Topband: KM9D at E51QMA
btippett at alum.mit.edu
Thu Nov 9 08:21:07 EST 2006
Copying this message from Mike to the list since I
thought it would be of general interest (I believe "today"
below is actually referring to yesterday). As most
probably know, Mike and his XYL Jan live on a sailboat
and he often shows up on Topband from rare spots.
73, Bill W4ZV
Conditions were not brilliant today, but I did manage to add another 100 Q's to
the 160M log. Lots of operators felt the need to dupe me on top-band, but it
was probably a way of offering encouragement as much as any thing else. Just
before I went to the station at midnight (zone time), we had a
and the local weather made for a noisy receiver; that coupled with
the fact that
signals were not especially loud made it very painful at times.
For antennas I used 3 transmission-lines.
The BigIR vertical antenna does 40M - 10M and it's mounted on a mast with the
feed-point 4-meter above the ground and I applied to 2 radials for each band.
The radials slope downward to approach a 50-ohm feed-point impedance and the
4-meter height seems to be the best compromise to achieve a 'low'
for the various bands.
For 80M I used a linear loaded vertical with 4 elevated (1/4 wave) radials. The
80M mast is a composite of aluminium tube and an (8-meter) fishing pole. The
overall height of the mast is about 16-meter and the loaded portion is in the
middle of the radiator. I can change the 'shape' of the loading (from the
ground with a piece of string) to move the antenna from cw to fone. The
feedpoint impedance is just more than 20-ohm and I use a home-made 'un-un'
transformer described by W2FMI.
For 160M I used a classical top-loaded vertical (or T-antenna). The radiator is
all aluminium tube (11-meter height) and I used 2 elevated (1/4 wave) radials.
The feedpoint features another W2FMI described 'un-un', but this one has
multiple taps to accommodate various impedance transformations. I've used
various 160M antennas, but I think I am going to build this one again.
I like to situate the BigIR between the 80M and 160M antennas and I
the element' to reduce the mutual coupling between the radiators.
I'd love to get on the air and compare my 100-watts with whatever they're using
on the other side at E51PDX.
I'll start taking things apart today, but leave the 80M antenna for a later
attempt at Europe. My friend Dietmar, DL3DXX was an operator at XF4DL and won't
arrive home till 11NOV. He needs North Cook on 80M and I want to give it a good
Oh, by the way, my 160M signal was copied RST229 at HA0DU this past week.
That's a very difficult path; I only received the report via e-mail
we made a concerted effort subsequent to that one instance, we were not able to
complete a QSO.
Thanks for your interest.
73 for now,
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