[Amps] power and db

Roger sub1 at rogerhalstead.com
Wed Feb 4 16:48:47 EST 2009



DAVE WHITE wrote:
> Probably so - in theory - and a conservatively run amp will run for far longer than one which is being thrashed to death.  The amp that's on the bench for repairs or awaiting components when KP1 (the last one I need) comes on the air is of no use to me.
>
> However - in a quote I believe was atttributed to a certain Prof. A. Einstein - "In theory, theory and practice are the same thing.  In practice they're not."
>
> In practice I'm sure that the human ear can discern a couple of dB if the signal is marginal.  In theory this would be nonsense but it seems to hold true for me particularly on 160m.
>
>   
In Theory :-)) 1 db is that change in audio which under ideal conditions 
can just be detected by the human ear.
When working AU on 6-meters, hams routinely work CW that is "in the 
noise" to the point it can not be seen on a scope, but the slight change 
in noise can be detected. There I'm sure even one db would be of help.

When working the pileups, technique may be paramount, but when it comes 
to the signal every little bit help from the antenna, feed line, to 
power run.

On normal, day-to-day operation even an S-unit here and there is pretty 
much meaningless.
OTOH, as a purely subjective comparison, I've found very little 
difference between my 1K PEP from the Tokyo Hy-Power HL-1.5Kfx and my 
legal limit Alpha. I've found the instant on of the 1.5Kfx to be of more 
use than the extra 500 watts PEP.
BUT when working the pileups and particularly AU in the noise I'd sure 
like to have the legal limit.
> The Hot-Rodders all tell us that there's no substitute for cubic inches and I personally don't believe there's any substitute for Watts ERP.  
>
>   
73

Roger (K8RI)
> Get it however you can, I think those little watts all count.  They certainly do in Europe where we have to compete with the Italians......
>
> cheers
> Dave G0OIL
>
> --- On Wed, 4/2/09, Paul Kraemer <elespe at lisco.com> wrote:
> From: Paul Kraemer <elespe at lisco.com>
> Subject: [Amps] power and db
> To: "AMPS" <amps at contesting.com>
> Date: Wednesday, 4 February, 2009, 4:26 PM
>
> Did I miss something in school? Probably. All the discussions on modifying 
> linears for a few more watts seems ridiculous, or at least frivolous. db=10 
> log P1 /P2 still applies doesn't it?
> Double the actual output power rating of that fine L 4 or SB220 from 1000 w 
> to 2000 w will only increase your signal strength on the receiving end by 
> 3db, 1/2 s unit.
> IF you could increase your output fourfold, 4000 watss output (that would be 
> illegal) you would only gain one S unit.
> Attempt to do either and you will only exponentially increase your problems.
> Have all the fun you want but increasing output on a kw linear by a couple 
> hundred watts just doesn't improve anything.
> Like the man says, work on your antenna where you can make a difference.
> And, if you are really disappointed with that L4 or SB220 you could send it 
> here. I'd like it just the way it is.
> Paul K0UYA 
>
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