Would it hurt anything to use loctite on UHF bulkhead connector nuts to prevent barrel from turning?

I only ever see them at hamfests but there are usually guys selling larger heavier nuts that you can actually put some torque on. I used a couple on my pass through and haven't had the problem with them loosing like before with the small nuts.

Just snug up the nut and you should not have any issues with it turning.

I don't see why it would case any issues using loctite. Just as long as it's not on the threads in the way of the connector making contact.

You guys rock! Always get good advice & quick help here, best dang Ham net on the web IMHO!

I used the heavy duty larger nuts & torqued em good. Last bulkhead I made had a similar set up & after repeated screwing on & off PL-259's, the barrels started spinning on me. I had to keep snugging them up, figured a dab of loctite would prevent that but didn't want to screw up good ground to the shields. It will just be where the nuts contact the barrel, nothing on the threads where PL-259 seats up.

Next project is getting some wire in the air.

Take care,
HS

Loctite would not be advisable because it may interfere with the electrical connection.  I wouldn't be too crazy about getting torque happy either.  My recommendation would be a piece of 3/4" heat shrink tubing.  You get a small measure of weather protection that way too.

But the real answer, for several reasons, is to switch to N connectors if you're willing.  That's my standard answer to anything involving "UHF" connectors (which really shouldn't be used above 30 MHz anyway).

Got too much time & money invested in what I have now to switch to type N. All my cables are Pl-259 as well.

Yep yep.  Understood.

Just curious, what sort of movement is causing them to loosen up?  Cables flexing in the wind?

I think just repeated taking them on & off caused them to loosen over time. Not a big deal to snug them back unless it's 10 degrees with snow blowing. I take my cables off when not in use or storms approach & stick ends in a waterproof box that has rubber grommet holes in bottom. Its not necessary but makes me feel better. I did a little better job on bulkhead this time around so maybe it won't even be an issue.

Makes sense.  That kinda torpedoes my idea of using heat shrink.  How about chewing gum?  

I understand you don't want to swap connectors, but BNC would make disconnects/reconnects easy and reliable.  You can safely put several hundred watts through BNC (Amphenol says 500 VRMS, which is 5 kW ), but they're even less weatherproof than the unfortunately named "UHF" connectors.

Just thinking out loud . . .

Would adding an extra nut on each side as a "lock nut" be an option? This way you would still maintain a good ground contact for the shield.

Chewing gum, there ya go!

Extra nuts & washers would be good. I would have to get longer barrel connectors to add much more & still have enough threads to get PL259 on. You can get them all kinds of lengths now. I'll save that for the next time I make a pass through panel.

I agree with TLF as long as you keep it off connector threads where you hook up it shouldn't hurt. You would have to slop it all over the barrel connector end to end to prevent ground. The ends of the UHF barrels have jagged edges that make contact with your PL-259 even if threads were covered.

I almost used a 1" x 10" board in my window instead of a 1" x 4" so I could put in 2 insulators for balanced line. Just in case I decide to buy, (or build) a true balanced tuner some day.

They make slide on/quick disconnect PL-239 connectors.... I have some that are Amphenol branded. They work good for a patch panel or window passthrough. Just another option...handy for someone who disconnects every time they turn off the radio.

I've not seen those, may have to try one of those puppies!

This is what i use on all of my VHF/UHF and field 100W HF radios. They are very handy and have performed well, so far. I'm a bit scared to use them on the kilowatt+ amplifier's output.

I've used mine at legal limit (Alpha 78)....but mind you, those are Amphenol; not chicom knock offs. I took them off because they ultimately weren't needed and added a bit more length than clearance allowed with my arrangement. Now I only use them when I'm testing a radio, and will be doing some cable swapping.

If I remember tonight, I can grab one and pull the part number.

Amphenol 83-5SPA

Where did you get your push on Amphenols? I see some on ebay from a dude in Canada, $8.95 each + $7 shipping, geesh!

It may have been him. I ordered like 4 or 5 at the time (same shipping cost). Pretty sure I came in under $10 each. But when you consider chicom crap is $7 each on amazon, the few extra bucks for Amphenol is well worth it (in my book).

I already ordered 2 from him.  

He had 6 available, down to 4 now.

Thx NAM!

The connection should be packed with dielectric grease.  If full of grease, then water cannot enter.

Then it should be wrapped with one spiral wrap of electrical tape sticky side out, or teflon plumber's tape to keep
the following from sticking to it.  Use only Scotch 3M.

