Thanks Dave,
I'll give that a try my "return loss" meter is actually pc based and provides a
sweep generator (AIMuhf) then graphs the results of the sweep so I can likely
run a sweep and see which direction I need to go in. Can't wait to give it a
try.
Paul
Date: Wed, 25 Jan 2012 10:25:15 -0000
From: "Dave"
Subject: Re: [Amps] 432 MHz stripline
To: amps@contesting.com
Message-ID: <4F1FD88B.5256.68A1AA@dave.g8kbv.demon.co.uk>
Content-Type: text/plain; charset=US-ASCII
> I do have a signal generator and return loss meter that is accurate up
Tube installed (no extra load resistor) Lid on and all screws in and
secure, no power in any way connected.
Feed your sig-gen or sweeper into the PA Output jack, via a 10dB (at
most) attenuator then the return loss bridge. The resonance will be
obvious.
The 10dB pad is to stabailse the impeedance the sig-gen sees, so you get
consistant results. Have that loacted at the end of the cable by the RL
bridge, that is itself fitted directly on the amp's PA deck output
connector. You will of course have to turn up the sig-gen output to
compensate for the loss of the attenuator.
Idealy, a nice VNA is what you'd use, but a simple tunable sig-gen or
sweeper will do the job just as well.
Note, the dip in VSWR can be very narrow and not so deep as you expect,
so tune slow and carefull.
Enjoy.
Dave G0WBX.
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