On Sun, 22 Apr 2012 23:18:17 -0600, "Irv Finkleman"
wrote:
I just want something quick and cheap so I've ruled out
anything like copper clad steel and such.
Will your 25ft span of copper wire support a few birds? If not,
please reconsider copperweld.
Just to clear things up on the geometry, the wire will run
out the window horizontally to the tree (about 25 ft) and
then drop vertically (another 25 ft approx) through the
tree to just above the
ground. Sort of an inverted letter "L". It is just a
random wire, and the best I can do at the moment
given my current situation.
Do you have an antenna tuner? The FT-817ND does not have a built in
antenna tuner. You're going to need one with your random wire and
random configuration.
The hole through the window frame is too small (1/4 in.)
for conduit but I plan to use a heavy plastic kids drinking
straw, tilted down on the outside, and plugged with some
silicon seal at each end where the wire enters and exits.
Ummm... is this an existing hole are you going to drill a new hole?
The modern windows that I've seen have the glass extend almost to the
edge of the frame with only a sheet rubber spacer in between. You're
highly likely to drill through the glass if you decide to drill the
frame.
I may even try loading the window
frame (aluminum, 5 ft x 5 ft (approx)) using a handy
sheet metal screw for the connection.
With 5 watts, that might work. Forget about building a magnetically
coupled loop. You would need to split the frame at some point, and
install a variable capacitor. That's probably not going to happen.
If your window proves to be uncoated glass (unlikely), you might
consider two squares of aluminum foil on both sides of the window to
couple through the RF via a ladder line. You won't get much
capacitance so it won't work on the lower frequencies, but should be
tolerable for the higher bands.
A reminder -- the ground system will be tuned counterpoise
wires running along the wall inside my apartment. I have an
MFJ-1623 tuner which will handle tuning the antenna and
the counterpoise in a very nice compact arrangement with
only one meter to watch!
Good, you have a tuner. However, that's designed specifically to
handle a 12ft balcony mount HF antenna. I don't know what it will do
with a longer antenna. Looking at the schematic:
http://www.mfjenterprises.com/pdffiles/MFJ-1623.pdf
it seems to be a crude L match, which isn't going to match every
combination of reactance and frequency. The meter does NOT indicate
VSWR, so you really won't know if the tuner is effective. My
guess(tm) is you're going to purchasing a more elaborate antenna
tuner, a VSWR meter, or using a 12ft piece of wire.
I once used a large sheet of WELDED chicken wire under the carpet for
a "ground". It has to be welded to prevent the galvanizing from
forming diodes. It sorta worked but nobody wanted the lumpy carpet.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558