R John
I gave up testing in the end , one minute wspr decodes , the next Op
over the same path , even 2 or 3 dB qsb over a 25 mile path to
Gary g4wgt from my qth ....... tests in the past with 3 tones over
longer paths 100 Hz apart , showed selective fades , so even
running 2 modes in parallel did not always give a true picture ,
could loose one of the tones for quite a while as well , at 75
miles out this was quite visible .
Op is a averaging system , with integration and non linear routines
(anti qrm /static) used to recover the signal from the 'noise' with a
numerical digital filter to detect the pulse envelope , so it will
take advantage of bursts , rn3agc , using a sdr on 136 is getting
some very low s/n decodes , I think partly as the sdr is presenting
the 'dsp' engine with the least modified signal to process
73 -G
--------------------------------------------------
From: "John Andrews" <[email protected]>
Sent: Friday, August 03, 2012 12:53 AM
To: <[email protected]>
Subject: Re: LF: Re: ALL de WE3XGR (United States): Beacon Op4 ..>>>>QRG
???<<<
Graham
what modes are you checking ?
OP4 and WSPR tonight. The combination of the 72 mile path and plenty of
high-angle radiation from my xmit loop makes for a pretty intense roller
coaster in the evening. At least the thunderstorm activity is a little
farther away tonight. Between the stuff on and offshore, it has been
pretty noisy lately.
John, W1TAG
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