Water has a very high dielectric constant, around 80, and it is a lousy
dielectric with high losses at any frequency you want to use it for. On top of
that, even distilled water is conductive if even so little. Once it get in
contact with any metal it will start to dissolve the metal and become ionized =
conducting.
Other than that, water would be very good for na dummy load with its high heat
capacity.
hans - N2JFS
-----Original Message-----
From: TexasRF <TexasRF@aol.com>
To: hanslg <hanslg@aol.com>; towertalk <towertalk@contesting.com>
Sent: Fri, Dec 4, 2015 12:45 pm
Subject: Re: [TowerTalk] Fwd: Oil For Dummy Load
What is wrong with using distilled water, $1.50 per gallon at Walmart? Works
just fine for amplifier cooling, no problem at 2000vdc and 1296 MHz. Not
flammable either!
73,
Gerald K5GW
In a message dated 12/4/2015 11:33:46 A.M. Central Standard Time,
towertalk@contesting.com writes:
I dime in the discussion, why not use something with the lowest viscosity
such as kerosene. That way the heat would be more efficiently removed.
Kerosene has a relatively low flam point so, unless you allow the temperature
to rise too much.
I, myself use a home made dummy load made from resistors packed in TO-220
capsules and mounted on a large, flat heat sink.
Hans - N2JFS.
-----Original Message-----
From: Bryan Swadener via TowerTalk <towertalk@contesting.com>
To: 'TowerTalk' <TowerTalk@contesting.com>
Sent: Tue, Dec 1, 2015 6:44 pm
Subject: Re: [TowerTalk] Oil For Dummy Load
Gary K4FMX asked only about the derating chart.
Fortunately for myself, oil viscosity is immaterial
since my HN31 won't ever see more than ~ 100W again
and I'll never need to change the FREE transformer oil.
Instead, for high power stuff, I use my scrap parts
1500W (100% D/C) DL that uses small flange-mounted
RF resistors. It's actually smaller than my HN-31.
vy 73,
Bryan WA7PRC
----- Original Message -----
> From: D. Scott MacKenzie
> To: Bryan WA7PRC
> Sent: Tuesday, December 1, 2015
> Subject: RE: [TowerTalk] Oil For Dummy Load
>
> Unfortunately they don't give the viscosity of the oil. Most transformer
> oil is mineral at a viscosity of 10-20 cst @ 40C. However, mineral oil can
> range from 10-1000 cSt. An identical viscosity mineral oil would perform in
> an identical fashion.
>
>
> -----Original Message-----
> From: Bryan WA7PRC
> Sent: Tuesday, December 01, 2015 12:53 AM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Oil For Dummy Load
>
> The chart is here: http://www.tinyurl.com/wa7prc-cantenna
>
> My scrap parts 1500W dummy load is here: http://www.tinyurl.com/wa7prc-dummy
> Though all the parts were free to me, outfits such as Henry Radio
>
> (http://stores.ebay.com/Henry-Radio) sell RF power resistors for
> reasonable
> cost on ebay.
> vy 73 es gl,
> Bryan WA7PRC
>
>> Date: Mon, 30 Nov 2015
>> From: Gary K4FMX
>> Subject: Re: [TowerTalk] Oil For Dummy Load
>>
>> There used to be a chart on the side of the Heath cantena that showed
>> the difference between transformer oil and mineral oil as far as
>> power/time. As I remember it was rather a significant difference.
>>
>> 73
>> Gary K4FMX
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