[Elecraft] LDMOS for QRO [OT]

[Gerry Hull]

Here's a 144MHz 1.5Kw water-cooled LDMOS amplifier putting out full power
in a June VHF contest, with me operating at W2SZ/1.
It was a cloudy day, and the amp was so cool, in fact, we were worried
about condensation.  Look at the size!  The power supply is a 50v/50a
surplus PC supply off of ebay.
The amp was built by Brian Justin, WA1ZMS.

I have found cold plates on the surplus market.   Every once in a while,
Electronic Surplus Sales in Manchester, NH has em.

Amp in Action:

https://www.youtube.com/watch?v=vegBv6ddAUA

73

Gerry Hull, W1VE   | Hancock, NH USA
AKA: VE1RM | VY2CDX | VO1CDX | 6Y6C | 8P9RM
<http://www.yccc.org> <http://www.yccc.org/>
<http://www.facebook.com/gerryhull>
<https://plus.google.com/+GerryHull/posts>     <http://www.twitter.com/w1ve>

On Sun, Dec 14, 2014 at 6:32 PM, David Cutter <d.cutter at ntlworld.com> wrote:
>
> I'm a little surprised that folks in this group haven't suggested liquid
> cooling for this modest application.  Semiconductor cold plates have been
> around for a long time, are economical to use and in my view a much better
> solution than forced air cooling.  They are compact, quiet, require far
> less cabinet space, keep junctions cooler and more stable than air could
> ever and enable higher reliability.
>
> Look at Aavid for instance, whose devices I used on many occasions:
> http://www.aavid.com/sites/default/files/products/liquid/
> pdf/liquid-cold-plate-datasheet-hicontact.pdf
>
> If you play your cards right, you can cool the amplifier and the power
> supply on a short 4-pass plate.  Put the heat somewhere convenient, not in
> your shack.
>
> 73
>
> David
> G3UNA
>
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