[hpsdr] hpsdr Digest, Vol 13, Issue 12

[Guy Atkins]

This is great to hear, Phil. My interest is in weak foreign signals that are
heard between the pounding 50 kW locals on medium wave. It is a situation
not unlike a crowded ham band during contest time; the RF requirements for
reception are very similar. My SDR-1000 with custom low pass filtering is
the best I've encountered for this application so far, but I'm looking
forward to Mercury to increase the close-in performance and do away with the
3X, 5X the LO response problems.

Guy Atkins
Puyallup, WA

-----------original message------------------
I have the same experience as Phil with the QS1R prototype.  With in band
signals I could overload my SDR-1000 long before the QS1R and they both seem
to have similar weak signal sensitivity.  I keep seeing these claims of the
"superior performance" of QSD based designs but then you continually hear
about little bug-a-boos like their response at 1/3, 1/5, and 1/7 the LO
frequency as well as increasing NF with frequency.  I much prefer the
Mercury/QS1R design over QSD based designs now.  The only filters I have
been using on the QS1R is the 30 MHz LPF and the 1.5 MHz HPF.  Most of the
time I only have the LPF active and leave the BPF off since I haven't had
any issues with strong broadcast stations.

Phil N8VB


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