[IRCA] New Antenna Works Out Well

[Barry McLarnon <bdm@xxxxxxxxxx>]

My main antenna for AM DX is a 1 m box loop, and it's served me well over the 
years, but the rising noise levels from computers and numerous other sources 
have become very discouraging, and the loop just isn't very useful anymore 
(it also has a very high Q, and constantly tuning it is a bit of a pain too).  
My only outside antenna that's of any use in the AM band has been an 
"inverted vee" drooping dipole cut for the 40 m  ham band.  The apex is on a 
roof-mounted pole, about 30 ft in the air.

My back yard is only 25 ft deep from the house to the property lines, and 
there are overhead power lines running across the back.  Also, the ground is 
good old "Canadian Shield" - mostly rock under a thin layer of topsoil (I 
grow veggies in raised beds), so it's very difficult to get an effective 
ground.  Even if I could somehow fit them in, ground-dependent antennas such 
as the K9AY or EWE probably wouldn't work very well.  I pondered 
ground-independent designs like the flag and pennant, and decided I could 
squeeze in a pennant.  Of course, everyone knows you should keep AM antennas 
well clear of noise sources like houses and power lines, but that's 
impossible in my case.  I ended up anchoring one end of the pennant (the 
"fat" end) on a corner of the house, and running it diagonally to a pole 
attached to the back fence (yep, right under the power lines).  I wasn't 
optimistic about the chances of this setup working well, so I didn't get 
fancy with variable terminations - I just used a fixed 900 ohm termination, 
and coupled to the antenna with a 600:50 ohm wideband transformer that I had 
in the junkbox, connected to a RG-58 feedline.  I didn't have much choice in 
the orientation of the pennant, but it ended up aimed ESE - WNW, favoring the 
latter direction... aimed, in fact, right into my neighbor's house, not more 
than 10-15 ft away. :-(  The lowest point of the pennant is about 6 ft off 
the ground, and the highest point about 20 ft up.

I got it up on Friday afternoon, and quickly checked it out with some 
groundwave signals... nothing remarkable noted in the way of signal 
strengths, but I was surprised and gratified to find that the pennant was 
noticeably less noisy than the 40 m dipole, even though the dipole is higher 
and more in the clear.

I came back a couple of hours later, an hour or so after sunset, and the new 
antenna proved itself almost immediately.  I logged CBON12, a 40 W repeater 
on 1090 in Mattawa ON, about 150 miles WNW of me.  I wasn't even aware of its 
existence until now.  Powerhouse WBAL was fairly subdued, apparently helped 
by the directional properties of the antenna.  This was extremely 
encouraging, and apparently not a fluke... last night I snagged much-wanted 
WJMS-590 in Ironwood MI, about 700 miles due west of me.  I also noticed very 
good signals from stations to the west such as CKLQ-880, CJGX-940, and 
KJJK-1020.  Before hitting the sack, I decided to try for one of my 
most-wanted stations , setting up on 1070 with overnight recording.  Sure 
enough, checking the recordings today, I found KNX several times, poking 
through pesty CHOK, with my other pest CBA nulled on the backside.  Now I 
don't have to wait for them to move to FM before I hear KNX. :-)

I wasn't expecting much, but in the first two days, I bagged three great new 
catches.  I'd say that new chunk of wire is a success!  Just goes to show it 
never hurts to try something out, even if conventional wisdom says that it 
isn't likely to work.

Barry

-- 
Barry McLarnon  VE3JF  Ottawa, ON
_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://arizona.hard-core-dx.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx