[AMPS] explain this one

[Radiodan W7RF]

Hi Lane and Phil,

Here is a picture of the HENRY solution to this problem in the 3K Premier
(160-10M) series. I had a good picture of this and whipped up a quick page.
See http://radiodan.com/Henry/misc/3kprf_shortbar.htm
They used a shorting bar driven by a cam on the bandswitch.
I don't see why an RJ-1 or other relay wouldn't work as well.

73, Dan Magro W7RF, (President WARC 1999, member SCDXC, SCCC)
Manufacturers Rep & Distributor for HENRY RF Power Amplifiers.
www.radiodan.com <http://www.radiodan.com>     RFpower@radiodan.com
<mailto:RFpower@radiodan.com> A trip to our web site is worth the click!




> -----Original Message-----
> From: owner-amps@contesting.com [mailto:owner-amps@contesting.com]On
> Behalf Of zeitler@ibm.net
> Sent: Sunday, August 01, 1999 11:22 PM
> To: Phil Clements; amps@contesting.com
> Subject: Re: [AMPS] explain this one
>
>
>
> Phil,
> So the solution to the autotransformer action was in your case to
> short out
> the 160 meter section with a relay when not in use? I have a
> similar problem
> with my HB 3-500Z deck. When on 75 meters it arcs big time around the 160
> meter position on the switch. I have a few RJ-1As laying around. Wonder it
> that would be suitable to short out the unused turns?
>
> Lane
> Ku7i
>
> PS sorry abt responding to this older post so late.
> -----Original Message-----
> From: Phil Clements <philk5pc@tyler.net>
> To: amps@contesting.com <amps@contesting.com>; Alek Petkovic
> <vk6apk@eon.net.au>
> Date: Friday, July 30, 1999 6:12 PM
> Subject: Re: [AMPS] explain this one
>
>
> >
> >>When I tune up on 10m, I get arcing on the 160m position on the
> >bandswitch
> >>to the frame of the switch. This position switches in the 160m
> >padding
> >>capacitor. Nothing in the 160m circuit is connected when it's on 10m.
> >The
> >>tubes also get extra warm in the 10m position.
> >>
> >You have an autotransformer going for you. With the addition of the
> >WARC
> >bands plus 160 meters a coupling problem exists within the tank
> >circuit.
> >
> >If you will notice on the schematic of any of the late model 9 band
> >amps,
> >they utilize a band switch that shorts out 3-4 of the unselected
> >positions
> >Just shorting out the unused part of the Pi coil is no longer
> >effective due to
> >the autotransformer action. Even with roller coils, as in the Henry
> >3-K and
> >8-K Ultras, half of the Pi roller coil is shorted out with a relay in
> >addition to
> >the shorting strap on the roller itself. This problem will show up on
> >other
> >bands also, depending on your layout and components. I pulled my hair
> >out a few years ago when constructing my first 9-bander. Instead of 10
> >meters
> >arcing the bandswitch, it was 40 meters in my case. This has nothing
> >to do
> >with any oscillations, it is because 160 meters is a LONG way  up the
> >coil
> >from 10 meters!
> >
> >GL!
> >
> >(((73)))
> >Phil, K5PC
> >
> >
> >
> >--
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> >
> >
>
>
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>


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