From: jfw@ksr.com (John F. Woods)
Newsgroups: rec.radio.cb
Subject: Re: AM or SSB
Date: 9 Apr 92 11:36:14 EDT

fisher2557@iscsvax.uni.edu writes:
>> What's the "max" range you can talk with two AM CB's and what about
>> SSB, when the one will be at the base and the other mobile?
>Last week, on SSB, I had a little chat with Belgium. (my FIRST
>contact in Europe, YEA!) Two minutes later, I had a short chat with a chap in
>the Bahamas.  This is DEFINITELY not normal skip.  I got LUCKY.

Um, not to flame, but that's perfectly normal "skip".  Remember, hams quite
routinely do the very same thing, and frequently with less than 5 watts.  When
propagation conditions are favorable in the upper HF region, you can get to
just about anywhere on the planet.  The local noise level on CB is higher than
in the ham bands, so perhaps you were "lucky" that the band was quiet enough
for you to hear and be heard.

>with skip, ANYTHING'S possible.  Point-to-point (ground waves; the reliable
>ones) normal for me is 30 miles.  That's my base (ground plane just abouve my
>house) to a mobile with a k-40.  If I had a beam, and was talking with another
>base with another beam, I could expect in excess of 100 miles.  When you get
>going THAT far, though, you're not really throwing the signal thru the air;
>your signal is almost totally on your ground-plane, so if you don't have a
>WELL grounded antennae, you're S.O.L....

"Ground wave" and "ground plane" have nothing to do with each other.
Quoting from the 1984 Radio Amateur's Handbook:
  The "ground wave" is that portion of the radiation which is directly affected
  by the surface of the earth.  It has two components, an earth-guided surface
  wave, and the space wave.  The latter is the resultant of two components,
  direct and ground reflected.

The ground plane of an elevated vertical antenna serves to make the antenna
work properly, by providing the "mirror image" of the missing half of the
dipole; if it is of poor quality, the antenna will not work efficiently and
you'll waste RF power as heat rather than as radiated RF.  (You will also
turn some of the incoming RF signals into heat instead of sound.) Note that
this affects all uses of the antenna, local or distant.  The design of the
ground plane will also affect the angle of radiation from a vertical ground-
plane antenna; a dipole, hung vertically several wavelengths above the earth,
would have the maximum of its radiation parallel to the earth; a quarter-wave
vertical with an infinite ground-plane has a maximum at some inclined angle
with respect to its ground plane (the handbook here doesn't list any numbers,
but it looks like maybe 20-30 degrees or so from the picture of the radiation
pattern.

Your local ground plane will not affect ground wave propagation much, unless
it happens to be a couple of hundred miles across.  Its design may lower the
angle of radiation and help some; a poor ground plane will make a vertical
antenna work poorly, both for ground wave and other forms of propagation.

The ARRL Antenna Book contains a lot of information about propagation and
antennas (naturally).

John Woods, WB7EEL
From: myers@hpfcso.FC.HP.COM (Bob Myers)
Date: Fri, 10 Apr 1992 19:58:48 GMT
Subject: Re: Dual Units and Dual Antennas
Organization: Hewlett-Packard, Fort Collins, CO, USA