[TenTec] DSP and older Ten Tecs

[Vic Klein]

I had good experience running a ClearSpeech speaker mobile, so when I got a
deal on another unit I grabbed it. These are extremely effective adaptive
noise reduction DSP units made by NCT (Noise Cancellation Technologies) and
you can go to their web site to listen to examples of how the system works.
The units were sold for years by AmCom, who recently folded, but NCT has
arranged with Heil Sound to distribute them, probably starting this month. I
wanted to add the DSP capability for my Paragon that I use at home.

Since I wanted to reduce clutter and I preferred the sound of the Ten Tec
speaker, I removed the ClearSpeech circuitry from the supplied speaker and
added it inside the 961 power supply and rewired the front panel on/off
switch to control the DSP unit. It works very well. The ClearSpeech unit
analyzes the sound and does a very good job of removing any steady noise in
about a second, hetrodynes included. It seems to do a reasonable job with
other stuff like atmospheric static and general trash, generally favoring
voices. In many cases, the result is like listening to local 2m FM. It
responds slow enough that it can be used with CW that isn't too fast, but I
prefer to shut it off and just tighten the filtering for that and RTTY. In
my case the proximity of the circuitry to the big power supply transformer
resulted in induced hum, but the DSP kills that as well in about a second
when the power is turned on. I've heard the SGC uni in operation, and it
seems to perform similarly.

=Vic=
WA4THR