Dear
Peter, LF Group,
As I recall, G0MRF's first trans-atlantic transmission
was done from the top
of a tower block with a down-sloping wire as "top
loading" - Perhaps David
would care to fill in the
details...
Cheers, Jim Moritz
73 de
M0BMU
Hello Jim / Peter.
I thought of the transatlantic contact when I read your post. However the
comparison to the EH antenna is a difficult one to make. In my case I was trying
to construct a center loaded dipole using 250 foot elements, or about 12
degrees at 136k, with the feed point perhaps 180 feet above
ground. In the event, the dipole proved very difficult to resonate and I
eventually settled for paralleling the two 250 ft wires and feeding them
against the several kilometres of copper water pipe running through the
building. That worked very nicely with good QRSS3 signals visible in VO1
with RF down to 300W at the TX site.
Sadly that building was demolished 2 years ago, so no opportunity for
another visit.
Unfortunately I never did manage to get my dipole working. However, 6
years later my homebrew N2PK vector network analyser is nearing completion and
later this summer I hope to 'borrow' some land on very poor earth and finally
put up a full size dipole and make some serious measurements. (The poor earth is
a key factor in the master plan! ) Will it work? - who knows! Certainly the
scale model on 21MHz positioned 50mm above my lawn made it to a rather
incredulous amateur in Romania.
Regards
David G0MRF
