Waterproofing a PL259 VHF Connection

whisper · 18 November 2010, 17:01

Hi, I have just bought a Icom M411 VHF and I’m planning on fitting it on the side of my SR4 console.

The whole unit will be exposed and although it is supposed to be waterproof the PL259 plug on the back will also be exposed. Is it as simple as wrapping the connection in electrical insulation tape? And is there anything else I need to consider?

Thanks in advance.

Erin · 18 November 2010, 19:10

I think you'll find self-amalgamating tape is a much better option. If done well, it'll be practically waterproof.

JABS · 18 November 2010, 19:31

I would also stuff the plug with silicone grease. Put in so much that when you apply it to the radio, it spews out of the back of the plug.

ashbypower · 18 November 2010, 19:36

Quote:

Originally Posted by JABS

I would also stuff the plug with silicone grease. Put in so much that when you apply it to the radio, it spews out of the back of the plug.

As silicone grease is an insulator, I would be very carefull where it is "stuffed" you would not want to insulate all the conecting surfaces !!

martini · 18 November 2010, 19:53

Quote:

Originally Posted by ashbypower

As silicone grease is an insulator, I would be very carefull where it is "stuffed" you would not want to insulate all the conecting surfaces !!

Probably better than using a conductive grease, which may create a short

ashbypower · 18 November 2010, 19:56

Quote:

Originally Posted by martini

Probably better than using a conductive grease, which may create a short

Totally agree however in the wrong place could be equally useless !!!

JABS · 18 November 2010, 20:04

Quote:

Originally Posted by martini

Probably better than using a conductive grease, which may create a short

At the risk of getting totally anorak,

The reason to use silicone grease in huge quantities is that, where there is a void, water will get in. If there is something in there already, such as grease, water is LESS LIKELY to get in.

Conducting surfaces are designed to scrape or rub together.

If a connector is designed correctly using grease should only help.

whisper · 18 November 2010, 20:45

Thanks for all the advice

What about moderately using some silicone on the threads and at the back of the connection and then covering it with hot melt glue from a glue gun a bit like a made to measure rubber cover. Then wrap the whole thing in self-amalgamating tape?

I’ve seen some PCB’s covered in hot melt glue to keep them waterproof.

ashbypower · 18 November 2010, 20:48

Silicone grease and adhesive lined heatshrink is how we do it. One of our boats done that way has been like it for 5 + years with no Problems at all.

BogMonster · 18 November 2010, 21:02

Quote:

Originally Posted by JABS

At the risk of getting totally anorak,

The reason to use silicone grease in huge quantities is that, where there is a void, water will get in. If there is something in there already, such as grease, water is LESS LIKELY to get in.

Conducting surfaces are designed to scrape or rub together.

If a connector is designed correctly using grease should only help.

I agree

This stuff is designed for aerial sealing:

http://www.saltyjohn.co.uk/bandit-silicone-tape.htm

GJ0KYZ · 18 November 2010, 22:00

I've had my three-element Steppir up for over four years now and I've had no problems. The approach I've used (and on my boat too) is to cover the plug completely in Sikaflex so you can't see any metal. Spread it around where the plug meets the appliance as well. It makes the best seal although it does mean it's hard to get the plug off at a later date.

I've used grease in the past and that works too but it can be eroded by heavy rain and hail. Tape of any description will fail after a while. Exposed connections are a big problem in the Ham world. You may find eham.net to be of use for enquiries of this nature.

And before anyone asks, yes it goes up higher (40ft), yes it annoys the neighbours, and yes I have planning permission.

Erin · 18 November 2010, 22:08

Bet you could get a lot of washing dried on that too

BogMonster · 18 November 2010, 23:29

My father used to build his own VHF ham radio aerials in the days before telephones were invented here. What he used to do was cut holes in a plastic lid (about something the size of a large aerosol can lid) and make the solder connections from the elements to the coax inside the lid. Then when ready he would fill up the lid with isopon P40 - wait until set - end result was very strong and totally waterproof

Of course if you isopon'ed the aerial into the back of a radio you'd never get it off again but it wouldn't leak

GaryC · 19 November 2010, 07:34

Our Club RIB has a rubber cup that is RG58 thick at one end and PL259 thick at the other. It covers the plug and socket and a small length of cable. It fits very snuggly and can make removing and replacing the plug a little difficult. You obviously have to fit the thing first. Although probably not water proof it is splash resistant.

Gary

lockieboi · 22 November 2010, 18:30

Self amalgamating tape will do the job just fine. If you wanna be safe replace the tape yearly. Or get a IP65 rated junction box if you can mount it somewhere and then do the connection in the JB.
Hope this helps.