On Wed, 25 Feb 2009 01:50:18 -0700, Bill W5WVO wrote: >While all these transmitters except >Channel 2 have fundamentals well above 54 MHz (I run a DCI bandpass filter to >keep it out of my preamp), the accumulated grunge from the transmitters' >perfectly legal low-level spurious emissions and passive mixes are enough to >render 6 meters unusable for weak-signal work in the direction of the
Yes. Several decades ago, I was on the tech committee that maintained ham repeaters on 2M, 220, and 440. All VHF and UHF broadcasters in Chicago are located on two buildings downtown -- Sears and Hancock. Thanks to that grunge, a 2M receiver was completely useless anywhere near downtown. I did manage to make a 220 MHz receiver in a 101st floor window at Hancock "sort of" work to fill in holes caused by shadowing of the main RX. It was shadowed by the building from the transmitters for Ch 9 and Ch 11. I suspect that your 6M problem will be greatly improved when your Ch 2 goes away. I had a Ch 2 to deal with in Chicago too, but they were only running about 20-30kW ERP. One very large blessing of DTV is that nearly all the low- band VHF channels are going away (that is, Ch 2-6). The reason is that DTV is rather susceptible to impulse noise, and impulse noise is much worse at low VHF than at higher frequencies. 73, Jim Brown K9YC ______________________________________________________________ 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
