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Author Topic: Is 500 Watts worth the cost?  (Read 88495 times)
W1BG
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Posts: 72




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« Reply #60 on: October 13, 2014, 07:53:57 AM »

    It's all relative.

    Versus a barefoot rig (i.e., 100w) a 10 dB power boost (1-kw) is huge, but above 1-kw all you're doing is competing with the big guns and spinning your electric meter. 2-kw is only 3 dB (1/2 an S-unit) stronger than 1-kw.

    In a former life servicing both commercial as well as ham (and CB) gear, a 10-dB power boost was always the sweet spot, from three perspectives:

       -  Single most significant signal strength improvement
       -  Best bang for the least buck
       -  Far less likely to cause problems or draw unwanted attention

    The above having been said, going from 100 watts to 200 watts would have the exact same effect as bumping-up a 5-watt transmitter to 10-watts.  In both cases it's only 3 dB (1/2 an S-unit) and is not ever going to spell the difference in being heard vs not being heard.

    Taken from another perspective, taking the typical ham rig from 100 watts to 10,000 watts (20 dB) would have the exact same effect as taking the typical 4-watt CB transmitter to 400 watts.  In both cases the operators are by that time very likely to be calling a great deal of unwanted attention to their operations and in any case far moreso than they would have been had they been content with a 10 dB boost.

    So back to the original question, 100w vs 500w.  A lot is going to depend on the antenna.  For someone hampered by HOA rules into operating in full stealth mode with a dipole mounted on a 6-ft privacy fence, the answer is *maybe* because when operating under these conditions you need all the signal you can possibly get, just be mindful of the radiation limits imposed by 97.13(c). If you run any amp at all on the ubiquitous fence-tenna, it needs to be a small one, and 500-w qualifies.

    For someone not so hamstrung, I would be inclined to point them more toward something like the AL-811H or equivalent 800~1000w amp because I think the ROI curve (return on investment) is better there ($1.10 to $1.20 per watt) than it is in any other power range as long as you stay with the more affordable brands.

    Only my 2¢ worth...
« Last Edit: October 13, 2014, 08:00:52 AM by WB9FOP » Logged

The Pay-TV Industry may not hold the patent on poor customer service, but Comcast in particular has made an art form of it.
NO9E
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Posts: 865




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« Reply #61 on: October 16, 2014, 08:05:12 AM »

The original question was whether going from 100 to 500W on 40/80m SSB is worth the cost.

Yes, if no better antenna can be installed.
No if you don't have a good radio with RF speech processor.

In A/B tests, well equalized radio with RF speech processor get 2 S better reports (ca 6 db). So if you have an radio with mediocre speech processor, get a better radio first. If you already have a good radio, the amp is next. 

How to find out whether you have a good speech processor? Crank the processor up. If the other side says you have a much stronger signal with perhaps more background noise, you have the good stuff. If your signal is only moderately stronger but readability goes down, the processor is not good.

Ignacy, NO9E 
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WY7CHY
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Posts: 933




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« Reply #62 on: October 16, 2014, 02:03:37 PM »

I've played with a few amps in my time over the last 40 years. An amplifier of ANY size can make a difference.

Some will talk all about the Math. E.g. double the power is 3 db; double again is 6db; 6db = 1 S unit; etc.... Math is fine. On paper it's accurate. In real life it's a different world. On some frequencies, at certain times of the day, trying to bounce to certain parts of the country or world....... going from 100 watts (About 70 watts average SSB talking real world OR 100 watts PEP) to 300 WATTS (225 watts average; 300 watts PEP; can make all the difference in the world of not being heard. Forget the "S" units and forget the "DB"s. The FACT IS........ 150 watts is MORE than 100. 200 watts is MORE than 100. 300 watts is MORE than 100. etc.... Whatever the extra amount of RF power you are sending, it may or may not be the extra little amount needed to bounce back and hit your destination.

I have take bare 100 watt transmitters and spoken from home to Russia and Lithuania. A week later, I couldn't hit it at all. But I could with a 300-500 watt amplifier. There's been times because of the atmosphere that I could talk from the rocky mountains to virginia on 5 watts. Sometimes I COULDN'T hit it will 100 watts. So anyone that says that an amplifier isn't significant under 500 watts is simply speaking mathematically. That's not reality.

