From: Gerald Wilson <[email protected]>
To: [email protected]
Subject: [Elecraft] Some "Cool" heat sink info.
Message-ID: <[email protected]>
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:
[email protected]
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