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Re: [TenTec] Solid State Amps

To: tentec@contesting.com
Subject: Re: [TenTec] Solid State Amps
From: Bill Fuqua <wlfuqu00@uky.edu>
Reply-to: tentec@contesting.com
Date: Mon, 08 Dec 2003 12:03:15 -0500
List-post: <mailto:tentec@contesting.com>
Wow, I did not expect so many emails between the first and the second.
But there are a lot of amplifiers that hams buy and modify for ham use that
are used in MRI, plasma generators, Sputtering systems, induction heating
etc. Many are very old. But in most cases are simply a box of parts that
are made into a useful amateur amplifier. A lot of this stuff works on 13.56MHz
(ISM) and is easily modified to serve as linear amplifiers for 20 meters. I have picked up
7 at University Auction sales. Not yet have had time to work on them.
I even got a FM broadcast transmitter for $1 one time and
found it was a collectable item. Sold it to another ham that is reconditioning it to show off at
the NAB show.
But any broad band RF amplifier will have to have a switchable low pass filter
following it to make sure that it does not produce harmonics that will cause others problems.


73
Bill wa4lav



At 11:19 AM 12/8/2003 -0500, Bill Fuqua wrote:


     (4) The amplifier is sold by an amateur operator to another amateur
     operator or to a dealer.

     (5) The amplifier is purchased in used condition by an equipment
     dealer from an amateur operator and the amplifier is further sold to
     another amateur operator for use at that operator's station.

So technically you can't use an non-type accepted amplifier built after April 28, 1978
if it is bought from a non-ham or from a vendor that bought it from a non-ham.

Now, after saying that I am sure that the FCC overlooks numerous cases where used equipment is
purchased that amateurs make amplifiers from or military surplus equipment is purchased for
amateur use.


However, one should suspect amplifiers built for the CB crowd to be of poor quality. They often
rate the power output 2 times or more greater than real PEP power as defined by the FCC.
What they (CBers) refer to as PEP Bird watts is the peak voltage squared divided by the load resistance.
This gives them twice the real PEP figure. Some even claim to get 1KW PEP from a single 4CX250B amplifier.
Which is an outrageous claim.
Also, the lack of harmonic filters to reduce spurious emissions is a real problem as well.
Many break into oscillation while in use.


73
Bill wa4lav

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