|BUTTERNUT (Bencher); HF2V vertical Antenna. 33 ft vertical
--small city lot style -- "the building stage" ---->> page 2
|HAMelectronics Magazine -- dot com Mar 1-2011)
Taking this antenna down for maintenance is pretty easy. The black insulating material below my left hand is the insulating plastic sleeve to insulate the
aluminum antenna from the bracket on the support post. Also visible in the picture is a fiberglass arm from a quad antenna. I want to add a side arm fiberglass
mast to help "guy" or support the vertical for when it gets real windy. Notice the forest in the back. We have strips of wooded areas in town around the houses
here and it is nice alright but the black bears tend to frequent these areas the odd time.
Close up of the tubing JUST ABOVE the fiberglass instulator at the top of the upper coil assembly. I measured outside dia of the tubing at 1-3/8 inch. HOSE clamps
were used liberally in this project. NOTE: the top coil has about 5 turns shorted out. Before I did this..I had a real problem with resonance of the antenna in that it
resonated down somewhere below 6.7 mhz. In the spring, I will do some further work on the antenna which should include cutting off this excess coil portion and
securing it properly.
The automatic tuner takes care of the SWR in the shack. Here is what the curves look like as plotted with the MFJ analyser. They are pretty good. A nice sharp
curve on 80 seems to indicate to me that the antenna is working reasonably well..despite that fact that my ground system is a buried counterpoise of 12 ft
copper pipes strapped togther like a spider web. I do have some resoant radials as well but my yard has structures in it such as sheds and garden and it is
only a city lot to boot. I do most of my operating down near the lower edges of the band ...so I was thinking of adding a tunable inductance ..perhaps motor
controlled to the base of this vertical. A roller inductor or some sort of TOP HAT (motorized) above the coils..might move the resonant point around nicely and
remote motor control. I saw a homebrew motorize top hat on a mobile antenna at one of our ham radio picnics here in Elliot Lake. Might work?? Anways..for
now..I'm sticking with remote tuning using my LDG automatic tuner in the shack. It works well although there may be a bit of loss.
Right at the top of the antenna is the Hustler mobile coil..the RM15. Also there is a hustler mobile antenna resonator bracket to allow additional mobile
resonators to be added..and it gives a wee bit of a capacity hat affect perhaps.
I have thought of adding a stainless steel or aluminum parallel antenna element for 30 meters to this antenna. Another thing I could try is shorting out the
loading coils to see if it would work as a type of 5/8 wave 20 meter antenna. I measured the diameter of the aluminum at the top of the antenna and it is 3/4 inch.
Pictured above: the lower piece of aluminum tubing which goes to ground. I made up a very basic tilt over scheme. Bare minimum. The insulator is merely a
rubber sheet wrapped around the aluminum with electrical tape. The hose clamp clamps down the coax connection to the vertical antenna. There is a bit of
give in the system. A brick is thrown into the mix and as well there is a tether rope and a a lash up of hold down wire. It works!!! Butt ugly but it works! The
antenna plays. If I get some spare time..I might weld up a lower bracket that clamps to my 4 by 4 inch post. Something that would allow a pivot down.
Commercially the DX Engineering site has a tilt over mast for verticals and there are others advertised on the web. With all the wild weather around these
days, it is a good idea to be able to take down the antenna at times.
By the way..I did try a larger coil at the top of this
vertical..the RM80 80 meter mobile coil. I was surprised
to find the resonant point of the vertical was around
3.508 mhz or so. with this larger coil at the top. I had
thought that the resonant point would be down
somewhere below 3.5 mhz.
Top loading is supposed to be the most efficient way to
load an antenna. I think that must be because most of
the radiation is near the feed point of the antenna.
The RM80 on the top of this antenna did cause it to
become a bit top heavy and it was significantly more
prone to whipping around in the wind.
Seen in this picture is the aluminum bracket that goes on
the Hustler Mobile antenna. It is for mounting of 3 other
mobile coils. This allows multiband operation of the
mobile antenna. I have it mounted here on my vertical. I
may want to try (simultaneously) adding more whips or a
top hat or something to this antenna and see what kind
of extra band coverage I can get.
|It does work reasonably well on 160. I have no comparison antenna however!
I had the section of coil in my junkbox and it
looked like it might work as a base loading coil on
To work 160 (ie I operate the contests a wee bit), I
have to go out and physically disconnect the feed
to the vertical and insert this coil.
I used an aligator clip to clip to the coax lead and
the other lead of the coil is hoseclamped to the
base of the vertical.
I don't do enough operating to know just how well
I am being heard with this 34 ft modified HF2V and
the base loading coil. All the contest reports are
59 or 599.
I do know, I make contacts during 160 meter
contests and I often make it through on the 1st
call. I'm talking local North America. I'm also
talking 100 watts output from my FT301D.