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Alan,
I don't think it's the fault of transmitters
failing to send proper dots, looking at mine on a scope the envelope is just the
same as it would be on HF. I do agree that it's the dots that get lost though,
and apart from those stations who don't seem to send any dots, I reckon it's in
the receive end of the path. The combination of very narrow RX filters (much
narrower than TX antenna/ATU bandwidth) and operation very close to the noise
floor means the dots get lost first.
So the moral is "good solid dots"
please!
73, Dave G3YXM
Hi After listening to some weak (to me)
stations on 136 this morning it occured to me that I was getting a solid,
well above the noise dash, but the dits were not at the same peak strength.
Noise was fairly low at the time, so it was not being carved up by static.
It occurs to me that it may be that some keyers, or even some 'fists', are
producing very shorts dots even at the relatively easy speeds used on 136.
Can it be that the Q's of aerials and tuning are such that the TX is not
rising to full power during a 'dit'?? I find that a bit hard to believe. I
do know that when I was learnimg my morse thanks to an old PO Telegraphist
up in Liverpool with a G3K call. He used to say that 'you had to send real
SOLID dots on old long trans-oceanic cables' otherwise he reckoned they
would not get to the other end! I wonder whether this is a lesson for
us ...its not so much the slowing down that helps copy on a weak signal so
much as the SOLID dot that the slower more deliberate transmission gives.
Being basically lazy and not having been an HF morse user I can't express an
opinion either way. It would certainly be interesting to know what the tx
rise-time (or maybe the aerial current rise-time) actually was with some of
your fairly high Q aerials.
Cheers de Alan
G3NYK
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