[Skimmertalk] Red Pitaya 1:14 impedance transformator + SV1AFN pre-amplifier

N4ZR n4zr at comcast.net
Sun Oct 22 12:33:31 EDT 2017


Saki, I run an 11-dB Clifton Labs preamp in front of both my QS1R and my 
Red Pitaya, both of which are running off the same active vertical.  
With the transformer in place, the Red Pitaya and the QS1R are 
approximately equal above 40M, while theRed Pitaya has a small advantage 
on the low bands.  The metrics I use for this are the SNRs on the same 
spot (quite iffy), the number of decoders spawned at a given time, and 
the number of spots over a given period of time.

Before I added the transformer, the QS1R was better above 40M, and the 
Red Pitaya was better on 40M and down.  QS1R users have long complained 
about low sensitivity above 20M, so the preamp was pretty important there.

73, Pete N4ZR
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On 10/22/2017 12:13 PM, DD5XX (Saki) wrote:
> Hello all,
>
> thanks to Bob (N6TV) I got one of those Red Pitaya impedance
> transformator 1:14. I wonder if anyone did try to add a pre-amplifier on
> the input and if so what is your experience ? I have heard and did read
> lots of positive feedback on the pre-amplifier offered by SV1AFN on his
> website. I would be interested in the kit "J310 push-pull HF pre-amp
> 0.5-54MHz" (see "https://www.sv1afn.com/j310preamp.html"). Do you think
> to gain some more dB performance with this combination ?
>
> Red Pitaya INPUT1 <---- 1:14 impedance transformator <---- SV1AFN pre-amp
>
> Looking forward into your comments.
>
> 73
> Saki, DD5XX
>
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