Hi Bob

Yes that is correct!

You may however get into larger losses from an "unmatched" antenna. This
depends on how you feed it. If you (for example) ran a dipole type setup
direct connected to the coax end, you will tend to have "notches" as the
feedpoint hits a very high impedance value (eg the wire being multiples
of a full wavelength but centre fed) Whether this will become an issue
or not depends on how much loss occurs. If you (say) cut a dipole for
7MHz there will be this kind of problem at 14 and 28MHz. My gut feel is
that both these freqs will be affected adversely. I havent gone to the
trouble to guess how wide these "notches" will be but the problem will
be worse the higher multiple you go. For transmitting purposes you get
around this by using open wire feeder and a tuner. (And for the purists
reading I have left out the topic of tuned feeders!)

As a general rule the impedance of a dipole dips to a minimum at
resonance. A half wave around 75 ohms and 3/2 wavelengths 150 ohms (I
think) In between there is a reactive component that adds to the overall
figure. Without consulting some books I dont know the average nunbers
off hand but impedances higher than a few thousand ohms are not uncommon.

Now for some quick maths.. If you try to feed an antenna with an input Z
of maybe 2500 ohms with your coax - resulting in a 50:1 VSWR, you will
lose about 3dB from the normal line length, plus another 10dB for the
mismatch.. I's say that will be upsetting maybe from 21MHz up.

This is why its a good reason to use a broadband transformer balun at
the antenna feedpoint. Realising that you are probably going to use
something like that anyhow..

Apologies for the waffle.. You did ask though!

Cheers Bob

Robert11 wrote:

Is it correct for me to say that the actual losses really aren't all that
significant or meaningful,
and that a good receiver, which I have, can easily make up for them ?

That the only thing of real concern would be the S/N ?

What are the caveats to my statement above ?