Topband: RX antenna on +200ft concrete buidling

[M. van Wijk]

Last friday we installed a 0.25 sloper from the 220ft high top corner of the
bulding (Technical University of Eindhoven/PI4TUE) in direction USA.
It worked superb at TX, each call was heard at the 1st call and every eu
pile up was easily broken. Have to mention that the take off area is clear
and flat in direction USA for at least 1000ft

But we did not have any decent RX. The sloper provided only few deep-down
legible sound characters in the noise from the top-10 stations. And ONLY
when they used their voice keyers. When they took the mic nothing was heard
and we were forced to check their 2nd over for confirmation on our call and
reports. It was that tight each time.  During the gray line we were able to
run some ourselves.

During sunday we received numerous remarks on the high bands from stations
who called us on 160 but were never heared.

Anyway, we did put up a DELTA RX antenna (F0AAA/ON4UN style)on the roof,
direction WNW. Its reception noise proved similar to my experiences with
beverages, but we did hear only local EU stations. There was enough RF noise
available on the 150ft run of thick coax. Our shack is on the top floor :)
None of the F/B, or better said, S/N enhancement on the target direction,
was noted. BTW direction is where the 1:12 balun(BN73 W8JI style) is
connected, thus opposite to bev directions. There were no vertical metal
objects around and our tribander was 150ft away, the sloper at least 250.

I have not checked any of the zilion antenna analyses on this type antenna
and am a believer of "trie first, compare and worry later".  So far my short
conclusion is that the delta and thus pennant/flag family seem not to work
on this building. But maybe I missed an important detail here?

Next try will be a K9AY on the top roof in two versions; one with 4 radials
1mtr under the loops, and one with the ground also connected to the metal
frames of the building. We would have had the K9AY available, where it not
that our home-garden setup, containing a DJ6NI thick wall glas fibre pole,
was fully loaded with water and we just had a minus 14 degree night. Celsius
that is. And unique in history for march in our country. Anyway, it proved
impossible to disassemble that setup.

If anyone has some experience on setting up RX antenna's at high buildings,
please share your results and thoughts. As we (PI4TUE) will also be in HB0
this summer again, we would like to hear your mountain top experiences too.

See you in the contests,

'73 Mark, PA5MW