SideBand wrote:
H. Adam Stevens, NQ5H wrote:
"SideBand" wrote in message
m...

Anyone out there know of any decent solution to getting 160M
working in a
mobile? The application is a semi-truck. I've got the Iron Horses
for 75,
40, 20, 15, and 10M, but I'd like to work something out for 160
meters
that will work on the truck.

Are the "iron horses" like hamsticks, but another brand? What I would
do is
get another one. Doesn't really matter what band, but I would get the
one
that is tallest physically, and uses a tall "stinger" whip. Then strip
it down,
and make a "plastic bugcatcher" with a new wider coil.
I use this type of antenna myself, except that mine is 80-10 with a
coil
than can be tapped for each band.
For a 160m whip with no hat, coil position will have a large influence
on
efficiency. So if say you used a junk 6 ft tall hamstick, I would wind
the
new coil at the top of that glass whip, and then clamp a tall "4-5 ft"
whip
to the top of that. Use a thin plastic form to wind the coil on. On
mine, the
the coil is wound on an appx 3 inch plastic tube, and is capped on each
end
with a plastic peanut butter jar cap. Melt a hole large enough for the
glass
whip to insert snugly up the middle of that coil form, and apply some
glue,
etc to hold it in place. For an 80m antenna built in this manner, you
would
need appx 80-85-90 turns or so, plus or minus...That is about a foots
worth of
winding on the 3 inch form, if the windings are made from an insulated
wire,
say 18 gauge or so.
The insulation will add some spacing to the windings, which is good..
My antenna is a 6 ft glass stick, with the coil at the 5 ft level. The
coil
is about a foot tall, end extends to the top of that glass mast. I use
a 5 ft
stinger whip, so my total length is 10 ft, or appx 3.3 m.
To use 160m on the same stick, your coil will be slightly more than 3
times
as long, to keep the same winding ratio. So if say on 80, the coil was
at the
5 ft level, on a 6 ft "1.5m" base mast stick, ".3 m coil length in
Reg's
vertload program", on 160m, the coil would be 1 meter long, and the
bottom
of the coil would drop to about the .8 m level, but still extend to the
top
of that glass mast. Thats a pretty tall coil, and will have some weight
with
all that wire..So I wouldn't get carried away with wire gauge...I'd use
16-18
gauge or so...
Anyway, thats about the cheapest way to make a 160m antenna that will
work
halfway well. It's a bugcatcher electrically...Of course, you will need
a
matching device..

To see a picture of mine, go to... http://web.wt.net/~nm5k/fd03-1.jpg
Thats about the only pix I can dig up that shows the whole antenna.
It's on the truck utility bed, about 4 ft off the ground at the base...
Even with the distant picture, you can make out the stinger whip at
top...
Will give you an idea what I'm talking about...
That one is 10 ft total. The glass whip was a 6 ft 20m hamstick, that
was
stripped of it's top coil. The stinger whip is 5 ft tall. You can see
the
homebrew coil at about the 5 ft level, extending to the top of the
glass
whip. The stinger is held on by two small hose clamps.
That's the 80m coil, which is nearly a foot tall. If you converted that
to
160m, the base of the coil would have to drop 2-3 ft, in order to have
the top
of the coil at the top of the glass stick.




I know I'm going to take an efficiency hit, but you're doing that
for
everything except 10M on a Semi anyway.. Just so I can get a signal
out
there to be heard, in the off chance.

Yep...Using vertload, my antenna has about a 14.7 % efficiency on 80m,
using
6 ohms as the ground loss number...On 160m, using the described 160m
coil, and
same overall length, ground loss number, efficiency would drop to
about 2.07 %
... But, thats the way the ball rolls....It will still work...
I've worked many 160m mobiles..
A small amp would help...
I think one of the "hamstick" type companies makes a 160m "hamstick",
if you
don't feel like making one...
One thing to remember....On 160m, ground losses will almost certainly
overshadow
coil losses, so trying to make a super duper efficient coil, with real
thick
wire, is generally a waste of time. Always use the longest stinger you
can get
away with..I also have a solid 3 ft base mast that I can add, and make
the
antenna longer "13 ft" and more efficient. In that case, the coil is
8ft up,
instead of 5 ft. Efficiency jumps up a good bit. It's not the prettiest
thing,
but it works real well on all bands 80-10. And the best part was it
didn't cost
me a dime. There is a black wire that taps the coil, but you can't
really see
it in that picture. I also would like to make a 160m antenna, and might
just
make me one like I described. I'll probably have a stand alone 160m
antenna,
and go back to that one, on the other bands. I have a quick disconnect.
MK

BTW, if you are curious...That truck is my 68 F-250...It's kinda old...
I now also have yet another old ford..."74 F-100" It's got a camper
also...
I'm trying to decide where to mount the antenna on it...Not as easy as
that 68.
...I'll probably have to install a ball mount on the cab on the other
truck...
I have a thing about old trucks...Kind of an illness...:/ I may
eventually swap
one out, and buy another small car...Can't decide which one I like best
though..
That 68 in the pix has nearly been rebuilt mechanically...New engine,
front end,
etc, etc, etc...Needs to be repainted though... But the 74 is a bit
smoother,
being a 1/2 ton, instead of a 3/4 like the 68..Maybe better for long
trips.
The camper is a bit bigger and about a ft taller on the 74 also...
Yes, we have newer cars too, but I don't drive them too much
myself...:/
I like my "war wagons". People stay out of my way...