[Amps] Yes SS needs ant tuner.

[Roger (K8RI)]

The antennas are fine and normal for those bands. Well maybe not quite 
normal as they are fan dipoles, but you are simply talking about remote 
tuning the antenna.  Close to what a remote tuner would do.  You can 
also just switch in series coils to essentially lengthen the antenna. 
It's just not continuous like the compressible coil. But both methods 
are essentially changing the ant frequency IOW, retuning.

73

Roger (K8RI)

On 12/14/2016 9:40 AM, Jim Thomson wrote:
> Date: Wed, 14 Dec 2016 02:59:16 -0500
> From: "Roger (K8RI)" <k8ri at rogerhalstead.com>
> To: amps at 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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