In a message dated 97-03-03 15:39:50 EST, ehayes@VNET.IBM.COM writes:
> I have decided to remove the half sloper I hung from my 50 ft tower
> and replace it with an inverted v for 40M. Do I need to worry about
> how close the apex of the V is to the tower? If so, what is considered
> a reasonable separation? The tower only has a CC A3S about 2 to 3 ft
> above the tower top.
Inverted vees are generally not very good performers due to calcellation
properties of that configuration. Here's a couple of better configurations
IMO:
1. A full sized dipole sloper. It'll have some directivity using the tower
as a passive reflector. Put up 2 or 3 of them and switch them for more
flexibility. I've got a pair up for 80M and there is many times up to 10-20
dB difference between them in the desired direction.
2. Take those same dipole slopers and bend the bottom half of the dipole
back towards the tower. For some reason, this change enhances DX/low angle
performance. See articles by K3LR, N7ML/W7LR, K7JA and others on this very
nifty antenna system for the lowbands.
I love it - simple and effective. BTW, your 50' tower is just right
for doing this.
BTW, the proposed inverted vee probably won't show any improvement over
the half sloper; all you're doing is adding the other half of the dipole
instead of using the tower for it.
73, Steve K7LXC
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Sponsored by: Akorn Access, Inc. & N4VJ / K4AAA
|