[Elecraft] LDMOS for QRO [OT]

[george fritkin via Elecraft]

Water cooling is OK for QRP.  A friend of mine was building a "special" contest amplifier.  He was working out the cooling which presented a problem because of the heat involved.  I suggested using an upright type freezer and put amp in the freezer,  It worked great!!
George, fritkin 

     On Sunday, December 14, 2014 3:55 PM, Mel Farrer via Elecraft <elecraft at mailman.qth.net> wrote:
   

 Good point David,
I have seen an industrial RF amplifier heat sink made out of a 1/4 " copper plate married to a aluminum water cooled plate.  Ran on a simple 120 VAC pump to a 5 gal tank, like my 5KW Bird water cooled dummy load that uses a total water waste system does the same dissipation.  As I remember, many years ago, it was rated at removing 5KW of heat.  I know should have the BTU but I don't remember.  
Mel, K6KBE

      From: David Cutter <d.cutter at ntlworld.com>
 To: elecraft at mailman.qth.net 
 Sent: Sunday, December 14, 2014 3:32 PM
 Subject: Re: [Elecraft] LDMOS for QRO [OT]
  
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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