[Elecraft] LDMOS for QRO [OT]

[Wes (N7WS)]

Unless you want to run fresh water down the drain (in Arizona we don't do this) 
you have to get the heat into the air someplace.  I'm not sure that running 
water lines to outside air is much easier than getting coax through a concrete wall.

Speaking of difficult, the U.S. Navy AIM-54A Phoenix Missile which with I was 
intimately familiar, used oil (Coolanol) cooling. Chassis were mounted on cold 
plates and the vacuum tube modulator and pulse transformer were immersed in oil 
and it also circulated through the PA klystron.  Lines ran from the missile 
umbilical to the wing or belly mounted launchers then to the F4 aircraft where a 
conditioning unit resided.  The stuff was insidious to work with.  I ruined lots 
of clothes,  And it was hygroscopic, just the thing to use on a ship-borne system.

Wes  N7WS
>
> On 12/14/2014 4:32 PM, David Cutter 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
>>
>