How Much Power?

[druid]

I have a Icom IC730 which, depending on what spec you read, puts out somewhere between 100 and 200 Watts on SSB. I measured its output into a 50 Ohm dummy load, and it looks like about 25 Watts. Which got me to thinking...

Notwithstanding those folks in California pushing 2 KW into a stacked Yagi array ( ) and those crazy QRP guys running a 2N107 final, how much power does the "average" ham run on HF SSB? 100W? 200W? 1000W? How much do YOU use? How much is "enough"?

druid
VA7LAS

[K7KBN]

What sort of meter were you using with the rig and dummy load? The specified 100 watt output from the 730 is PEP, so if you were using an average-power responding meter, you'd only see around 25 watts or so. Try it with CW or FM - that should read closer to the 100 watt mark.

You need a true-PEP meter for making PEP measurements; most meters (including those built in to most transceivers) are average-responding.

[druid]

What sort of meter were you using with the rig and dummy load?

Oscilloscope. The ONLY way to really see what's going on. And I was using the CW mode so I got a pure carrier.

But that wasn't my question: what power are YOU using?

druid
VA7LAS

[techiesteve]

At home I tend to run 100W SSB HF, presuming the transceiver is putting out that much. When portable HF I run 5 or 10W, usually into an inverted V. Sometimes I'll operate stationary mobile when using a leisure battery on the floor of the car, running something between 40 - 50W. The only linear I sometimes use is a mighty 25W, used with my FT-290R on 2m SSB.

[AB3NK]

Transmitted power is a lot like a light bulb.
All signals reduce at the square of the distance away.
A light bulb - we can see and we can measure light by how well we can see it. It is very easy to understand.
Unfortunately a radio signal is not quite the same.

Eventually at some point - the light the light from the bulb gets so dim we can't read a newspaper anymore, or it only travels so far and unless it has something to reflect off of - goes no further.

Now we know that the S meters in our radios were origionally designed to move one S unit per each power increase of 4 X. I believe that it was the Collins company that came up with that scheme - That is up to S - 9 level.

At S - 9 to move the S meters one S unit we need to multiply the transmitted power 100 times.


A person that contests with a beam antenna and high dollar rig, expects a S - 9 signal report with 100 watts , that is a given, and expects at least 2 decible points more over S - 9 with a 1500 watt amplifier, that is a misnomer.
On the other hand, if they understood that it takes a power increse of 100 times to move the S meter one unit - or 10,000 watts of power, then you would understand that the 1000 or 1500 watt amplifier does absolutely nothing to improve your situation.
It does make your audio louder and it does make your signal wider - which makes you less popular in the ham radio world when those of us that does use low power has problems hearing who we are talking to because their signals gets excessively wide and takes up more bandwidth then necessary.

If a transmitter putting out 100 watts is at S -7, to move the S meter one more unit, we would need 400 watts of transmit power. That we can see on the meter.

To move the meter 2 S units - we would need to use 1600 watts of power. That we can also see.
Is it worth it to be unpopular, and be illegal, just to impress someone or to improve our signal report to use excessive power, just to make ourselves louder?
It does not matter if our signal is S - 5 or S -7 as long as our audio is a 5, you can't improve upon that.

On the flip side, I have listened to hundreds of people who use a amplifier and most if not all times, their audio sounds lousy with the amplifier turned on.

There is more gains to be had by using a beam type antenna with increased gain, then to use a long wire antenna and a amplifier. You need to remember that unless you can hear what you are talking to - what good does it do you to be heard but can't talk back.

Amplifiers does not amplify the receive only the transmit.

http://en.wikipedia.org/wiki/Incandescent_light_bulb

http://www.signalengineering.com/ultimate/yagi.html

http://www.signalengineering.com/ult...na_basics.html

[K7KBN]

100W CW - no voice.

[G6NHU]

'Enough' is the minimum required to make the QSO.

[AB3NK]

'Enough' is the minimum required to make the QSO.

Congradulations - you are a real ham.

I guess you get it!

The difference between a 100 watt radio and a 200 watt radio is significant if the person you are talking to is real close.

If the person was 1000 miles away, there would be very little change in the movement of the S meter or the amount of perceived audio available unless the difference between making the contact and not making the contact was 1/2 of 1 S unit of power.

By comparison - lets use KDKA 1020 AM in Pittsburgh PA
Kdka broadcasts from a tower 218 meters / (715 feet ) tall with a ERP of 50 KW, day and night. It has a effective range of about 200 miles in the daytime and could be heard up and down the eastern sea board at night before they went to a more modern digital vs tube type transmitter.

