What is a rhetorical question? 
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Can’t compete I’m afraid. Since 2004, my max has been 100W (and probably 70W-80W with the batteries I use) but usually only on 160m in daylight, where I would deem it inadequate. Current norm is 30W or 50W on HF.
Before 2004, 1/2W to 5W of VHFM but almost nobody used any more back then.
John
2.5W though occasionally I go QRO and run 5W
73 Chris M0RSF
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Turned IC706 up to 100W to work Sweden on SSB from Mt Pacifico Southern California a few years ago 20Ah LiPo. Carried the kit on my bicycle so much easier than on my back.
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For HF sky wave, I remember years ago an old Radio Officer instructor telling me 75 Watts and a dipole was all you needed to work anywhere in the World if the condx are good. Over the years, I have found this to be a good rule of thumb. Sure, if the propagation is excellent 5W or less will do and if a band is dead 400W or more is useless. However, I reckon 50-75W with reasonable condx and a dipole should get through and counteract QSB/QRM/QRN reasonably well. Of course, increasing power for less efficient antennas might help.
What about power to weight ratio? If you are hauling all the kit up in a backpack, is it worth considering ERP/weight or ERP Watts per Kilogram? An antenna with gain may weigh less than a linear and extra batteries?
To answer the question, for SOTA activation, 5W max. so far.
My experiences with SSB only here, I’m only just dipping my toes into the water of CW…
That mirror’s my experience very nicely - and I think probably a large number of SOTA activators. If you are QRP then 10 watts is a healthy figure, 5 watts (half the power remember!) is a little more of a struggle.
For QRO I have found that 40 watts does very nicely into a dipole. Where I have worked S2S with folk using 5 watts they seem to hear me a lot better than I hear them. I always try to concentrate on what multiple of 5 watts I am running to get the power level into perspective and give an idea of the relative power.
min QRP, or 2.5 watts, I’m running 1/2 the power.
QRP, or 5 watts, I’m running 1 x the power.
QRO, or 40 watts, I am running 8 times the power.
max QRO, or 140 watts, I am running 28 x the power (but on 3.5x QRO power)
Now what we need to come up with is a name for the unit for 5 watts - a QRP?, an FT-817? That’s were the debate is really going to go…
Have fun is the main thing! Mark. M0NOM
p.s. it took me a while to locate this video again, ‘I like building crazy things’ - it is well worth a view!
In a way, the least power used for a successful activation might be more interesting.
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Well, that’s a good example of when dB are useful, comparing power levels to some reference point.
You could use “dB5W” as the reference, so that 5W = 0dB, 2.5W = -3dB, 10W = +3dB, 50W = +10dB etc.
Given that “S points” are generally thought of as 6dB steps, it gives some indication of how the changes in power might be perceived at the receiver. Of course, not all S meters are calibrated…
Not all S-meter users are calibrated either, some give nonsense reports!
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Yes, we Amateurs are quick to complain about RF interference, but still tend to enjoy getting reports such as “you are 60 over 9 plus plus”! To which our response should be, perhaps “sorry, I must be running far too much power, I’ll turn it down”.
In many cases the high power is used to beat other hams in pile ups etc, rather than to overcome the path loss by few dB. Mea culpa over the years…
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A slightly different take on this issue.
Considering the high path loss at the bottom of the SS cycle, ever Watt is valuable. Effective communications to the satisfaction of Activator and Chaser alike is my aim.
My thinking is:
What can I carry?
Answer 100W rig and 10Ah of batteries for a 14hr day. With a bit more grunt, a second battery for a second activation can be added.
How long on the summit?
Answer: 2 hrs is as much as I and can endure in British weather.
What reports do I want?
Answer: I prefer reports to be 579 down to 339 in QSB (by ear). Often the reports I am given are 1 S point below the reports I give the Chasers. Reports are very important to me. They can (among other things) indicate when the mast has fallen down, a plug has come loose or when “Old Cloth Ears” has only opened one aerial link. Strings of 599 reports has no place on SOTA.
What QSO rate?
Answer:About 1 per minute. Lets enjoy the experience, but not keep people waiting.
Which bands and modes?
Answer: As many as possible to satisfy the Chasers and as conditions dictate.
What transmit power levels?
Answer: Taking the above constraints into consideration, 80Wpep on CW and SSB, 20W on 2m FM but I moderate these values as circumstances dictate. The battery still has life after 2hrs.
However if I was activating pointy alpine peaks, my thinking would be very different.
Horses for courses.
Regards
David G0EVV currently 9H3DS in the sunshine at 27C
.
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Don’t we already have a standard bit of professional terminology for power levels referenced to 1 milliwatt (dbm) or 1 watt (dbW)?
Users of WSPR specify their output power in dbm.
Surely SOTA ops can learn to use an existing standard rather than inventing something different which I suggest does not really make for any easier calculations.
It would gladden any engineer’s heart to read people saying that 40 watts is 9 db greater than 5 watts, instead of saying “8 times the power!” Until we understand that the ratios of powers are more important than an extra watt (ref multitudinous comments about the power level of an ft818), we won’t be able to realistically plan our power levels.
As an example, assessing the power requirements for 100w compared with 40w would reveal that double the battery weight would generally be required for the same battery technology, duration of activation and duty cycle (allowing for same mix of modes and T/R ratio). Yet against that doubling of mass in battery AND an increase in the mass of the radio or amplifier, we need to offset the likely increase in contact rate from a 4 db increase in output power.
