I have a similar problem. I have a 1KW AM station about 1/2 mile away (1100W by day, 110W by night). With nothing connected to the radio, and even with a 50-ohm terminator on RX Ant in, I can clearly hear the signal at several places, most prominently at 14.220 MHz. Nothing I've tried, including expensive filters, shielded cables, etc. has helped. I get some relief using a RX Loop antenna basically nulled (broadside) to the tower, but that antenna is not always the best one for band and/or conditions. :( Some frequencies are simply unusable, and it overloads a front end protector I purchased to try to kill the COR relay clicking when I transmit, making it unusable.
Chris K1AY On Wed, Feb 10, 2016 at 5:53 PM, Fred Jensen <[email protected]> wrote: > I easily could have misread the original emailed problem, but he included > the note that this RFI occurred with all antennas [and I guess other > cables] disconnected which is very strange indeed. If that is so, then I > doubt stubs/filters on the antenna circuits would cure the problem. > > His list of frequencies might suggest some sort of intermod between > constant signals, one being the FM carrier, and possibly their harmonics. > Very strange problem at any rate. FWIW, and Phil can correct me, but US > FM/TV stations are usually authorized in EIRP, I think ... we referred to > KSBY-TV, where I worked while in college, as "Full-power television for the > Central coast, one hundred thousand watts on Channel 6 in San Luis Obispo" > on ID's. That was EIRP, 10 KW to a 10 dB turnstile. If that's still true, > it would seem a 2 KW EIRP FM station 2 miles away shouldn't be a big deal. > > 73, > > Fred K6DGW > - Northern California Contest Club > - CU in the Cal QSO Party 1-2 Oct 2016 > - www.cqp.org > > > On 2/10/2016 2:04 PM, Ron D'Eau Claire wrote: > >> I agree. Even better. >> >> 73, Ron AC7AC >> >> -----Original Message----- >> From: Elecraft [mailto:[email protected]] On Behalf Of Bob >> McGraw K4TAX >> Sent: Wednesday, February 10, 2016 9:18 AM >> To: [email protected] >> Subject: Re: [Elecraft] 12 meter K3 RFI from nearby FM station >> >> An electrical 1/4 wavelength of coax as an open stub at the FM frequency, >> connected using a T at the receiver input, will notch the FM TX signal. >> It >> won't attenuate other frequencies across the ham bands including 6M. Plus >> one can transmit with the stub arrangement in place. >> >> 73 >> Bob, K4TAX >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > -- Life is like Linux - it never stands still. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
