Just wonder what other's might do to keep moisture
from getting into the semi-hollow 9913 type low
loss coax. It would seem inevitiable with changes
in temperature and pressure that moist air would
eventually work its way into the coax and then
condense.

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone
sealant but I am not really sure that this has been
effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above
address)

As with all of my external cable connections (excluding mobile
installs), I use good quality plugs that physically screw together. The
when I am finished, I use self amalgamating tape (costs about $20 Aust
per roll) which provides a weatherproof seal around the connection -
have cut the tape off plugs which I have done ten or more years
previously to find them as dry as the day I put them together. On top
of the self amalgamating tape, I use the normal electrical tape to give
the birds something to peck at before they reach the self amalgamating
tape (bloody cockies can be ferocious with antennas and coaxial cable
here).
I believe that the only way that coax is going to become water effected
is if it directly exposed to water (i.e. rain), and once you have put
the connector on the end of the cable, screwed it into the antenna and
taped it up, the chances of water getting into it are very remote (bar
the outer layer being cracked, cut or abraded). In my opinion,
pressurising the cable is not something that is needed for the average
hobbyist.




Matt

Dave Woolf wrote in message
...

Just wonder what other's might do to keep moisture
from getting into the semi-hollow 9913 type low
loss coax. It would seem inevitiable with changes
in temperature and pressure that moist air would
eventually work its way into the coax and then
condense.

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone
sealant but I am not really sure that this has been
effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above
address)

On Wed, 31 Dec 2003 16:08:10 +1100, "Matt"
wrote:

As with all of my external cable connections (excluding mobile
installs), I use good quality plugs that physically screw together. The
when I am finished, I use self amalgamating tape (costs about $20 Aust
per roll) which provides a weatherproof seal around the connection -
have cut the tape off plugs which I have done ten or more years
previously to find them as dry as the day I put them together. On top
of the self amalgamating tape, I use the normal electrical tape to give
the birds something to peck at before they reach the self amalgamating
tape (bloody cockies can be ferocious with antennas and coaxial cable
here).
I believe that the only way that coax is going to become water effected
is if it directly exposed to water (i.e. rain), and once you have put
the connector on the end of the cable, screwed it into the antenna and
taped it up, the chances of water getting into it are very remote (bar
the outer layer being cracked, cut or abraded). In my opinion,
pressurising the cable is not something that is needed for the average
hobbyist.


It only took one lightening strike to change my mind about
waterproofing 9913.

I used coax seal and taped over that. The tower took a hit that
removed every single bit of tape and coax seal from up there. I found
the coax seal on the ground. It looked like some one had cut down one
side and peeled it off. Then cut it so it looked like one of those
pieces of expanded metal. It even removed the silver plating from the
connectors.

15 minutes after the lightening strike I had water running out of my
2-meter rig.

I ordered 1500 feet of LMR 400 right soon after.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com



Matt

Dave Woolf wrote in message
...

Just wonder what other's might do to keep moisture
from getting into the semi-hollow 9913 type low
loss coax. It would seem inevitiable with changes
in temperature and pressure that moist air would
eventually work its way into the coax and then
condense.

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone
sealant but I am not really sure that this has been
effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above
address)

Nasty, but unusual - in 20 years of playing with radios, I have not had
the problem that you have mentioned, but then again, I guess that I
don't have a huge lightening rod of a tower that you do (bloody nice
BTW). For the average user, the procedures I have mentioned will
suffice 99.99% of the time (looks anxiously up into the sky to check for
lighteningg).



Matt

Roger Halstead wrote in message
...
On Wed, 31 Dec 2003 16:08:10 +1100, "Matt"
wrote:

As with all of my external cable connections (excluding mobile
installs), I use good quality plugs that physically screw together.
The
when I am finished, I use self amalgamating tape (costs about $20
Aust
per roll) which provides a weatherproof seal around the connection -
have cut the tape off plugs which I have done ten or more years
previously to find them as dry as the day I put them together. On
top
of the self amalgamating tape, I use the normal electrical tape to
give
the birds something to peck at before they reach the self
amalgamating
tape (bloody cockies can be ferocious with antennas and coaxial cable
here).
I believe that the only way that coax is going to become water
effected
is if it directly exposed to water (i.e. rain), and once you have put
the connector on the end of the cable, screwed it into the antenna
and
taped it up, the chances of water getting into it are very remote
(bar
the outer layer being cracked, cut or abraded). In my opinion,
pressurising the cable is not something that is needed for the
average
hobbyist.


