There's no doubt that many, or most, people could reduce their power by
a factor of 10 and still communicate ok. But 10 dB isn't a trivial
amount ("only 1-2 S units").

On my Icom 730, a 10 dB reduction will reduce an S9 reading to S6, S7 to
S2, or S6 to below S1. Have you tried a 10 dB reduction in signal
strength on your receiver and seen how the S meter responds?

If you had 10 dB feedline loss and decided you needed to get it back by
increasing your antenna gain, you'd need a 7 element Yagi on a boom
considerably longer than 1 wavelength. I can see it now -- an
advertisement for a 7 element long-boom beam -- "One to two S-Units gain!"

Roy Lewallen, W7EL

JGBOYLES wrote:

I've got about a 70 foot +/- run of RG-8X that I use to feed my 40
meter dipole.


Out of curiosity can
someone tell me about how much a a signal loss I've got compared to
having an antenna that's actually cut for 30 meters ?


Hi Gary, According to my calculations the feedline loss is around 90%, so if
you are running 100 watts, and the tuner is lossless, 90 watts are lost in
RG-8X. The good news is 10% efficiency is only 1-2 S units down from 100% on
the recieving end. The bad news is, no tuner is lossless.
You will have loss using a 40m dipole on 30m. Does that satisfy your
curiosity:-)?
73 Gary N4AST