eHam Forums => Mobile Ham => Topic started by: N7EMW on September 19, 2007, 10:33:43 AM

Title: SO239 nuts rusting
Post by: N7EMW on September 19, 2007, 10:33:43 AM
Has anyone had the OPEK HDM-1 heavy-duty SO239 nuts rust?

The rust starts even after one fairly heavy rain on my mobile antenna mount (without road salt). The body of the nuts rusts a bit but less than the threads. The rust can quickly be removed by using fine steel wool. I do weather proof most of the PL259/SO239 connections but have not totally sealed the top of

Has anyone found a stainless steel version of these heavy-duty nuts?

I had one nut nickel plated (electroless nickel) and after 1 day in a salt bath they seem to not be rusting. The "stock" nut has already started to rust - while this can be removed I would rather have no rust!

Is anyone interested in nickel plated SO239 nuts - if so I might have a batch plated - save a lot if done in quantity.

Dick, N7EMW

Title: SO239 nuts rusting
Post by: K0BG on September 19, 2007, 01:11:53 PM
This is a common occurrence with most import antennas. The fittings are typically stamped steel (not brass), and the plating is usually what is called "Japanned". It rusts very easily. Finding suitable replacements is difficult, and not always inexpensive. Silver plated, brass replacement nuts can be ordered from Mouser or Digikey, and they're about $3 each.

The other issue is, SO239s don't make very good antenna mounts, but they seem to be the norm for imports. Adding insult, they aren't waterproof.

It's a little late now, but you've discovered (the hard way), that bargain antennas aren't always the bargain they appear to be on the surface. This is one of the reasons most old timers will tell you to purchase an NMO2/70BK or similar quality antenna.

Alan, KØBG

Title: SO239 nuts rusting
Post by: N7EMW on September 19, 2007, 07:07:46 PM

The SO239 barrels with the rusting nuts are on the coax connector that feeds my USA-made motorized HF antenna and low-band load inductor. I do use a 1/4 wave 6m antenna with an S0239 "import" antenna base (modified VHF-HF OPEK antenna).

You can fully water proof SO239 bases/connectors via exterior/automotive sealer, coax seal (putty) and/or black tape/self fusing tape. In my installation with the rusting nuts I wanted to have the PL259 easily removable, hence the water exposure to the Korean-made nuts.

I agree with using NMO bases, which is the base on all my other antennas - 6 years of use no rust!

Dick, N7EMW

Title: SO239 nuts rusting
Post by: N5EAT on October 03, 2007, 11:20:30 PM
You might want to have a urologist take a look at this....