2020-11-15, 15:02:35
(This post was last modified: 2020-11-15, 15:07:38 by VE3WI Dave.)
I've seen designs for a couple of cloud-burner NVIS antennas, basically 2 el. vertical Yagis (dipoles with reflectors directly underneath).
Off-topic:
A crossed dipole inverted-v is a simple, easy to erect antenna for portable ops. The antennas are also the guys. They don't interact when they are at 90°, and they can be fed by a single feedline. 80m/40m is pretty big, but an antenna for 40m/20m or higher bands is very manageable.
The 4' stackable mil surplus fibreglass poles are great. I bought a bunch from Bob Morton (Maple Leaf Comm) but I don't think he has any more. Princess Auto used to have some but maybe Bobby bought them all :-) If we can ever get back to Dayton, there's always lots of both the fibreglass & aluminum versions in the fleamarket.
(Hint: much less risk of failure at the joints if you glue hardwood dowels into the male ends and tighten hose clamps around the female ends after assembly. I had 8 of them assembled like this holding up an inverted-v for two years.)
73
Dave, VE3WI
- One was a full size 40m dipole at 35' el. with a 5% longer reflector at 7'. Author claimed good results for nearby contacts during Field Day.
- The other was a short centre-loaded 80m dipole with four 10' sections and two 70 uH loading coils. It was located at 12' el. with a 5% longer reflector at 2'. Author also claimed good performance.
Off-topic:
A crossed dipole inverted-v is a simple, easy to erect antenna for portable ops. The antennas are also the guys. They don't interact when they are at 90°, and they can be fed by a single feedline. 80m/40m is pretty big, but an antenna for 40m/20m or higher bands is very manageable.
The 4' stackable mil surplus fibreglass poles are great. I bought a bunch from Bob Morton (Maple Leaf Comm) but I don't think he has any more. Princess Auto used to have some but maybe Bobby bought them all :-) If we can ever get back to Dayton, there's always lots of both the fibreglass & aluminum versions in the fleamarket.
(Hint: much less risk of failure at the joints if you glue hardwood dowels into the male ends and tighten hose clamps around the female ends after assembly. I had 8 of them assembled like this holding up an inverted-v for two years.)
73
Dave, VE3WI