The router is right at 147.580 to almost 147.595. The repeater input is 147.600. So I plan to take that offline. All that cables are double shielded with no adapters ect. I do not have anything between the isolator and the duplexer.
Where is a good dealer for a 5" or 8" band pass for the receiver? I may look at going with that for the first step as it is not very bad but a bugger that pops up now and then. Thanks for the help. Scott --- In Repeater-Builder@yahoogroups.com, "Eric Lemmon" <wb6...@...> wrote: > > Scott, > > A likely suspect is a carrier being emitted by a nearby computer or > microprocessor. A few years ago, I was setting up a GR1225 repeater on a > VHF channel, and I noticed that the receive indicator LED was lit steadily. > My spectrum analyzer revealed that there was a low-level but steady carrier > a few kHz off from my receive frequency. I then used my T-Hunt equipment to > pinpoint my desktop computer as the source. In the course of my > investigation, I also found weak but benign carriers being emitted from my > TV set, my idle microwave oven, and my programmable thermostat. > > If it is an intermod problem, perhaps a DCI filter is far too wide to be of > much help. I'd strongly suggest putting a 5" or 8" bandpass cavity ahead of > the receiver- it is much sharper than the DCI product. Do you have a second > harmonic notch filter, or a low-pass filter, following the isolator? Are > all of the jumper cables double-shielded, with proper connectors on each > end- that is, no adapters or barrels? > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of offtracks1 > Sent: Monday, December 07, 2009 12:49 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Rolling Pipe Sound > > > > Thanks for all the post and for the web site and group. > It's been very helpful to me as I have been setting up my system. > > My repeater system is a Kenwood TKR-750 K2, Telewave TPRD-1556 duplexer set > (6 cavities), A Telewave Isolator on the PA. Running 1/2" Heilax to a Andrew > DB224E antenna. This a repeater at my home as I am on a small hill. The > antenna is about 40 feet vertical and 60 feet horizontally from the > repeater/office. > > It works very well but I have had intermod issue that rears its head now and > then that sounds like rolling pipe or hollow sound. I am runing a PL on both > TX and RX. This sound opens up the receiver even. So my tx pl is getting > back into the system. I have hunted down many noise makers in the office > that could have been helping out. One was the Linksys router. I am going to > replace it anyway as it makes a ton of noise I found. Changing my network > from 100 to 10 on the card speed also reduced the noise levels. > > Still I get the rolling pipe sound now and then and it leaves as fast as it > shows up. If I use my other antenna a Diamond F22 also fed with 1/2 Heliax I > also get the same result. I do use a preamp but it also seems to not change > with or without it. I have even ran it so the receive antenna is alone and > the transmit is the other (split). I still get the rolling pipes now and > then. > > I do have a FM radio station on 92.1 about 4 miles from me that is known to > have a sloppy signal. Could it be that this is mixing with my system and > creating this? > > Looking at getting a DCI Band pass filter on the receiver side but I am not > sure if that is just throwing more money at this project and not getting > anywhere still. > > Just wanted to see if anyone had some ideas? > > Scott KB7DZR >
