[Amps] Distilled water in a dummy load ?
jim.thom at telus.net
Tue Feb 23 15:34:24 EST 2021
Date: Mon, 22 Feb 2021 18:04:35 +0000
From: "Fuqua, William L." <wlfuqu00 at uky.edu>
To: 'Amps group' <amps at contesting.com>
Subject: Re: [Amps] Distilled water in a dummy load ?
<You know that radiator coolant that Jack Leno talks about that is non-corrosive? I looked into it and found that it has half the heat capacity of water. It would be a good choice for cantenna perhaps, high boiling point and non-flamable and easy to clean up. I did <not keep track of this discussion but what about dielectric constants?
## Tell that to the 4 guys here in town who overheated and blew up their hot rods using that junk. It amounts to 100 % glycol. Sure the boiling point is sky high, and even higher with the typ 10-15 psi in a radiator loop.
Problem is, it does not extract heat worth a darn. On our local stock car track, they are NOT allowed to use glycol at all. Has to be 100% distilled water and ..water wetter, like redline etc. The water wetter stops the bubbles from
forming. Dunno, but I believe any additives would reduce the resistivity of the distilled water, which can cause grief, even though the peak RF voltages are no where near as high as say in Paul, W9ACs water cooled, vapour phase cooled alpha amp.
## I checked out the dielectric constant of plane tap water...and also distilled water. Tap water has a dielectric constant of 80. Distilled water also has a dielectric constant of 80. Air and also a vacuum has a dielectric constant of just 1.
Mineral oil and xfmr oil has a dielectric constant of 2.
## As I feared, the sky high dielectric constant of water and distilled water, being 40 times greater than mineral oil and also xfmr oil, will increase the stray C by a factor of 40... which will screw up the SWR.
## Good news is, I have easy access to real deal xfmr oil, like what is used in power company xfmrs. I just dont like my brazed and stacked steel paint containers, even though they hold 7- 8 gallons. They need to go into a bigger container, to ensure
if anything leaks, it would be contained. I can also get a hold of the steel pole pig power xfmr round casing, with removable top lid, and with no xfmr inside, leaves plenty of room for the array of resistors. I just found out I have access to longer version of the 200 ohm globars I currently have designed around. Mine are currently 1 inch diam x 12 inches long. I can also get them in 1 inch diam x 18 inches long, but that will involve welding all new alum tubes.
## The palstar, mfj etc, wont handle my power levels, so took them off the list. I also have a surplus 50 ohm load, with the same 4 x 1 inch diam x 12 inch long globars, in an air cooled chamber setup, but these are the old CX type, and can not be
immersed in oil. If in oil, the CX types will absorb the oil, and dc resistance will skyrocket..per the engineer folks at globar, per the phone call. CX types are .25 inch thick wall....and are dull grey in color. The SP types are shiny black, and are called glass coated...designed for oil immersion..and only have a .125 wall thickness. I dont have the mating air pump for the air cooled load.
## I will search about, and see if I can find a slightly bigger container to put the brazed 8 gal container inside of..to contain any oil leaks. I had one oil spill years ago, and it made a helluva mess on the concrete floor of my shop, and that was
just a very small qty, like 1 pint.
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