[TenTec] RX320 performance

[Jim FitzSimons]

Mark, your results are probably correct. You can correct the offset on the
RX-320 very well if you are using the N4PY software. I have both the Pegasus
and the RX-320. The offset on my RX-320 is -119 Hz. The offset on my Pegasus
is 12 Hz. The Pegasus has a TCXO to keep the frequency stable and the
RX-320 has a bare crystal in the same place. The 300 Hz filter is wider than
300 Hz. It works great for psk31, RTTY, and MFSK16. It is a DSP filter so it
does not distort these digital signals. The easiest way to check the
frequency
is to use the FFT spectrum display on a soundcard software.
One with a narrow display like WinPsk or MixW is easier to use.
Tune below WWV and see the frequency of the peak on the display.
Peace, Jim FitzSimons W7ANF

----- Original Message -----
From: "Mark Erbaugh" <mark@microenh.com>
To: <tentec@contesting.com>
Sent: Sunday, October 15, 2000 1:10 PM
Subject: [TenTec] RX320 performance


>
> 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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