Topband: 160 m inverted L

[Mike Smith VE9AA]

I’ve never owned a vacuum variable.  What I have been using for decades are
very large air variables hung from a stick, or tree or whatever and I cover
it up with a 2L pop bottle* with the bottom cut out of it.  Fix in place
with rope, string, tape, fishing line, whatever.

I can’t take credit for this trick (I don’t think anyways) as I have seen
hardline coax splices made much the same way many moons ago at the famous
VE1ZZ antenna farm.

It’s pretty rare for this to ever fail, or even have wx issues.  Of course
if you get screaming high winds with freezing rain going horizontal it is
possible to get a little frozen moisture up inside the bottle and then onto
the plates of the cap, but transmitting a few times usually solves the
problem.

 

*would  the equivalent of 2L pop bottle be ½ gallon soda bottle?

 

Mike VE9AA

 

 

A vacuum variable for L impedance matching is unnecessary.  Vacuum

variable capacitors leak eventually.  It take a long time for them to

go through their ranges and you have to have the mechanics outside if

you perform remote tuning, to sense or count turns to track when the

v.v. is nearing its maximum or minimum.  It is far far easier and

faster to use an air variable that rotates freely.  You only need to

keep it sheltered.

 

Elevated radials are fine provided they are high enough to be

decoupled from earth, which for most hams is difficult to accomplish

on 160 m.

 

73

 

Rob

K5UJ

 

Mike, Coreen & Corey

Keswick Ridge, NB