The Riddler Strikes Again!

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W3SLK:
One of my favorite classic episodes of Batman, (Adam West & Burt Ward), are reading a clue left to them by the Riddler, (Frank Gorshin). 'Robin' reads the clue, "When is a door not a door?" After contemplating he recites the answer: "When its ajar!!!" So to paraphrase this, when is an antenna not an antenna? When its a resistor! A few years ago prior to 'darkening' my station, I discovered that people were having a difficult time hearing me even when running the 'big rigs'. So I turned my attention to the radiating element and discovered that my 160M dipole that I fed with coax, had developed a hard ~750K~1.5M (DC)resistance. I had some 600Ω ladder line and decided to feed it with that. I had quite a bit of difficulty getting it to play on 160, (as I would later learn) but my slopbucket rig with the auto tuner in it was able to accommodate it and so I didn't worry. 8 years later, (yeah I know!) I decide to get back on the air. Once again I find that 160, 1.885Mhz. for that matter, still would not work, (I expected a miracle to occur over all those years). I could find satisfactory response on 75 but 160 was a no-go, (about 5~6:1 SWR). So the other night I discussed this with my friend and fellow antenna gumbah Pat, KN2T. He brought me back to some of the realizations that I had forgotten about a dipole: 1)the characteristic impedance is ~70Ω; 2)the added open line changed the resonant point from 1.9Mhz. to somewhere around 1.6Mhz.
So to return to the beginning, the dipole was fed with RG-213, (yeah a slight mis-match but very managable). I used an 'N' connector, (for whatever reason, I ignored the words of my buddy Eric, WB4VVI(SK) echoing in my head about the center pin being too small and causing issues during cold weather), but I felt if it was good enough for the military it was good enough for me. It was at this connection point that I discovered the resistance and some corrosion. I (thought) I had sealed the connection well enough with rubberized splicing tape and covering that with a layer of vinyl tape. Obviously over the years moisture still managed to migrate into the junction. So now the plan is to reconnect with RG-213 again until I have the components in place to remotely tune the antenna system. The reason I am putting this out there is that should you find yourself in a similar situation I will have seeded your minds and not have to 'trod over plowed ground'! As always, constructive comments and criticism are welcome!

Jim, W5JO:
To help avoid this kind of thing fill the void in your type N connectors with Dow Corning 4 and seal.  Keeps condensation down and prevents corrosion because  of that.  I used it on PL 259 connectors that is on an Ameritron Remote Coax Antenna Switch about 8 years ago.  Recently I replaced the switch with a new one and the connectors were all just fine.

Steve - K4HX:
I second the dielectric toothpaste in the coax connector. I've been using that stuff for years. Never had any moisture get in any of my antenna coax connections.

W3SLK:
I'll do that if I can find some at the local hardware store. I'm going to reinstall it with a SO-239 and seal it up with splicing tape. If I can get a photo that is reduced in pixels, I will post a picture of the N connector.

Jim, W5JO:
Mike, I suggest you look for "spark plug" grease or whatever they call it  Take a look at the MSDS of DC 4 and see if the spark plug isn't about the same.  DC 4 is expensive but the stuff they put on spark plugs is not quite so bad and all auto stores have it. 

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