[Elecraft] Some "Cool" heat sink info.

[Edward R Cole]

From: Gerald Wilson <kf5jnu at gmail.com>
To: Elecraft at mailman.qth.net
Subject: [Elecraft] Some "Cool" heat sink info.
Message-ID: <53E89DA2.6040208 at gmail.com>
Content-Type: text/plain; charset=utf-8

It is a little long but has some good info and surprising results in it.

https://www.youtube.com/watch?feature=player_embedded&v=8ML1tRnUIZo

73,
KF5JNU
----------------

Pretty basic side-by-side test.

What it tells me is the thermal mass of the heat sink is more 
significant  than the  interface between radio and heat sink.  Both 
are aluminum, I assume, so thermal conductivity is probably the same.

I would have expected a uncoated smooth surface interface would work 
better, but in this example apparently no difference is detectable.

I have one of the "Coo!er KX" heat sinks installed on my KX3.
http://www.ve7fmn.ca/

I was an early buyer so Fred has done quite a bit of development 
since I bought mine.  I opted for the unpainted bare aluminum, 
thinking it might conduct a bit better.

The you-tube demo would suggest it may not have any significant 
difference from the powder-coated heat sink which looks nicer.

I performed the Elecraft Thermal Compensation Procedure on my KX3 and 
then ran some heat vs frequency tests using 5w RF output on 6m:
http://www.kl7uw.com/KX3.htm
http://www.kl7uw.com/KX3_FREQ_DRIFT_TABLE.pdf

Note the first ten curves were done before performing Temp 
Compensation. Frequency drift is up to 30-Hz in one minute 
key-down.  After the Compensation drift is most noticeable in the 
first couple minutes and tames to 5-Hz after 15-minutes running.  The 
frequency "bump" at 20-seconds running is probably due to a bad data 
point in the Temp. Comp. curve so I plan to repeat the Temp. Comp. Procedure.

I do not have curves published after installing the heat sink but 
drift drops to about 2-Hz, after the first three sequences from a 
cold-start.  I will repeat these tests for the 2M module.  Regarding 
drift at HF I would expect it to be proportionately less as Frequency is lower.


73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
Dubus Mag business:
     dubususa at gmail.com