[Elecraft] KPA1500 Cooling

[Luis V. Romero]

In the analog NTSC days, Harris UHF broadcast transmitters were liquid
cooled by stuff called UCARTHERM-HTF 6141 (If memory serves me). 

We called it "Vulcan Blood".  It was a special Ethylene Glycol much like
automotive anti-freeze but thicker and with lots of other goodies inside.
It was an interesting MSDS sheet.

An older RCA UHF TV Transmitter I remember "fondly" used distilled water.
There was a resistance sensor on the circulation system that measured the
resistance of the water.  The meter pointer on the yellow part of the meter
meant a long Friday overnight to Saturday morning session that week.
Usually quarterly. 

And, don't even think of turning the rig off during cold winter nights! The
heat exchanger had no heating element, and if you left the rig off for more
than a couple of hours, the water would freeze and crack it open, which was
a really bad thing to happen. 

No snow ever gathered in the vicinity of the heat exchanger exhaust duct.
There could be two feet of snow on the driveway, but there was always a spot
on the side of the building that was not only snow free, but often dry.
Often, the icicles on the adjacent windows were legendary!

Nobody ever thought of bypassing some of that heat into the building...
Those were the days of cheap energy.

Lu - W4LT 

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Date: Thu, 23 Jul 2020 16:46:00 -0400
From: <tony.kaz at verizon.net>
To: "'Paul Christensen'" <w9ac at arrl.net>,	<elecraft at mailman.qth.net>
Subject: Re: [Elecraft] KPA1500 Cooling
Message-ID: <02b001d66132$4664f990$d32eecb0$@verizon.net>
Content-Type: text/plain;	charset="utf-8"

Hi Paul,
I can't remember what we used to use for closed loop cooling. I don't think
we used distilled water because it's resistance would increase over time
from picking up ions from the metal. In our case it was cooling loops in a
copper 37" electrode. I thought it was some kind of antifreeze or maybe an
oil? And also isn't distilled water quite reactive?
To many bourbons ago ?
N2TK, Tony