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Silicone Grease In Coax Connectors; Comments And Questions ?



 
 
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  #1  
Old February 26th 06, 05:15 PM posted to rec.radio.shortwave
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Default Silicone Grease In Coax Connectors; Comments And Questions ?

Hello:

Regarding those Si paste products that one see advertised to coat the
innards of a coax
type of connector to prevent moisture seepage, be an anti-oxidant, and all
other great things:

e.g. from ICE:

"Model 615 items are comprised of a synthetic silicon grease material, thick
but easily spreadable. Suggested uses are to fill the void of RE connections
or high voltage joints. Grease is easily pushed out of the way by mating
conductors, but fills the void around them to prevent air and moisture from
settling in. Excellent dielectric characteristics, non-miscible with most
chemical agents or vapors, grease is opaque and maintains thick viscous
nature in temperatures ranging from -60F to 500F."

Not at all certain about this, but my guess is that even after pushing the
contacts together, the boundary layer film that separates the metal male and
female parts would be at least of the order of a micron; probably more.

For transmitting power levels, I guess there is more than enough current
flow to puncture thru easily.

But what about for a receiving only application, with what, micro-amps,
across the gap ?

Does this silicone "layer" present any problems, or signal degradation, in
your experiences ?

Good thing to use in coax connectors going to a receiving antenna ? Or,...?

Thanks,
Bob


  #2  
Old February 26th 06, 05:27 PM posted to rec.radio.shortwave
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Default Silicone Grease In Coax Connectors; Comments And Questions ?

On Sun, 26 Feb 2006 12:15:54 -0500, "Robert11"
wrote:

Hello:

Regarding those Si paste products that one see advertised to coat the
innards of a coax
type of connector to prevent moisture seepage, be an anti-oxidant, and all
other great things:

e.g. from ICE:

"Model 615 items are comprised of a synthetic silicon grease material, thick
but easily spreadable. Suggested uses are to fill the void of RE connections
or high voltage joints. Grease is easily pushed out of the way by mating
conductors, but fills the void around them to prevent air and moisture from
settling in. Excellent dielectric characteristics, non-miscible with most
chemical agents or vapors, grease is opaque and maintains thick viscous
nature in temperatures ranging from -60F to 500F."

Not at all certain about this, but my guess is that even after pushing the
contacts together, the boundary layer film that separates the metal male and
female parts would be at least of the order of a micron; probably more.

For transmitting power levels, I guess there is more than enough current
flow to puncture thru easily.

But what about for a receiving only application, with what, micro-amps,
across the gap ?

Does this silicone "layer" present any problems, or signal degradation, in
your experiences ?

Good thing to use in coax connectors going to a receiving antenna ? Or,...?

Thanks,
Bob


Why?



  #3  
Old February 26th 06, 06:44 PM posted to rec.radio.shortwave
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Posts: n/a
Default Silicone Grease In Coax Connectors; Comments And Questions ?

Robert11 wrote:

For transmitting power levels, I guess there is more than enough current
flow to puncture thru easily.

But what about for a receiving only application, with what, micro-amps,
across the gap ?

Does this silicone "layer" present any problems, or signal degradation, in
your experiences ?

Good thing to use in coax connectors going to a receiving antenna ? Or,...?



There is bound to be a voltage drop across across almost any
mechanically joined conductors. A light switch has a voltage drop across
it's contacts. A solder joint would a greatly decreased drop, but it's
there regardless. A solder joint is a mechanical connection, while a
weld is a chemical fusing.

I wouldn't think the silicon layer is consistent throughout the contact
area. There are most likely high areas of metal to metal contact, with
the paste filling in the valleys.

Any loss of the borderline contact areas due to silicon invasiveness
would be more than made up for by the protection from oxygen, ozone and
water given to the good 'peak' areas. The good stays good longer.

We could do a simple test with a connector, some coax, a small battery,
a limiting resistor and an accurate voltmeter. A series of before and
after tests could be performed, trying different substances. Vaseline
has been used for battery post connectors for years.

As an unrelated side note, I met a mechanic once who carefully cleaned
off all that white grease from back of regulators and diodes before
installing them. It took him years to figure out what the stuff was
meant to do. He had a real 'sinking' feeling when he found out.


mike
  #4  
Old February 26th 06, 06:59 PM posted to rec.radio.shortwave
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Posts: n/a
Default Silicone Grease In Coax Connectors; Comments And Questions ?

On Sun, 26 Feb 2006 18:44:47 GMT, m II wrote:

Robert11 wrote:

For transmitting power levels, I guess there is more than enough current
flow to puncture thru easily.

But what about for a receiving only application, with what, micro-amps,
across the gap ?

Does this silicone "layer" present any problems, or signal degradation, in
your experiences ?

Good thing to use in coax connectors going to a receiving antenna ? Or,...?



There is bound to be a voltage drop across across almost any
mechanically joined conductors. A light switch has a voltage drop across
it's contacts. A solder joint would a greatly decreased drop, but it's
there regardless. A solder joint is a mechanical connection, while a
weld is a chemical fusing.

I wouldn't think the silicon layer is consistent throughout the contact
area. There are most likely high areas of metal to metal contact, with
the paste filling in the valleys.

Any loss of the borderline contact areas due to silicon invasiveness
would be more than made up for by the protection from oxygen, ozone and
water given to the good 'peak' areas. The good stays good longer.

We could do a simple test with a connector, some coax, a small battery,
a limiting resistor and an accurate voltmeter. A series of before and
after tests could be performed, trying different substances. Vaseline
has been used for battery post connectors for years.

