Re: [TowerTalk] Heath Cantenna

[Jim Lux <jimlux@earthlink.net>]

Mineral oil and Transformer Oil (i.e. Diala AX) ARE the same thing... The 
MSDS for Diala AX says that it is mineral oil (more precisely: highly 
refined petroleum oils).

Maybe it's a viscosity thing... Mineral oil from the drugstore comes in 
several viscosities.  Diala is pretty non-viscous and runny (not as thin as 
water... about like room temperature cooking oil)

The other differences are subtle chemical things. USP mineral oil has a 
limit on PolyAromatic Hydrocarbons (PAHs) which are potentially 
carcinogenic (if you immerse yourself in the stuff for long periods of 
time, there's an increased incidence of testicular cancer... in the context 
of oil mist/spray from machining operations), while transformer oil doesn't 
claim to be particularly free of it.

Diala is also slightly yellowish (straw colored), while USP mineral oil has 
to be "water white".  However, that's not due to particulate contamination 
(i.e. soot) which would kill the dielectric properties, but due to less 
refining of the oil, so there are some colored compounds in there (probably 
things with benzene rings...PAH's among others).

$25/gallon for the real thing is quite high... Unless it included shipping 
and tax, considering you can buy 5 gallons for under $30.  Somehow, I doubt 
MFJ is going to certify the water/contaminant content, as delivered, too.

http://www.shell-lubricants.com/products/product_list.php?subcatid=26

Here's the Diala A and AX data sheet:
http://www.shell-lubricants.com/products/pdf/DialaA&AX.pdf

There's also a Diala M
http://www.shell-lubricants.com/products/pdf/DIALA%20OIL%20M.PDF

and HFX, which is fire resistant
http://www.shell-lubricants.com/products/pdf/DIALA%20OIL%20HFX.PDF

At 09:07 AM 6/7/2004 -0700, Michael Tope wrote:
> ----- Original Message -----
> From: "Jim Lux" <jimlux@earthlink.net>
>
> >
> >
> > Thermal properties are basically the same as USP mineral oil (drugstore
> > oil).  The big differences:
> >
>
> Jim are you sure about that? The reason I ask is that both
> the Heath and the MFJ Cantenna style dummy loads specify
> duty cycle curves for mineral oil and "transformer oil". For
> 1KW, the duty cycle for mineral oil goes to zero, whereas they
> specify 10 minutes (I assume this is from a room temperature
> oil baseline) for transformer oil. Either Heath and MFJ cooked
> the numbers to sell more transformer oil (MFJ sells it for
> $25/gallon), or "transformer oil" is actually better at pulling heat
> away from the Carborundum resistor.
>
> In any case, if this is wrong, I would like to know. Getting
> mineral oil in small quantities is a lot easier and cheaper than
> trying to find real transformer oil.
>
> 73 de Mike, W4EF...............................................
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless 
> Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with 
> any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________

See: http://www.mscomputer.com  for "Self Supporting Towers", "Wireless Weather Stations", and lot's more.  Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk