I've had a chance to do some preliminary testing (playing <g>) with my new
RX320 that I purchased last weekend and have a couple of questions:
1) It seems that the frequency is off (to my ears) about 130 Hz (i.e. I get
the best sound out of WWV on 15 MHz at 14.998.700. I notice that there is a
setting in the software to 'fudge' the frequency and I have corrected it
that way, but I wonder if it shouldn't be closer than that. The published
specs are +/- 100 Hz.
2) I used the Spectrogram software and a simple white noise generator
(actually my MFJ MatchMaker) to measure, albeit crudely, the response of the
narrower filters. This was prompted by the fact that the waterfall in
DigiPan didn't seem to be as narrow as the filter would indicate. I used
the N4PY software since it has a PBT adjustment and adjusted it so the peak
was around 1 kHz. I then measured the peak and recorded the -6db points for
each of the filters:
RX320 Filter : measured -6db range
300 : 447
330 : 405
375 : 527
450 : 640
525 : 657
600 : 710
675 : 835
750 : 942
900 : 974 :
1050 : 1136
1200 : 1313
1350 : 1491
Interesting note that the 330 filter actually measured narrower than the
300. This is probably due to my inaccurate measurement technique!
Does these numbers seem high? Could there be something wrong with my RX320?
73,
Mark
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