[TowerTalk] 160 meter vertical construction

[Fred Hopengarten]

From:
Fred Hopengarten  K1VR               617/259-0088
Six Willarch Road
Lincoln, MA 01773-5105
permanent e-mail address:  fhopengarten@mba1972.hbs.edu

>On Tue, 14 Oct 1997 21:12:28 -0700, Richard Karlquist <rick@area.com>
>wrote:
>
>>My situation is slightly different than most of you.  I do *not*
>>have or plan to get a tower with Yagi(s) for 40 thru 10 meters.
>>Hence I do not have a skyhook from which to hang a 160 meter 
>vertical.
>>I would like to simply build a dedicated 160 meter vertical, 
>>perferrably at least 90 feet high.  Of course, I could get 9 sections
>>of Rohn 25, but that would be overkill (I guess), and I don't want
>>to do any climbing.  Would it be possible to get say 40 feet of 
>aluminum
>>tower sections and attach 50 feet of aluminum tubing to the top, say
>>2 inch with .120 or .058 wall?  Could this be walked up, assuming 
>helpers
>>on the guy ropes?  BTW, it is not a problem to have to guy this 
>tower.
>>Seems like this might work, but I haven't actually heard of anyone 
>>doing it.  I would probably put a loading coil in series electrically
>>between the top of the tower proper and the tubing extension (center
>>loading).
>>
>>Rick Karlquist N6RK
>>rick@area.com
>_______________________________________________________________
>I've tried this several times and gave up each time.  Going over about
>30-40 feet with a thin, wobbly mast is incredibly difficult, but I
>suppose if one had lots of helpers and guyed it every 15 feet or so,
>it could be done.  I ended up using a bow and arrow to put a 65 foot
>wire over a tree and it works fine.  
>
>I'd also recommend using a base mounted loading coil instead of the
>center one.  When they're away from metal, base loading coils work
>just as well as center ones, maybe better because they're smaller for
>a given length of antenna.  Base loading got a bad name with mobiles
>because the proximity of the car body lowered their Q.  In a backyard
>installation, that's not the case.  And of course, if you need to
>tweak it, it's right down there on the ground.  Try that with one 45
>feet in the air.  :-)
>
>73, Bill W7TI


K1VR:  I take a compromise position.  Go up as high as you can, as Bill
proposes, then use a TOP HAT (three wires, or more, which act both as
your top set of guys and additional loading). Top hat loading is
efficient, you don't have to worry about Q, and cheap.  

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