[Milsurplus] Power supplies for boatanchor radios

Sun, 09 Jun 2002 09:18:21 -0400

Hi,

Most motor loads (like a dynamotor) will be a bit hard on the supply by it's
self. As you suspect the startup transient will trip the current limit as
well.

One simple solution would be to parallel the Astron and the battery.

The problem you get into is that most Astron supplies have foldback current
limit. The startup transient trips them out and they go into a low voltage
mode. At that point things don't work well and you may have to do something
about the fire :)

The parallel setup works pretty well if you get one of the supplies with
both constant voltage and constant current capability.  A lot of people will
run the supply through a *big* low forward drop diode into the battery. That
way if something goes wrong there is no fire. The constant current /
constant voltage combo is a bit more common on HP supplies than on Astrons.
These days with the world dumping test equipment for next to nothing you may
be able to find an HP for the price of an Astron.

    Take Care!

        Bob
        KB8TQ

----- Original Message -----
From: "J. Forster" <[email protected]>
To: "ARC-5" <[email protected]>; <[email protected]>;
<[email protected]>; <[email protected]>; "Milsurplus"
<[email protected]>
Sent: Sunday, June 09, 2002 2:44 AM
Subject: [Milsurplus] Power supplies for boatanchor radios

> Has anyone tried (and succeeded or failed) to run boatanchor radios, like
a WS
> 19 MK III, from power supplies like the Astron?
>
> I am currently using a deep discharge marine battery with float charger,
but it
> appears there is frequency drift as the battery discharges during a
> transmission. In this set, the dynamotor kicks in only when the set goes
into
> transmit mode. I am concerned about the supply's ability to handle the
startup
> transient.
>
> TIA,
> -John
>
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