It only took one lightening strike to change my mind about
waterproofing 9913.

I used coax seal and taped over that. The tower took a hit that
removed every single bit of tape and coax seal from up there. I found
the coax seal on the ground. It looked like some one had cut down one
side and peeled it off. Then cut it so it looked like one of those
pieces of expanded metal. It even removed the silver plating from the
connectors.

15 minutes after the lightening strike I had water running out of my
2-meter rig.

I ordered 1500 feet of LMR 400 right soon after.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com



Matt

Dave Woolf wrote in message
...

Just wonder what other's might do to keep moisture
from getting into the semi-hollow 9913 type low
loss coax. It would seem inevitiable with changes
in temperature and pressure that moist air would
eventually work its way into the coax and then
condense.

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone
sealant but I am not really sure that this has been
effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above
address)

Dave Woolf wrote:

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

Just out of curiosity: how exactly did he do this?

73 .... WA7AA


--

Anti-spam measu look me up on qrz.com if you need to reply directly

On Wed, 31 Dec 2003 17:44:21 +1100, "Matt"
wrote:

Nasty, but unusual - in 20 years of playing with radios, I have not had
the problem that you have mentioned, but then again, I guess that I
don't have a huge lightening rod of a tower that you do (bloody nice
BTW). For the average user, the procedures I have mentioned will
suffice 99.99% of the time (looks anxiously up into the sky to check for
lighteningg).

The hit was on the old tower, but that still put the base of the
repeater antenna at 90 feet, so the top would have been close to 112
feet. It hasn't been up in years.

The surprising thing is the bolt took out the 7/8" Heliax about 30
feet down from the top of the tower. I did lose the front end out of
one solid state 2-meter rig, but that was it. Everything else was
still working including the one with the water running out.

The current tower and even the old were getting hit about three times
a year, but there hasn't been any damage in a while.

My neighbor was looking across his back yard this past summer when the
top took a direct hit. It apparently really impressed him. Now the
neighbors really believe me when I tell them it's the neighborhood
lightening rod:-)). OTOH I was out by the end of the driveway
talking to the neighbor across the road with a storm in the distance.
A strong bolt hit the power pole about 30 feet from us. We both
decided we needed to be some where else... Quickly.

Currently my biggest concern from lightening is the computer network.
It's a 130 foot run to the shop and 25 feet in the other direction to
my wife's computer. The pone line comes in underground, but it
doesn't take much induced current to cost many dollars.

So far, I haven't had any problems with the satellite dishes and
feeds, but I have lost the antenna mounted preamp to the top UHF TV
antenna. Course that may have been due to 2-meters instead of
lightening.:-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com



Matt

Roger Halstead wrote in message
.. .
On Wed, 31 Dec 2003 16:08:10 +1100, "Matt"
wrote:

As with all of my external cable connections (excluding mobile
installs), I use good quality plugs that physically screw together.
The
when I am finished, I use self amalgamating tape (costs about $20
Aust
per roll) which provides a weatherproof seal around the connection -
have cut the tape off plugs which I have done ten or more years
previously to find them as dry as the day I put them together. On
top
of the self amalgamating tape, I use the normal electrical tape to
give
the birds something to peck at before they reach the self
amalgamating
tape (bloody cockies can be ferocious with antennas and coaxial cable
here).
I believe that the only way that coax is going to become water
effected
is if it directly exposed to water (i.e. rain), and once you have put
the connector on the end of the cable, screwed it into the antenna
and
taped it up, the chances of water getting into it are very remote
(bar
the outer layer being cracked, cut or abraded). In my opinion,
pressurising the cable is not something that is needed for the
average
hobbyist.


