"John Smith" wrote in message
...
wrote:
Transformer oil.

Try your local power company. typically they will either sell it to
you, or, sometimes when they find out that you only need a gallon or
so, they'll just give it to you. Mine did.
- 'Doc

No one knows about silicone oils? Break down is a few hundreds of
degrees, good thermal conductivity, ... benign to all components,
including any gaskets, I can possibly think of, etc. Also, if you are
into health/toxic concerns, purchase a food grade ...

Regards,
JS


Silicone oils are excellent from a health standpoint and usually very good
from a flammability standpoint. However, the Cantenna relies on natural
convection of the oil for cooling and the higher viscosity of commonly
available silicone oils will limit the power handling capability of the
Cantenna. Remember that the Cantenna must be de-rated when used for long
duty cycles, and a high viscosity oil will lower the power rating still
more. Also remember that silicone oils are not cheap (and my buddy at Dow
would only send me small samples).

I would suggest using modern RF terminations made by Bourns and other
companies. These are designed to be bolted to a large heatsink. The
CHF9838CNF series is rated for 50 ohms, 250 watts, VSWR below 1.1 from DC
to 2.2 GHz. It only costs $27.50 in single lot quantities. I think this
is higher than the continuous rating of the Cantenna. I don't know for
sure as I disposed of my Cantenna years ago. Digi-Key sells these Bourns
terminations if you want one.

I had used transformer oil given to me by the local electric cooperative.
I didn't learn until a few years later that the oil was contaminated with
Aroclor, a PCB oil. Proper disposal was easy for me as I then worked in
the research labs of a major chemical company that had an EPA licensed
incinerator specifically rated for PCB destruction. Even so, I had to
repackage the oil into special disposal bottles and give the incinerator
operators instructions that only one of the bottles could be burned daily.
Before anyone asks can they send their oil to me for disposal, I left that
company over 10 years ago and am now retired, so the answer will be no.

I did quite a bit of research on trade names of PCB containing oils. In
fact, the EPA's list found at
http://www.epa.gov/epawaste/hazard/t...bs/aroclor.htm is partly a
result of my study. About a third of the trade names on this list were
unknown to the EPA until I provided them to the Atlanta EPA office.

Barry L. Ornitz, PhD WA4VZQ

funkbastler,
To the best of my knowledge, yes.
- 'Doc


....I'm afraid to ask...

John Smith wrote:
John Smith wrote:

...
No one knows about silicone oils? Break down is a few hundreds of
degrees, good thermal conductivity, ... benign to all components,
including any gaskets, I can possibly think of, etc. Also, if you are
into health/toxic concerns, purchase a food grade ...

Regards,
JS

Actually, I don't know why anyone would use or suggest the use of
anything but silicone.

You can tear the case off your TV/radio, sit the chassis down in an
aquarium full of the stuff, turn it on and watch it! Pull it out,
remove the silicone, put it back in its' case and expect it to go to
live expectancy, or beyond ...

Try that with anything else ...

Regards,
JS

The word "overkill" leaps to mind.

NoSPAM wrote:


I would suggest using modern RF terminations made by Bourns and other
companies. These are designed to be bolted to a large heatsink. The
CHF9838CNF series is rated for 50 ohms, 250 watts, VSWR below 1.1 from
DC to 2.2 GHz. It only costs $27.50 in single lot quantities. ...Digi-Key sells these
Bourns terminations if you want one.

Thanks, Doc.

That's News I Can Use.

Erich wrote:
Jim-NN7K wrote:
funkbastler wrote:
On Thu, 01 Jan 2009 17:41:27 +0000, Dave wrote:

KC8QJP wrote:
a crisco can works well

http://www.mfjenterprises.com/Produc...uctid=MFJ-250X

Where's a good place to find transformer oil (besides at the top
of the utility pole outside the house)? Or, what's an acceptable
substitute?



Mineral Oil (available at your local drug store).

Just be prepared for some strange looks when you purchase a gallon of
mineral oil all at once. :-O

Is motor oil a conductor?

