Topband: Inverted-L Summary
Chuck Sudds
chuck at dxham.net
Sat Jan 17 00:23:24 EST 2004
I was asked by several people to post a summary of the information I
received concerning my upcoming Inverted-L project, so here goes:
The more radials, the better BUT even one (or a few) are better than
nothing AND will work. Several had elevated radials, which seem to work
great and suggested them. (Unfortunately, I cannot use elevated radials
because of the tower placement.)
Keep the wire away from the tower by:
"At least 3 ft"
"Probably 5 ft"
"3 ft at the top and 4ft at the bottom"
"3 ft from the tower"
"2 to 3ft will not cause any problems"
"8-10ft from the tower"
"Attach a string in the middle of the wire to pull it away from the tower
to help loading & reduce coupling"
The total length of wire should be:
195ft
170ft
165ft
192ft
160ft
160-165ft (My choice. 85' vertical and 80' horizontal or nearly so)
Beg, borrow or steal an antenna analyzer (I may just buy one.)
Seal the end(s) of any coaxial capacitors used and tie and coil them
up. Do not just lay them out on the ground. (I have NO idea how to
"estimate" the capacitance of a variable capacitor!! Guess I will cut and
try here.)
Several suggested shunt-feeding the tower itself. Unfortunately, I have 6
uninsulated guy-wires attached to it AND a number of control cables and
coaxes coming off the tower at the 30ft level and running to the shack in
an elevated manner, for about 90ft.
Today, I added one radial to the three existing radials and I fabricated a
tower bracket with insulator to hang the vertical wire 5 feet from the Rohn
45G. Now, I need to go out and buy the actual wire (Number 14???)
Hope this fills in the gaps for anyone following this thread. More
information as the project progresses, although I understand more Wintery
weather is on it's way to the Midwest!! Thanks again to all who participated!!
73 & DX!
Chuck KØTVD
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