[Elecraft] SSB Contesting filtering out contesters

[Ron D'Eau Claire]

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:elecraft-bounces at mailman.qth.net] On Behalf Of David
Smith
Sent: Friday, September 2, 2016 10:51 AM
To: elecraft at mailman.qth.net
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)