On 6/14/2010 1:06 PM, Kok Chen wrote:
> On Jun 14, 2010, at 6/14 4:39 AM, Stephen/Marilyn Haines wrote:
>> The difference between 45 and 75
>> baud pushes me from "yes it's hard but I enjoy it" to "It's impossible
>> -- why bother." Is there anyone else on the list with a truly weak
>> signal that had the same reaction?
> Since you mentioned the power that you are using, I assume the
> diffculty is because you are not heard by others, and not because you
> can't copy the others, correct? Do you get a lot of AGN, AGN when you
> call them?
> One does lose a couple of dB in SNR when demodulating 75 baud versus
> 45.45 baud. Most big guns that are heard in a contest are way, way
> over the threshold of decodability however (perhaps not from ZP,
> though), so losing a couple of dB usually means that a previously
> decodable big gun signal is still perfectly decodable at 75 baud.
> Copy should only become difficult for the marginal signals -- ones
> that are just barely over the noise floor of the receiving system
> before. I.e., people who used to throw an error or two at 45.45 baud
> would now, at 75 baud be fully garbled.
Hi Chen . . . and many thanks for your always-thoughtful response.
Really I have both difficulties, and both are related to my poor
antenna. At 75 baud I had a LOT more trouble decoding anyone. Whereas at
45 baud I might find a dozen readable signals on a pass thru 20 meters,
at 75 baud I would print two. The other part is laughable if it weren't
so sad! At 45 baud I get a lot of AGN? AGN? or QRZ? at 75 baud all I get
is CQ CQ !! What's so maddening is that I want to play and would be a
desirable multiplier IF anyone could hear me -- I'm the only current
RTTY contester in ZP (I think), and usually the only CW contester from
here (Doug ZP6CW is a pedal-to-the-metal CW op, but doesn't do tests
I realize that my poor signal and poor reception are my responsibility.
It's possible that there are very few operators who really suffer a loss
of enjoyment in the contest when the speed is increased, but sadly, I'm
one of them :-( If we do get to vote (grin), I'm for 45 baud! 73 de
> If others can no longer copy you at 75 baud, your signal might be
> right at the edge of copy for most people even when you were using
> 45.45 baud.
> One experiment you can perform is by lowering your RF power from 40
> watts to between 24 and 25 watts during the next contest and then try
> to work people at 45.45 baud. Do you have the same difficulty as
> using 40 watts at 75 baud? If you do have the same problem being
> heard, then yes, short of raising your RF output or adding some gain
> to your antenna system, it is a problem that is going to be hard to
> fix (other people would need better modems or their antennas need to
> point your way, etc).
> Now, on the other hand, if the problem is due to your not being able
> to copy the other folks cleanly, it is probably some setup thing (for
> example, using I.F. filters that are too narrow for 75 baud) that can
> be fixed.
> Chen, W7AY
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