RE: [Repeater-Builder] Commercial-Grade Repeaters for 6m
I have VHF and UHF that I converted down from the commercial bands. They took slight retuning and a very small software hack. I liked what I saw so much I inquired about six meters. I was told that they would make any ham frequency I wanted. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net
RE: [Repeater-Builder] Commercial-Grade Repeaters for 6m
Try DX radios their repeater are very flexible. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net
RE: [Repeater-Builder] Motorola Suitcase repeater
I am asking 400 for it. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net
[Repeater-Builder] Motorola Suitcase repeater
I have a Motorola Suitcase UHF Repeater for sale. This repeater has been put on the amateur bands by a Motorola service shop. Notch duplexers and tone. Anyone interested send me an email. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net image001.gif
[Repeater-Builder] Repeater for sale
I have an RF Technology VHF repeater for sale. !00 watts 140-162Mhz programmable frequency and pl tone. Comes with or without power supply. Programming software and cable. Never put into service. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net image001.gif
[Repeater-Builder] DB 4062 Duplexer
Has anyone replaced the jumpers on a DB 4062 duplexer with Andrews ¼ inch hardline? David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net image001.gif
[Repeater-Builder] East Central Indiana Repeaters
I would like to let the owners/trustees of amateur repeaters in east central Indiana know that there are several hams using local repeaters for business. These individuals have been warned but do not seem to care. You may contact me directly for the call signs. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net image001.gif
RE: [Repeater-Builder] Re: PURC5000 Repeater Controller Interfacing?
Use L 12 for your audio input David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Home 765.584.7283 Cell765.546.2592 n9...@arrl.net
[Repeater-Builder] Microwave modem
I am in need of the channel switch configuration for a Granger DTL-7300 channel modem. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Cell765.546.2592 n9...@arrl.net image001.gif
RE: [Repeater-Builder] supply
I have seen that supply on Micor repeaters. David Epley, N9CZV Randolph County Emergency Coordinator 4866N 400E Winchester, Indiana 47394 Home 765.584.7283 Cell765.546.2592 n9...@arrl.net
RE: [Repeater-Builder] Anyone have experience with RF Technology Pty Ltd. repeater gear?
I have several in service on the ham bands. They work very well. David Epley, N9CZV Winchester, Indiana
[Repeater-Builder] Receiver overload
I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: RE: [Repeater-Builder] Receiver overload
Analyzer was connected to the receiver port of the duplexers. The noise floor looked good. The amount of degradation does not seem to change. There are 900mhz pager transmitters on site but none are on full time and I do not see any change as each one transmits. I can also have my transmitter turned off and the degradation is still here. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, November 22, 2007 9:19 AM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Receiver overload David, Your problem might be harmonic related. Might do some calculator work. I can see no muliple of 104.9 related to your 2 frequencies or IF related. There are other 900 MHz stuff around. Would be good to get a spectrum analyzer on your receiver port, but know spectrum analyzers are not easy to come by. Might be noise floor emissions from the FM station which could be on your receiver input. Now this one would be a real problem. 73, ron, n9ee/r From: David Epley [EMAIL PROTECTED] mailto:depley%40starband.net net Date: 2007/11/22 Thu AM 07:32:46 CST To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload I just tried a pair of Celwave 8 inch bandpass cavities with no noticeable improvement. David N9CZV From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Jim Brown Sent: Thursday, November 22, 20076:13 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder]Receiver overload David,try using one or two band pass only cavaties in the receive side instead of the BpBr type. The BpBr filters often do not discriminate against signals far off the pass frequency, and you may not be getting enough rejection out of your input cavities. 73 - Jim W5ZIT --- David Epley [EMAIL PROTECTED] mailto:depley%40starband.net netwrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana __ Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See how. http://overview. http://overview.mail.yahoo.com/ mail.yahoo.com/ Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
RE: RE: [Repeater-Builder] Receiver overload
Same antenna and feedline at both sites Decible 896-960mhz with 15/8 feedline. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, November 22, 2007 9:22 AM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Receiver overload David, I assume the antenna system at the now location was different than the other that worked. What kind of feedline and antenna??? 73, ron, n9ee/r From: David Epley [EMAIL PROTECTED] mailto:depley%40starband.net net Date: 2007/11/22 Thu AM 07:32:46 CST To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload I just tried a pair of Celwave 8 inch bandpass cavities with no noticeable improvement. David N9CZV From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Jim Brown Sent: Thursday, November 22, 20076:13 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder]Receiver overload David,try using one or two band pass only cavaties in the receive side instead of the BpBr type. The BpBr filters often do not discriminate against signals far off the pass frequency, and you may not be getting enough rejection out of your input cavities. 73 - Jim W5ZIT --- David Epley [EMAIL PROTECTED] mailto:depley%40starband.net netwrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana __ Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See how. http://overview. http://overview.mail.yahoo.com/ mail.yahoo.com/ Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
