[BC] In search of Harris SX1

[dynotherm at earthlink.net]

BE AM-1A's are shipped back to Quincy for frequency change. There are
"irregularities" not easily dealt with in the field according to a very
senior ex-BE engineering manager. Fortunately, the size of the AM-1A
makes shipping easy, and factory charges for frequency change are
reasonable. I don't know how this plays out with Nautel or Harris in
their current rack mount models (J-1000 and DAX-1 respectively).

I do know if you are going to do a Harris (either SX or Gates) that 
Mike is dead on. Either you have a working RFVNA and someone who
knows how to use it as well as knowing RF network design and 
construction, you will not pass go, but you may find funny numbers
you can't begin to fix in the NRSC if one is done. You may also
find the box develops an extreme appetite for PA transistors.

My point is that unless you can find a Gates 1 box ON FREQUENCY and
in good condition, by the time you buy it, ship it, refurbish it, 
put it on frequency, get a clean match and get a clean NRSC, you
probably will spend close to if not more than a new box. Notice
I said ON frequency - not near frequency.

On frequency, the Gates 1 is not a bad choice or tight space because
it has about half a rack or maybe a little more available for 
mounting equipment in the unused space in the built-in rack of the
cabinet. But, if the station insists on trying to do a lashup of
an off frequency box, they will attract undesirable attention and
will get fined. The station probably will find PA transistor 
replacement eating them alive. 

Paul, this station may be broke, but one way to guarantee they will
be "more broke - or broker" is for them to try using an old Gates 1
that came out of Quincy on some other frequency, especially if they
insist on trying to do it on some kind of "temporary lashup."

You have gotten a lot of good advice in this thread. The consequences
of ignoring this advice will be either spending a lot of money to put
the transmitter on frequency or a) violating the license which requires
a type accepted transmitter; b) illegally radiating a grossly excessive
3rd harmonic signal which will be easily detected at many locations in
the eastern US; c) a high probability of PA transistor over-dissipation.
These are the results of engineering facts rooted in the unique design
of the output network of the Gates 1 and all similar models.

I wish you good luck.

Phil Alexander, CSRE, AMD

-----Original Message-----
>From: Mike McCarthy <Towers at mre.com>
>
>I think that applies to many TX's these days.  The parts variations and 
>configurations used across the two octaves of the AM band are quite diverse.
>
>I used a NA to fine tune one of my SX-5's after one of the C-1 door knobs 
>failed.  Let me tell you it was 4 hours of fun.  But we did get it nailed 
>and found and cured a few others things going on in the process.  The box 
>is still not operating right.  But we KNOW the output network is where it 
>belongs.