Topbanders. I hope all enjoyed the BCS .jpeg that I sent to those that
requested it. Now, What do you make of this...............? :>>>
Just fed my 48' tower about 2' up from the base, hoping to obtain a
match on 80m or at the very least 40m.
I fed it directly with 40' of rg59, through about a 250pf variable
capacitor, and tied the braid into an extensive ground screen
composing of nearly 1 mile of wire. (ok maybe 3/4 of a mile-I live in
the country. It just seems longer-(grin)
I thought I would get a close match on 80m as I had shunt fed the
tower at about the 30' mark last year and it worked so-so.
--------+++++++++++++++++++++++++++++++++------------
Well, wouldn't you know it, but this provided me a near 1.1:1swr
smack dab on 10.100Mhz!!! Also the tower is about 3-6DB better on most
signals than the full size aluminum vertical designed for 30m!
The tower is a 48' delhi, topped with a TH6DXX, then 16' of mast
then a long 24' boom 6m beam, then a Ringo on 2m.
The bottom of the tower is sunk 4' into cement, but not electrically
tied into the radial system or any ground rods. The QRN is a lot
worse from a power line leak (or whatever) nearby, but signals are a
lot louder.
What does the group feel is the best way to resonate the tower on
40/80or 160m ?
Maybe connect a wire at the very top for 160m, bringing it down to a
cap at the bottom, as a kind of folded unipole?
Feed it 1/3 of the way up for 80m? (like last year)
But what about 40m? Maybe up 10-20 feet would do it?
I am still surprised that it resonates on 30m. I can't get over it,
as with all the beams, etc. on the tower, I make it to be about 70'
tall, with capacitance loading. this would be well over 3WL long on
30m. Weird, but FUN stuff.
MIKE
......comments, ideas, questions, critiques?
Michael & Coreen Smith (AA Antennas & Wynder Photography)
271 Smith Rd, Waterville,
Sunbury Co.,NB, Canada
E2V 2G3
6M Vhf buffs;
See the *NEW* AA Antenna web page at:
http://members.tripod.com/~ve9aa/index.html
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