eHam
eHam Forums => Mobile Ham => Topic started by: KC1SOZ on March 11, 2023, 02:20:55 PM
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Now that I figured out that an HF radio doesn't play well with the VHF/UHF repeater world, I went to Ham Radio Source and picked up an older FT-1900R for less than $90. I read the reviews beforehand, and understand that these have an overheating problem if they are transmitting for too long.
So my question is... has anyone installed a fan on the VERY large heat sink that is essentially the entire bottom and rear of the unit? I don't want to reinvent the wheel and get into trial-and-error mode if someone has already done this.
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The radio was designed to use just the heatsink. Why not just ensure that the heatsnk has sufficient air flow to properly convect and don't use a nuclear weapon to kill a cock roach. A fan might be over kill unless you are going to run this thing 100% non stop all the time constantly.
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these have an overheating problem if they are transmitting for too long.
What is "too long" -?
To be fair, adding a fan probably wouldn't hurt. It would be useful to know though under what conditions it will actually make a difference, e.g. prevent the radio from going into thermal limit. Fans add cost and reduce reliability, so it's a tradeoff between that and imposing a duty cycle.
I've added fans to equipment over the years and it doesn't take a lot. Running a 24V fan, or 2 12V fans in series results in sufficient airflow and almost no noise.
Even easier is to drop the power back. 50W out translates to about 50W dissipated, so at 25W out the heat generation is cut in half, but the signal strength goes down only a few dB. Sometimes that can make a difference but not often. You may find at 25W the duty cycle goes up enough that there's no thermal issue at all when operated the way you will use it.
Mark K5LXP
Albuquerque, NM