Most power ever on HF activation?

So I’m curious, what has been the highest power HF activation and what amplifier/battery were they running?

Tom, N2YTF


180w, Hombrew amplifier, 4s LiPo. That’s the most I can put out currently with my setup driven by a KX3.

But you really don’t need that much. Its what it can deliver though, useful on the higher bands


I ran 150W out to a 5 element yagi on 2m SSB from Craig y Castell GW/NW-074 in December 2008. A total of 8 chasers were worked, the most remarkable contact being that with Don G0RQL down in Devon by backscatter. I had to beam east as nearby Cadair Idris GW/NW-009 was between us. The 12AH SLAB used didn’t last for that many activations after that! Needless to say I didn’t drag the linear and battery up Cadair Idris later in the day. :grinning:

Current HF capability is the FT-857D running a potential 100W on HF with 16.4AH of LiPO + NiMH on board.

About 500W ERP. So far.


I once borrowed a 10w linear - but it was overkill really, entirely unnecessary.


Twisting a bit the question, the most power(ful) I’ve ever been on HF from a SOTA activation was in August 2nd 2016, when I called CQ SOTA on 30m with my FT-817ND at 5h40 utc running just 5 watts to en endfed sloper wire and got replied by VK7CW in the isle of Tasmania, :wink:

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Following on this theme …
2.5 watts SSB from the 817 to a dipole at 5m AGL 3rd. April 2014 0500-0600 UTC from DL/AM-001 as well as lots of EU contacts also brought contacts with W1AW/3, VK5PAS, VK2DAG, VK3DET and almost a completed S2S with VK2LAX/P on VK2/HU-093.

It should have been 5w - I wasn’t clear how to read the output level from the display at the time, I only found out after the activation when I got home that NO BARS means 5watts !


Tell us more…100w to an HF yagi?

Hi Tom,

Tell us more … what are you up to? Do you want to break any barriers?

I use as much as 10W from my KX2 for initial CQs, typically 3-6W once I have QSOs running.

73 Heinz

Old Yaesu FT-100 and a Bioenno BLF-1206 in my very very early SOTA days. That kit is too heavy or my liking so now QRO is 12/15W using a KX3 and the same battery. The rest of the ruck and it’s owner is on a diet. :wink:
Hoping for cooler Wx and less rain.


For the activator, a few watts and CW will produce contacts and make an activation viable.
For the chaser, the more power and better the antenna the activator uses, the more likely the chaser in a noisy environment will be able to have contacts.

So 5W and CW is fine for me as an activator but I’m sure I’d have worked many more chasers yesterday if I’d been running 25W.

I see the key power values as 1W, 5W, 25W, 100W, 400W. The battery requirements for 25W are not massive and 100W for short (< 1hour) is feasible. Of course, a system with 100W output plus battery is going to be massive compared to some Altoids tin CW set but what do you expect.

Is there a reason to run such higher powers on an activation? Well it’s interesting (from my point of view) to see the differences it can make. Is there a sweet point that gives the best for chasers (signal strength) and activators (weight vs operating time)?


Having some means of quickly switching power levels as necessary might make best use of the battery capacity. I don’t mean just turning down the PA drive power, as that is generally very inefficient.

I’m pondering something along those lines for 23 Cm. Something like this, maybe:


Unfortunately that’s not the only factor. You’ve time of day, choice of day, location, etc.

Seems you’ll need to build for the area pure operating in. Right tool to crack the right nut.

2.5w with a knackered battery into half a 20m dipole - still got W4ZV from GM/SS-140. Went home!

So nobody has ever run a KW (off of a generator) on Field Day from a North American SOTA summit?

I realize that is hardly what SOTA is about, but pretty sure that has happened here in the States, but maybe they did not submit the log as an Activation into SOTA…


Only if the generator is not powered by fossil-fuel. See SOTA rules. 3.7.1 #6
With hydrogen-fuelcell or windpower this could work if you bring them with you. Permanently installed at summit also does not count.

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OK…thanks Joe for that…missed the part about fossil fuels…

50 Watts max for me on a few s2s events in the past…


I have used the Sommerkamp SLA-817 from Gummer’s How a few times - it puts out around 140 watts on 80m SSB when using LifePo-4 batteries. As amps go it is fairly lightweight and I have to say I’ve been very impressed with both the performance and protection.

Not sure what Richard @G3CWI would say about me pushing a SOTABeams Quadbander with 140 watts but it seems to cope admirably, so far at least :wink:

p.s. not noticed any difference between this and the MiniPA50 which puts out around 40 watts, but then you wouldn’t really would you?

Yes, so you can make the S2S you have planned.

…and cook the sausages at the same time.