Hi Jerry,
Yes the little fan is a screamer. It's job is to remove heat from within
the K2 chassis rather than cool the actual PS transistors.
Now to rake over old coals.
A few years ago I was providing a signal source, QRSS 30 seconds dot
period for a mutual grey line propagation investigation between the
Falklands and the UK/EU. The fan became a problem because I left the K2
keying overnight at 20W and the shack is adjacent to the bedroom. The
lady of the house was unimpressed. To overcome this I purchased a 80mm
square 12V computer fan and experimented with location and orientation
to determine the best solution.
This is where there is a divergence of opinion. I found that by propping
up one side of the fan on a simple square wire loop so that it was 45
degrees inclined to the heat sink and blowing down on it at the location
of the PA's I could run the K2 at 30W output overnight and the fan never
activated, the heat sink remained cool and was acceptably quiet. Shack
ambient about +20C (68F).
At that time some hotly recommended that the correct way to orient the
fan was to place it directly on the heat sink sucking air through the
fins. I tried this but did not find this to be the most effective solution.
My logic, if you can call it that, is simply if I am faced with a hot
object, say a spoon full of soup, if I want to cool it a little I blow
gently on it, not try and suck air from all around it.
Whatever, I'm not going to die in a ditch over it.
I only used this arrangement for the rather extended duration of the
tests. Normal DXing which at the time netted me 200+ DXCC before I built
a K3 seldom activated the little screamer.
I can email you a picture of the setup if you wish.
Regards,
Mike VP8NO
On 07/08/2021 22:35, jerry wrote:
All,
Not sure if I'll actually be using this PA... The fan is just so
LOUD! It's like a mini turbine engine running on my desk.
- Jerry KF6VB
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