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The 1 Kilo HF challenge. A multiband activation pack below 1 kilogram


One KG challenge accepted. My multi-band HF complete set up is about 500 grams.

To do it:

Radio is an MTR, small, light, and functions quite adeqautely. I get as much as six watts out after careful tweaking.

Paddle is the Pico-Palm, weighs 16 grams. I put a little bit of steel on the side of the MTR, the paddle sticks to it.

Battery is a 3S LiPO 250 mAH. I seem to average less than 5 mAH per QSO, so it is plenty for an activation. It is velcroed to the side of the radio.

Earbuds are on a retractor. They stay plugged into the radio, just pull and play.

Eliminated connectors, coax, or any feedline. I tape the EFHW wire to the pole with a about a meter and a half of slack left. Wire end has a 2 mm plug on it. The end of the wire doesn’t radiate anyway, so no reason not to use it for the feedline.

Eliminated any tuner. Instead use an impedance transformer built inside the MTR. it consists of a capacitor and a toroid, would for 81:1. The wire is cut to be 1.1:1.

The back of the radio supports a single cut to fit sheet of write-in-the-rain plastic paper for the log. I hold the radio in one hand, write and key with the other.

Writing utensil is a mini-spacepen, 4 grams, writes upside down underwater, on butter. The pen is tethered to the radio, so I can just drop it if I want to.

Pole is 18 feet tall (5.5M) collapses to 2 feet, and weighs about 7 ounces.

Antenna is 53 feet of #28 teflon wire with two homemade traps using T50-6 toroids, each trap weighs ten grams, operates 20/30/40 instant, no tune band changing. It is wound on a figure-8 winder, total weight about 70 grams.

Set up or tear down is typically 4 to 6 minutes once a suitable location is chosen.

The pack weighed more than the entire set up, so it had to be replaced. I now use a pack made of nylon gauze that weighs only about 200 grams. < http://www.ultimatedirection.com/p-629-sj-ultra-vest-20.aspx?category=hydration-packs >

Water is the heaviest burden, now have a filter/straw so that I can drink from any streams encountered, OR, I have a filter in the hose to my hydrapak, so i can carry less and refill from streams.

Essentially all our activations are over 10,000 feet (about 3,200 meters), with some as high as 14,400 feet. It is a whole lot better to be lighter!

73, Fred KT5X (aka WS0TA)


Wow Fred!!!
you took the challenge to another universe! I think I won’t beat you at 500 grams… Congratulations!
I thought you were using peanut and roaster to get your Acom + Optibeam to the summits :smile:
Now I see you just carry your kit inside a doughnut then ready for the lunch break!

Sharing a picture with us would be much appreciated if you can. Just for the fun of looking such a nice setup.

It would be nice to get details to build myself that antenna as well.
Mine has a coil as for the trap for 40m and it’s a little bulky, but your design with toroids is very interesting. Maybe I’ll drop an email to ask for details.

Thanks everybody for your comments. I hope to do an activation this saturday and try my kilo-pack.

Take care, 73

First test of '1 kilo HF Challenge'

Will try, Ignacio. I cut out and then carefully sanded a piece of perfboard into an oval. The #28 wire goes into a hole, and that is all that is needed for strain relief. Toroid goes on one side, cap on the other. More inductance is generally better than less, but any combination can work, just must get it resonant some below the target frequency.

The three traps shown in photo are, left to right, 30M, 20M, and 15M. Single wire does 15/20/30/40 and wound on a figure-8 winder totals 75 grams.

Realizing that I could eliminate any feedline at all, along with its connectors, also helped a lot.

  • Fred KT5X (aka WS0TA)


I suggest to replace tcvr for ATS-3A or B… Most liteweight setup with KD1JV tuner (both in Altoids cans) and mini paddle and AA cells!
Good luck
73 - Petr, ok1rp


Reviving an old thread here, but I love this idea; I recently did a 10 day hike and 4kg for radio gear was too much, but live and learn. A thread like this has reinforced that Morse is the way to go for super lightweight, and if I can do 5-10mA per QSO that also means that if I want to charge anything, I can use a small solar cell just to top up the battery (or even potentially run off solar power with a regulator and a big enough capacitor). I say this because I plan on doing more week long hikes in the future.

The only thing I would add, and most aren’t multi-band, are the DSB kits and homebrew radios out there, I have an ozQRP MDT (40m only) that weighs in at 260g, then you only need to add a mic, 100g (could probably get that lower). with an EFHW and L-match you’re only up to 600g. I won’t talk about batteries, as I have nothing that qualifies (yet).

73, Marcus, VK3TST.


