[1000mp] MPV Driving Amp

[Mike Schatzberg]

Hello Win:

Since you have a good match in the bypass position and don't require the
tuner, do try the Collins approach to lower the SWR when driving the
amplifier.

Take a 20 foot length of high quality RG 8 type cable, and permanently
install a PL 259 on one end.  Prepare the other end much the same way, but
do not install a connector.  Place the center conductor on that end
carefully into the SO 239 input connector (or what ever input connector is
used on your amp), being sure that no shielding is shorted to the center
conductor, and it is not shorted to ground.  Use a wooden clothespin to hold
the braided shield onto the ground side of the input connector.

Use low input power and tune your amplifier for maximum power output.  Check
your SWR on the radio internal SWR meter.  If the match is close to 1:1,
solder another connector onto the coax and you are done.  If it isn't quite
close enough, trim about 6 inches of coax, and measure again.  You should be
able to minimize the SWR in this manner.  Then, if you have a tuned input on
your amp, further adjust the input for minimum SWR on your internal meter.
When you have finished these low power adjustments, double check your work
at full power output.

73 and Happy DXing,

Mike
W2AJI
----- Original Message ----- 
From: "Win" <w0lz at winlyn.us>
To: <1000mp at mailman.qth.net>
Sent: Sunday, October 22, 2006 4:43 PM
Subject: Re: [1000mp] MPV Driving Amp


I think the reason I didn't have the drive I wanted was because the radio
was folding back power, because of the 2:1 SWR.  With the tuner out, I have
a 1:1 SWR through the bypass to the antenna on 15 meters.

Thank you all.  I now know a lot more than I did.

Win
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