Cold wx activation

I’m accustomed to (and have the equipment for) being out of doors in that temp range, but I have never operated a radio in it.

You may take at least one, better two additional pullovers with you. The more you operate, the less you move and the colder you’ll get… :wink:



I would actually take a 2-person bivy bag with me, something like this:

This will keep you pretty warm. Don’t try “superlight” bivy bags, they are just useful for a one-time emergency use (they are just thin rescue foil laminated at the edges).

73 de Martin, DK3IT

Hi Joe,
You may be interested in the thread posted here on High altitude activations.

If I had to summarize my experience from the Canadian Rockies in winter, it is “speed and simplicity”.
This is not the time to use multiple bands, antennas that have links, tuners to manually adjust, etc.

Have at least one chaser ready to respond and spot you.
Get in, do the activation and get out.


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A couple of elements for 0F operating…IMO

  1. Keeping dry (not sweating) on the hike in… this will help prevent Hypothermia once you stop.
  2. A wind shelter of some kind
  3. Spare DRY layers if you plan an extended activation
  4. A willingness to stop the activation and get moving /back to safety if you feel you’re unable to maintain a comfortable (warm) temperature once stationary/activating…

I’ve never had issues with battery capacity in a cold weather environment… I use A123 LifeP04 26650 packs…

Good Luck.
Richard // N2GBR


Hi Joe,
You may wish to consider the gloves you will have on. Are you able to operate all equipment with them on? If you intend self spotting using a smart phone, often the phone will not respond trough the glove material. A stylus can help here if you are to avoid reming your gloves. Sometimes in the cold my smart phone simply does react correctly at all on the touch screen when it gets cold.

A bivvy (or Bothy) bag is a VERY GOOD idea!

73 Ed.

So would you actually get into it? My plans are to be in heavy duty snow pants, parka, boots etc. I definitely wouldn’t want to remove any of those. I’ve never used a bivy sack, so pardon the ignorance of their operation. I am going to have my partner in adventure (my wife) with me, btw.

Thanks for the suggestions (a stylus is a great idea!) so far. We’ve decided to keep total stationary time on the hilltops to 30min or less whether we’ve gotten 4 contacts or not, just to be on the safe side.

How do your LCD screens on radios work at that temp?

A 2-Person bivy sack should be easy to pull over boots etc. There are also some (I think the Pieps model) that are pulled over your head and are open at the bottom.

You need a good stand, though.

I have been using a bothy bag also in winter, no problems @ minus 30 C.
I always keep one in my rucksack, very usefull also in rain. Mine is green as I use it also while hunting.

73 Marko OH9XX

No issue seen on KX3 down to -2F ambient.

Richard // N2GBR

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Hi Joe,

For a planned day trip, Bivy bags can be a life saver if forced to wait out storm or spend an unintended night out in the wilderness. In the winter especially though, make sure you have a Z-rest or other lightweight pad to insulate between you and snow/ground. (Actually they are great to sit on in snow during day trips).
As usual, the balance between what you need for a brief trip and what you would need if an emergency arose, is something we need to think about, usually comes down to your skills/equipment weight/likelihood of event/etc. Even more to think about in winter.
Stay safe and have fun!

Mark / K6MTS

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Walt, WØCP has a nice, short tutorial on cold wx ops here:
(W0CP: 10 Essentials for Hiking in Colorado -- High Altitude Mountaineering Tips). It’s oriented primarily toward high altitude operation in Colorado, but contains some good general purpose info.

Good Luck!

Larry, KØRS


Hello Joe, below is link to some photos taken at the day of my activation of SP/BZ-036 one year ago.
Temperature was minus 27 Celsius. I worked on 2m FM only. All batteries were kept in the internal pockets of my softshell and during activation one of them (it was enough to use one) worked perfectly.

Jarek, SP9MA

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Joe, I was on my 2nd winter activation on my local hill Sonnenberg, HB/LU-028, this Sunday, two days ago. It was a longer activation (80 minutes) with +/– favorable conditions: temperature around 4 °C, no snow, no wind, a table for my stuff nearby the hunters’ hut and a fence for my mast. So the equipment could acclimatize: the PA temperature of my KX2 showed around 11 °C.

