[Elecraft] K3 and Alpha 87A SWR

[Dick Green WC1M]

I've been running a K3 into an Alpha 87A for years, and SWR is just fine.
The coax between the K3 and amp happens to be 15-20 feet, but that length is
just what was necessary for the run between the shack and an equipment
closet in the basement where the amp is located. I have found in the past,
however, that it's best if the coax is at least 6' long, as recommended by
Alpha.

High input SWR on some bands most likely means something is wrong in the
input circuit, such as bad contacts on the wafer switch, burned out
resistors or inductors, etc. You can also get high SWR if the contacts on
the large band switch aren't properly aligned. The alignment is set by the
factory and stored in program memory. There's a simple procedure for
re-aligning the band switch and storing the new stepper motor position in
memory.

I suggest you contact RF Concepts and ask them for help.

73, Dick WC1M

> -----Original Message-----
> From: Merv Schweigert [mailto:k9fd at flex.com]
> Sent: Wednesday, August 22, 2012 8:10 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3 and Alpha 87A SWR
> 
> I use a 99 with the K3 and any length coax works just fine,  it there is
> SWR on the
> line there is a problem someplace,   have never had to cut a coax to any
> particular
> length.
> If theres SWR its either a ground differential problem between the amp
> and radio chassis or the tuned input is not correct,  or the amps input
> resistor has been cooked.
> Merv K9FD/KH6
> > On Aug 22, 2012, at 1:01 PM, Jim Brown<jim at audiosystemsgroup.com>
> wrote:
> >
> >
> >> You
> >> might try engaging the auto tuner in the K3 if you have one.
> >>
> > Be aware that both the Alpha 87A and 99 manuals tell you "NEVER use an
> automatic antenna tuner into or through the [87A or 99].  This will
> cause damage to the Input Wattmeter&  Input Relay."
> >
> > It's largely because of this prohibition that I don't even have a KAT3
> in my K3.
> >
> > Bud, W2RU
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