Power at 1kw plus

Just thinking, if I wanted to push out 1 Kw +, what Antenna would cope with that ??,  A scaffold pole? also what sort of radio could be used, and how would it be powered ?? 

There is plenty of commercially available kit rated at 1kw. The typical set up would be a normal radio driving a linear amplifier to an appropriate antenna.

The amplifier would usually be mains powered.

Your installation needs to be impeccable and properly grounded. At this kind of power the risk of stray RF and EMC problems is very high.

It's also worth considering that power is a game of diminishing returns with each doubling of output power giving you roughly one 'S' point at the receiving station.

73's Gary.

C.T. Admin.

High voltage thermionic valves or high current LDMOS (laterally diffused metal oxide semiconductor) devices are the order of the day Bernie.

That and an impeccable setup so that stray RF doesn't come-a-biting!

As Gary mentions there are diminishing returns with an increase of power as explained well in the following links :-

https://qso365.co.uk/2017/10/increasing-transmitter-output-power-what-effect-does-it-really-have/

https://www.youtube.com/watch?v=0rRs75Kdwq8


Of course there will always be others that will argue to the contrary but if everyone in the 'restaurant' is 'shouting' it is much harder for the rest of us to have polite conversation.


Great posting Bernie, always good to see such questions on the forum.

Well, a standard wire antenna will be just fine - it's the matching components that have to be up to the task.  Despite a limit of 400w here, the transformer on my EFHW happens to have a 1.5kW rating for our US friends legal limit, and it's just a stacked torroid core and high voltage capacitor really.  Nothing special at all.

As for what will do it - well, my LDMOS 1.2kW amp (With an attenuator inline internally) will do 400w with a drive of just 15-20W depending on band. 

Just remember, as others have said, power vs. S-meter readings are not linear.  An S-unit is usually 6dB, so 100w to 400w is a single S-point on receive, and therefore full legal limit in the US (1.5kW on most bands) is less than 2 S-points more than 100w.  

That said, I have had plenty of times where I couldn't be heard at 100w, but flick the amp on and that nice bit of DX came straight back to me.

Wow! I thank you all for the answers, The reason I ask is I picked a chap in Italy who claimed 2.5 Kw and was hitting me at 30+ on triple 5 usb, I was thinking he will not get a response from my 10 watts on a magmount 

As Mark hit New Zealand on 10 watts I am thinking what is the point. 
Very interesting answers thou.

Thanks Vic & Jeff for the accurate numbers.

Bernie I think the point here is to make your antenna the best it can possibly be before introducing more power.

Remember also to work them you've got to hear them and antenna gain is helpful on transmit and receive. Just increasing your output power on its own won't help you hear other stations any better.

Best of luck Gary.

As I am now, Just getting out around 30 miles at home base, is good enough for me for now.
I am getting to know the 11 mtr nets around the south coast, still learning the etiquette for International contacts, more power later, baby steps for now. Just a big learning curve, thanks again for the info.

After watching the video, Victor, that makes things clearer to understand.

It was a great posting Bernie and I'm so pleased that a few of us here did our very best to answer for you.  

Remember that although a lot of our Mediterranean cousins scream out about how many kilowatts they're transmitting, some seem to measure it all a little differently than the rest of us.
(Although some do actually transmit those levels!)

As Gary mentions running more power out won't help you receive any better and you could become the infamous 'alligator station' or in other words all-mouth-and-no-ears. It's only when an equally deficient station pumps out silly watts as well that the former station finally picks them up much to the bereft of others. Think of the restaurant analogy I mentioned and what would happen if everyone shouted as loud or louder as each other with complete disregard for the other restaurant goers? Breaking a pile-up by pumping more power and screaming over others is not at all very 'gentlemanly'.

As for transmission distances with small amounts of power it's down to what Mother Nature gives us and what we choose to use. On some of the Ham bands you can get incredible distances with very little power especially with modes such as CW and FT8 which are much harder to do with voice modes, even SSB. I was really chuffed that I got to one end of the UK to the other on the CT 40m net recently with 10W SSB but always blown away with contacts in my log such as Australia, Japan and Chile with FT8.


If you hear the typical "Hola-Hola, Coca-Cola, one-keee-lo-watt" on the triple five you're not very likely to get back to them unless you're running huge power as well....even then you're not guaranteed to 'make your own propagation' if others are in competition doing the same.

But sometimes an opening appears, the air waves are clear and even a little CB can herald a contact with a far flung country....and boy is that as exciting as heck!!


Brilliant stuff there Bernie. An enjoyable discussion.

Thank you Victor, I did feel that a Kw of power was a bit silly considering the gain in distance is, as you say its is up to nature, I was on the Yanki Foxtrot net last night with only 10 volts from one leisure batterie, so added another batterie and out put was not much better although watts went up, it wasn't until the back ground hash diminished that they said I was much clearer.
I think if I quadrupled the watts to say 120 watts from 30 watts it would only have pushed my signal up by 1.5 ish on there meter.
As the hash came down to almost zero that I could hear everybody in a 30 ish mile radius. I turned the power down to 10 watts that put the batteries up to 12.5v but no noticeable return report.

Wheel Nut wrote:

I think if I quadrupled the watts to say 120 watts from 30 watts it would only have pushed my signal up by 1.5 ish on there meter.

On a properly calibrated s-meter, that would be 1 s-unit of difference.

Doubling of power is 3dB, so 4x the power is 6dB, which is 1 s-unit. 

Remember though, however little change to their s-meter, if that change gets you out of their noise, it's the likely difference between being heard and not being heard.

Thinking about Watts again.  I am very interested in Astrophysics and just been looking at the Voyager 2 probe launched 38 years ago that is billions of miles away now, and only chucking out .4 of a watt, messages take 20 or so hours to reach us, so ____Who needs a Burner any way.
I think I will stay as I am for now.

The modest silver rod will run a kiloWatt, but mostly for SSB and not constant carrier, etc.  The problem I have seen is the poor quality soldering on the matching transformer (coil).

https://charlietangodxgroup.forumotion.com/t5343-some-silver-rod-repairs