Louis Wilcox wrote:
>I have a Cushcraft 26B2, a pair of 13 element 2 meter beams,
>that I have been using for 2 meter FM. I just purchased a FT-847
>and need a 2 meter SSB antenna.
>
> I am planning on turning one of the antennas horizontal and
>running separate coax for each antenna to the radio.
>
> I have two questions:
>
> Should I use a nonmetallic cross boom between the two antennas?
>
> How do I route the coax from the horizontal antenna to the
>mast? I.E. around the reflector end, or dropping down then over?
>
Good, you already see the basic problem - you don't want any horizontal
metalwork (and that includes the feedline) running through the same
plane as the horizontal elements, or near.
A non-metallic cross-boom would be OK, with the feedline running out the
rear of the yagi, but it's messy.
Probably the best method is to mount the horizontal yagi straight on the
vertical mast (if you have enough height) and put something else on the
free end of the cross-boom to keep the windload roughly balanced.
My web pages have information on basic principles for stacking yagis for
the same or different bands, and also probably more detail than you want
to know about making cross-polarized yagis work.
> There was an earlier post about wrapping coax around the mast
>instead of using large loops, will this have any affect at 70 cm
>frequencies?
No problem - it's only a few extra feet of cable, and the most important
thing is to make sure that the cable rotates freely and without wear.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.demon.co.uk/g3sek
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