[Amps] Distilled water in a dummy load ?

Jim Thomson 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?
<Bill wa4lav

##  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.  

Jim  VE7RF

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