[Amps] Water cooled amp question

Steve Thompson g8gsq at ic24.net
Sat Mar 5 10:01:18 EST 2005


Karl-Arne Markström wrote:
> As far as I know ethylene glycol as automotive anti-freeze dates from
> the mid-20's
> when the "Prestolite" anti-freeze mixture was first marketed.
>
> It is believed that the high-enthalpy and high-boiling point
> properties were known before, and glycol used as a liquid coolant for
> aircraft engines in the same time period.
>
> If very high speed from a piston-engine powered aircraft was needed,
> a last resort could be
> to use almost pure ethylene glycol as a coolant, ...

Of interest to UK readers in particular, for some years I ran a very
modified 1300GT, which needed pure ethylene glycol as coolant otherwise the
cylinders furthest from the water pump would overheat and take out the head
gasket (in no time at all, as opposed to monthly...).
>
> My own experience from liquid-cooled "amps" come from the HF 1 kW
> SSA1000 and VHF/UHF 1 kW PA204
> solid-state units, both built in the 80's by  ITT-Standard Radio in
> Sweden.
>
> They are intended to use Fluorinert as coolant, but as it is very
> expensive and has an enerving tendency to escape through even very
> minute leaks, the amateur users I know of use a 50-50 mixture of
> distilled water and glycol.

One place I worked prototyped a 10kW mobile hf amp using Freon to cool a
4CX10000. The cooling was fine, but the circulation system worked like a Van
de Graaf generator and an almighty discharge took out the cooler section.
Happy days.

Steve



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