Re: [amsat-bb] Dual Dipoles for Echo?

[DOBarrows@xxxxxxx]

David,

I have dipoles for 2m and 70cm mounted on separate masts about 20 feet apart.
They work well for AO-7 and fairly ok for FO-29, but not too well for the FM 
birds,
including Echo.  I have better luck with my Arrow antenna indoors than the 
dipole
outdoors for the FM sats.  I agree that it is a pain in the but to drag 
everything out
and then have to put it back up after the pass.

The dipoles are easier to construct than homebrew egg beater antennas and 
worked
 nearly as well for me (I have tried both).  I am not much of an antenna 
builder.

As far as height above ground goes, you will probably have the antennas well 
above
the height where ground reflection is a factor.  You have to worry about such 
things
more with hf antennas.

Dave W8IJ
Camp Hill, PA
>Dragging my Arrow antenna (with elements sticking out every direction) and 
>camera tripod out to work Echo, along with having to track it, is getting a 
>bit old.  I've come up with the idea to build two simple dipoles (2m & 
>70cm), mounted some distance apart on a piece of wood or Plexiglas, with 
>the elements parallel (Sort of a lop-sided H shape).
>
>In prep for a pass the thing would be oriented so the donut-shaped patterns 
>would hit the arc of the satellite's path across the sky.
>
>Advantages: no re-aiming during the pass, and a bit more compact than the 
>Arrow, should work better than a vertical for high-elevation passes.
>Disadvantages: lower gain than the Arrow.
>
>Any ideas how far apart the two dipoles should be?  The Arrow has them on 
>the same boom, but the driven elements are 20-30 cm apart and they're 
>polarized differently.
>
>Would there be an optimum distance off the ground each dipole should be in 
>order to take advantage of ground reflection?
>
>Any other thoughts on this?
>
>David, KY7DR
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