Posted by
Ron D'Eau Claire-2 on
Nov 02, 2006; 9:28pm
URL: http://elecraft.85.s1.nabble.com/ASTRON-PS-and-KX1-tp395046p395048.html
Unless you're going to double your power, it's hardly worth the effort from
a technical point of view. Doubling the power raises you signal by what is
considered by communications specialists to be a "just barely discernable
change" in an on-air signal. (Yes, I know that is the definition of one
decibel under audio laboratory conditions, but communications engineers have
long used 3 dB or a 2:1 power change as the standard for a barely
discernable change in "on air" conditions where there is some QSB, always
some background QRN, etc. )
A 3 dB power change (2:1 change in power) is also about 1/2 of one S-unit on
most meters.
Sure, it's good practice to pursue good efficiency and take steps not to
waste power, but the effect of a change like this are, at best, miniscule.
Now if it stirs up the Mojo in the KX1 because it *feels* like it's getting
out better with another half watt or so, that's another story.
Ron AC7AC
-----Original Message-----
Elecrafters,
While reading the thread re: charging batteries I saw the note re: adjusting
the Astron.
It occured to me that I could bump the ouput up from 13.8 to the "legal
limit" for my KX1. The goal of course is "more power" out!
Is this a bad idea? I say "bad" because I know that many will say that
small increases in power are not of much value given the nature of decibels
and the human hear, but unless this is a "bad" idea, I prefer to experiment
and see what results I get!
The ads for my RS-70M say it is adjustabe and my schematic shows a 20K ohm
pot on the input to the V meter and a 500 ohm pot on the input to the I
meter. I have not popped the top of the ps yet so I don't know what visual
inspection will reveal. After I get some feedback on my idea I'll take a
look and see what I can do!
BTW, my Kenwood TS-570D specifies 13.8 VDC plus or minus 15%. This gives me
a ceiling on 15.87. I am only going to 14.2 for KX1! I run them both of
the RS-70M when I am operating from home.
Thanks,
Jack, AE6GC
_
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