As an unrelated side note, I met a mechanic once who carefully cleaned
off all that white grease from back of regulators and diodes before
installing them. It took him years to figure out what the stuff was
meant to do. He had a real 'sinking' feeling when he found out.


mike


I have made thousands of professional RF connections (not Cable TV)
and never have I seen a connector that requires greasing.

We use Andrew 221213 Waterproofing Kits, on the OUTSIDE of the
connection. Good RF connectors are usually silver plated and require
no grease.

  #5  
Old February 26th 06, 07:11 PM posted to rec.radio.shortwave
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Posts: n/a
Default Silicone Grease In Coax Connectors; Comments And Questions ?

David wrote:

I have made thousands of professional RF connections (not Cable TV)
and never have I seen a connector that requires greasing.

We use Andrew 221213 Waterproofing Kits, on the OUTSIDE of the
connection. Good RF connectors are usually silver plated and require
no grease.



I can see that. I'd imagine the waterproofing kits have to be pretty
well made to keep moisture out. Silver, while a lot better conductor
than gold, oxidizes very easily. Lots of oxides don't conduct
electricity at all.




mike
  #6  
Old February 26th 06, 07:31 PM posted to rec.radio.shortwave
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Posts: n/a
Default Silicone Grease In Coax Connectors; Comments And Questions ?

On Sun, 26 Feb 2006 19:11:14 GMT, m II wrote:

David wrote:

I have made thousands of professional RF connections (not Cable TV)
and never have I seen a connector that requires greasing.

We use Andrew 221213 Waterproofing Kits, on the OUTSIDE of the
connection. Good RF connectors are usually silver plated and require
no grease.



I can see that. I'd imagine the waterproofing kits have to be pretty
well made to keep moisture out. Silver, while a lot better conductor
than gold, oxidizes very easily. Lots of oxides don't conduct
electricity at all.




mike

If the metal to metal contact is firm oxidation will not bother it.

It is not unusual for a typical TV station to have dozens of
''silver'' bullets in the transmission line (these join the inner
conductorsin rigid line) last for decades with no ill effects. They
are kept dry, of course.

  #7  
Old February 26th 06, 10:20 PM posted to rec.radio.shortwave
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Posts: n/a
Default Silicone Grease In Coax Connectors; Comments And Questions ?

In article ,
"Robert11" wrote:

Hello:

Regarding those Si paste products that one see advertised to coat the
innards of a coax type of connector to prevent moisture seepage, be
an anti-oxidant, and all other great things:

e.g. from ICE:

"Model 615 items are comprised of a synthetic silicon grease
material, thick but easily spreadable. Suggested uses are to fill the
void of RE connections or high voltage joints. Grease is easily
pushed out of the way by mating conductors, but fills the void around
them to prevent air and moisture from settling in. Excellent
dielectric characteristics, non-miscible with most chemical agents or
vapors, grease is opaque and maintains thick viscous nature in
temperatures ranging from -60F to 500F."

Not at all certain about this, but my guess is that even after
pushing the contacts together, the boundary layer film that separates
the metal male and female parts would be at least of the order of a
micron; probably more.

For transmitting power levels, I guess there is more than enough
current flow to puncture thru easily.

But what about for a receiving only application, with what,
micro-amps, across the gap ?

Does this silicone "layer" present any problems, or signal
degradation, in your experiences ?

Good thing to use in coax connectors going to a receiving antenna ?
Or,...?


I would not expect the silicone to remain as a barrier layer between
the male and female contacts. The contact pressure should cause metal
to metal contact. You could verify this with an ohm meter with a before
and after measurement.

If an insulative barrier was formed then it would form a capacitor.
This cap would behave as a high pass filter. The larger the cap formed
the lower the corner frequency on the high pass filter.

--
Telamon
Ventura, California
  #8  
Old February 26th 06, 10:51 PM posted to rec.radio.shortwave
Guest
 
Posts: n/a
Default Silicone Grease In Coax Connectors; Comments And Questions ?

On Sun, 26 Feb 2006 12:15:54 -0500, "Robert11"
wrote:

Hello:

Regarding those Si paste products that one see advertised to coat the
innards of a coax
type of connector to prevent moisture seepage, be an anti-oxidant, and all
other great things:

e.g. from ICE:

"Model 615 items are comprised of a synthetic silicon grease material, thick
but easily spreadable. Suggested uses are to fill the void of RE connections
or high voltage joints. Grease is easily pushed out of the way by mating
conductors, but fills the void around them to prevent air and moisture from
settling in. Excellent dielectric characteristics, non-miscible with most
chemical agents or vapors, grease is opaque and maintains thick viscous
nature in temperatures ranging from -60F to 500F."

Not at all certain about this, but my guess is that even after pushing the
contacts together, the boundary layer film that separates the metal male and
female parts would be at least of the order of a micron; probably more.

For transmitting power levels, I guess there is more than enough current
flow to puncture thru easily.

But what about for a receiving only application, with what, micro-amps,
across the gap ?

Does this silicone "layer" present any problems, or signal degradation, in
your experiences ?

Good thing to use in coax connectors going to a receiving antenna ? Or,...?

Thanks,
Bob


I suppose this product exists, but I have never heard of any ham using
silicone grease in his/her coax fittings.

(Of course, I don't normally ask people such things. Still...)

Robert, just because a product exists, that doesn't mean you have to
attach it to your antenna :-)

Simple is better...

bob
k5qwg

 




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