Spiral wrap the entire connection and out to the coax with rubber tape (Scotch 130C).

Final wrap with electrical tape (again, I use only Scotch 3M).

With the above weatherproofing your connector will not unscrew.


Why the first wrap of inside-out tape or teflon?  

That's so when you do your once a year check and service the sticky rubber tape won't be difficult to remove.  You'll
only need to make a slice along it and peel it off.  You will find it has formed a solid rubber boot on the connector, as
it should have.

See?  There is no need for Locktite.

You're welcome.

Snug it up, and then coat the whole thing with epoxy.  It will keep the water out, and it won't come loose, either.







Oh, just kidding.

I hate to keep being the naysayer, but I'd strongly recommend against dielectric grease inside the connector.  Several years ago, I put a layer of it on the SO-239 of my TM-D700 just below the threads so the connector would screw on then reach the grease at the end to seal the entrance.  The radio is installed under the back seat of my truck.  After about 3 years, I was having a lot of TX/RX problems (which first cropped up while supporting a bike race).

Upon investigation, I discovered that the grease had worked its way up the threads and had eaten away at the connector.  Some locking teeth were dissolved.  There was green copper oxides bunched up around the center pin inside the radio.  The connector was totally toast.  I ended up having to replace the connector on the radio and scrapping the end of the cable.  I'm sworn off dielectric grease for RF use forever.

Another reason not to put it up inside the connector is that it is intended as an insulating protectant.  Its purpose is to coat connections externally to retard oxidation.  Exactly why it was incompatible with the plating (and base metal) on the Kenwood's factory connector, I don't know.  I've never seen it eat anything else before.  I suspect the RF played a role though.

And now you know the underlying reason I don't think that *anything* gooping up inside an RF connector is a good idea.

YMMV

I endorse Jupiter's other recommendations though.  Good advice there.


ETA:  On closer examination, I don't think Jupiter meant to pack the grease inside the connector, but that wasn't really clear on the initial read.  Still, I won't get it anywhere near my RF connectors.

Harbor Freight sells their version of the self amalgamating "Coax-Wrap" tape.  Unlike the name brand stuff though it only comes in black, but it's only a few bucks a roll.  Makes for a water tight seal and removes without leaving any residue.

Linky.

Yes I did.  In the hole where the pin from the plug will insert, the insulator, etc, so that all of that is full of dielectric grease.

I've used this stuff outside for years and never had a problem with corrosion.  It all disassembles and wipes clean.  I service it about every 2 years, removing it, wiping clean, applying fresh dielectric grease, rewrap with fresh tape.

Inside your truck I see no need, and see no reason why it would corrode.

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See?  2 years since the last service and the connector STILL looks like new.
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Scotch 3M electrical tape, Scotch 3M 130C Linerless Rubber tape, and silicone dielectric grease.
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Put the dielectric grease in the hole of the socket, on the insulator, on the pin of the plug and insulator, so that
when you plug it together it oozes out all around.  Wipe off excess then screw on the sleeve by hand.

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Regular electrical tape, wrapped sticky side out.  Start with one wrap stuck to the coax, twist the tape 180 degrees,
then continue wrapping sticky side out.  You can also make this wrap with plumber's teflon tape.  This first layer of
tape or teflon is to keep the rubber tape from sticking to the connector:
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Now the Scotch 3M 130C rubber tape:
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Final wrap of Scotch 3M electrical tape sticky side in.  Why 3M?  Because other cheap tape lets go after a short while.  
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Finally, just to give myself the warm fuzzies, a tie wrap on the final turn of the electrical tape to
just make sure.

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Not done yet in this photo, but I also removed the nuts where the antenna wire (this is a 3-band multidipole) connected
to the insulator, cleaned, applied dielectric grease, and tightened the nuts back up.  The brass nut and stud get a little
patina, but don't continue to corrode.  Still, needs to be cleaned once a year or so.  Easy since this is lowered and hoisted
back up with a good quality marine-grade pulley.  I've had the same pulley for more than 10 years and it still looks
good and works freely.

Edit:  Yep, that is not white paint on the insulator.

Or for a lot less trouble, you could just use an N connector and fugitaboutit.    Especially the clamp type connectors that are double-gasketed.

For outdoor N connectors, I go overboard and put some 3/4" heat shrink over the junction too, but I've never had the slightest problem.  Overall, it's much less effort and no mess and it comes apart in seconds.  I hate the sticky stuff.

You know what they say . . . different connectors for different folks!  Well, maybe they don't say that, but . . .