Mineral Oil (available at your local drug store).

Just be prepared for some strange looks when you purchase a gallon of
mineral oil all at once. :-O

Is motor oil a conductor?

Might burn and sludge up your resistor. Lots of additives you just don't
need.

I had a cantenna for 20 years with light mineral oil. there was a little
seepage to the top of the lid through the vent. I actually had transformer
oil but never used it because of the thought of that stuff seeping. It
really is a lot cleaner. Check feed stores, Vet supply stores, paint
stores, hardware. Check this out:
http://www.pugetsystems.com/submerged.php

On Jan 2, 10:23*am, "JB" wrote:
* Mineral Oil (available at your local drug store).



Just be prepared for some strange looks when you purchase a gallon of
mineral oil all at once. :-O

Is motor oil a conductor?

Might burn and sludge up your resistor. *Lots of additives you just don't
need.

I had a cantenna for 20 years with light mineral oil. *there was a little
seepage to the top of the lid through the vent. *I actually had transformer
oil but never used it because of the thought of that stuff seeping. *It
really is a lot cleaner. *Check feed stores, Vet supply stores, paint
stores, hardware. *Check this out:http://www.pugetsystems.com/submerged..php

One mistake I made with a cantenna was letting it sit on a concrete
floor. The bottom of the can rusted through from the outside. The
replacement can got a good coating of zinc chromate primer, followed
wirh red oxide, then acrylic enamel auto paint.

Jimmie

One mistake I made with a cantenna was letting it sit on a concrete
floor. The bottom of the can rusted through from the outside. The
replacement can got a good coating of zinc chromate primer, followed
wirh red oxide, then acrylic enamel auto paint.

Jimmie

Mine was always inside and never rusted. I have seen them rust outside
though. I put mine in a tray, worrying about seepage getting on the carpet
but it would only pool up on the top.

Might be worthwhile to shoot the new can with BBQ paint.

NoSPAM wrote:

...
Silicone oils are excellent from a health standpoint and usually very
good from a flammability standpoint. However, the Cantenna relies on
natural convection of the oil for cooling and the higher viscosity of
commonly available silicone oils will limit the power handling
capability of the Cantenna. Remember that the Cantenna must be de-rated
when used for long duty cycles, and a high viscosity oil will lower the
power rating still more. Also remember that silicone oils are not cheap
(and my buddy at Dow would only send me small samples).
...
unknown to the EPA until I provided them to the Atlanta EPA office.

Barry L. Ornitz, PhD WA4VZQ

Well, yeah ...

However, the last silicone oil I purchased was at an auction. I was a
cannery being close, about 2-3 years ago. It was a 5 gal. tin, seems to
be about 10w-15w (no zahn cup to even begin guessing viscosity with); it
was $20.00, if I remember correctly. (a lucky fluke, I admit, and food
grade to boot!)

However, if I had to choose a 2nd, easily available source, and cheap, I
would get some pint bottles of 100% silicone spray used for protecting
seats, dashboards, panels, etc. in autos. At $1.88 + tax--a pint, a
gallon would be under $20.00. And, again, a cheap easily available
source to all--without shipping costs ...

Presently, I used the auctioned silicone I purchased, on my car
interior, tires, etc. ... lol

You know, if everyone has so many problems in doing the simplest things,
makes one wonder what they do when they hit a real snag! scratches-head

Regards,
JS

Barry L. Ornitz, PhD WA4VZQ wrote:

Silicone oils are excellent from a health standpoint...

John Smith wrote:

However, the last silicone oil I purchased was at an auction... and
food grade to boot!)


I am a bit puzzled. IIRC, the silicone in women's breast implants
would/could/did leak and cause fairly serious health problems. Yet, Dr.
Ornitz says "Silicone oils are excellent from a health standpoint" and
Mr. Smith says: "food grade".

Could anyone take a shot at explaining this apparent dichotomy?

Inquiring minds want to know.