(See how easy it is to calculate dbs from a few basic facts. 2x power is 3 db, so 4 times is 6db. 10 times is 10 db. So db difference between 40 and 100 is 4 db. )
And we know that 4db might be discernable, and indeed on many radios a 4 db increase may well increase the S meter reading by an entire S point. If that is between s1 and s2 it would probably be very helpful. But between any higher S readings, it probably does not make a contact possible that was impossible at the lower power level. So, I would conclude that very few extra contacts are likely to be made (in typical conditions) by running 100w instead of 40.
So in planning my power level I decided that 100w was too much battery and radio to carry. And when I only need 5w the 100w radio is too much to carry, and also consumes more standing current in the final than the entire 5w radio consumes (roughly). Some users do not understand that turning the power down on a 100w radio merely reduces the drive level and does not change the class AB1 standing current of the final amplifier, which remains constant whatever power level is chosen. This is partly why a FT817 at 5w consumes less DC power overall than the FT857 or IC706 producing the same 5w of RF power. (Other power hogs in the higher powered radios include the CPU, other control circuitry and the display lighting - larger displays need more lighting behind them).
So my choice was to add a 40w amplifier to the kit, as an optional extra. Advantages: no extra current when not required. Only a bit more weight and my existing battery can handle it for long enough for most activations. 8 db more output power, a definite S point and at many points of the S meter scale, 2 or more. (The 6db standard is never reliably followed by manufacturers so should be regarded as a design ideal that is never met).
However 40w is a compromise between increasing the probability of completing an activation, providing a summit for chasers, and the extra mass in the backpack.
A special mention must be made of FM mode. It’s a disaster for battery powered operations. Unless you can easily get lots of battery power to your AZ, it is better in my view to focus on the CW and SSB modes. Digital users, you know what the answer is.
Apologies if this takes the thread further off topic, which I think was seeking comments and experiences of running high power as an activator. I’m assuming high power means more than 100w. I don’t have any amplifiers capable of more than 100w on HF. And the SB220 on 6m is not an option for SOTA activations. 
Andrew VK1DA/VK2UH
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…And throw in attenuators, preamps, ipo’s etc & I can pretty well make your signal on my S meter what ever you want it to be.
Compton
Hi Andrew,
Yes, if I carry my 100W rig I have to double the battery also. When I got my 100W IC706-2G in 1999, I tested it for current consumption. Later I did a weight reducing exercise for SOTA. As you will know, like most 100W rigs, the 706 is rated at 100W output for 13.8V / 20A input.
Using a fully charged SLAB (12.6VOC - 11.1V key down at rig input set to full RF out - maybe about 70 to 80W considering the voltage input) I got the following results which are approximate due to lack of an absorption Wattmeter that would do the power:
Rig on setting H: 16.3 Amps input (about 70 to 80W?) (Highest power setting)
Rig on setting 7: 13 Amps input (about 50W)
Rig on setting 5: 10.3 Amps input (about 23W)
Rig on setting 3: 7.8 Amps input (about 10W)
Rig on setting 2: 6.6 Amps input (about 3W)
Rig on setting 1: 5.6 Amps input (about 2W)
Rig on setting L: 5.4 Amps input (less than 2W) (Lowest power setting)
I used the rig for SOTA for a number of years, sometimes multiple summits with over 5000ft ascent and SLAB’s. I knew that reducing power below about 40W was futile and would cost me double. That is, efficiency becomes ridiculously poor but not only that QSO rate would drop with RST repeats more frequently required.
The lightened rig plus short coax leads, power leads and circuit breaker weighs 2.6kg.
Nowadays, it’s rare I need this rig for SOTA unless I’m trying to do 160m in daylight and/or maybe a VHF band as well, when to quote Dave’s words, every Watt counts.
Nowadays I use an FT817ND coupled to a 50W amp, the MX-P50M. This combi’ weights about 2kg inc leads etc. and needs 7 or 8 amps to run a more than useful power output of 40 to 50W. Receive current on the 817 is far lower than the 1.1 Amp required for the big rig. Batteries seem to last far longer than you’d expect and I only need one 5Ah Li-Po as against two in parallel for any useful life with the IC706. I have not discounted the use of the 706 however. It is still needed and taken to summits in certain circumstances, like GD/GD-003 recently.
Conclusion: You are dead right! Standing current on a big PA is always sucking your battery no matter how much you try to save.
PS: That doesn’t mean I don’t agree with how Dave G0EVV operates using his FT857D; he is aware of the above circumstances, is prepared to carry the weight required and is more than capable. Keeps you fit anyway! According to my SOTA chaser friend across the road Roy G4SSH, the chaser experience is almost always very good when Dave is operating.
Thanks for posting.
73, John
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I’m glad that the summer silly season (SSS) is coming to an end…
One KW using the Heathkit KW Kompact with DC supply and Kenwood 430S, powered by a 100 amp hour communications battery for the amp. SSB only. RF feedback required some re-positioning from what is shown in the picture. Battery weighs 80 pounds. Drive-on summit, of course. No need for that much power, but Eric, KU6J, dared me to do it. Once was enough. The usual amp is an HF Packer Amp at 35 watts.
Elliott, K6EL
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I think we have a winner! I can’t see anyone beating 1 kW anytime soon.
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That’s just setting the bar for the challenge though Richard!
