[Elecraft] [KX3] A Comparative Performance Assessment (of Aftermarket KX3 Heatsinks)

[Fred Townsend]

Gary radiation effects do not vary linearly as a function of ambient temperature  and are IMHO, a bigger error factor than anything Don has mentioned therefore ambient temperature should be stated. Also, again IMHO thermal resistance is a much better comparison between heatsinks. Ambient temp is needed if thermal resistance is to be computed.

73
Fred, AE6QL


-----Original Message-----
>From: "Gary W. Hvizdak" <gary.hvizdak at cfl.rr.com>
>Sent: Sep 2, 2014 12:23 PM
>To: elecraft at mailman.qth.net
>Subject: Re: [Elecraft] [KX3] A Comparative Performance Assessment (of	Aftermarket KX3 Heatsinks)
>
>Don (W3FPR) recently wrote ...
>
>"why does still air have to be in quotes?"
>
>Hi Don,
>
>    That was done so the wording "in still air" wouldn't seem like a
>grammatical error.  More importantly, here's an excerpt from a recent email
>from Adrian, addressing your inquiry regarding ambient temperature:
>
>"The ambient temperature was constantly monitored on the test bench by the
>transceiver using a very sensitive aviation anemometer.  This instrument can
>measure airflow down to fractions of a knot, and does so by monitoring
>temperature changes of a heated thermistor, as well as using a ducted fan
>whose speed is measured via a pulse-counting technique for higher speeds.  I
>managed to keep the ambient temperature stable throughout the test to within
>an indicated 0.5 degree C, so I was quite pleased with the actual test
>results."
>
>--- - - - ---
>
>    I certainly could have included details like this in the final report,
>but tried to avoid providing too much information, and also tried to limit
>the document to two pages without resorting to a tiny font.  More
>importantly, IMHO Adrian's test environment and methodology were sufficient
>for his intended objective, which was to compare the performance of the
>various aftermarket offerings to one another, for the purpose of ranking
>them.  Yes, higher resolution temperature measurements would have made the
>results more meaningful; but that evaluation is left as an exercise for the
>reader.
>
>    BTW, check out http://www.ve7fmn.ca/faqs/#about_testing for a
>description and photo of the setup Adrian had used for his original
>comparison of the factory/stock heatsink and his Cooler KX(TM) Lite, which
>used an entirely different methodology.
>
>73,
>Gary  KI4GGX
>webmaster http://www.ve7fmn.ca/
>
>
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