I want to thank everybody for responding.
I am always lookong for intersting 160 and 80 antennas. Specially these days
that I am buiding a new 75' selfsupporting tower. Since 1969 I have used the
following antennas in 160 so far:
80 m LW in 30 ft.
INV V with apex in 48 ft.
GAP Voyager DX
48 ft tower with Sommer beam XP708, with buried radials, in sloper
same with Delta match,
twinwire INV L with 48 ft vertical sections,
Magnetic Half LOOP on ground,
60 ft vertical as coil on 2" fiber pipe.
I worked to W and JA but none of these antennas was really good in DX.
My location is a small hill of clay, with a down slope of about 10 degree in 3
directions, down about 60 ft.
I used a vertical polarized Delta Loop on 80 with good success, so I first
wanted to try this type also on 160 with my new higher tower. Apex would be 75
ft, lower horizontal wire is 12 ft above ground and 120 ft long. When I made
simulations with EZNEC I found out that the supporting 75 ft tower will have a
rather bad influence on Zant. Max gain will be 4.6 dBi at 24 degrees elevation,
min gain will be -10 dBi , Zant = 9 Ohms, BW= 10 kc for SWR 2:1. So now I am
thinking to try also the following configurations:
Vertical INV V with 90 degree apex and two T wires on each end, with top T in
about 75 ft and bottom T in about 12 ft. Tower influence is still here but
smaller as if the vertical wire would be close and parallel to the tower. EZNEC
shows G=0.96 dBi at 25 degrees elevation, Zant=15 Ohms, BW=30kc for SWR 2:1
Tower inside a cage type vertical element of 4 ft diameter with two T wires on
top and bottom, same height as antenna above. EZNEC shows G=1.31 dBi ant 26
degrees elevation, Zant=23 Ohms, BW= 120 kc for SWR 2:1.
How does that sound? Has anyone tried similar configurations?
EZNEC files may be requested at email@example.com.
73's Gerhard OE3GBB
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