John,

That's why I used a tuner in between the rig and the amp because sometimes 
tuned inputs need to be retuned because that jump is seen when the power 
goes from 100 to 1000 watts.

I ran an SB220 myself and I often had to fine tune, after tuning under 100 
watts of drive, when I punched in the amp to over a KW.  Sometimes just the 
RF generated in the room can effect the SWR although it is 1 to 1 when 
running just the radio without the amp but you punch that amp, any amp, up 
to full power, and it is going to generate extra RF in the room.


Phil.
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----- Original Message ----- 
From: "John Miller" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, October 20, 2009 11:06 AM
Subject: Re: Amplifiers and SWR.


> It shouldn't jump that much, 1.0 to a 1.4 maybe but not over 2, something
> else is going on there. Mine doesn't change the tiniest little bit.
> ----- Original Message ----- 
> From: "Phil Scovell" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, October 20, 2009 12:59 PM
> Subject: Re: Amplifiers and SWR.
>
>
>> It is commonplace, one you are tuned at low power settings, for the SWR 
>> to
>> jump up a ways when you punch the big power into it.  Just turn the SWR
>> down
>> and you'll be fine.  I've used double tuners myself when I didn't have a
>> tuned input on the amp, and using two tuners works fine as well.
>>
>> Phil.
>> [log in to unmask]
>