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[TowerTalk] 40 m. antenna

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Subject: [TowerTalk] 40 m. antenna
From: (Rob Atkinson, K5UJ)
Date: Mon Jun 16 19:18:07 2003
Over Memorial Day weekend I put up an 88' long dipole made of #14 7 strand 
copper wire and fed it with 600 ohm open wire feedline.  I have it up only 
25 to 30 feet high.  I wanted another antenna as a standby, a rx antenna, 
something to compare my vertical to, and besides, who has too many antennas? 
  One end is held by a weight through a pulley roped to a tree; the middle 
and opposite end are held up by fiberglass poles.   I used them because I 
did not want metal to detune a vertical I have (I'm on a small lot).  The 
feed comes into the shack through a plexiglass basement window to a balanced 
transmatch.   There's a lot here that was new to me (open wire feed, 
fiberglass poles, doing the slingshot thing to get one end of the antenna 
over the tree, balanced transmatch) so the experience has been kind of 
exciting.  I still can't get over that open wire feedline really works, 
being a coax user for all of my ham years.  The stuff seems like magic.

My dipole is a real cloud burner but from my experience so far, I'd say the 
horiz. loop and open wire feed are the way to go.  Since you don't care 
about dx for this, you don't need to have it up real high.  At 30 or 40'  
(BTW, don't strain yourself to get it up real high because no one will 
notice the difference on 40 m. between say, 30 feet and 45 feet) it should 
get all over the U.S.   The dipole I put up loads on 80 - 17 m. and I don't 
think I've gotten a report of less than 10 db over 9 within 1500 miles.  For 
ragchewing I don't even bother with the vertical on 80 and 40 now.  After I 
see how the fiberglass holds up for a year, I'll extend the dipole to make a 
horiz. loop which is my goal.  The dipole was my way of sticking a toe in 
the water and trying out the feedline etc.  Loops are especially good on 
exciter power which is probably what you will have for FD.  I've worked guys 
with them running 100w. and I'd swear they were using 1 kw amps.  the only 
giveaway was that they had slightly deeper qsb nulls than they would have 
had qro.

Rob Atkinson

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