It only took one lightening strike to change my mind about
waterproofing 9913.

I used coax seal and taped over that. The tower took a hit that
removed every single bit of tape and coax seal from up there. I found
the coax seal on the ground. It looked like some one had cut down one
side and peeled it off. Then cut it so it looked like one of those
pieces of expanded metal. It even removed the silver plating from the
connectors.

15 minutes after the lightening strike I had water running out of my
2-meter rig.

I ordered 1500 feet of LMR 400 right soon after.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com



Matt

Dave Woolf wrote in message
...

Just wonder what other's might do to keep moisture
from getting into the semi-hollow 9913 type low
loss coax. It would seem inevitiable with changes
in temperature and pressure that moist air would
eventually work its way into the coax and then
condense.

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone
sealant but I am not really sure that this has been
effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above
address)

On Wed, 31 Dec 2003 07:11:34 GMT, Zoran Brlecic
wrote:

Dave Woolf wrote:

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

Just out of curiosity: how exactly did he do this?

I'd go the commercial way and just purge it with a slight positive
pressure.

With 9913 you can seal the ends and use a small plastic tube in
through the side. Flood the bottom connector to seal it (just the
opposite of normal) then work a small hole through the jacket, braid,
and into the inner tube. You can build a tap sorta like they use for
a gas line, or water line, but smaller. You can also put a tap on the
side of the coax connector. As far as I know you'd have to make your
own as I've not seen any for the PL259s or N connectors although they
may be available. The only coax I've ever seen purged was commercial
hard line. (It looks like copper water pipe) They actually had a tap
soldered on the side of the line with a flow meter connected. It was
a very low flow and on a 900 foot run that was gasketed. They
replaced it with what appeared to be 4" Heliax. (How'd you like to
lift 900 feet of that?) You hook up a tank of N2, only run a few
inches of water pressure and use a small flow meter to regulate the
flow. Typically you'd purge the thing and then flood the top as well.
you will still get a small flow. If the coax seal loses integrity the
flow will increase.

Lot of work and about $20 to $30 for N2 every few months.

It's almost impossible to keep something like 9913 completely sealed.
Even the PL259s and N connectors will leak through some.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com

73 .... WA7AA

Damn lightning - there should be a law against it g. I saw your tower
raising epic on one of your webpages, and was very impressed with it -
would love that at my QTH, but am currently renting, and as I move
around very frequently with work (10 times in the last 13 years), a
tower would need to be very portable, and the hassles of doing something
like your setup every 18 months or so would really **** me off.
Currently I use a variety of wire antennas, and a number of poles to get
the verticals at about the 25 foot level. Certainly no powerhouse, but
able to get to pretty much wherever I want to (within reason of course).




Matt

Roger Halstead wrote in message
...
On Wed, 31 Dec 2003 17:44:21 +1100, "Matt"
wrote:

Nasty, but unusual - in 20 years of playing with radios, I have not
had
the problem that you have mentioned, but then again, I guess that I
don't have a huge lightening rod of a tower that you do (bloody nice
BTW). For the average user, the procedures I have mentioned will
suffice 99.99% of the time (looks anxiously up into the sky to check
for
lighteningg).

The hit was on the old tower, but that still put the base of the
repeater antenna at 90 feet, so the top would have been close to 112
feet. It hasn't been up in years.

The surprising thing is the bolt took out the 7/8" Heliax about 30
feet down from the top of the tower. I did lose the front end out of
one solid state 2-meter rig, but that was it. Everything else was
still working including the one with the water running out.

The current tower and even the old were getting hit about three times
a year, but there hasn't been any damage in a while.

My neighbor was looking across his back yard this past summer when the
top took a direct hit. It apparently really impressed him. Now the
neighbors really believe me when I tell them it's the neighborhood
lightening rod:-)). OTOH I was out by the end of the driveway
talking to the neighbor across the road with a storm in the distance.
A strong bolt hit the power pole about 30 feet from us. We both
decided we needed to be some where else... Quickly.

