This was published in WorldRadio, a monthly mag , years ago.  I even receive 5 dollars for it.  The second article they published was about talking devices for blind hams but I didn't get paid for that one.  I was mildly famous for a day, haha.  Anyway, this small vertical really worked well for me and though I have posted it here on blind-hams before, it's been some time so I thought I'd do it again.  Send your donations to... haha.



A SHORT VERTICAL FOR THE TOP BAND 


By Phil Scovell  K0NX

     Soon after purchasing a transceiver with 160 meter
capability, I decided to go for the Top Band.  At that time, I was
renting a bi-level duplex with the smallest backyard I had ever
seen as a ham.  It was only about 30-by-40 feet and the front yard
was even worse.  To complicate matters, I had 38 feet of Rohn 25G
bolted to the back of the house at the 14 foot level, with a
single set of guys at 35 feet  Perched on top was a 4 element 20
meter yagi on a 24 foot. boom.  The tower itself was simply too
short to shunt feed and a 160 meter inverted L was out of the
question.  Even an adequate ground system in that limited space
was impossible.  I did the only thing left to do - made a short
top loaded vertical.

     Most of us have always considered 160 meters to be limited to
those with miles of open range and super tall towers.  Few, in the
city, have much more than 260 feet of yard space, the needed
length for a half wave on 1.8 MHZ, or even enough room; not to
mention the money, for a 130 foot tower - the length of a quarter
wave for 160 meters.  For those of us with small yards and even
smaller towers and limited budgets, there is no hope?  Not so!  My
vertical was only 32 feet

     Short top loaded verticals for 160 are commonly used and
their advantages are numerous.  Conveniently, they need almost no
ground.  The nicest thing about top loaded verticals is their
radiation pattern:  The antenna radiates from the top instead of
the bottom; thus allowing the signal to be projected from above
ground where it does the most good.

                          CONSTRUCTION

     Using the remains of a telescoping push-up mast from Radio
Shack, I bolted 24 feet of vertical mast to the peak of the duplex
on the west side of the house at the 20 foot level.  Sandwiching a
piece of plastic between the house bracket and the edge of the
roof helped insure the antenna was adequately insulated.  My
telescoping mast was once about 40 feet. but only 24 feet remained
after a 100 MPH plus wind storm - you use what you have.  

     Setting the mast on a block of wood, again using a piece of
plastic for insulation, I planted the antenna.  The braid, shield,
goes to ground.  Your ground can be, as in my case, a nearby chain
link fence, or a ground rod, or even a cold water pipe.  If there
is room, lay out as many wires, no matter how short, as you can;
and attach your shield to the wires.  The larger the diameter of
wire, the better.  Yes, you can use insulated wire; in fact, it is
preferred if you plan to bury it.  The center conductor goes to
the base of the antenna.

TOP ASSEMBLY

     The top of the vertical was made up of A:- 4 feet of 1 inch
aluminum tubing, B:- 3 feet of 2.5 inch plastic tubing: PVC pipe,
and C:- an additional 7 feet of 1 inch aluminum tubing.  I used
2.5 inch diameter PVC for my coil form because I had no idea how
large a 160 meter resonator should be.  Later, of course, I
discovered I could have gotten along with something smaller. 
Learning is what home brewing is all about.

     I bolted both the 4 foot and 7 foot pieces of aluminum tubing
to either end of my 3 foot PVC pipe - a few inches down inside
either end to insure structural strength - the 4 feet length on
the bottom and the 7 feet poking out the top.

RESONATOR

     The coil, or the 160 meter resonator, was a winding of 14
gage insulated wire rapped around the middle of my PVC pipe.  How
much wire did it take?  I wanted my antenna to resonate near the
bottom of the band, 1800 KHZ, since I was mostly interested in CW. 
A quarter wave at that frequency is 130 feet. The total length of
my vertical, I judged, would be about 32 feet; so I wound the
difference, 98 feet around the plastic pipe and tied the ends of
the wire to the bolts used to secure the aluminum tubing to the
PVC coil form.

     HIGH VOLTAGE

     The voltage on such a coil is very high.  If high power is to
be used, a heavier insulated wire, such as RG8U, should be used
for the winding to prevent arcing.  Some hams even used quarter
inch copper tubing wound on a coil form when running a KW.  My 100
watts, however, presented no such problem; thus the 14 gage
insulated wire was satisfactory.

