Saturday, June 16, 2012

Afedri SDR-Net - Better Than Anticipated?

The screendump below is from the 31 meter band with rather high signal levels. I am running the Afedri at +24 dB VGA, which equals around -104 dBm sensitivity. At this VGA setting it's in fact a tad more sensitive than the NetSDR, yet there is no indication on the waterfalls of any overload. Very cool. This may indicate that the Afedri will perform well during the coming autumn's MW openings.
Earlier today I also did a recording test, with both SDRs recording 1250 kHz into an internal hard drive simultaneously. No hiccups or stuttering, and very low CPU. Maybe the Ethernet connection makes it easier for the CPU and that the network board does some or most of the processing. I don't know, but what I do know is that when you record from USB based SDRs stuttering may often be a problem.

5 comments:

Anonymous said...

Bjarne, your findings coincide very much with what I have found! Running it at full amplification (35 dB gain) tends to lead to overloading, but using 24 dB gain mostly works fine! Funny thing is, though, that when I run the AFERI with 24 dB gain and add a 10 dB Norton preamp between the Rx and the antenna, overload problem is slightly less than with full internal gain!! On the whole, I think this Rx is quite good bang for the buck! I will, however, add some external filtering later on, probably a 500 kHz high pass filter, a 1700 kHz high pass and maybe a 10 MHz high pass, switchable in wanted configuration. During night time just now, running it with a Norton amp gives no problem at all!
73/Arne

Bjarne Mjelde said...

Arne, would you care to send me your email address. I'd like to discuss an issue with you.

Anonymous said...

Curious...what issue? /johan

Anonymous said...

Bjarne, jag skickade ett mail till din kongsfjord-adress!
Har du fått det?
Arne

Bjarne Mjelde said...

Arne: Ikke mottatt. Send til bjarne dot mjelde at gmail dot com.