Now lets compare - a person with a 100 watt transmitter and a 100' tower can be heard 100 miles away and 5000 miles away on a good day on 160 meters.
So even huge increases in power only nets small returns in distance when it comes to broadcasting.
Can KDKA be heard across the ocean, no - not unless all the other commercial broadcast stations on 1020 Khz were to shut off their transmitters and there was no other noise to compete with their signal - such as was the case more then 100 years ago before most commercial broadcasting took place.

Can we hear your station with 100 watts into a good resonant antenna across the pond on 160 meters - probably on a good day when the propogation was good.

I can talk on 10 meters SSB right now to Germany with 100 watts into a verticle antenna with no problem. So does more power get us? Not much.

The difference between a 100 watt signal and a 200 watt signal would probably be like comparing a 60 and a 75 watt light bulb. At 300 yards away, you probably couldn't see any difference between the two if only one bulb was illuminated at a time.

[mu0chn]

'Enough' is the minimum required to make the QSO.

Spot on Keith. Strait to the point, no need for 25 lines of bridle that you get board with half way through

[G6NHU]

Actually I need to make an addition.

'Enough' can also be as much as you need to make sure you're not swamped by the fifty other stations in the pileup who are calling the DX.

In other words, 'enough' is not a fixed figure.

[druid]

'Enough' is the minimum required to make the QSO.

Of course, this is the mantra of the QRP set. In fact, I hear there's a regulation that says you're not supposed to USE more power than "enough"

So as you say, it's a relative term. To a QRP'er, it's usually less than 5W. But judging from the people I'm hearing (mainly from the US), some think that 1000W is NOT "enough". I'd guess one reason for this is if someone is using 800W and get's a QSO, he assumes that's "enough". I think few people turn down their rigs after initial contact to see how little they can use and still get through. So "enough" becomes whatever you're using

So I'm just trying to get a handle on what the "typical" ham considers "enough".

druid
VA7LAS

[G6NHU]

I don't think there's such thing as a typical ham.

QRPers will tell you that 'enough' is the output power that their homebrew transmitter produces.

Your average (and I hesitate to use that word) black-box operator will tell you that 100 watts is enough because that's what their stock radio transmits.

A satellite operator (repeaters in the sky) will tell you that 10 watts is enough.

A QRSS beacon user will tell you that 100mW is enough.

A JT65A user will tell you that 20 watts is enough.

A serious DXer will tell you that whatever the legal limit in his country is, is enough. Although in the UK, some may feel that the 400 watts we're allowed isn't enough

All of these answers are correct.

I've just put up a Cushcraft MA5B mini beam and am working loads with it. I'm not breaking my way through pileups with the 100 watts output from my wireless but I'm generally getting through eventually. So for me, at the moment, my 100 watts probably isn't quite enough, I'd like just a little more.

It's a simple question with a far from simple reply because it's so subjective.

[G0DJA]

On 1296MHz I've been using 10W (usually CW) and done OK, with contacts into Scandinavia, Poland and parts of Germany. However, I am hoping to increase the power to nearer 100W to make things easier for the people at the other end who often have to listen very hard to my signals.

On 10GHz I usually use 5W, as the PA is permanently inline on my set up.

[AB3NK]

I don't think there's such thing as a typical ham.

QRPers will tell you that 'enough' is the output power that their homebrew transmitter produces.

Your average (and I hesitate to use that word) black-box operator will tell you that 100 watts is enough because that's what their stock radio transmits.

A satellite operator (repeaters in the sky) will tell you that 10 watts is enough.

A QRSS beacon user will tell you that 100mW is enough.

A JT65A user will tell you that 20 watts is enough.

A serious DXer will tell you that whatever the legal limit in his country is, is enough. Although in the UK, some may feel that the 400 watts we're allowed isn't enough

All of these answers are correct.

I've just put up a Cushcraft MA5B mini beam and am working loads with it. I'm not breaking my way through pileups with the 100 watts output from my wireless but I'm generally getting through eventually. So for me, at the moment, my 100 watts probably isn't quite enough, I'd like just a little more.

It's a simple question with a far from simple reply because it's so subjective.

I write and I write and I write - please get someone to read all this to you.

There is more significant gains to be had by using a better antenna then by using a amplifier with a poor antenna and trying to amplify the signal.

You can't get much effect with a amplifier - as you can with a higher gain antenna.
Doubling your power only gives you about 2.85 DB of improvement.

As I said before - you can't hardly see the difference between a 100 watt signal and a 200 watt signal.

YOU MOST DEFINATELY CAN SEE A DIFFERENCE BETWEEN SOMEONE SIGNAL WHEN THEY USE A DIPOLE ANTENNA VS USING A 3 OR 4 ELEMENT BEAM ANTENNA.