I’d be unhappy, when I could not spot my SSB activation or not do the minimum number of QSOs for a proper activation. I experienced two things:

  • The iPhone shut down two times by itself and showed confusing percentages of battery charge afterwards. I had to keep it near the body for a minute or two to be able to turn it on again, although I had had it connected to a USB battery block feeding permanently. This could have been a problem for self-spotting, since this would affect sending SMS or using an app for spotting.

  • The output power of the KX2 went back from 10 watts to 5 watts in the last third of the activation time very often. Since I could not perceive any real technical reasons like antenna mismatch I suppose that the reason for this is the low temperature, too. Unfortunately, I did not observe the voltage in the display of the KX2. The vendor of my KX2 had informed my that they had never had problems with low temperatures on their own activations on higher mountains (rather the need of the operators for a cup of tea, hi).

No problems at all with the small tablet and VK port-a-log.

So my conclusion was: keep the batteries warm and the activation time short - by avoiding long stays outside at cold temperatures (incl. hiking time).

  • Can anybody from the readers contribute about their experience to keep the phone operating 100%? I cannot take it out and put it back into my clothes constantly, since I want to use it for SOTA watch, hi.

  • Has anyone experience with these small bags that are shaked initially and provide warmth for a certain period? Other/better ideas for longer activations? I think of keeping the KX2 battery in my clothes and connect it via cable to the power connector of the KX2.

It was an interesting testing afternoon for me on Sonnenberg to check out such details under harmless conditions.

Vy 73 de Markus, HB9DIZ

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Hi Joe,

a lot of useful hints provided so far by the others…
Here some contribution: handwarmers.

You can get details in the reflector, here:

There are some more threads with related info if you do a search.

I don’t use them very often (not such extreme weather here in Spain), but when I do in very cold days they provide a good way to keep me operational (specially if I need to use my hands out of the gloves).

They could be used as a good way to keep batteries warm? I think so.
Good luck and stay safe!
73 de Ignacio

If you good with the temps, then when you pack your pack, throw another jacket in. Depending on your radio put your battery inside your jacket when hiking and move outwards a few layers when operating. Get a simplest set up antenna / mast wise possible and practice at home numerous times so things go quick during the activation.
And, personally I that a small thermos with very hot sweet tea. Mechanical pencil also along with spares and a large booklet to write on.
Good luck and let us know how you made out.

Edit to add: If you can find it get yourself some Polyurethane jacketed coax. I did awhile ago and it makes life great for cable management. It staying flexible in the cold.


I’ve learned a ton from this thread. Thanks to each one of you who have made suggestions. We’ll be implementing a whole bunch of them on this and future winter activations.


Sounds like you are experienced in outdoor activities in the cold and so maybe this is moot but not going alone seems a good idea.


Some really good comments happening here… may I add that some electronic materials, some insulations, stiffen, lose flexibility, and shatter in the cold. i have had good luck with teflon wire for the antenna (which gets unwound and wound with each activation). I had used a cheaper wire with less satisfaction. - fred (aka WS0TA)


Hi Joe,
You live in Chicago so you know how to deal with cold weather and such! Your winter conditions are probably not that much different than being on a summit here in Colorado…below 0 degs F, wind, and such. It sounds like you’re mainly interested in radio and battery related stuff in cold conditions. You posted that you’re only climbing about 30 minutes from the trailhead so you don’t need to deal with all the extra gear that is required for the backcountry. I assume you already know how to deal with car related stuff in cold conditions.

So, I think the main thing to deal with is extra batteries for your cell phone and rig. Keeping them warm is a good idea. I carry my phone and batteries close to my chest in the winter. You should also have some protection from the wind…ie Bothy bag, tarp, etc…and hopefully you can find an operating position out of the wind. Having a thermos full of warm tea/coffee is also nice to have. I also bring some thinner gloves for operating the radio and paddle. Hands will suffer from the cold first but you already know that!

Of course, if you venture further into the backcountry and climb harder mountains, you’ll need more equipment as others have posted.

73, Brad