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Author Topic: PL-259...SO-239 corrosion-oxidation protection  (Read 7828 times)
W8ATA
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Posts: 327




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« on: February 16, 2013, 09:57:51 AM »

I take pride in sealing my coax connectors to prevent and corrosion or oxidation but sometimes I find a slight film of oxidation on the plug tip. So my question is...should I consider a very thin film of NoAlox or Penetrox on the plug of the 259 or in the jack of the 239?  I realize that there could be the risk of creating a current path I would want to avoid but just wondered if a minute amount of either treatment might be warranted? I live in Ohio far from any salt environment.

73 and thanks,
Russs
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W4IOW
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Posts: 34




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« Reply #1 on: February 16, 2013, 11:55:27 AM »

My thought would be to use a non-conductive grease rather than penetrox, etc. I have used such a grease with good results. RadioWorks is on place that sells it, but I am sure there are others.

Good luck.
Ray W4IOW
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W8ATA
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Posts: 327




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« Reply #2 on: February 16, 2013, 12:15:15 PM »

Thanks Ray but perhaps I wasn't clear in my post. I want to inhibit any oxidation where the center lead plug seats in the center lead jack. Would think I need conductive grease. But I will check RadioWorks website.

73,
Russ
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AA4PB
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Posts: 13032




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« Reply #3 on: February 16, 2013, 12:29:20 PM »

I'd use the electrical silicone grease that you get from automotive stores, designed for use on ignition-spark plug connections. Any grease you use will scrape off the pin, leaving a metal to metal contact but also sealing the connection from the air. If you use conductive grease it may bridge the pin to shield contacts and cause a high resistance short.

For outside connections, I also wrap the whole PL-259 in plastic electrical tap and then coat it with clear plastic spray.

Amphenol makes plastic boots for the PL-259 that they supply with a small tube of silicone grease.
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N1CX
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Posts: 138




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« Reply #4 on: February 16, 2013, 01:04:40 PM »

I'd be extremely careful putting anything inside a connector that isn't rated at RF frequencies.

Scotch 33+ tape up and down pulled tight then cover with a mastic patch. Knead in by hand and that's all you should ever need.

If you got to take it off then cut into it with a knife and pull the whole thing off.
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WB2EOD
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Posts: 221




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« Reply #5 on: February 16, 2013, 01:20:29 PM »

The trick is corrosion/oxidation prevention is to keep the moisture out of the connection.  My personal favorite is the self-adhesive silicone based tape. When stretched and wrapped around the cable and connector, the layers stick to the cable, the connector and themselves.  When I slit and peeled off the tape, connections made 2 years ago were as bright and clean as the day I wrapped them


Hope this helps
73
WB2EOD
 
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KB4QAA
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Posts: 2490




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« Reply #6 on: February 16, 2013, 03:39:59 PM »

Do NOT use any conductive grease on a connector.  Consider that RF systems can sometimes develop a couple thousand volts, depending on the VSWR and mismatch.  RF WILL find a way to short.

If you decide to lube things, then use a non-conductive grease like DC-4 Dow Corning silicone non-conductive grease or similar (I'm not familiar with Noalox or Penetrox).  Use only a very thin coating.

The key is keeping moisture out.  The best way is to properly seal the connection with three layers of tape:

- 3m "88" electrical tape
- Silicone/Rubber self amalgamating tape, or Coax Seal
- 3m "88" electrical tape.

When ready to remove, slit with a knife and it will all peel off clean.
Overlap tape by 50%, and always wrap from bottom to top, so water cannot get between layers.
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W8ATA
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Posts: 327




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« Reply #7 on: February 17, 2013, 05:19:54 AM »

Thanks guys for your wisdom. I am a good sealer using 3M 2228 moisture sealing tape and Super 88. For some reason I got the obsession to make it even better with some grease. I will follow your collective advice.

73,
Russ
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AA4HA
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Posts: 1640




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« Reply #8 on: February 17, 2013, 05:29:49 AM »

I take pride in sealing my coax connectors to prevent and corrosion or oxidation but sometimes I find a slight film of oxidation on the plug tip...
To a large extent it will also depend upon what the base metal is. Connector contact areas that are properly plated with a corrosion resistant metal or alloy will show much less oxidation. If you are soldering the tip (I am assuming you do, few amateurs use or or own crimped PL/SO connectors) then you are introducing an alloy (lead,tin,zinc or some other combination) that will show oxidation much more readily.

To minimize the oxidation you just need to keep oxygen or reactive elements/ chemicals away from the metal. It does not need to be a conductive grease as the finger tension of the connector should keep a metal-metal attachment on the center pin. A good silicone grease (inert, non-reactive, water resistant) would do just fine. Where there needs to be a metal-metal connection the finger tension will break through that barrier and allow an electrical connection. All other parts of the connector will remain protected behind the thin coating of silicone grease.

