At 06:39 AM 9/21/2007, Scott Wilson wrote:
There are apparently several stations.
How sure is everyone that the QRM is on the uplink frequency? I have noticed some QRM, but it's usually MUCH stronger than the downlink, and will almost always completely over power the satellite signal. I've just assumed that it's local 70cm activity from some locals who don't know any better.
Well, there are ways of telling. Doppler shift is one. Does the QRM follow the Doppler shift? Then there's the issue of uplink interference. If you have a keen ear, it is possible to tell by subtle differences in the audio whether the signal is on the uplink or downlink, especially when you're running headphones. Similarly, it's also possible to tell if you are experiencing downlink problems or if the other station is not making the uplink, if you know what to listen for (without looking at the S meter).
The above (except for Doppler shift, of course) also apply to terrestrial repeaters.
73 de VK3JED http://vkradio.com