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Old May 28th 07, 04:51 PM posted to rec.radio.amateur.antenna
Bob Bob Bob Bob is offline
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First recorded activity by RadioBanter: Nov 2006
Posts: 85
Default End fed aerial designs for 2M and 70cms ?

Nick

Something I forgot to mention - don't laugh.

How about a high speed/small wing kite to get the j pole up 20ft or so?
If you get out of range just let the thing stream out behind and above
you for greater range.

No doubt real dangerous but there may be a way to reduce the risks some..

I remember doing some propagation tests for a pager service some years
ago. The difference between a low vehicle mounted 1/2 wave and the same
antenna on a 12ft pole was about 10dB. I think this was about 15 miles
from the TX site. 10dB isn't a huge help once you get over the horizon
or obstructed, but every bit helps. Height is might!

Keep in mind that if you use omni gain antennas on 70cm you will reduce
the sky radiation and thus lose the ability to get high angle
reflections from mountains etc. You also get significant pattern lift if
the antenna goes off vertical. I realize you are talking 1/2 waves but
thought it worth mentioning.

It isn't worth using mobile directive antennas BTW (like a quad or
yagi). Your signal reflects from all places around you. The end effect
seems to be higher peaks but lower average signal level.

I am surprised by your only 2-3 miles range. I use to run mobile to
mobile 10W on 2M FM driving around Sydney. It certainly got flaky in
places but 5-10 miles was more the usable range. Perhaps it was a higher
route I was driving on. Never thought about it much before. Might be
worth doing some modeling.

Enough ranting from me!

Bob

Nick wrote:
Hi Bob,

Thanks a lot for your long and detailed reply...