Weatherproofing the connector (88, mastic-butyl, 88 or some type of boot) will keep the free water away. Any moisture in the coax (there always is some) is going to be trapped by that same sealing... under the weatherproofing... and can continue to cause oxidation of the copper braid, connector or soldering alloy. Just remember that weatherproofing works both ways.
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
W3HKK
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Posts: 621




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« Reply #9 on: February 17, 2013, 05:07:12 PM »

Hi Russ.

Being an old goat, Ive seen many  lengths of coax come and go, and used many barrel connectors to splice them together.    And if Im out of barrel connectors or the PL=259s  arent on the end of the coax I have, I dont mind splicing and taping them together!  Sacre Bleu!! It's never been a problem, at least enough of one that ive recognized it...

But what I do have problems with is  critters and lawn mowers gnawing at the vinyl jacket of my coax, allowing moisture to get in and ruin coax. SWR goes wacky.  And I go looking at the connectors, the antennas, and finally pull up the  run of coax thru the grass or under the ground. No fun.  But I usually find the problem in the grass!  I then   go back a couple of feet and cut out the bad section.  If the  jacket looks ok, I splice.

A second problem  has been the usually buried barrel connectors and PL 259s  corroding over time, when they get wet.  My  vinyl taping hasnt always been perfect and water gets in, so I sandpaper or scrape with a knife edge and reconnect.  No Penetrox.  I only use penetrox  between aluminum yagi  or vertical antenna sections on assembly. And it does a great job.

Recently I cleaned most (dozens) of my coax PL 259s ( some date back 30-40 years)  with  DeOxIt and was surprised at the   oxides that came off both the center conductor and the   outside threaded  screw on connectors.  Resin, corrosion, bugs.  So the DeOxIt made a big difference in brightening up the  surfaces on a bunch of coax and 12-18-24" coax jumpers. 

I sleep better at  night - and have eliminated a  several annoying, erratic swr issues here in the shack from what I am pretty sure were corroded - but still good -   jumpers.  Once cleaned, they dont have the jitters any more when I move coax round on my antenna switches, swr meters, and rigs.

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W6UV
Member

Posts: 540




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« Reply #10 on: February 17, 2013, 07:07:59 PM »

If you're using silver plated connectors, don't worry about the black oxidation that forms on them. Silver oxides are conductive and will not impair operation of the connectors. Aggressive cleaning may even remove the silver plating.
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W8ATA
Member

Posts: 327




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« Reply #11 on: February 17, 2013, 08:07:27 PM »

Again thanks to all. Ms. Tisha, you make some good observations. Bob, this old goat is older than you, you old goat. I heard about your spraying the northern part of the county with DeOxit. Grin  It is good stuff. Right now I'm thinking of just making sure the connectors are clean and seal them with my 3M 2228 moisture sealing tape and Super 88 over that.

73, Russ
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WH7DX
Member

Posts: 1029




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« Reply #12 on: February 18, 2013, 10:15:48 AM »

I live close to the ocean with salt spray.  I've taken down connectors after 1 year that look great.  I put quite a bit of electric grease on the threads and just a little on the center connector.   Then wrap it tight with tape.   The grease is still on the threads when I take it off.   It helps to keep any moisture from getting inside the connector.   I don't see how a little grease on the center will hurt.  Just enough to coat it lightly.   I monitor the antennas with a meter every few months and record everything.   They never move much.
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W5CPT
Member

Posts: 561




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« Reply #13 on: February 18, 2013, 10:25:05 AM »

I use Stuf - According to the Radio Works website:

"This is a viscous, white compound with dielectric properties that exceed those of the connectors to which it is applied. STUF forces air and moisture out of the connector from the inside during assembly, sealing it from the inside. One tube will fill several connectors. The tube contains 3.2 cubic inches of STUF, enough to weatherproof a couple of dozen PL-259 connectors. Do Not Use without Coax Seal or Cold Shrink Tape for outer protection."

I use the self vulcanizing tape over the connection with a layer of good electrical tape over that as the self vulcanizing does not do well in the sun. I hate and will never use Coax Seal.

See it here: (about 3/4 down the page)

http://www.radioworks.com/ccoaxseal.html

Clint - W5CPT -
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AE5JU
Member

Posts: 236




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« Reply #14 on: March 05, 2013, 05:40:20 PM »

http://k9zw.wordpress.com/2010/05/12/guest-post-weatherproofing-antenna-coax-by-paul-ae5ju/

Try this.  With pictures and everything.

Since this was written a friend suggested using plumber's teflon tape for the initial wrap of the connection to keep the Scotch 130C (butyl rubber tape) from sticking to the connector.  Next time I redress the connection I'll do that.

73,
Paul - AE5JU
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