Sure sounds like the effects of resistance either in the cells
themselves or in the external circuit. From your description, I would
suspect the cells.
Interesting . . . we tend to think of batteries as "perfect" d-c sources
and forget that they have internal resistance just like other sources.
--
72/73, George W5YR - the Yellow Rose of Texas
Fairview, TX 30 mi NE Dallas in Collin county QRP-L 1373
Amateur Radio W5YR, in the 55th year and it just keeps getting better!
Icom IC-756 PRO #02121 (9/00) Kachina #91900556 (12/99) IC-765 (6/90)
Chuck Brudtkuhl wrote:
>
> >My attempts to operate my Delta II on a 12V deep cycle
> battery have
> >produced reports of distorted audio, which could only be
> eliminated by
> >reducing the output to below 40 watts. I have been advised
> that the rig
> >was probably FMing. This radio is only happy when fed with
> at least 13
> >volts, and comes into it's own at the magic 13.8vdc level.
>
> This thread may be dead, but I'm catching up on my reading.
> I just want to raise the awareness that all batteries are
> not created equally. This scenario fits a historic scenario
> of mine perfectly.
>
> I tried running 100W sideband off a Telco battery string. I
> was using a total of four strands of #6 stranded copper for
> the 15ft run .. plenty of capacity there for 100w. I also
> had slight FMing on SSB. It turns out that the batteries
> themselves, designed for steady current loads, responded to
> the near-instantaneous transition from 1/2 amp to 20 amp
> peak .. by dropping the voltage about 2 volts during that
> transition period. They'd take a steady state 20A load no
> problem (which is what they're designed for) .. but the
> transition period is what was causing the FMing .. and since
> SSB is continuous transition periods .... hence it may not
> be the radio ... likely is NOT the radio. You can test the
> radio by running it on a REGULATED supply at low voltage.
> May have been the battery.
>
> I'm no battery expert, but I've never forgotten this real
> life situation. I always wanted to try it sometime with
> some hefty caps across the line to help "fill" the
> transition periods .. but never did.
>
> 73 de Chuck
--
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