Given that aircraft or satellite at a "high angle"
are nearly overhead, you can use a 5/8 wave
to catch those on the horizon and those overhead.
I used a 5/8 cut for the 136.n weather satellites
with very good coverage. On passes that went
diredctly (withn 2 or 3 degrees, I had to use a
horizontal dipole. There were a lot more like
maybe 30:1) high angle, but not directly overhead
passes then driectly overhead. Then I went to a QDH
and it receives overhead and on the horizon. Check
out QST, or do a web search, for construction details.
I have made one for milair, but ahven;t had a chance
to test it. I am in the middle of a maojor shack redesign
and rebuild. so it is going to be a while.
Shucks, even a ~20 years old radio shack discone
does a good job on milair, ad a not so bad job for
wX sats.
Terry