I do agree that 100 watts with a perfect antenna, (Preferably with beam type gain), is better than a 200-300 watt transmitter and a crappy antenna. But once your antenna is as good as you're going to get because of your limitations, and you decide to go with an amplifier, a 300 watt amp is better than NO AMP. A 500 watt is better than a 300. A 1000 watt is better than a 500. Now...... Is it "BETTER" for the "PRICE"Huh? That's an individual call. If you have no problem spending the money on whatever amp it is you are buying, then go for it. But to talk about amplifiers strictly in DB's and S-units is not reality. That's simply "Paper Math". The truth is: 200 watts can sometimes get you to a destination that 100 watts can't. And so on up the scale.
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Born Wild - Raised Proud: 73
Cheyenne, Wyoming
N3DT
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Posts: 1595




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« Reply #63 on: October 17, 2014, 06:01:40 PM »

I have to say that my AL-80B makes a huge difference (almost 10 dB), but that's 800W not 500, only 2 dB delta, quite a bit less than an S unit, but most of the time it's night and day compared to the 100W. Right now the 80B is down for QSK upgrade and I really miss it. With the 80B I usually get 1st or 2nd replies. Dipoles at 45 and 70', no beams.
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W8JX
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Posts: 13268




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« Reply #64 on: October 18, 2014, 04:46:46 AM »

I very rarely run 100 watts barefoot. My old Dentron amp takes 50 watts drive for about 800+ out and 60 for 1000+ watts. I leave rig at 50 watts out all the time so when I turn on amp I get 12db+.  I also have a SB-200 that will make about 500 out with 50 in or about 10 db. I never use anywhere close to 100 watts drive to get that last few watts out. To me audio/linearity is far more important than watt meter.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
ZENKI
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Posts: 1610




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« Reply #65 on: October 18, 2014, 05:13:00 AM »

The first 6db from the amplifier is always the most beneficial power level.

In most places these days the HF noise can be terrible that is before we start talking about  inter station interference from band crowding.
6db is a lot of gain. Consider how much effort it would take to get 6db more antenna gain over what you have now. Its a massive engineering task if you take the antenna tower route.

If your antenna is 50ft and below and you can do it, raising your antenna is a  very good investment as well. You can easily get 6 to 10 db going to something like 70 to 100ft.
This is  simply takeoff angle gain from getting more gain at lower angles. If you antennas are already at 70 or better, the 6db from any amp would make you a big gun.

These days a big gun is someone with a 500 watt amp and a directional antenna at 70ft. Getting 6db  more from either your antenna or amplifier  above the 70ft and 500 watt level  for non contesters is largely a waste of money especially on the bands on 40 meters and higher. The only place where another 3 to 6db is really needed is the 75 meters and 160 meter bands working DX.

A super station is one who has his antenna at least 1 wavelength above the ground, has 6db of amplifier gain and  also has 6db of gain over dipole on many bands. Going beyond these minimums buys you little but costs you  very dearly for very little improvement.  So 6db from a 500 watt is well worth the trouble and expense.  On average most of the stations that I work in the USA are running between 500 and 1kw, even when their amps are capable of running much more output.
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G3RZP
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Posts: 1090




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« Reply #66 on: October 18, 2014, 07:48:00 AM »

6 or 7dB more when DXing on 80 and 160 can make an enormous difference........On the higher bands, with a good antenna, it can sometimes make a big difference, and in other cases, is unnecessary.
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W8JX
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Posts: 13268




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« Reply #67 on: October 18, 2014, 08:17:12 AM »

6 or 7dB more when DXing on 80 and 160 can make an enormous difference........On the higher bands, with a good antenna, it can sometimes make a big difference, and in other cases, is unnecessary.

It can help a lot on 40m too. As far as 160, you really need all the db you can get.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
G3RZP
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Posts: 1090




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« Reply #68 on: October 18, 2014, 01:46:38 PM »

>As far as 160, you really need all the db you can get<

And then some more!!
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NV2A
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Posts: 174




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« Reply #69 on: October 19, 2014, 05:07:42 PM »

And now this response from Left Field.  I think you can do as much good with a quality narrow response mic.  Full blown wide open audio is hard to copy unless the noise level is nil and no one else is on the band to compete with.  If you travel in one of those circles where everyone wants to sound like an FM Broadcast station you are going to need much more than  1 S unit to be heard and more importantly, understood.
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W8JX
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« Reply #70 on: October 19, 2014, 05:29:36 PM »

And now this response from Left Field.  I think you can do as much good with a quality narrow response mic.  Full blown wide open audio is hard to copy unless the noise level is nil and no one else is on the band to compete with.  If you travel in one of those circles where everyone wants to sound like an FM Broadcast station you are going to need much more than  1 S unit to be heard and more importantly, understood.



Narrow audio can be unpleasant to copy. As far as broad HiFi audio goes, I do find Flex Audio hardtop copy in marginal conditions. You do not need a narrow mic to do well.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
W1BR
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Posts: 4146




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« Reply #71 on: October 20, 2014, 07:56:28 AM »

In my experience, based on chasing DX for over thirty years, going from 80 to 100 watts output to a pwr level of 600 to 1kW has always proved to be extremely beneficial. Over, and over, and over again.  When the situation becomes competitive, power does have some advantages in being heard.
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