RE: [Repeater-Builder] Receiver overload
The only transmitter that is on all the time is the FM broadcast My tx plays no part in the noise _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Joe Sent: Thursday, November 22, 2007 9:55 AM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Receiver overload Can you give us a list of all the transmitters that are at/near the site? Ones that are on the air all the time such as the FM station. Does your transmitter have to be keyed to get the desense? 73, Joe, K1ike David Epley wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: [Repeater-Builder] Re: Receiver overload
Yes I have looked + and - the IF for a signal _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Steve Sent: Thursday, November 22, 2007 11:10 AM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Receiver overload The 900 MHz Maxtrac receiver's IF is 45.1 MHz I believe. Have you looked around there for any possible signals? And are there any studio transmitter links around 947-950 MHz? --- In Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com, David Epley [EMAIL PROTECTED] wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: [Repeater-Builder] Receiver overload
I have tried all the above. I even change out the mini UHF connector to an N female when I use the maxtrac for repeater use. All cables are ¼ hardline. When I use a 900mhz dish mounted at the same level as my primary antenna but pointed away from the FM Broadcast tower I have considerably less degradation. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon Sent: Thursday, November 22, 2007 11:10 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload David, My first move would be to add a bandpass cavity in front of the receiver. All cabling between the receiver and the RX output of the duplexer should be double-shielded, with proper connectors on each end- no adapters, and no nickel-plated connectors. The mini-UHF connector going to the MaxTrac should be the only exception, but it's okay if very tight. If that doesn't cure the problem, then enclose the receiver in a shielded box, and bring the signal and power leads out through feedthrough capacitors. The MaxTrac radio has a lot of plastic in its case, and is susceptible to signal intrusion. The best shielded box to use is a die-cast aluminum enclosure from Hammond. I have assumed that the FM transmitter carrier is pure, without harmonics or spurious artifacts. If the FM transmitter is radiating on a frequency close to your desired input frequency, the above fixes may not have any effect. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of David Epley Sent: Thursday, November 22, 2007 7:02 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload The only transmitter that is on all the time is the FM broadcast My tx plays no part in the noise From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Joe Sent: Thursday, November 22, 2007 9:55 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Receiver overload Can you give us a list of all the transmitters that are at/near the site? Ones that are on the air all the time such as the FM station. Does your transmitter have to be keyed to get the desense? 73, Joe, K1ike David Epley wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: RE: [Repeater-Builder] Receiver overload
Yes when broadcast goes off problem goes away _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Ron Wright Sent: Thursday, November 22, 2007 11:14 AM To: Repeater-Builder@yahoogroups.com Subject: Re: RE: [Repeater-Builder] Receiver overload David, Have we ask if you can verify the problem is the FM transmitter??? 73, ron, n9ee/r From: Eric Lemmon [EMAIL PROTECTED] mailto:wb6fly%40verizon.net net Date: 2007/11/22 Thu AM 10:10:19 CST To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload David, My first move would be to add a bandpass cavity in front of the receiver. All cabling between the receiver and the RX output of the duplexer should be double-shielded, with proper connectors on each end- no adapters, and no nickel-plated connectors. The mini-UHF connector going to the MaxTrac should be the only exception, but it's okay if very tight. If that doesn't cure the problem, then enclose the receiver in a shielded box, and bring the signal and power leads out through feedthrough capacitors. The MaxTrac radio has a lot of plastic in its case, and is susceptible to signal intrusion. The best shielded box to use is a die-cast aluminum enclosure from Hammond. I have assumed that the FM transmitter carrier is pure, without harmonics or spurious artifacts. If the FM transmitter is radiating on a frequency close to your desired input frequency, the above fixes may not have any effect. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of David Epley Sent: Thursday, November 22, 2007 7:02 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload The only transmitter that is on all the time is the FM broadcast My tx plays no part in the noise From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Joe Sent: Thursday, November 22, 2007 9:55 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Receiver overload Can you give us a list of all the transmitters that are at/near the site? Ones that are on the air all the time such as the FM station. Does your transmitter have to be keyed to get the desense? 73, Joe, K1ike David Epley wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
