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[AMPS] Benefit

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Subject: [AMPS] Benefit
From: (Richard W. Ehrhorn)
Date: Fri, 13 Mar 1998 23:17:01 -0000
Hi Jon...

Generally agree with you, but IMHO if (for instance) you're trying to work 
VK0IR through a 20M pileup the 1.76 dB difference between 1.0 & 1.5 kW may 
considerably shorten your wait.

Also, if you're using a nice beam with, say, a 40' boom - on any band - I 
think it'll take a lot of aluminum and sweat to squeeze another 1.76 dB out 
of it!

73,    Dick

-----Original Message-----
From:   Jon Ogden []
Sent:   Friday, March 13, 1998 10:12 PM
To:     John Kjos; AMPS
Subject:        Re: [AMPS] Benefit

>Is there really ant signal benefit between the AL-80B at 1000 watts or
>the AL-1200 at 1500 watts?I can't make up my mind,am looking for some
>opinions.Thanks   John KB9RPM

Well, the actual benefit is not as great as you would think or as to what
people might have you believe.

S-meters on a radio are calibrated in dB.  If at 100 watts your signal is
at S9, at 1000 Watts you would be 10 over 9 at best.  1000 watts is 10 dB
greater than 100 watts.

However, realize that everytime you double your watts, you only increase
your signal by 3 dB.  So going from 100 to 200 watts is a 3 dB increase.
3 dB higher than 1000 watts is 2000 watts and 3 db over 2000 watts is
4000 watts, ad naseum.  This is because the dB scale is a logarithmic
scale and not linear.

1500 Watts is therfore only about 1.5 dB more power than 1000 watts.
Going back to our signal strength example of above, a 10 over 9 signal at
1000 watts would only be a 11.5 over 9 signal at 1500 watts, and even at
2000 watts it would be just 13 dB over 9.  Hardly noticeable.

1500 Watts over 1000 Watts will NOT make a 10 dB over 9 signal a 20 dB
over 9 signal.

The only time when it might make a real difference is when you are so far
down in the noise that the extra 1.5 dB actually brings you above the
noise floor.  Then it is a benefit.

Frankly, you'd probably be better off getting a higher gain antenna.

Don't get me wrong, when my amp is finished, I want it running with as
much Pout as legally possible.  You just have to realize that the benefit
for the extra 500 watts is really not that much.




Jon Ogden

"A life lived in fear is a life half lived."

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