Rich, coming from a man who professes to know about MD22s, but doesnt.
Thank you. Thats exactly what I did, boat in Albufeira, SWMBO up mast, Vaseline, instrument started doing what it should do and still is 6 ish months later! PRACTICAL Boat Owner!
Apology accepted, virtual pint paid for!
The only job of the grease in the connector is to keep moisture (and salt) away from the conducting metal bits, and pretty much any waterproof grease can do this job. This works well because no moisture means no corrosion, and it's the corrosion that leads to failure, because most corrosion products do not conduct electricity so the connection surface gets smaller and smaller and the resistance higher and higher until things stops working and some poor bastard has to climb up the mast and wiggle the plug.
Vaseline is a trade name for a series of skin care products made by Unilever, some (but not all) of which are made of petroleum jelly. As everyone who has ever read the instructions on a condom knows, you shouldn't use petroleum based lubricants on natural rubber (latex based) products, because it will attack and dissolve the rubber and gets you STDs and/or babies. That's also the reason Vaseline is not recommended for use on rubber gaskets, seals etc. - although most of them contain little or no natural rubber anymore.
If you look at a material compatibility table, you'll find that Vaseline and other petroleum based products do harm certain elastomers and slightly attack certain plastics (ABS). Some of these materials may be present in the rest of the connector, i.e. the plastic screw-on caps, rubber seals, or Butyl sealant which is often found on boats. Therefore while petroleum jelly will do the job, it is not ideal and can cause harm to other components, although in most cases it would take years to make a difference, except to Butyl. Spray a bit of WD-40 on some Butyl tape for an experiment and you'll have the messy results sticking to your fingers in seconds (clean up with more WD-40 or white spirit, i.e. other petroleum products).
So for electrical conductors I'd recommend Silicone grease instead, or if you must, an overpriced branded version of it, such as Contralube. The difference in most cases does however not warrant climbing up the mast in wild panic to go clean off the vaseline (Butyl tape is excellent for bedding deck fittings, but I've not seen it used on masts much).
By the way, neither of these greases have particularly good dielectric properties, they're simply insulators, and that's the way you want them to be. Dielectric (able to be polarized) material would be undesirable in most connectors, unless you wanted to build a capacitor in there (you don't). The term "dielectric grease" is therefore a bit misleading and should go in the same bin as "AIS transponder" (they're transceivers).
STDs and/or babies. Home made contraptions. Rubber inner tubes. Vaseline ..........................The mind boggles
This one actually involved teenage schoolchildren, rubber ducks, and faux-zebra-skin gloves...
Pete
You're not a Catholic Priest are you ?