[TowerTalk] Balun on a vertical

[Ian White GM3SEK]

Dan Zimmerman N3OX wrote:
>Wow, though... I just looked at the price of the titanex GP 160/10... I 
>find 600 Euros? Something to consider is that using the fiberglass pole 
>+ wire like I've done would give you basically the same antenna with 
>lots and lots of Euros left to spend on the matching networks and other 
>contesting gear.  I think the fiberglass pole is Eur 89 or so.
>
>For Eur 200 you can get an 18m fiberglass pole which would do better on 
>160 and 80.
>
>I guess the longevity of a heavy aluminum vertical might be more than 
>the fiberglass poles, but I suppose that depends on the particulars of 
>location and weather.  fiberglass + wire is going to explode in a 
>lightning strike, I expect, but would do better in salt air than 
>aluminum. A wire vertical will also have a faster reactance change than 
>a 50mm base diameter aluminum vertical, and therefore, I guess it has 
>less useable bandwidth.  There are things to consider other than price 
>if you're going to go this route, but if you're really looking for 
>"cheap and cheerful, " though, I can recommend Spiderbeam's stuff.
> I'd expect my 12m pole to take quite a wind and still stand back up 
>straight afterward.

Mine certainly has - tied to an 8ft post, on a hilltop only two miles 
from the Irish Sea. The top quite frequently bends below horizontal in 
the gales, but it comes back again.

Since the constant swaying is always trying to loosen the joints of 
telescoping poles, the optional clamp kit is a good investment.  A set 
of very light guys at the 30ft level is also a big help to reduce the 
swaying. I used pale blue plastic binder twine ("farmer's friend") which 
is almost invisible.

We just installed another 40ft Spiderbeam pole and vertical wire at 
GM4PMK's place, which is right on the seashore. As Dan suggests, the 
money saved (compared with buying a complex multiband antenna) will be 
spent on an auto-ATU to go at the foot of his pole.

I agree entirely with Andrew ZS6AAA's reservations about using 
parallel-line with a vertical with radials, for exactly the reasons he 
gives. "Balanced", it ain't.


-- 
73 from Ian GM3SEK