Dear John:
Under the conditions you have described, where you do not wish to
attract undesired attention, I would try for 20 to 30 feet of height. I
would also try to place the wire antenna so as to be away from likely
sources of noise. (Signal-to-noise ratio is the important factor.)
Trees, if any, could be a factor in occluding the antenna. I would also
select the color of the wire used for minimum visibility. The diameter
of the wire need be no more than what is required to keep the antenna
supported.
For what I think that you wish to do, I suggest that you use a
balanced antenna and not just a piece of wire with one end attached to
your receiver. In other words: use goals that include (1) a height for
much of the antenna of more than 20 feet; (2) an orientation that
minimizes visibility and that tries to keep distant from dwellings and
power poles; and (3) the use of a center fed, balanced, doublet type of
antenna that is fed at its center by a transmission line (for your
purposes, it makes little difference what kind of transmission line -
coax with a connector that is compatible with your receiver is the most
likely choice).
You might wish to make a sketch, based on measurements, of your back
yard. A centrally located tree would be an ideal place for the center
of the doublet. Do a bit of planning. If you use a doublet and keep
some distance from obvious noise sources, I doubt that the difference in
performance between the worst and best location in your back yard will
be significant.
Good luck. 73 Mac N8TT

--
J. Mc Laughlin - Michigan USA
Home:

"John Quinn" wrote in message
news
What would be a recommended height in an urban area? I'm in a
residential area, there aren't such things as large buildings, but
stuff like a two story house next door to my single floor home. I
don't want to get it too high and attract the attention of the City
Orindance Police.

On Tue, 30 Dec 2003 19:41:04 -0500, "J. McLaughlin"
wrote:

Dear John:
A wire antenna for short-wave (HF) that is ten feet above ground
is
likely not to have strong directional preferences. In other words,
the
orientation of the wire antenna is unlikely to make any significant
difference in your reception. However, if in an urban environment,
some
orientations are likely to pick up more locally generated noise than
other orientations.
Experimentation is called for. More height is desirable. 73
Mac
N8TT