To: | [email protected] |
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Subject: | Re: LF: Re: 136 propagation a QRO secret ? |
From: | Andy Talbot <[email protected]> |
Date: | Sat, 21 Apr 2012 18:58:14 +0100 |
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One conclusion Peter 'PLX reached on our original 73kHz SlowCW (the proper term we used then, none of this new fangled Q code stuff) was that although the 73kHz path was very bursty with non Gaussian interfernec ewhen looked at in audible bandwidths, by the time it was averaged out over teh 40 second dot period we used, its properties were indistinguishable from pure AWGN. I can't recally if 73kHz was worse or better than 137kHz in the nature of interference, but I think you can safely assume that in bandwidths of much less than [30seconds]^-1 the background noise is near-enough pure random Gaussian. So normal error curves apply. 3s dots may be susceptible though. Andy www.g4jnt.com > > S/N is an interesting point, I have no doubt people like Andy may have more > knowledge, but LF noise is not like other radio noise it is very "spikey" > and "bursty" (I believe the last term is actually an approved definition > :-)) A lot of tests assume it is random Gaussian and I dont really believe > that, though I have no data to dispute it. > > |
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