[eagle] Re: Going into the deep Echo archives.

Robert McGwier rwmcgwier at gmail.com
Tue Sep 4 02:49:31 PDT 2007

Tom Clark, K3IO wrote:
> Bill Ress wrote:
>> If I read the Excel spreadsheet correctly, if says that -100 dBm into 
>> the SQRX at 28 Mhz was full quiting??? Is that directly into the coupler 
>> you installed?
> Lyle should verify for sure, but I believe it is into the 2M whip's SMA
> on the "top".
>> Any idea what signal is needed at the 18" whip at 28 MHz to provide a 
>> usable signal from the SQRX in the SSB mode? You know were I'm going 
>> with this, don't you? Or have I lost the bubble here and that mode has 
>> already been tried??
> Remember that the 18" whip is pretty short at 10M. The equivalent
> circuit is a capacitor and a radiation resistance that can be more than
> an ohm. So the sensitivity is quite low.

CAN NOT BE more than an ohm.  I am sure the intent was clear but just 
wanted to make sure.

> Yes, it has been tried in SSB (i.e. linear receiver), mostly for some
> PSK31 tests. PSK31 signals (at whatever doppler is applicable) would
> them modulate the NBFM xmtr. So you tune your favorite PSK31 demod on
> the noise output from your 70cm rcvr. Downlink doppler is irrelevant.
> Drew/Gould should offer comments, but I believe some signal were copied
> by no QSOs made. The stations were (as I recall) running ~100 watts out
> from a typical HF xcvr.
> Again the problem is that the 18" whip is too short by a factor ~6.
> Tom

AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
"If you're going to be crazy, you have to get paid for it or
else you're going to be locked up." Hunter S. Thompson

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