There is no logic in using vacuum relays in place of a bandswitch in a ham
amp at 2500-3200V or so. The senior Ameritrons certainly dont have a blown
bandswitch reputation even at 3200V.
If an amp arcs then fix the problem with some engineering and not mask it
with brute force or no personal experience.
Carl
KM1H
----- Original Message -----
From: "Al Kozakiewicz" <akozak@hourglass.com>
To: "MU 4CX250B" <4cx250b@miamioh.edu>
Cc: <amps@contesting.com>
Sent: Sunday, January 19, 2014 10:43 AM
Subject: Re: [Amps] Building an Amp 101
To make it clear, I've never tried this so I'm not speaking from personal
experience.
But it seems logical to me that if a vacuum relay is required for the
voltages and duty involved, then a bandswitch is out of the question as
well, isn't it? My thought is that, putting aside questions around
stray-L that might arise from the insertion of a relay, it's easier to
find a relay with sufficient contact spacing than it is to find a
bandswitch with a large enough diameter to maintain the same spacing
between contact elements.
I guess these sorts of problems is why it's called engineering and not
science!
Al
AB2ZY
-----Original Message-----
From: MU 4CX250B [mailto:4cx250b@miamioh.edu]
Sent: Sunday, January 19, 2014 9:32 AM
To: Al Kozakiewicz
Cc: amps@contesting.com
Subject: Re: [Amps] Building an Amp 101
Relays are certainly a possibility, Al, but for a nine band amplifier
things get a bit complicated. My latest project ( 90% completed) is a
duo - band 80m/160m amplifier with a pi- L tank circuit, and for that I am
using two DPDT vacuum relays, each of which cost over $100.
Scaling that up to a nine band amplifier doesn't seem very practical or
cost-effective.
73,
Jim w8zr
Sent from my iPhone
On Jan 18, 2014, at 8:52 AM, Al Kozakiewicz <akozak@hourglass.com> wrote:
Why not use relays appropriate for the switching duty? Then the
bandswitch can be just about anything or even remotely controlled. Plus
you can locate the switch where it's convenient to operate instead of
being constrained by the necessity to place it close to the RF
components.
Al
AB2ZY
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