RE: RE: [Repeater-Builder] Receiver overload
The conversion was done per the repeater builders page on maxtrac conversions. I first used the standard 2 pole gigifilters you can for 900mhz later replaced with 3 pole filters. This improved the site degradation by about 5 db. I remove the PA and install a female N connector on the back of the maxtrac. I also pull the DC power connector from the PA and install it on the back of the Maxtrac. I have one maxtrac that I installed in a 19 rack extruded aluminum box with an N RF connector and all inputs\outputs going thru feed thru caps. This showed no improvement. I do not believe I am dealing with a signal on the input frequency but with a very high level of RF energy at the receiver input that it is affecting the sensitivity of the Receiver. David N9CZV _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Eric Lemmon Sent: Thursday, November 22, 2007 12:59 PM To: Repeater-Builder@yahoogroups.com Subject: RE: RE: [Repeater-Builder] Receiver overload David, This is definitely an interesting thread! I cannot think of a more suitable topic to discuss in this forum. You mentioned in your original post that you are using a converted 800 MHz MaxTrac mobile radio as your 900 MHz receiver. Could you please elaborate a bit on what you did in this conversion? Also, please advise what model number of MaxTrac you began with. There may be some aspect of the conversion that makes your receive radio especially vulnerable. If you have already tried bandpass cavity filters on the receiver input, with the radio inside a shielded box and all penetrations suitably filtered, and not seen any reduction in desense, then the offending signal must be on or very close to your desired receive frequency. That brings us back to a spurious or harmonic signal being generated by the FM broadcast transmitter, or perhaps there is an IM product being created between the FM station carrier and another transmitter that has yet to be identified. It may be instructive to use a good (i. e., well-shielded) spectrum analyzer with a bandpass cavity on its input to filter out everything but signals very close to your 900 MHz input frequency. This technique once helped me track down a alarm system motion detector that was operating around 900 MHz. Some spectrum analyzers are poorly shielded, and are practically useless when immersed in a high-RF environment. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of David Epley Sent: Thursday, November 22, 2007 9:17 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: RE: [Repeater-Builder] Receiver overload It is linked but there is only an STL link receiver at the site From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of n9wys Sent: Thursday, November 22, 2007 12:08 PM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: RE: RE: [Repeater-Builder] Receiver overload Is the FM broadcast studio located at the transmitter site, or is it linked? If the studio is remote to the transmitter, it could be a harmonic of the studio uplink freq. But now I:m shooting in the dark. Mark - N9WYS From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com On Behalf Of David Epley Analyzer was connected to the receiver port of the duplexers. The noise floor looked good. The amount of degradation does not seem to change. There are 900mhz pager transmitters on site but none are on full time and I do not see any change as each one transmits. I can also have my transmitter turned off and the degradation is still here. From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com On Behalf Of Ron Wright David, Your problem might be harmonic related. Might do some calculator work. I can see no muliple of 104.9 related to your 2 frequencies or IF related. There are other 900 MHz stuff around. Would be good to get a spectrum analyzer on your receiver port, but know spectrum analyzers are not easy to come by. Might be noise floor emissions from the FM station which could be on your receiver input. Now this one would be a real problem. 73, ron, n9ee/r From: David Epley Date: 2007/11/22 Thu AM 07:32:46 CST To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Subject: RE: [Repeater-Builder] Receiver overload I just tried a pair of Celwave 8 inch bandpass cavities with no noticeable improvement. David N9CZV From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com
RE: [Repeater-Builder] Re: Receiver overload
I have a handful of different size attenuators and will try in the morning. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Thursday, November 22, 2007 2:03 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Receiver overload If you're sure the just rf at the front end of receiver is the entire problem..? Install a High-Q Notch cavity (with a probe dc ground return) on the receiver and try a 3dB pad (on the receiver) to start things out. I sourced a similar problem with a Yaesu/Vertex repeater... their receivers like many other brands always seem to be red-hot with front end gain. The problem required a combination of the cavity and the eventual 1dB value attenuator pad remaining in place. cheers, s. David Epley [EMAIL PROTECTED] wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: [Repeater-Builder] Re: Receiver overload
