There seemed to be quite a few of them in 10m contest. The better the
propagation, the worse they look. If one's signal is a picture of the
operator, then it is not a pretty one.
We should really check our signals before firing up into the heat of the
contests. The reasons are obvious, unnecessary interference (unless one wants
"dirty" elbow room and clear frequency - illegally), risking disqualification
and reflection of the operator's ability. Also, things happen during the
contest or operation that can make good signal rotten, without us knowing it.
Definitely, the "offender" should be told. You don't always know what is
getting out of the antenna. You might hear it OK on the rigs monitor, but
amplifiers and bad connections can add nasty things to the quality of signals
and harmonics. If told, especially by the few stations, one should seriously
check it out and take corrective action. Some have thick skin or do it on
purpose, they will not correct the problem and keep going, offending the rest
of us.
Way to check the own signal is first to listen on built in monitor, to
check the audio and the amount of compression. Too much compression might
look "good" on the output meter, but can actually take away from the
legibility. There are some "champs" that are louder when they are not talking
into the mike, rather when talking. Negative compression? It can happen with
some ALC circuits. Do the final check with some distant station (with good
radio) and ask for signal quality report. That should do for preparation
before the contest. The same goes for clix on CW. Know your signal.
There are also problematic "reporters" like I experienced during WW SSB
on 80m. Bunch of next door old timers on the QRU weather net with Eico 753
"latest" model, complaining that "you are too wide and running too much
power". Subsequent checks with known contesters confirmed that there is
nothing wrong with my signal (besides being loud locally with 3 el wire
beam). I also got some reports that my signal audio or CW tone was raspy. At
the times I was feeding two antennas simultaneously and phase shifts due to
propagation would cause beating and aurora like sounding signals. Again
switching to one antenna and check with reputable station confirmed no
problem.
But then AFTER the WW CW contest I was told that while on 80m I had
harmonic on 40m and even small pileup going there. I wish I was told about
this DURING the contest. I could have made quick checks and see if the
harmonic disappeared and what caused it. I will investigate it. At the time I
was using IC781 on transmit and also used split RX feature. I have read that
IC775 had similar problem when using dual VFO for receive. Normally,
synthesized rig and linear amp that is not overdriven should not generate
appreciable harmonics. Anyone else had similar experience?
So when "inspecting" signals, first check that your RX is OK and not
being overloaded (TS870 before filter mods used to do that), use the
attenuator, bring the signal to about S9 and see how it sounds. Make sure you
have noise blanker (!) off, DSP off, notch off. Then if signals sound rotten
do not hesitate to inform the "proud" owner. When few reports are received
and verified, the corrective action would and should be taken. Perhaps those
persisting on driving "garbage truck" on our radio highways chould be put on
the "dirty signal honor roll", maybe it would help to clean up the act.
Beware of small and low drive amplifiers, they can be overdriven by
simply line voltage going up after midnight (or down) and working condition
being changed by the fluctuation in the line voltage.
To check compression level on SSB, the best thing is to step on the foot
switch and keep quiet. Watch the power meter. If you get deflection more than
just a hair above zero, then you are transmitting background noise and QRMing
yourself. Turn the mike gain down untill you see just a hair increase, then
adjust amount of compression while saying 'ooooola. Some ALC systems (like
TS870) can actually cut the average power down if too much compression and
drive is applied.
Lets keep it clean and make more room for new little pistols.
73, MX & HNY2K
Yuri, K3BU, VC1A
http://members.aol.com/k3bu/
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