[hpsdr] A real newbie question

[Helmut]

Pete,

 

I guess you know that some modifications of the frontend are necessary to
use the RP as an appropriate SDR. Impedance transformation from high to 50
ohms seems helpful as well as sufficient low-pass filtering for the 1.
Nyquist zone. The preamp for frequencies > 7 MHz needs a redesign. When you
have done this work calibration can be taken as Warren has described. To get
best accuracy a high reference (signal source) level should be used to
employ as much bits of the ADC as possible (just below clipping).

 

73, Helmut, DC6NY

 

Von: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] Im Auftrag von Pete
Smith N4ZR
Gesendet: Mittwoch, 26. Oktober 2016 20:25
An: hpsdr at openhpsdr.org
Betreff: [hpsdr] A real newbie question

 





 

I'm one of the RBN team, and am comparison testing the QS1R and Red Pitaya
receivers with VE3NEA's CW Skimserv. I'm getting some anomalies that I can't
explain with my 1960's level of electronic sophistication, so I'm looking to
begin comparing the two receivers for things like sensitivity, MDS, and so
on.

A very useful tool would be an SDR console capable of running with both the
QS1R and the Red Pitaya (with software by Pavel Demin).  I have SDRMAXV for
the QS1R and PowerSDR from your website, but have no idea whether the signal
level readouts on the two programs are in any way comparable.

Does anyone know of a console that will run with both sets of hardware and
provide signal levels in dBm?

Alternatively, can anyone tell me if PowerSDRmRX PS is fairly accurate with
its signal strength readouts, or at least consistent from 160 to 10M?  I'm
seeing about a 20 dB reduction in sensitivity of the Red Pitaya at 20M and
above compared with 40 and below.

TIA




73, Pete N4ZR
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For spots, please use your favorite 
"retail" DX cluster.

 



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