I am looking for a cavity now _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Thursday, November 22, 2007 2:07 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Receiver overload In this case... I would expect the band-pass cavity option to be a popcorn fart. See my post about the High-Q notch cavity (with the dc return probe) and the attenuator, which should help if the problem is source to the RF coming in the coax port is the sole source. s. David Epley [EMAIL PROTECTED] wrote: I just tried a pair of Celwave 8 inch band pass cavities with no noticeable improvement. David N9CZV _ From: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com [mailto:Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com] On Behalf Of Jim Brown Sent: Thursday, November 22, 2007 6:13 AM To: Repeater-Builder@ mailto:Repeater-Builder%40yahoogroups.com yahoogroups.com Subject: Re: [Repeater-Builder] Receiver overload David, try using one or two band pass only cavaties in the receive side instead of the BpBr type. The BpBr filters often do not discriminate against signals far off the pass frequency, and you may not be getting enough rejection out of your input cavities. 73 - Jim W5ZIT --- David Epley [EMAIL PROTECTED] mailto:depley%40starband.net net wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana __ Be a better pen pal. Text or chat with friends inside Yahoo! Mail. See how. http://overview. http://overview. http://overview.mail.yahoo.com/ mail.yahoo.com/ mail.yahoo.com/
RE: [Repeater-Builder] Re: Receiver overload
What is your opinion on a ¼ wave open stub installed in the receiver side cut for 104.9? _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Al Wolfe Sent: Thursday, November 22, 2007 5:50 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Receiver overload David, I suspect that the issue is 104.9 mhz energy coming down the outside of the feedline and into your receiver. As others have mentioned the maxtrac has a lot of plastic. A shielded box with no unbypassed wires going in and out may help. Ferrites on the feedline or a coil in the feedline may help as well as some more grounds on the feedline. There are also isolation transformers that could be used at 900 mhz. but they are rare. Mini Circuits may have them. I once had to mount a UHF Micor receiver in a shielded box as it picked up cell phones otherwise. I have operated amateur repeaters in broadcast facilities since the 1970's. It's not unusual to measure +30 or even +40 dbm coming down a feedline from an antenna mounted not far from an FM broadcasting antenna. I have been bitten with RF burns from such feedlines more than one. I have enjoyed much success getting rid of these problems with just a 1/4 wave shorted stub at the repeater frequencies. However, this apparently is not your situation. With all the things you've tried to no avail, any 104.9 mhz. energy on the inside of the feedline doesn't sound like the culprit. That's why I think it is RF on the shield. I have been in a great many broadcasting facilities. Many are very well done with much attention to details. You could eat off the floor and feel good about it. But many are a real pit with little attention to detail - just get it on the air. The grounding in these installations is next to non-existant. Having not seen your neigbor's setup on 104.9, I can't evaluate it. I also don't know the amount of grounding and bypassing on your 900 mhz. setup. But, based on my experience, I would suspect a feedline hot with RFon its outside. It might be interesting to visit your neighbor and see how he is receiving his 940 mhz. studio-transmitter link, which is apparently unaffected by his 104.9 mhz. transmitter. Al, K9SI, BC Engineer/consultant, RETIRED! David Epley wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: [Repeater-Builder] Receiver overload
Muncie Indiana _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Joe Sent: Thursday, November 22, 2007 9:32 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Receiver overload Are you sure that 104.9 (WINN?) is the only FM station near your repeater? Looking at the data, it looks like 100.3 WYGB is possibly on the same tower. This is assuming that your repeater is in Columbus, IN. 73, Joe, K1ike David Epley wrote: I have a repeater receiver overload problem I am trying to cure. The repeater is a 900mhz 927.7125/902.7125. There is an FM broadcast station 100 yards away 104.9mhz. The repeater works fine at another site. My transmitter is a Motorola Purc 5000 running 75 watts the receiver is a converted maxtrac 800mhz radio. Duplexers are Telwave BpBr 4 cavity. I have 10 to 12 db degradation when plugged into 3 different antennas on the tower. When I use a 900mhz dish antenna pointed away from broadcast tower I only have 3 db degradation. I have tried 3 different maxtrac receivers, added 2 more BpBr cavities in the receiver side and used 3 pole filters in the receivers with no improvement. Today I looked at the signal level getting to the receiver at 104.9. To my surprise I was getting -8 dbm at the receiver. I believe this level is overloading the front end of my repeater. I was wondering if a stub cut for the broadcast frequency would work. Any thoughts would be greatly appreciated. David Epley, N9CZV Winchester, Indiana
RE: [Repeater-Builder] Re: Receiver overload
70s Rock _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of skipp025 Sent: Thursday, November 22, 2007 10:11 PM To: Repeater-Builder@yahoogroups.com Subject: [Repeater-Builder] Re: Receiver overload Anyone bother to ask what format is playing on the broadcast station? You could have some hip-hop or thug music playing and that could be a potential problem? :-) s. Are you sure that 104.9 (WINN?) is the only FM station near your repeater? Looking at the data, it looks like 100.3 WYGB is possibly on the same tower. This is assuming that your repeater is in Columbus, IN.
RE: [Repeater-Builder] DX Radio Systems Repeaters
You can also contact me off list I have run several of these for over 10 years David Epley, N9CZV Winchester, Indiana
