tower. Like you said, we really need to know the frequencies involved and what specific kinds of equipment are on the ham repeater, ie duplexer model and if a preamp is being used. If the mix is external to the ham repeater, the fix may be difficult but not impossible to do. If the mix is occurring inside the repeater receiver, a notch filter to reduce the paging signals may work. Joe --- Eric Lemmon [EMAIL PROTECTED] wrote: Ken, Please advise exactly what frequencies these pager transmitters are operating on. There are a number of possibilities for intermod, but knowing the offending frequencies is crucial to a solution. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
RE: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
We have a problem here in Temple, Texas where one paging carrier operates a 152 system and another has 157 about a mile North of the 152 site. I cannot remember the exact frequencies, but 3 times one minus 2 times the other hit 147.240. This only happened when both paging transmitters were active. Adding a bandpass cavity at the 152 site really helped. Incidentally, both systems had clean signals, neither used ferrite isolators or cavity filters. Sometimes just complying with the rules is not enough to keep peace in the neighborhood. Ssb -Original Message- From: Joe [mailto:[EMAIL PROTECTED] Sent: Tuesday, December 21, 2004 6:13 AM To: Repeater-Builder@yahoogroups.com --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.818 / Virus Database: 556 - Release Date: 12/17/2004 Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
All paging transmitters involved should have narrow bandpass cavities and circulators on their outputs. That's usually considered a must at any site. If the paging company isn't willing to spend the money for that, then they aren't to serious about staying in business. The good news is that VHF common carrier paging is slowly going away, and the remaining frequencies will likely be dropped and released back into the general pool in a few years, or less. There is virtually no VHF paging here in NE Ohio anymore. -- Jim Barbour WD8CHL kc4ih wrote: We have 146.04/.64 repeater on a nearby mountain top. It worked great for years with a range of 100 miles or more. Since the phone company and a pager company installed their high power transmitters near the site of the repeater (within 100 yards) the repeater is virtually useless. After much head scratching I believe that the difference in frequency of the pager transmitter of 600 khz is the problem but have no idea how to solve the problem without going to an odd split. The repeater coordinator for this area of Virginia won't even consider that as an option. The equipment that we are using is excellent. The transmitter and receiver on the repeater are both Motorola Micor and were modified with to the repeater frequencies by FCC 1st class licensed hams using Motorola parts. This is not an equipment problem. We are running a set of Wacom cavities which were bought new and are correctly tuned and the antenna is a Phelps-Dodge Stationmaster. When the intermod occurs it is dependant on BOTH pagers transmitting at the same time. If only one pager is transmitting there is no problem. This may at first sound unusual but the pagers are in the 150 mhz band and they are exactly 600 kc apart. These transmitter are both 250 watts or more output. My theory is that the 600 kc (difference of the 2 pagers) is mixing with the output of the repeater 146.64 and producing the 146.04 signal, the repeater input frequency. We are using sub-audible tone for repeater access and as soon as a station working the repeater drops carrier the repeater drops. The intermod cannot hold up the machine once the tone is removed. This may be happening in the antenna or hardline connectors prior to the cavities. Every test I have run, and there have been many, supports this conclusion. We are not the only 2 meter repeater that has fallen victim of this problem and in every case we have found two pager transmitters situated 600 kc apart near the repeater. Most of the other machines have been taken off the air, others just put up with it. No one has been able to solve the problem and many technicians have studied it. Moving the repeater far enough away is not an option since the peak of the mountain is so small. Also we are using an existing tower which we would not have access to at other locations. The searches I have done on Google has turned up the stock answer of helical resonators which would apply to 2 meter radios but not repeaters. If you are familiar with the Micor equipment you know that the receiver has excellent helical resonators built in. Tonight I have considered the possibility of splitting the receiver and the transmitter of the repeater and linking the rx signal by a 220 mhz link. I am hoping that by reducing the level of the 146.64 signal by 50-60 db would alleviate the problem. Maybe not, but I'm out of ideas. This split would be only about 100 yards but could that be sufficient to relieve the problem? Have any of you ever had this problem and solved it? Any input (pun intended) on this matter would be appreciated. Ken Sturgill, KC4IH Marion VA please reply to ([EMAIL PROTECTED]) Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
