[SBE] SBE Digest, Vol 542, Issue 1
Mark Heller
wgbw at lsol.net
Thu Oct 4 14:05:51 EDT 2012
Respectfully Disagree, Henry. Remember, he has a weep hole, with either a
rubber plug or
electrical tape, at the lowest point....added to 'another' leak,
undiscovered and undefined...
only 'supposed' to be at end of connector....but he didn't climb up, and
inspect. (could have
been a B-B gun pellet, who knows?)
A half-pound simply will not make it, for the entire 300 foot run. I'd
think three pounds would
suffice.
Clearly, if you were climbing this tower, to inspect the 'leak', with a Joy
bottle for bubbles, you
wouldn't charge the line at a half pound.
Mark Heller
----------------------------------------
From: a9xw at cs.com
Sent: Thursday, October 04, 2012 11:27 AM
To: sbe at sbe.org
Subject: Re: [SBE] SBE Digest, Vol 542, Issue 1
TO minimize loss, any pressure above 1/2 lb is a waste. All you need to do
is keep positive pressure (above outside air) to keep the out out and the
in in. Henry -----Original Message-----
From: Rolin Lintag <rolin.lintag at vtntv.com>
To: sbe <sbe at sbe.org>
Sent: Thu, Oct 4, 2012 11:05 am
Subject: Re: [SBE] SBE Digest, Vol 542, Issue 1
Hi Dean, Fixing the leaks is priority number one. However, since you are
looking for the second best, I suggest that you get a dehydrator, big air
reservoir and an air regulator. The set-up can be similar to the third
system I described in below link:
http://broadcastengineering.com/mag/pressurizing-coaxial-cable You can
pressurize the reservoir tank to 50 psi or so depending on the tank and
then feed the coax through an air regulator (available at Bellofram) set at
2 psi. There are one way valves available from HVAC supply stores and they
are useful in keeping the air flow one way. Coax systems leak one way or
another and becomes a concern for a tower climb if the dehydrator is
running too often. "Too often" depends on the dehydrator size. We have two
Andrew MT2000 that run every 25 minutes and that is still OK. Hope this
helps. Rolin Romualdo "Rolin" Lintag Chief Engineer Victory Television
Network KVTN-DT 25.1 Little Rock, AR KVTH-DT 26.1 Hot Springs, AR KVTJ-DT
48.1 Jonesboro, AR www.vtntv.com -----Original Message----- From:
sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of
sbe-request at sbe.org Sent: Thursday, October 04, 2012 9:01 AM To:
sbe at sbe.org Subject: SBE Digest, Vol 542, Issue 1 Send SBE mailing list
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SBE digest..." SBE Roundtable Today's Topics: 1. Re: "modifying
co-ax" to drain moisture (Vic Jester) 2. Re: "modifying co-ax" to
drain moisture (Cowboy) 3. Re: "modifying co-ax" to drain moisture
(Cowboy) 4. Re: "modifying co-ax" to drain moisture (a9xw at cs.com) 5.
Re: "modifying co-ax" to drain moisture (-jer)
----------------------------------------------------------------------
Message: 1 Date: Wed, 3 Oct 2012 12:14:06 -0500 (GMT-05:00) From: Vic
Jester <vjester at mindspring.com> Subject: Re: [SBE] "modifying co-ax" to
drain moisture To: sbe member discussion mail list <sbe at sbe.org>
Message-ID:
<33331722.1349284447553.JavaMail.root at mswamui-backed.atl.sa.earthlink.net>
Content-Type: text/plain; charset="us-ascii" An HTML attachment was
scrubbed... URL:
<http://seven.pairlist.net/pipermail/sbe/attachments/20121003/c9b19ab6/attac
hment-0001.htm> ------------------------------ Message: 2 Date: Wed, 3
Oct 2012 14:15:28 -0400 From: Cowboy <curt at cwf1.com> Subject: Re: [SBE]
"modifying co-ax" to drain moisture To: sbe member discussion mail list
<sbe at sbe.org> Message-ID: <201210031415.28446.curt at cwf1.com> Content-Type:
text/plain; charset="utf-8" On Wednesday 03 October 2012 12:38:33 pm Dean
wrote: > I?m looking for a long range answer, without having to climb the
> tower, replace the co-ax, etc. ? That's not going to happen. Band-aids
are exactly that. I'd put a compressor on it and let it run, but only
until you can get a competent climber up there to seal whatever, and give
you your options for a permanent fix. You're still going to have to run
quite a bit of *dry* nitrogen through that line to purge it properly,
when it's permanently sealed. Where are you ? 300 isn't too tall, and I
can do this sort of thing. -- Cowboy http://cowboy.cwf1.com SHIFT TO THE
LEFT! SHIFT TO THE RIGHT! POP UP, PUSH DOWN, BYTE, BYTE, BYTE!
