[RTTY] BARTG 75 Sprint

[Stephen/Marilyn Haines]

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?
>
>
> Steve,
>
> 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 
anymore).

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 
Steve ZP9EH

>
> 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.
>
> 73
> Chen, W7AY
>
>