Hi Don.
Thanks for the info.
The PSU has 33000uF reservoir already, and all other radios tried on the
supply work fine.
I'm going to check out the internal wiring etc. of the TT radio and if
nothing found a car battery will be tried.
Paul MW0CDO
----- Original Message -----
From: <VE1BN@aol.com>
To: <gw7lhi@hotmail.com>
Sent: Wednesday, March 27, 2002 1:36 PM
Subject: Re: [TenTec] RE: Omni V Fm'ing
> Hello Paul -
>
> Perhaps you need a much larger filter capacitor in your PS to increase its
> dynamic stability.
>
> Many (not all) PS today are a bit "undercapt" with the result the steady
> no-load voltage output will drop instantaneously (and relatively deeply)
at
> the start of a CW or SSB load for a few milliseconds, then recover. It is
> quite noticeable on an oscilloscope looking at the output voltage.
Remember
> these drops are only at the instantaneous starting of a load and are very
> short. Probably enough of a drop to vary the voltage on a sensitive
circuit
> to cause the "FM-ing" you are plagued with.
>
> I found by adding capacity, a large one for the 12-15 volts high current
PS
> needed by today's rigs, the voltage will not have this effect, and remains
> steady. My homemade regulated PS have a minimum cap of 30,000 uF.
>
> Steady state voltage under load (minimum change from load to no load) is
> really a problem with insufficient capability of the power transformer or
the
> general dynamics of the PS. If the output voltage droops too far, then
the
> transformer is to be blamed. But - this is not what would cause your
> "FM-ing". Just another thought (ha).
>
> Hope this will give you some food for thought, and will be of help. Good
> luck.
>
> 73 -
>
> Don ve1bn@aol.com
>
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