[TenTec] DSP Engine in New Rig?

[Larry Kayser]

Paul:

>I just checked this on my Pegasus.  The CW sidetone is up at approximately
>25% of full volume and is not affected by the DSP notch/NR function.  If
>your sidetone is being affected by the DSP system, you may a have problem
>with the transceiver.

No Paul, I dont have a problem with the transceiver and I sent the Pegasus
back to TT some time back.

DSP notch/NR function is not involved and the residual CW sidetone in the RX
audio output of the Pegasus receiver is, as I said earlier, below the audio
noise level coming out of the receiver.  The tone is siting there, and is
found easily by any of the DSP waterfall weak signal programs that are in
common use by the weak signal community these days.  The easiest one to use
would be ARGO these days as it has been dumed down so there are almost no
setup things to do.

Put a dummy load on the antenna set the levels to nominal for internal
speaker operation and connect the associated computers sound card input to
the speaker terminals.

In a few minutes you will see a line on the screen which is the CW sidetone
way down in the noise.  You can test this by moving the side tone
programatically and the displayed line frequency will move along with it.

I have tested one Jupiter and it has the same thing although the tone looks
somewhat dispursed, commonly called "dithering" which might be a TT attempt
to bury the tone deeper into the noise - if so it didnt work.

If you want to have some excellent entertainment you can take the ARGO
program and look around, you will sometimes find some very interesting
things.  If you look on the HF beacon frequencies 14,100 and 28,200 etc, you
will see on occasion very weak signal stations working each other with very
slow CW, dit lengths in the order of 30 to 300 seconds.  Several of these
stations, in a very exclusive club, are running less than 1 milliwatt to
small antennas and are working frequently at intercontinental distances.  If
you want to optimize the bucket width, read filter width, of the receiver,
you will come to an optimum width at 300 seconds of about 2 milliHz wide
receive filter.  This is very slow signalling, it takes about 2 hours to
send a callsign.  You will also find during the winter months similar
signals on 1999.9 to 1999.99 kHz, it is not uncommon now to find three or
four signals within a total bandwidth of 1/2 Hz.  My weakest signal last
winter on 1999.945 kHz was heard over 900 miles with less than .08 of a
milliwatt.  I used a 10 dB pad on the output of a 3V logic signal after a
shaping filter.  Nobody in this activity bothers with aural audio speakers
anymore, the signals are rarely ever heard (even locally) loud enough to be
heard by ear.

These are weak signals, I hope you will agree.

Larry
VA3LK




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