[hpsdr] Proposal for a 'low-end' RX/TX board for HPSDR

[Robert McGwier]

The six meter band is so quiet that the optimal QSD will not be quiet 
enough in all cases and a preamp will be required.  It is good we know 
we are starting with circuits that have the noisier as we go higher 
problem.  This minimizes the amount of gain and the attendant decrease 
in OIP3 that results.

Bob
N4HY


KD5NWA wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
> Lower QSD noise is a good thing, and a worthy goal, but is not the 6M band so 
> quiet that it would benefit from a pre-amp anyway in order to receive very 
> weak signals?
>
> Signals so weak that in the lower bands they are masked out by atmospheric 
> noise but not so in the 6M band.
>
> Even with lower QSD noise the noise of the sound card has to be overcomed 
> also, although the figures comming out of the Janus are simply wonderful.
>
> Fix the QSD problem if it's fixable but I would not count out a low noise 
> pre-amp. With a lower noise QSD you might not need very much gain but it 
> might be nice to be able to kick it in if needed.
>
>
>   

-- 
AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,
NJQRP/AMQRP, QRP ARCI, QCWA, FRC. ARRL SDR Wrk Grp Chairman
"An expert is a man who has made all the mistakes which can be
made in a very narrow field."  Niels Bohr


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