Everett,
Based on your statement that you "work DX most of the time", I'll assume
you want to optimize your DX work. I'll also assume you have fairly
"level" terrain for 10 wavelengths around your tower. That said, I think
you're on the right track.
The 40 M beam just begins to "work" at 100 feet and will work better at 125
ft.
The optimum height for a 20M beam for "DX" work is 100 ft, no higher, no
lower. (There are minor exceptions for extremely low angle work, but
probably not worth considering since you can't go up to 200 ft). That
said, 20M is probably going to be better at 105 than 125, although you can
model this and get the exact difference and see the takeoff angle of the
lowest lobe. That lobe will be lower at 125 than 105 feet, so you'll have
to see if your stack will allow you to have the angles you need for the
propagation you want to achieve. This is probably more important in
contest work than DXing, so you'll be "OK".
Placing your lower antenna at 45 feet is only a little bit low (52.5 ft
would be perfect), but I doubt you'll see any difference. Be sure you phase
them properly. (More on this in another message if you need it.)
Sounds like you'll have a nice setup there.
Question, why not put the 40 at 135 ft? At that height it would be 1
wavelength high and perform even better!! I have my upper 40M beam at 134
ft! Check out my web site: http://www.erols.com/n3rr
73
Bill, N3RR
jackson@cyberzane.net wrote:
> Hi,
> I have a 135' tower and can place ants at 45' 65' 85' 105' 135'
> At 85' last year the 40 meter 3 el did very well. At 125' the 20 meter
> 5 ele did very well. NOW for the question..If I place the 40 meter
> 3 ele at 125' will it do better, and the 5 ele 20 meter at 105' stacked
> with the other at 45' I would think that lowering the 20 meter to 105'
> is still good but that moving the 40 meter from 85' to 125' is a much
> better thing to do.. What do some of you think? I work DX most of
> the time. 73 Everett WZ8P cul
>
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