David, it's called QRM and has been with us since the first spark transmitters were on the air.
On CW how does the frequency of the interfering stations compare with the ones you are trying to hear? I'm referring to the audio frequency of the CW signal you hear in the speaker or headphones compared to the desired signal. If they are very nearly the same, it's because the interfering signal is on the same frequency as the one you want to hear. Since Ham bands are not "channelized", any station can operate on any frequency within the band. Interfering stations can end up on your frequency in several ways. It might just be a careless operator who didn't listen first or one who didn't care if other signals were present. Unfortunately, this happens a lot in contests. Just as likely, it may be because of propagation. It's common for other stations in different locations to not be able to hear the signals you do. That's why good Ham protocol is to send QRL? (is the frequency in use?) before starting a call. In that case you could send an "R" indicating the frequency is in use even though the other station could not hear. But, again, that is often overlooked in Contesting. Also, it's possible for the interfering station to not be able to hear either of you due to high noise levels, poor receiver, etc. Another possibility that is becoming very rare with modern equipment is that the interfering signal might be a spurious (unintended) signal on a frequency far from the other station's main signal. Yes, directional antennas help, but on HF especially many Hams must make do with whatever antenna they can put up in their yard or garden. 73, Ron AC7AC -----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of David Smith Sent: Friday, September 2, 2016 10:51 AM To: [email protected] Subject: [Elecraft] SSB Contesting filtering out contesters Have a question I feel I know the answer to. I am an avid contester and when contesting thru the years (since 1978 and especially on 40 meters) have always had problems filtering out on my receive other contest stations who bleed over to my receive frequency their signals so I care hear the weaker stations coming back to me, mainly domestic contests. Thru the years operated IC 765, Omni 6+ and now the K3S. Still with DSP filtering, etc. I feel this is a way of life with contesting. Have had this discussion with many of my big gun contesters and we feel this must be a way of life with ssb contests. CW contests are much easier to filter out the side to side stations. My directional antennas on these bands help a lot but guess this is the way of life with ssb contesting. Would like other input from your experiences. Thanks David, ND4Y (KS3, KS2, KX2 owner) ______________________________________________________________ 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]