You will find less and less narrow band cavities on paging transmitters lately. As the paging industry slowly goes into their death spiral of loosing customers, they no longer need 2, 4 or more transmitters at each site to deal with the capacity of pagers out there. What some companies are doing is leaving one transmitter at the site and doing multi-frequencies out of a single transmitter (This is assuming they were all on the same band, 900Mhz for example.) When they multi-frequency a transmitter they need to remove any narrow band filters off the transmitter output. This may explain why some ham repeater sites that were quiet now have noise problems. The irony of it is that you see paging transmitters leaving a site and think that the noise floor is going to go down, only to find that the nose increases tenfold. 73, Joe, K1ike At 09:53 AM 12/21/2004, you wrote: All paging transmitters involved should have narrow bandpass cavities and circulators on their outputs. That's usually considered a must at any site. If the paging company isn't willing to spend the money for that, then they aren't to serious about staying in business. The good news is that VHF common carrier paging is slowly going away, and the remaining frequencies will likely be dropped and released back into the general pool in a few years, or less. There is virtually no VHF paging here in NE Ohio anymore. -- Jim Barbour WD8CHL All outgoing email scanned with Norton AntiVirus2004. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Except that the vast majority of VHF transmitters/networks weren't really capable of multi-freq on the fly as you describe. At least around here, anyway, they were virtually all Micor PURC stations. And most sites would not have allowed the transmitters to remain without cavites anyway. -- Jim Barbour WD8CHL Joe wrote: You will find less and less narrow band cavities on paging transmitters lately. As the paging industry slowly goes into their death spiral of loosing customers, they no longer need 2, 4 or more transmitters at each site to deal with the capacity of pagers out there. What some companies are doing is leaving one transmitter at the site and doing multi-frequencies out of a single transmitter (This is assuming they were all on the same band, 900Mhz for example.) When they multi-frequency a transmitter they need to remove any narrow band filters off the transmitter output. This may explain why some ham repeater sites that were quiet now have noise problems. The irony of it is that you see paging transmitters leaving a site and think that the noise floor is going to go down, only to find that the nose increases tenfold. 73, Joe, K1ike At 09:53 AM 12/21/2004, you wrote: All paging transmitters involved should have narrow bandpass cavities and circulators on their outputs. That's usually considered a must at any site. If the paging company isn't willing to spend the money for that, then they aren't to serious about staying in business. The good news is that VHF common carrier paging is slowly going away, and the remaining frequencies will likely be dropped and released back into the general pool in a few years, or less. There is virtually no VHF paging here in NE Ohio anymore. -- Jim Barbour WD8CHL Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Sounds like a similar problem here in Portland, Oregon. We have a guy running an IRLP node here on what is commonly thought of as 2 meter simplex frequencies. The station is on a broadcast tower with high elevation running about 375 watts ERP!!! Mobiles 100 miles away can clearly hear the IRLP node!! The IRLP node is made from amateur grade RF equipement has had SEVERAL problems with causing interference with the inputs of other repeaters in the area. Attempting to talk to the owner suggesting he put sharp cavity filters on the transmitter resulted in his reply of then I wouldn't be able to be frequency agile. Meanwhile, his deviation has been measured at +/- 9 KHz, and he argues that there is nothing wrong because a telecom service agency measured set his deviation. -- Original Message -- Received: Tue, 21 Dec 2004 09:23:57 AM CST From: Jim B. [EMAIL PROTECTED] To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters Except that the vast majority of VHF transmitters/networks weren't really capable of multi-freq on the fly as you describe. At least around here, anyway, they were