Posted by
G3VVT on
Oct 14, 2004; 5:36am
URL: http://elecraft.85.s1.nabble.com/Question-about-K2-s-T7-windings-tp370877p370880.html
There you go Jim shooting yourself in the foot straight off by referring
your dB to power!
> and I increase my transmitter power by 4:1 (6 dB)............
Of course the two entities voltage and power are mathematically related, but
unless you say to what reference you are using, they can be somewhat
meaningless. In the 17 years I spent in the Cable TV industry pre the advent of
satellite technology, the dB was always related to voltage at 75 ohms and was
understood to be so. The only occasion I remember using dB related to power was
when using multiple phased antenna arrays to work out the total output as the
gain was increased by a ratio of 3dB in power every time the number of
separate arrays was doubled.
With a sideways shift into telecoms for the last 20+ years I had to start
thinking about dB related to power where 4 times gain or loss when related to
power is 6dB as you say. The same 4 times gain or loss is 12dB when related to
voltage as used in Cable TV. Irrespective of how the measuring systems for
the two industries work, they are calibrated in dB relative to the system you
are working with and as such are not directly compatible, thus making a
reference when referring to dB gain or loss essential.
Perhaps a topic to be discussed further off the Elecraft Reflector if needed.
Bob, G3VVT
_______________________________________________
Elecraft mailing list
Post to:
[hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help:
http://mailman.qth.net/subscribers.htmElecraft web page:
http://www.elecraft.com