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'....

(only joking)

--
from
Aero Spike

"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

"Spike" wrote

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'....

(only joking)

--
from
Aero Spike

That is funny. But since this has now become rec.batteries.car (just
kidding):

The reaction from battery acids, air and dirt are minimized with grease. But
mechanics who grease the inside of the cable-clamp and outside of the
battery post *before the connection is made* are not helping the electrical
connection - they're applying preventative maintenance for idiots - who
never clean their battery posts. Conductive paste is much more expensive
than grease. Those who know what they are doing use the former. Conductive
paste is specified in US Lightning protection (NEC-70/NFPA-780), and grease
is not allowed to be used in any mechanical connection there. Back to
antennas for a moment, we all know that grease (or conductive pate) does not
provide waterproofing of any kind. And most of you will accept that grease
is a dialectric, not a conductor. But after making a mechanical joint with
conductive paste (ensuring no air enters the joint, and conductivity remains
per the connected materials), and proper waterproofing is applied, you have
a safe and maintenance-free joint that will last for years. Or it would
anyway, if the same codes didn't require you to expose and mechanically
tighten every such joint once a year. That's why the expensive exothermic
(welding) of all grounding electrode conductor joints becomes a savings in
the long run. Unfortunately that is never practical along rooflines up on
masts and towers. So those mechanical joints must provide as little
impedance as possible, and survival of the equipment depends on this.

Because all transmitter antenna radials automatically become a part of the
lightning protection system, the materials used should be the best you could
afford, not the cheapest you can find. And the connections should likewise
be the best possible. The transmission system will be more efficient, and
safer.

Jack Painter
Virginia Beach, Virginia

On Sun, 9 Jan 2005 22:51:14 +0000, "Ian White, G3SEK" wrote:

wrote:
get a mechanised pizza cutter to make the wire slots and place it on
the wheel of a wheel barrow

Art, you're a genius!

SM2CEW's website describes a radial plough which attaches to the back of
a tractor, and can lay a full-sized Top Band radial in 2 minutes. I had
been lamenting the lack of a Volvo tractor (or the space to lay such
long radials) but a blade attached to a wheelbarrow might just do it...
or even to the lawn mower.

Opens up a whole new perspective on mowing the lawn.


Jock.

--

"Education is a progressive discovery of our
own ignorance."
- Will Durant

On Sun, 9 Jan 2005 22:51:14 +0000, "Ian White, G3SEK"
wrote:

wrote:
get a mechanised pizza cutter to make the wire slots and place it on
the wheel of a wheel barrow

Art, you're a genius!

SM2CEW's website describes a radial plough which attaches to the back of
a tractor, and can lay a full-sized Top Band radial in 2 minutes. I had
been lamenting the lack of a Volvo tractor (or the space to lay such
long radials) but a blade attached to a wheelbarrow might just do it...
or even to the lawn mower.

I just checked one of my catalogs from a restaurant supply store
(Bridge Kitchenware in New York City), and I notice they sell pizza
cutters with wheels as big as 5 inches in diameter. If you used hose
clamps to attach the handle of a pizza cutter to the end of a broom
handle, I bet that would make a dandy lawn slit cutter for laying
radials.

Bob
k5qwg

Spike wrote in
:

On Sun, 09 Jan 2005 15:52:22 GMT, David Edmonds
wrote:

Maybe it's the installation and not supplying that is under question -
though typically our government bring in a silly law such as this -
while they know that there is no right of entry to inspect.

The problem arises when you try to sell your house. A prospective
purchaser's solicitor will ask for the certificates for any work you
admit to having been done post Jan 1.

So you don't admit to any!

"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?

Bob
The idea is to not mess up the lawn PLUS controlling the depth of the cut.
When the slicer is on the wheel the main weight of the barrow is directly
over the slicer thus making it easir to slice the lawn at a controled depth
reducing the possibility of jamming at a lower depth.
The whole idea is not to mess up the lawn and by taking some flower pots
from one end and changing them over at the other end will look like you are
working hard in the garden and shaming the neigbors in front of yjeir wifes.
Cheers
Art
I might add I used a tractor system when I did mine which also inserted the
wire but you just don't mess with an English lawn or you will lose the
impression of perfection
and where wifes are known to use treezers for the final touch.
Reminds me of a story where a yank admired a particular lawn
at some notable tourist site.
He asked the ground keeper how he could duplicate it when he got home,
Certainly the groundskeeper replied but firt you must start the lawn several
centeries ago!
"Bob Miller" wrote in message
...
On Sun, 9 Jan 2005 22:51:14 +0000, "Ian White, G3SEK"
wrote:

wrote:
get a mechanised pizza cutter to make the wire slots and place it on
the wheel of a wheel barrow

Art, you're a genius!

SM2CEW's website describes a radial plough which attaches to the back of
a tractor, and can lay a full-sized Top Band radial in 2 minutes. I had
been lamenting the lack of a Volvo tractor (or the space to lay such
long radials) but a blade attached to a wheelbarrow might just do it...
or even to the lawn mower.

I just checked one of my catalogs from a restaurant supply store
(Bridge Kitchenware in New York City), and I notice they sell pizza
cutters with wheels as big as 5 inches in diameter. If you used hose
clamps to attach the handle of a pizza cutter to the end of a broom
handle, I bet that would make a dandy lawn slit cutter for laying
radials.

Bob
k5qwg

Following up all these comments, I hadn't expected such a comprehensive
and useful set of responses! Commiserations to the guy with "only" half
an acre. If only my yard were anything like as big as that.

Many thanks to everyone. Now where do I find the nearest horse doctor
....?

--
73
Ian, G3NRW

"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