Hi Marcus,

glad that you found this thread interesting. It would have been perfect for your long hike if you had planned some similar setup in your side. Maybe in the future? You need that battery then you’re ready. Doing more with less is always rewarding.

Barry, thanks for your idea, I would fully support it, like other nice events we have in the SOTA community, unless you have changed your mind.

I’m still working to improve my setup and reduce even more the weight… I’ll post any significant improvement.
VY 73 de Ignacio


I use the X1M - a small mobile multi bander multi mode - does cw and phone, and handles from most hf bands. It weighs only 400g and pumps out 5w. My problem is the battery. What battery can you get under 1Kg?

Dave, ZS2DH, South Africa


Dave, a quick search on this reflector will bring up many threads on portable power.

Lithium technology batteries are the most commonly used, SLABs are used only by the hardy these days :smiley:

73, Colin


How about two of these in series, for a small, lightweight cheap solution (264g total):

If you want to stay with just one battery, while somewhat heavier and quite a bit more expensive (but will last longer), you could go with this LifePO battery (560 Grams):



I posted this earlier, but I think it got deleted due to my fumbling about.

I love the idea of the 1kg challenge. I give Colin M1BUU part of the credit for my inspiration because I’ve always been amazed at how good a signal he always seems to put out with such tiny equipment :wink:

I get even more excited by the idea of working others who are also using sub 1kg stations, S2S. In this scenario, I’m not so inspired by working QRO chasers. So my half-baked idea would be an event where sub 1kg activators would primarily be attempting to work each other S2S and perhaps also QRP chasers. This to me would be in the perfect spirit of SOTA. I don’t even know if this is feasible or if many folks would even agree with this.

When I think of it, besides the <1kg activator component of such an event, I do really like the idea of setting aside a Saturday or Sunday where all SOTA chasers must use QRP. How’s that for stirring up the pot? :wink:

73, Barry N1EU


I fully support that idea, Barry, as I already proposed long time ago,

but it didn’t seem to raise much interest at the time.
Hopefully your leadership will be stronger tan mine…

Best 73 de Guru


When I was back in Australia, there was a couple of days where it was requested that all chasers used QRP (10w PEP SSB or 5w CW or digital) - it actually went quite well as a “novel” event. I’m happy to take the “after burners” off here if we want to arrange a similar European event. We could even make the amount of power been used part of the exchange, to see who can get really low (QRPp) levels to work. It’s all in the locaton and the antenna in any case - as proved by Karl M3FEH and other Foundation class licence chasers as they MUST run QRP - they have no choice!



When I was back in Australia, there was a couple of days where it was requested that all chasers used QRP (10w PEP SSB or 5w CW or digital) - it actually went quite well as a “novel” event. I’m happy to take the “after burners” off here if we want to arrange a similar European event. We could even make the amount of power been used part of the exchange, to see who can get really low (QRPp) levels to work.

I love the idea, but let’s make it a world-wide, not just European, event!

Barry N1EU


From my side world-wide would be fine - I was just thinking of time differences. I guess if we make it a weekend - i.e. two UTC days, that should work?

It is probably too late now, bt it would have been nice to co-ordinate this with World Radio Day, which is this coming Sunday - how about on the weekend nearest to the ITU World Telecommunications day - 17th May? By May it’ll be a little warmer for the activators in the Northern Hemisphere.


Perhaps we should make this a new thread??


I think it is a great idea!

What about world QRP day - 17 June ?

Thanks, also, for the help with the batteries. All noted :wink:

73 Dave


Nice idea, it would certainly create a buzz to work long distance QRP to QRP with minimalist stations.

I go along with Guru though, the small rig QRP CW operator seems to be a rare beast.

Barry, I’m not so sure that I do put out a good signal, it’s only stations with good ears (ESP) that can pick me out! I feel the need to get the RockMites out again, but then again, I’d like to do some more operating with the MTR-5B, it’s only been on the air about 3 or 4 times. I have built a five band dipole in coordinating orange to go with my rig, I just need an opportunity to tune the elements.

I also thought it might be fun to have a straight key operating event :smile:

So many ideas, so little time to put them in action! I have a corker of an idea for my Mountain Goat activation, but you’ll just have to wait and see :smiley:

73, Colin


Thanks Colin,

Yes I use a SLAB - cos they make us tough here in Africa LOL.

Thanks for the help!

73, Dave


We don’t have a 2016/17 challenge yet do we, can we put something like this in as a suggestion? :smiley:


I love the idea, but shouldn’t it be 18 June, on a Saturday? The Saturday closest to Summer Solstice!

73, Barry N1EU


There’s always QRPTTF which many of us partake in!