virtually all Micor PURC stations. And most sites would not have allowed the transmitters to remain without cavites anyway. -- Jim Barbour WD8CHL Joe wrote: You will find less and less narrow band cavities on paging transmitters lately. As the paging industry slowly goes into their death spiral of loosing customers, they no longer need 2, 4 or more transmitters at each site to deal with the capacity of pagers out there. What some companies are doing is leaving one transmitter at the site and doing multi-frequencies out of a single transmitter (This is assuming they were all on the same band, 900Mhz for example.) When they multi-frequency a transmitter they need to remove any narrow band filters off the transmitter output. This may explain why some ham repeater sites that were quiet now have noise problems. The irony of it is that you see paging transmitters leaving a site and think that the noise floor is going to go down, only to find that the nose increases tenfold. 73, Joe, K1ike At 09:53 AM 12/21/2004, you wrote: All paging transmitters involved should have narrow bandpass cavities and circulators on their outputs. That's usually considered a must at any site. If the paging company isn't willing to spend the money for that, then they aren't to serious about staying in business. The good news is that VHF common carrier paging is slowly going away, and the remaining frequencies will likely be dropped and released back into the general pool in a few years, or less. There is virtually no VHF paging here in NE Ohio anymore. -- Jim Barbour WD8CHL Yahoo! Groups Links Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
The paging companies were more up to date here in the Northeast, Motorola Nucleus and Glenayre/Quintron equipment. Some were capable of up to 16 frequencies in the same band. Joe At 10:23 AM 12/21/2004, you wrote: Except that the vast majority of VHF transmitters/networks weren't really capable of multi-freq on the fly as you describe. At least around here, anyway, they were virtually all Micor PURC stations. And most sites would not have allowed the transmitters to remain without cavites anyway. -- Jim Barbour WD8CHL Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Joe, Do you have any info on the Motorola Nucleus gear... I have a high power PA for 900MHz that I thought about trying to make use of, but can find no docs... TIA, mike At 12:56 PM 12/21/2004 -0500, you wrote: The paging companies were more up to date here in the Northeast, Motorola Nucleus and Glenayre/Quintron equipment. Some were capable of up to 16 frequencies in the same band. Joe At 10:23 AM 12/21/2004, you wrote: Except that the vast majority of VHF transmitters/networks weren't really capable of multi-freq on the fly as you describe. At least around here, anyway, they were virtually all Micor PURC stations. And most sites would not have allowed the transmitters to remain without cavites anyway. -- Jim Barbour WD8CHL Yahoo! Groups Links - Mike PerrymanCavell, Mertz Davis, Inc. [EMAIL PROTECTED] Consulting Engineers http://www.cmdconsulting.com 7839 Ashton Avenue K5JMPManassas, VA 20109 USA (703) 392-9090; (703) 392-9559 fax; DC Line (202) 332-0110 - Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] HELP: 2 meter repeater intermod problem from pager transmitters
Thanks a ton!! Not sure what I will use it for, thought of maybe ATV (FM modulation scheme)repeater or something... in on 1.2 and out on 900. I didn't really give it much though, especially since the elusive docs and what-not. I have a 75 watt PA for 800 from a Micor that I had considered converting.. but the Nuke would be native... and hopefully easier to deal with. I will give Mr. Malicki a try... thanks again. mike At 01:20 PM 12/21/2004 -0500, you wrote: Try emailing [EMAIL PROTECTED] , Dave got one running on 927Mhz and I think he was able to get 300 watts out of it. The Nuke PA would do 300 watts, but lasted much longer at 275 or, better yet, 250 watts. Do you need cavities? 73, Joe, k1ike At 01:06 PM 12/21/2004, you wrote: Joe, Do you have any info on the Motorola Nucleus gear... I have a high power PA for 900MHz that I thought about trying to make use of, but can find no docs... TIA, mike All outgoing email scanned with Norton AntiVirus2004. Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * To unsubscribe from this group, send an email to: [EMAIL PROTECTED] * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/ - Mike Perryman Cavell, Mertz Davis, Inc. [EMAIL PROTECTED] Consulting Engineers http://www.cmdconsulting.com 7839 Ashton Avenue K5JMP Manassas, VA 20109 USA (703) 392-9090; (703) 392-9559 fax; DC Line (202) 332-0110 - Yahoo! Groups Links To visit your group on the web, go to:http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to:[EMAIL PROTECTED] Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