CAPACITY HAT

     After dropping my top assembly a foot or two down inside the
24 foot vertical mast already bolted to the edge of the roof, and
securing it with a U clap, I hurried to the basement and fired up
the transmitter.  You guessed it...it didn't work!  I found that
not only would the antenna not load, but there was no resonate
frequency anywhere on the band.  I rechecked everything and made
numerous adjustments but the results were the same.  I even added
and subtracted wire from my coil, but nothing changed.  

     Sitting on the roof, contemplating my dilemma, I suddenly
recalled that trapped verticals used capacity hats.  Crawling over
to my home brew 5 element 6 meter beam, which I had recently
removed from the tower and left laying on the roof, I plucked off
two elements.  Quickly clamping these 2 aluminum elements in an X-
formation to the top of my vertical, I dropped the entire assembly
- now looking like a giant TV antenna - back down inside the 24
foot vertical mast and tightened it down.

     Hurrying to the basement, I once again tried to load the
antenna.  It worked!  It resonated at about 1815 KHZ.  Playing
with various lengths, I was able to raise the resonate frequency
enough to allow me about 50 KHZ of room before the SWR became too
unreasonable.  My capacity hat was over 9 feet in diameter but
without it, the antenna would not resonate.

RESULTS

     Just because an antenna can be made to resonate, does not
mean it will radiate.  I have made 3 feet of coax laying on the
back of my desk resonate but could not talk across town with it. 
This antenna, however, worked; and worked well.

     I finished my antenna project in early May and operated
almost nightly until mid July when I pulled down everything to
move to a new location.  I made dozens of contacts during this
period of time and worked both East and West coasts often.  On
sideband, I often received reports of 10 and 20 DB over S9 from
W5, W6, and W7.  Although the summer time conditions from Colorado
are not the best for working the East Coast, do to high static
levels, I worked a few, none out of the northeast however, with
reasonable reports on the better nights.  Most think that 160 does
not propagate during the summer because of the low frequency. 
Although this is certainly not true, you better plan on getting
used to listening to the static.  Interestingly enough, the static
level is almost nil a few minutes before sunrise each morning and
the band goes long during that window opening.  

     I found that the top loaded vertical is one of the most
commonly used antennas on 160 meters and often are only 30-to-40
feet in total length.  Simple 30-to-50 foot telescoping masts are
often used for the vertical element which can be easily purchased
from most radio and hobby stores.  Capacity hats range from 3-to-
10 feet in diameter and sometimes even greater.  A friend of mine
in Texas has used 22 foot diameter cap-hats when using short
verticals under 40 feet in height; thus getting as much signal
above ground as possible.

GROUND SYSTEMS

     On 160 meters the greater your ground system, usually the
better your signal.  This, however, is perhaps the greatest
benefit of the top loaded vertical for the Top Band.  I have
worked hams on 160 who have been using 40 foot push-up masts and
5 foot diameter capacity hats with no more ground system than a
single short ground rod driven in at the base of the antenna. 
Some use nothing more than a wire running over to a nearby cold
water pipe.  Top loaded verticals simply work well with little
ground and signals from such antenni compare well with the larger
base loaded antenni - shunt fed towers with large ground systems
for example.

     There seems to be one additional advantage to a short top
loaded vertical on the Top Band over many other antenni.  Because
of its size, it has reduced signal capture area.  This means, in
high static conditions, the shorter antenna often is able to hear
the weaker signals, - perhaps do to the fact it is less resonate
at the static frequency - compared to shunt fed towers for
example.  I know some will take issue with this statement, but I
have personally observe this to be true.  Many times, when
comparing incoming signals with local stations using larger
antenni who have not been able to copy a weaker signal, I have, on
the other hand, with the shorter antenna, been able to hear and
copy clearly.

                           CONCLUSION

     If you have a 160 meter position on your transceiver, now you
can try it out.  In recent years, the top band has become more
popular with hams who have discovered that short antenni indeed
work well at low frequencies.  Of course, the winter conditions
are the most favorable for 160 meter communications, but you will
find even the summer to be good for under 1,000 miles.  An
amplifier certainly helps on any band, especially during the
noisy summer time, but I have no problem working the western half
of the U.S. from Colorado even with 100 watts.  If you want to try
the top band but are short on money, space, and tower; try the
short top loaded vertical.  You won't be disappointed.

End of article.