[TenTec] RF in audio

[Steve Ellington]

Don't you just love these answers? "It's not a TenTec problem" etc. Look
folks....All you have to do is compare construction techniques with the
other brands to see that TenTec rigs have always been laxed in the shielding
and bypass department. Even my beloved Omni C has an aluminum lid covered
with contact paper. The paper actually insulates the lid from the rig's
frame and insulated washers are used under the screw heads that further
insulate the cover.

Now why would anyone design it like this knowing full well that the lid and
bottom should be firmly grounded at as many points as possible?
Look at the Omni 6...Those screws that hold the lid on...don't they have
insulated washers under them? What kind of deal is that?
Then there's the circuitry. Look at how the circuit boards are gounded to
the chassis. In the older TT rigs they used sheet metal screws through the
circuit board and straight into black plastic sockets. The only ground was
via some wires. Again, poor design practice.
So we end up trying all these tricks to reduce RFI. Moving wires, moving
power supplies, redressing leads, bypass capacitors and torroids. Is it any
wonder?
So if your shack has any RF floating around and you are using a TT rig then
it should be no surprise if you have problems. The cure is to finish what
TenTec didn't. Put in those bypass caps, ground that lid etc.

How many of us have had problems with RFI and MFJ keyers? Quite a few I
would say. Look they way they are constructed. Painted aluminum covers with
obvious lack of grounding and poor bypassing.

Now look at the old Johnson Transmitters. I have here a Johnson Navigator
with no less than 17 bolts to hold the front panel on and a Matchbox with 37
screws on the back cover. Back in those days manufactures knew how to shield
equipment. What happened?

I also have a Kenmore TS-930 on the bench. It weights 41 pounds! The bottom,
chassis and lid are made of steel. Chrome plated steel bolts bond everything
together instead of sheet metal screws. Sub chassis are heavily shielded,
feedthru and bypass capacitors are everywhere. The main tuning knob spins
smoothly beyond compare. The potentiometers feel like silk with no scratchey
sounds even after 18 years of use. QSK is so fast that I can easily hear
between 60wpm dits and there are no clicks, thumps, tails, pops or
distortion of any kind to the sidetone.

Who ever heard of a rig other then TenTec that the placement of the power
supply makes any difference?
Try sitting the TT supply on the right hand side of a Corsair and see what
happens.

Now it's time for me to get back to rebuilding this PTO out of an Omni A. A
good overnight soak in some degreaser and reapplication of some good silicon
grease should do the trick. I guess I just like messing with radios. TenTec
rigs give me plenty to keep me busy and I like that. Weird eh? 73
Steve Ellington
N4LQ
-----Original Message-----
From: Ken Kinyon - W7TS <W7TS@Qwest.net>
To: tentec@contesting.com <tentec@contesting.com>
Date: Thursday, March 08, 2001 4:28 PM
Subject: RE: [TenTec] RF in audio


>
>Hello,
>I would like to pose a question to the reflector.
>
>I am on my third Ten-Tec transceiver. I started with a paragon in about
1988
>or so and am now using a Omni-VI+.
>I have over the years used lots of other rigs.  I also subscribe to
>reflectors for Yaesu and Icom.
>
>Why is it only Ten-Tec rigs that have this RF into the rig problem?
>
>I have fought it several times myself with a lot of work and frustration.
I
>am afraid to hook anything new to the transceiver for fear of encountering
>this all over.  Right now it is the main reason that I'm not on RTTY.  I
>don't feel like dealing with it.
>
>I am beginning to think "Why don't I just buy a FT-1000MP and have done
with
>all the nuisance?"
>
> I would like opinions and comments on why this seems to be a Ten-Tec only
>problem.
>
>thanks,
>Ken W7TS
>
>
>-------------------
>Kenneth E.  Kinyon
>34 Princeton Circle
>Longmont, CO 80503-2106
>Voice/fax  (303) 684-0037
>E-mail: W7TS@Qwest.net
>   W7TS@qsl.net
>   W7TS@arrl.net
>ALPCA #8339
>ARRL-LM
>-------------------
>
>--
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>
>


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