Securing radios against moisture

[andrew30]

Hi,
as I'm avid expedition "goer" and active in SOTA, this topic is rather important to me.
How do you secure your radios against moisture when going uphill, especially above 1000 m.a.s.l ?
I suppose filling the casing with desiccant such as silicagel isn't widely accepted. Another method would be to paint the PCB with something hygroscopic...

Thoughts are welcome

[108EH002]

Are you talking about all radios in general,or a CB/HF set ? = just that sometimes I have/many use Hf amateur radios with built in fans

[andrew30]

In general, but mostly fanless design.

[108EH002]

One of my mates uses ex military waterproof metal boxes,they have a rubber seal around the lid,with many thumb screws that have springs on the threaded shank.The boxes he uses originally contained old military testing equipment for radios, my amateur mate converted it into a GOBOX,it had a 30 amp gel battery/foam/body of mobile Yaesu/face off on top with a power point for recharching the battery/a lcd power meter to observe remaining power in gel batt plus many other things,as he is an electronic engineer,look them up on youtube = amateur gobox,hope this helps.

P.s. = his boxes were ex raf/army/navy,navy should be pretty waterproof as it was off a submarine eh.

Look up online for ex military radio testing gear boxes.

[The Collector]

Maybe a sealable waterproof radio bag if it's a handheld? They float if dropped in water too. I've seen them somewhere on ebay, most probably in with the marine radio stuff.

Otherwise - for a mobile/homebase unit - maybe a big sealable freezer bag used for turkeys etc (double seal) with the mic' cable poking through the end of the seal with some electrical tape to help matters seal-wise. The sound should still come out somewhat I reckon. Perhaps also pop a small bag or two of silica-gel in for good measure in case of internal condensation. If it's not full of air and is a bit vacuum-packed, you should be able to get to the controls ok.

[108EH002]

1 of the "other things" andrew30,one was a SO 239 fitted on the top (old hole from the removal of unwanted fitting) just drilled bigger with a patch lead to the radio inside,and this allows the connection of any antenna system with a PL 259 plug on the coax/or with a SO239 base connected mobile whip.......more of an earth than a polly bag.

[andrew30]

ex military waterproof metal boxes

That might increase weight considerably. Water-tight seal won't prevent condensation if my understanding is correct.

Maybe a sealable waterproof radio bag if it's a handheld?

This might work well, except for long fringe antennas, yet same problem as previously. The air inside contains level of moisture on its own, when cooled down, droplets will start to form even with water-tight / air-tight seal.
However a combination of enough desiccant to keep the air dry AND air-tight seal might be just right. Quick glimpse inside both my 817ND and Albrecht AE6080 reveals there's enough space for several dozens of silicagel packs (which are available on eBay for $2 per 100).

Thinking about functional consequences of filling the space with silica gel - I can't think of anything negative. Finals are cooled down by external heatsink and/or are glued with thermal compound to the case.

Then a simple freezer bag from IKEA might do the rest...

[M3VBS]

Lomo drybags. Compress the air out of the bag as you seal it, should eliminate condensation risk at the sacrafice of floatability. Swear by them on the bike!

[paulears]

Pelicases are really popular now for delicate kit that needs to be protected from mechanical or humidity caused problems. They also come in loads of colours.

[The Collector]

The only disadvantage of some sort of sealed bag I suppose is the radio may get too hot and may need to breathe unless it's reeeeaally cold where it's being used.

[Chanty Wrassler]

If you intend to pierce the casing with an antenna coupling, use an N connector, as they're designed to be inherently watertight. SO239s definitely aren't. I think BNC are too, because the military had no hesitation about using them on the Clansman kit.

[andrew30]

I'm going for this:
https://www.aliexpress.com/item/Silica- ... 44530.html
combined with sealed bag as a most cost effective solution. Heat might be an issue indeed, I'll watch it closely and if need be, just leave the silicagel inside.