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[Amps] Yes SS needs ant tuner.

To: <amps@contesting.com>
Subject: [Amps] Yes SS needs ant tuner.
From: "Jim Thomson" <jim.thom@telus.net>
Date: Wed, 14 Dec 2016 06:40:54 -0800
List-post: <amps@contesting.com">mailto:amps@contesting.com>
Date: Wed, 14 Dec 2016 02:59:16 -0500
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
To: amps@contesting.com
Subject: Re: [Amps] Yes SS needs ant tuner.

On 160, 74, and even 40 those built in tuners are incapable of wide 
frequency changes.  I have 4 SS rigs. One is 200W while the others are 
all 100W out. None can cover all of those three bands unaided. The big 
Palstar tuners take care of the tuning with the aid of an AIM.

73

Roger (K8RI)

##  and just how far outa whack are your ants  for 160 /80 / 40m ? 
Feed the SS xcvrs  into the amp, then let the amp  worry about the swr,
which may well not work out....so u end up with having to manually tweak
an external tuner in the shack. 

##  id try an fix the ants using whatever method will work.   Seco systems
even makes a tornado drive, that only compress / expands one tubing coil.
That would work good for vert ants.   Then with the 10 x pre-sets, you
could quickly cover the entire band on either 160 or 80..or even 40m.
Bring up the closest pre-set, then manually tune the compressible coil
from there, with its up /down function.    It uses the Ameritron
SDC-102  screwdriver control box.   12 vdc motor inside the
seco tornado drive compresses the coil or expands it.

##  But they are not like a roller coil...which will go down to 0 uh.
The compressible coils  will  provide for a 2:1  ratio for max to min uh.
IE:  12-6 uh...or   8-4uh... or  20-10 uh etc.   You wont blow up
plastic coated .25 inch OD  cu tubing any time soon.  The digital
turns counter on the SDC-102 works superb. 

## thats one option. Vac relays and coils at the feedpoint is another option.
Another option is a motor driven vac cap,  we did that on a buddys  160m
vert.   Which consisted of a  T type top loading on a 100 ft tall wire..with 
elevated
grnd plane.   Flat swr across the entire 160m band. 

##  On any of these schemes, no tuner required in the shack, swr is always flat
across  160 /80 /40m..... so the tube or SS amp  or  SS xcvr is always happy..
and ditto with coax and coax connectors.  

##  then swr BW becomes a non issue.

Jim  VE7RF

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