[Repeater-Builder] An intermod problem
Hey guys, Alright, need some advice on this one. I have a uhf, and a little big from what we can tell has been in the receiver for a long time. The output of my machine is 449.225 with an input of 444.225. We're running a wacom wp678 duplexer, which is tuned up just fine. One problem, right next to my repeater is the evil paging transmitter outputting on 152.6. As soon as it keys up, with a weak signal on my receiver, it totally desenses it. I can have a signal that is dfq with no paging transmitter, but as soon as it keys up, it is weak. Any ideas for getting rid of this? The third harmonic of the paging transmitter is 457.8. Thoughts? Thanks, Jed
Re: [Repeater-Builder] An intermod problem
The desense is probably caused by broadband noise at the paging transmitter's third harmonic. A notch cavity on the output of the paging transmitter might be the lowest-loss, most cost-effective remedy. Time to find out if you're a diplomat! 73, Paul, AE4KR - Original Message - From: Jed Barton To: Repeater-Builder@yahoogroups.com Sent: Monday, December 29, 2008 4:59 PM Subject: [Repeater-Builder] An intermod problem Hey guys, Alright, need some advice on this one. I have a uhf, and a little big from what we can tell has been in the receiver for a long time. The output of my machine is 449.225 with an input of 444.225. We're running a wacom wp678 duplexer, which is tuned up just fine. One problem, right next to my repeater is the evil paging transmitter outputting on 152.6. As soon as it keys up, with a weak signal on my receiver, it totally desenses it. I can have a signal that is dfq with no paging transmitter, but as soon as it keys up, it is weak. Any ideas for getting rid of this? The third harmonic of the paging transmitter is 457.8. Thoughts? Thanks, Jed
[Repeater-Builder] Repeater Intermod Problem
I have a 440 repeater transmitting 442.850 and receiving on 447.850. We are hearing interference on the repeater from 453.550 which we confirmed on a scanner. This 453.550 frequency is not at the same site as the repeater (it isn't extremely strong), however there are many other transmitters on the same hill. We figured that maybe the 453.550 frequency is mixing with the transmitter frequency of 442.850 to give 10.7MHz, which is the first IF of the receiver. The receiver is a Hamtronics R304. The duplexers are Wacom WP-678-R2. Originally, I was thinking of buying a bandpass filter such as one from DCI, but it seems that this would not attenuate the 453MHz frequency very much. Could the transmitter signal be getting into the receiver and mixing there? What could be causing this problem and how would I correct it? 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] Repeater Intermod Problem
If that is the issue, it seems the easiest way would be to replace the receiver with something that doesn't have a 10.7 MHz IF. Or, even with a higher quality receiver. Joe M. dgrapach wrote: I have a 440 repeater transmitting 442.850 and receiving on 447.850. We are hearing interference on the repeater from 453.550 which we confirmed on a scanner. This 453.550 frequency is not at the same site as the repeater (it isn't extremely strong), however there are many other transmitters on the same hill. We figured that maybe the 453.550 frequency is mixing with the transmitter frequency of 442.850 to give 10.7MHz, which is the first IF of the receiver. The receiver is a Hamtronics R304. The duplexers are Wacom WP-678-R2. Originally, I was thinking of buying a bandpass filter such as one from DCI, but it seems that this would not attenuate the 453MHz frequency very much. Could the transmitter signal be getting into the receiver and mixing there? What could be causing this problem and how would I correct it? 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/
