The short answer is 'No' - you don't need to 'tune' the input of the amplifier.
A 1.4:1 VSWR is pretty darn good. The VSWR straight through just says that
your load (I'm assuming your antenna) is pretty close to 50 ohms. When you cut
in the amplifier, you are now looking at the amplifier input and it's input
impedance is a function of lots of things including the output tuning. So it is
not at all uncommon to see a less than perfect VSWR on the input to the
amplifier and, indeed, it is not all that important as long as it doesn't the
higher VSWR doesn't cause your transceiver or transmitter to cut back the drive
too severely.
73
Bob Groh, WA2CKY
________________________________
From: Tomas Hood <nw7us.heliophile@gmail.com>
To: Amps reflector <amps@contesting.com>
Sent: Friday, September 11, 2009 7:00:41 PM
Subject: [Amps] Input SWR
Another question:
When I am bypassing the amp (amp is in Standby mode), the SWR reading
on my Icom IC-7000 exciter shows nearly 1:1 through the amp into the
antenna tuner/matching network. When I switch from Standby to Operate
mode (Ameritron AL-80A), the SWR reading moves closer to 1.4:1 - is
this an indication that the input stage of the amp needs to be
aligned?
I am very new to this amp world... thanks for helping me get my bearings...
--
73 de NW7US, Tomas David Hood - Bitterroot Valley of Montana
Singer/Songwriter/Guitarist : http://tomasdavidhood.com
Contributing editor:
CQ Magazine, CQ VHF, Popular Communications
Main Page: http://hfradio.org/
Twitter Space WX : @hfradiospacewx
Twitter NW7US : @NW7US
Podcast: http://podcast.hfradio.org/
Linux User #32405 - Since 1996
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