[TowerTalk] What do do on 80 when height restricted?

[Grant Saviers]

one more -

I used 2x 20' by 3" irrigation pipe and a top hat for 80m.  Two guys top 
and at 60% high would be better than mine at top and 50% which coupled 
wind induced vibrations into both lengths.

The top hat was 8x x 6' 3/8 6061 Al tubing and a aluminum fence 
perimeter wire, 13ga IIRC.  Self supporting.

Worked great on a metal barn roof, although birds wiped out the 
perimeter wire a couple of times.  In a city, I would think not much 
needed as guys, so the angles good be high to minimize the footprint.

EZNEC easily models this, so perhaps 8' long top hat tubing would 
resonate on 80m at 35' (guess no modeling).  The feedpoint Z will be 
lower than 50 ohms because it is shorter, unless the Rg (ground) is high.

Not mentioned so far is the work of Rudy N6LF on top loaded antennas:  
antennasbyn6lf.com.  Also a huge amount of research re elevated 
radials.  All very good stuff.

DX Engineering sells self supporting full size 80m verticals in a couple 
of strengths, so it would be easy to copy either the top or bottom 
tapers with their stock tube sizes to make a self supporting shorty with 
top hat.

Grant KZ1W