"Spike" wrote in message
...
On Sun, 9 Jan 2005 16:35:20 -0500, "Jack Painter"
wrote:

Guys, the last time I checked, this was not rec.car.battery. We're
talking
about antennas and RF, not DC connections to your car battery. Using
grease,
even outside the made connection, will eventually penetrate the spaces.
Maybe this doesn't matter to the 50-100w user, but it matters to high
power
connections, the most notable of which is lightning.

Here in the UK I'll think you'll find the lightning conductors have
greased joints.

I always thought it was the origin of the term 'greased lightning'....


Plus, of course, the issue isn't so much the power as the current when
thinking of high resistance connections. The cranking current drawn via a
car battery terminal is around 100A. If the grease ingress caused a high
resistance connection, the car wouldn't start. In practice, ungreased
connections tend to 'go high' due to corrosion.



--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898

"Brian Reay" wrote in
:


"Spike" wrote in message
...
On Sun, 9 Jan 2005 16:35:20 -0500, "Jack Painter"
wrote:

Guys, the last time I checked, this was not rec.car.battery. We're
talking about antennas and RF, not DC connections to your car battery.
Using grease, even outside the made connection, will eventually
penetrate the spaces. Maybe this doesn't matter to the 50-100w user,
but it matters to high power connections, the most notable of which
is lightning.

Here in the UK I'll think you'll find the lightning conductors have
greased joints.

I always thought it was the origin of the term 'greased lightning'....


Plus, of course, the issue isn't so much the power as the current when
thinking of high resistance connections. The cranking current drawn via
a car battery terminal is around 100A. If the grease ingress caused a
high resistance connection, the car wouldn't start. In practice,
ungreased connections tend to 'go high' due to corrosion.




It's not normally grease, it's vaseline, which is conductive. I don't know
how vaseline behaves at RF, though. Maybe not too well?

"Alun" wrote in message
...

Plus, of course, the issue isn't so much the power as the current when
thinking of high resistance connections. The cranking current drawn via
a car battery terminal is around 100A. If the grease ingress caused a
high resistance connection, the car wouldn't start. In practice,
ungreased connections tend to 'go high' due to corrosion.

It's not normally grease, it's vaseline, which is conductive. I don't know
how vaseline behaves at RF, though. Maybe not too well?

If it isn't in the the current path (ie between the mating surfaces) and
also not acting as an unwanted path (eg between the earth clap and the
antenna), does it matter? OK, you may get some local absortion of RF energy,
but how much grease are you going to use? Not enough to absorb much RF and
the mass of grease (or vaseline) will be far less than other unquantified RF
conductors and absorbers in the vicinity.

You need to look at things like this in the context of the problem.

--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898

On Mon, 10 Jan 2005 06:25:05 -0000, "Brian Reay"
wrote:

You need to look at things like this in the context of the problem.

Brian,

I replied to Jack Painter elsewhere (q.v.) in which I quoted your
posting as part of my reply. Hope you don't mind.
--
from
Aero Spike

"Spike" wrote in message
...
On Mon, 10 Jan 2005 06:25:05 -0000, "Brian Reay"
wrote:

You need to look at things like this in the context of the problem.

Brian,

I replied to Jack Painter elsewhere (q.v.) in which I quoted your
posting as part of my reply. Hope you don't mind.

Not at all, I'll send a bill for my normal fee ;-)
--
Brian Reay
www.g8osn.org.uk
www.amateurradiotraining.org.uk
FP#898

On 10 Jan 2005 03:52:38 GMT, Alun wrote:

It's not normally grease, it's vaseline, which is conductive. I don't know
how vaseline behaves at RF, though. Maybe not too well?

What about silicon grease?


Jock.

--

"The graveyards are full of indispensable men."
- Charles de Gaulle (1890-1970)

Jock. wrote:

: On 10 Jan 2005 03:52:38 GMT, Alun wrote:
:
: It's not normally grease, it's vaseline, which is conductive. I don't know
: how vaseline behaves at RF, though. Maybe not too well?
:
: What about silicon grease?
:

ah now Jock.... thats just too technical... next thing you'll be
mentioning which ''number'' of grease which will really confuse them!

ZZZPK wrote:

Jock. wrote:
: What about silicon grease?

ah now Jock.... thats just too technical... next thing you'll be
mentioning which ''number'' of grease which will really confuse them!

I hear that KY has introduced a heat producing grease.
--
73, Cecil http://www.qsl.net/w5dxp


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