[TowerTalk] Fwd: Oil For Dummy Load

[Hans Hammarquist]

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 at contesting.com>
To: 'TowerTalk' <TowerTalk at 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 at 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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