O.K., Appreciate all the comments and on hand experience, that is what this forum is all about!! Now I am back to using a product I have used for years to keep like and unlike metals for oxidize, No-Ox,
Tnx! de WB5UMG
In the 30 or so years I spent as a radio officer (sparks) on merchant ships, I never used anything but high quality milspec tape. Of course I used
quality amphinol crimp connectors on well prepared coax using high quality tools. In all that time, the only moisture that got into a coax run got
in because of chafing.. and that was only one time. That's a lot of coax and connectors.. I did inspect them often. At least once a month.
Seldom was the tape in such shape that I would have had to replace it. If it was a nice day and since I was aloft anyhow, I would sometimes
replace the tape just as an excuse to enjoy the view.
That's right. That's why you have to stretch-wrap electrical tape over the entire connection. The several layers of electrical tape must conform perfectly to the connectors and the coax, and not have any creases, loose areas, or wrinkles.
Originally Posted by KM3F
But even doing that, I saw corrosion, until I started also filling them with good silicone dielectric compound. I have done this with many, many UHF connectors, and have never seen any corrosion whatsoever, even after the connector was disassembled after being outdoors in all kinds of weather for many years.
Not if you do it right. And I'm by no means the only ham who's ever successfully used that time-tested and proven method of keeping moisture out.
Using or filling the inside to try making them water tight is just a hope and a guess.
Note that I am mostly speaking of sealing splices using two PL-259s and a barrel connector, or F connectors. Sealing a PL-259 plugged into an SO-239 is another matter (although it certainly can be done).
Last edited by W0BTU; 04-22-2012 at 12:27 PM.
I will add my $.02.
I have used Dow/Corning #4 silicone grease for over 40 years and it has never let water in or broken down due to high voltage/SWR. I fill the whole connector also, wrap with rubber stretch tape and wrap again with a good vinyl electrical tape.
I have measured the connectors with and without the grease up through 500 MHz and I was unable to detect any change in RF characteristics. I was working for AT&T Bell Labs at the time using some pretty sophisticated test equipment.
I use the #4 grease on all my outdoor connections.
Where do you get Dow Corning #4?
The first stuff I used (back in the '70s) was marked 'Dow Corning 5 Compound'. We just called it DC-5, and all outdoor connectors in a large CATV system were routinely filled with it.
I wonder what the difference is between the two compounds.
Last edited by W0BTU; 04-22-2012 at 05:29 PM.
I think trielectric grease is better. It's what they uses on the warp coils.
"The more you know, the less you don't know."
I would think there is a point where the mess caused by loading anything into a connector and all the 'excess' wrapping, needs to be dictated by the application and circumstance.
I agree that using the ' right ' filler may not upset impedence or cause a breakdown, but why do this when it's not needed for the average amateur installation..
A look in the very highly reguarded PASTENAK catalog of some 900 pages of just about every kind and type RF connector known, shows absolutly no sealants of any kind offered or recomended.
The inside of the average N type connector uses a rubber like gasket to face seal as well as a seal ring on the coaxs.
In the UHF connector there is about a 1/8 space left between connector faces that could also use a gasket but the outer seal still is missing with just teeth used for locating and stopping the connection from rotating.
The N types normally dosenot stop rotating movement but seals very well so there is some improvement left to do on a UHF design if some company wants to do it..
BTW the N types have their own issues especially when reconnection is done many times in a test setup and even over tighening.
The newer warp coils require no grease. Any lubricant can cause problems when transiting between warp drive
and "normal" drive.. [
QUOTE=KL7AJ;2529143]I think trielectric grease is better. It's what they uses on the warp coils.[/QUOTE]
In 1942, moisture in aircraft engines and the formation of corona discharge from aircraft electrical systems at high altitudes made high-altitude flight all but impossible.
Dr. Shailer Bass developed Dow Corning's first product, a simple silicone grease (Dow Corning #4 Compound) that solved the problem.
Dow Corning was formally established in 1943 specifically to explore the potential of silicones.
Dow Corning emerged from bankruptcy in 2004, after the silicon breast implant lawsuits.
Last edited by W9GB; 04-22-2012 at 06:10 PM.
We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths. -- Walt Disney
That's my take.. I had good results for a long long time aboard ships just using tape.. Plus regular inspections.. No mess, no wasted time..
plus, on a windy day the fewer items carried aloft, the better.
Originally Posted by KM3F