------------------------------ Message: 3 Date: Wed, 3 Oct 2012 14:55:33
-0400 From: Cowboy <curt at cwf1.com> Subject: Re: [SBE] "modifying co-ax" to
drain moisture To: sbe member discussion mail list <sbe at sbe.org>
Message-ID: <201210031455.33297.curt at cwf1.com> Content-Type: text/plain;
charset="utf-8" On Wednesday 03 October 2012 02:15:28 pm Cowboy wrote: >
Where are you ? I see it now. Not far, but your defective spam filter is
preventing me from making a direct contact. -- Cowboy
------------------------------ Message: 4 Date: Wed, 3 Oct 2012 15:35:21
-0400 (EDT) From: a9xw at cs.com Subject: Re: [SBE] "modifying co-ax" to
drain moisture To: sbe at sbe.org Message-ID:
<8CF6FB55C8615B0-1098-77FA9 at webmail-m135.sysops.aol.com> Content-Type:
text/plain; charset="utf-8" Depending on how much oxidation your inner
conductor has from your leak, you may have to replace the entire line. The
weep hole is likely letting in more moisture than letting out because
temperature changes are causing your line to "breath" Since it is causing
VSWR shut down, you might even have internal arcing burning your inner
conductor and that will lead to line failure. Considering thecost of
labor for 2-3 trips up the tower and the low cost of coax, you are likely
better off replacing the coax now before it fails and you are off the air
for days/weeks. Make sure you don't have a lightning hole in the antenna.
If the antenna is also pressurized from the coax line, it is much more
likely you have an antenna hole than a coax hole. Having a weep hole at
the bottom is never a good idea, and whomever "planned" that was no
engineer. The correct method would be to have an airseal at the end of the
coax and pressurize from the end to the top. You could already have insect
eggs in the line from the hole. Henry Ruhwiedel (ret) 46 yrs CE R_TV
-----Original Message----- From: Dean <dspencer at hpcisp.com> To: sbe
member discussion mail list <sbe at sbe.org> Sent: Wed, Oct 3, 2012 11:48 am
Subject: [SBE] "modifying co-ax" to drain moisture I have a 300 foot
run of 1-5/8? air-filled coax up one of our towers that apparently has a
bad seal at the top end, and it seems to be admitting water (sort of like
an open drinking straw) which is collecting at the bottom in a ?loop? of
co-ax we left deliberately when it was installed to collect water outside
the transmitter and transmitter building. The ?low point? is collecting
water as we planned, but eventually it ?fills? the insulation space where
the drip loop is, and causes the transmitter to drop way back in power,
due to high reflected power through the water route. I can give the
co-ax a blast of compressed nitrogen, and after about 15 seconds the water
is ?forced out? through a small drain hole we have drilled in the co-ax
jacket and outer conductor, and the reflected power drops to a normal
value, the transmitter output current and power return to normal and we?re
off and running. My problem is: I cannot leave the co-ax pressurized or
the leaky seals at the top will bleed down my bottle of nitrogen in a
short time (about an hour or so). So, whenever it looks like a rainy
siege is coming, I give the co-ax a ?blast? of nitrogen, and hope it will
keep the water out for the duration of the rain storm. What if I
increased the size of my co-ax ?weep hole? to about ? inch diameter.
Would this cause any problems? What if I coupled a small air compressor
(with a dryer attached) operating off 120 volts to the co-ax and left it
running (cycling on and off on pressure)? Would this work? I?m looking
for a long range answer, without having to climb the tower, replace the
co-ax, etc. Any suggestions? DEAN SPENCER WBIW/WQRK/WPHZ
dspencer at hpcisp.com P.O. Box 1307 Bedford, IN. Ph.812-275-7555 Fax
812-279-8046 Cell 812-797-3612 wbiw.com superoldies.net
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Oct 2012 23:00:51 +0000 From: "-jer" <jerhil at frontier.com> Subject: Re:
[SBE] "modifying co-ax" to drain moisture To: "sbe member discussion mail
list" <sbe at sbe.org> Message-ID:
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-jer -----Original Message----- From: Cowboy <curt at cwf1.com> Sender:
sbe-bounces at sbe.org Date: Wed, 3 Oct 2012 14:15:28 To: sbe member
discussion mail list<sbe at sbe.org> Reply-To: sbe member discussion mail list
<sbe at sbe.org> Subject: Re: [SBE] "modifying co-ax" to drain moisture On
Wednesday 03 October 2012 12:38:33 pm Dean wrote: > I?m looking for a long
range answer, without having to climb the tower, > replace the co-ax, etc.
? That's not going to happen. Band-aids are exactly that. I'd put a
compressor on it and let it run, but only until you can get a competent
climber up there to seal whatever, and give you your options for a
permanent fix. You're still going to have to run quite a bit of *dry*
nitrogen through that line to purge it properly, when it's permanently
sealed. Where are you ? 300 isn't too tall, and I can do this sort of
thing. -- Cowboy http://cowboy.cwf1.com SHIFT TO THE LEFT! SHIFT TO
THE RIGHT! POP UP, PUSH DOWN, BYTE, BYTE, BYTE!
_______________________________________________ The SBE Roundtable,
SBE at sbe.org To unsubscribe, go to
http://seven.pairlist.net/mailman/options/sbe
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