Currently my biggest concern from lightening is the computer network.
It's a 130 foot run to the shop and 25 feet in the other direction to
my wife's computer. The pone line comes in underground, but it
doesn't take much induced current to cost many dollars.

So far, I haven't had any problems with the satellite dishes and
feeds, but I have lost the antenna mounted preamp to the top UHF TV
antenna. Course that may have been due to 2-meters instead of
lightening.:-))

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com



Matt

Roger Halstead wrote in message
.. .
On Wed, 31 Dec 2003 16:08:10 +1100, "Matt"

wrote:

As with all of my external cable connections (excluding mobile
installs), I use good quality plugs that physically screw
together.
The
when I am finished, I use self amalgamating tape (costs about $20
Aust
per roll) which provides a weatherproof seal around the
connection -
have cut the tape off plugs which I have done ten or more years
previously to find them as dry as the day I put them together. On
top
of the self amalgamating tape, I use the normal electrical tape to
give
the birds something to peck at before they reach the self
amalgamating
tape (bloody cockies can be ferocious with antennas and coaxial
cable
here).
I believe that the only way that coax is going to become water
effected
is if it directly exposed to water (i.e. rain), and once you have
put
the connector on the end of the cable, screwed it into the antenna
and
taped it up, the chances of water getting into it are very remote
(bar
the outer layer being cracked, cut or abraded). In my opinion,
pressurising the cable is not something that is needed for the
average
hobbyist.


It only took one lightening strike to change my mind about
waterproofing 9913.

I used coax seal and taped over that. The tower took a hit that
removed every single bit of tape and coax seal from up there. I
found
the coax seal on the ground. It looked like some one had cut down
one
side and peeled it off. Then cut it so it looked like one of those
pieces of expanded metal. It even removed the silver plating from
the
connectors.

15 minutes after the lightening strike I had water running out of
my
2-meter rig.

I ordered 1500 feet of LMR 400 right soon after.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com



Matt

Dave Woolf wrote in message
...

Just wonder what other's might do to keep moisture
from getting into the semi-hollow 9913 type low
loss coax. It would seem inevitiable with changes
in temperature and pressure that moist air would
eventually work its way into the coax and then
condense.

I had a fellow ham that took the precaution of
pressurizing this type of coax to maintain
positive pressure and keep out outside air.
Seemed like a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone
sealant but I am not really sure that this has been
effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above
address)

On Wed, 31 Dec 2003 02:51:26 +0000, Dave Woolf wrote:


Just wonder what other's might do to keep moisture from getting into the
semi-hollow 9913 type low loss coax. It would seem inevitiable with
changes in temperature and pressure that moist air would eventually work
its way into the coax and then condense.

I had a fellow ham that took the precaution of pressurizing this type of
coax to maintain positive pressure and keep out outside air. Seemed like
a lot of effort but maybe it is necessary.

I have tried to seal the ends of the coax with silicone sealant but I am
not really sure that this has been effective in the long term.

What do others do? What has been your experience?

Dave - K8RSP
(to reply to me directly remove NOSPAM from above address)

Butyl rubber based self amalgamating tape, Electrical Tape, Top Coat, I
use a coat of UV Stabilized clear Spray paint Tape:
http://www.surplussales.com/Antennas/Antennas-7.html

Over the years I have cleaned up a lot of messes where they connectors
were not sealed properly. I have taken apart my connections to replace
Damaged antennas and the connections are dry as a bone. after 10 years of
more in the air.

IMHO: Take a close look at Times Microwave cables, I think it's a better
products than the equivalent Beldon.

Ron

"Ron" wrote in message
news
On Wed, 31 Dec 2003 02:51:26 +0000, Dave Woolf wrote:


Just wonder what other's might do to keep moisture from getting into the
semi-hollow 9913 type low loss coax. It would seem inevitiable with
changes in temperature and pressure that moist air would eventually work
its way into the coax and then condense.



I'd think it makes sense to seal the top, but let the connectors at the
bottom
breath, that would alleviate moisture ladden air from being drawn in at
the top. Especially during rain storms! Another idea would be having the
top sealed, and the bottom allowed to breathe through a plastic jar of
desiccant.

Pete