THE BEAM ANTENNA FOCUSES ALL OF THE POWER IN ONE DIRECTION, ACTUALLY TWO BECAUSE A LITTLE IS LOST OFF THE BACK SIDE.
THE BEAM ANTENNA DIRECTS MOST OF THE POWER INTO A MORE FOCUSED BEAM OF ENERGY.

Take a balloon and squeeze it in the middle, that is gain.
The more you squeeze the balloon, the further outwards away from your hands it moves, at the expense of width - because the balloon gets narrower in the middle.

The second most important thing is LOCATION.
You don't put up a antenna tower next to your house because it is convienent.
You put the tower on top of a hill, so the terrain does not block your signal and so that you use less tower.

If you live in the middle of a bowl someplace or behind a cliff, your signal will not radiate in the direction it cannot travel.

A high gain antenna at the proper height will improve your signal a thousand times better then the best amplifier and a crappy antenna.

[G6NHU]

Why are you shouting at me? That's rude, please don't do it. I'm finding many of your posts quite offensive, how dare you suggest that I need to have someone read your post to me as if you're insinuating I can't read. That's disgraceful.

It's also incredible because two posts before, you said that I'm a real ham and that I 'get it', yet now you feel the need to shout at me.

If you'd bothered to read my post properly (how ironic, suggesting someone needs to read your post to me when you failed to read mine properly), you'd have seen that I have just put up a new aerial on a new mast, a Cushcraft MA5B, significantly better than the wire loop I had previously.

I'm fully aware of how a beam aerial works, thank you.

All this because I said that I'd like to run a little extra power. Words absolutely fail me

[M0VFC]

Firstly, to answer druid's original question: from home, at most 100W (i.e. barefoot). Any more than that is asking for trouble with the neighbours :-).

Out playing SOTA? Normally 5W (SSB). It's a challenge, but a fun one.

In a contest? The lower of the category limit (which varies - often I enter restricted, which means 100W), the legal limit (400W in the UK), or the limit of my equipment (500W on HF; 100W on 2m; 35W on 70cm). Which of these I hit first depends on the band and the contest.

On a DX'pedition? It depends where to: a rarer destination demands less power, as with sufficient demand, there will be a sufficient number of stations who can do "the hard work" at their end (i.e. large antennas); somewhere more common, and it helps to have a little more power to be able to work the smaller guys more effectively. More on that below...

If the person was 1000 miles away, there would be very little change in the movement of the S meter or the amount of perceived audio available unless the difference between making the contact and not making the contact was 1/2 of 1 S unit of power.

...

I can talk on 10 meters SSB right now to Germany with 100 watts into a verticle antenna with no problem. So does more power get us? Not much.

The difference between a 100 watt signal and a 200 watt signal would probably be like comparing a 60 and a 75 watt light bulb. At 300 yards away, you probably couldn't see any difference between the two if only one bulb was illuminated at a time.

All of that is true, but the question of whether going from 100W to 1kW for "just" a couple of S-points is valid only once the signal is strong enough. If I'm out /P on the top of a hill in the middle of nowhere, I don't care if someone is S1 or S9 - it's Q5 either way. At home, my noise floor on the HF bands is at least S7, and sometimes higher. I probably won't notice an S7 signal as I tune across the band; I probably will notice someone who is S8 or S9. It may only be 3-6dB more, but when the difference is 0dB signal-to-noise ratio or 6dB, that's a huge deal, and the surprisingly common case.

Many of those we work on our less exotic trips are people in similar situations to myself at home - high noise due to an urban environment, and compromised antennas (with a 24' x 40' back garden, your options are restricted). A DX station running a bit more power really helps there - and since they probably have a low noise floor at their end, it makes the path relatively reciprocal: they hear my 100W just fine.

Finally, whilst I can't give you firm data on the exact effect (although it would be an interesting exercise to do), running 400W results in a very significantly higher number of DX cluster spots (much more than 4x) than 100W, which in the less rare locations can lead to a significant boost to your rate. Again, if you're somewhere rare, it's less of an issue as you'll have plenty of interest anyway.

Cheers,
Rob, M0VFC

[M0TTB]

Why are you shouting at me? That's rude, please don't do it. I'm finding many of your posts quite offensive, how dare you suggest that I need to have someone read your post to me as if you're insinuating I can't read. That's disgraceful.

Don't worry Keith...he's like that with everyone everywhere.
from W8JI at eham (one of many from a variety of highly respected radio amateurs who expressed similar views of AB3NK

"I don't mind a new fellow to radio, like AB3NK, making mistakes about how the ARRL, FCC, radios, amplifiers, and everything else works. That all part of being new.
It's the way he insults people while making so many mistakes that is annoying. :-) "

[K7KBN]

Maybe one day his grammar and spelling will improve and he might be taken seriously.