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Re: [TenTec] Amp question

To: tentec@contesting.com
Subject: Re: [TenTec] Amp question
From: Robert & Linda McGraw K4TAX <RMcGraw@blomand.net>
Reply-to: tentec@contesting.com
Date: Sat, 23 Aug 2003 06:29:33 -0500
List-post: <mailto:tentec@contesting.com>

I use the Tentec Paragon  in the TUNE mode for my initial tune-up source
because it has variable output from about 1 watt to slightly over 100 watts.
As to the 15 watt level, well that comes from a Heathkit DX-60.  It has been
modified and the modulation method changed from control carrier to true
screen modulation.  With no modulation the resting carrier output of the
DX-60 is 15 watts.  This drives the Centurion to about 275 watts.  The
modifications on the DX-60 were to enhance the audio and allow the
percentage of modulation to exceed 100% on the positive cycle while not
exceeding 100% on the negative cycle.  All in all it works great, and
reports are that it sounds great.  Frequency response is very flat and
distortion at 100% modulation is less than 1% THD+n.  With the Centurion
operating at 250 to 275 watts output it shows no compression on modulation
peaks at 110%.

I've used a "pulser" which is very similar to the keyer for tuning.  While
it works great and keeps the duty cycle down, the tune up process in my case
is quite quick as I use resonant antennas which are always very close to 50
ohms at my choice operating frequencies.

I made some contacts on 40 M recently and noticed the tubes in the Centurion
were showing a good bit more color than on 160 M or 75 M under the exact
same conditions.

Thanks for the ideas.

Bob, K4TAX

----- Original Message -----
From: "Rob Atkinson K5UJ" <k5uj@hotmail.com>
To: <tentec@contesting.com>
Cc: <k5uj@hotmail.com>
Sent: Friday, August 22, 2003 9:16 AM
Subject: [TenTec] Amp question

> Hi Bob,
> I'm curious about what mode you are operating where you drive the amp to
> 275 watts out.  I'm guessing it must be either cw or AM with a carrier?
> anyway, as Jerry said, just tune it for max output--I find the LED bar
> handy for this, and I also suggest forgetting about the tune button and
> instead, put the exciter on cw and tune for max output while giving the
> about 30-50 watts of dahs from the exciter.  if you want to really fine
> it (the tune cap -- load isn't as touchy) give it a few single widely
> dahs to touch it up.  you can't do it this way with an electromechanical
> meter--it's not fast enough but the leds work great.
> 73,
> Rob
> K5UJ
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