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.

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.

ANY suggestions or ideas would be greatly appreciated.

73 de AI8W, Chris


Big screwdriver with a proper top hat and a good impedance match at
resonance.
The resonant feed point impedance must be a bit less than 10 ohms.
I recall in QST a while back a guy who'd done WAS on 160 from his pickup, so
it can work.
73
H.


And where, on a semi-truck, would you mount a big screwdriver with a
proper top-hat? I'm not discounting the suggestion, but at the same
time, I can't think of where I could possibly mount one.

I was thinking something more along the lines of a mono bander that I
could mount on one of the mirrors, that wouldn't be too large. Say,
something with a loading coil somewhere along its length, and something
that wouldn't be too expensive (Hopefully less than $50.00 US) to
construct. However, I'm not sure that's the best solution, either, which
is why I asked here.

A screwdriver is not in my near future. I'm recovering financially from
3 months off last year due to a gallstone the size of a golf ball, and
an accident in the truck earlier this month.

Thanks for the suggestion. Any other thoughts?

de AI8W, Chris

On Thu, 27 Jan 2005 22:37:24 GMT, SideBand wrote:

Thanks for the suggestion. Any other thoughts?

Hi Chris,

Is this a tractor/trailer rig? Put a monster whip up front and pull
it back to the trailer (where-ever) with a monster coil at the end and
make the trailer the -ahem- top hat.

Everything that could go wrong probably will....

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Thu, 27 Jan 2005 22:37:24 GMT, SideBand wrote:

Thanks for the suggestion. Any other thoughts?

Hi Chris,

Is this a tractor/trailer rig? Put a monster whip up front and pull
it back to the trailer (where-ever) with a monster coil at the end and
make the trailer the -ahem- top hat.

Everything that could go wrong probably will....

73's
Richard Clark, KB7QHC
Richard, you beat me to it.
H.

Richard Clark wrote:
On Thu, 27 Jan 2005 22:37:24 GMT, SideBand wrote:


Thanks for the suggestion. Any other thoughts?


Hi Chris,

Is this a tractor/trailer rig? Put a monster whip up front and pull
it back to the trailer (where-ever) with a monster coil at the end and
make the trailer the -ahem- top hat.

Everything that could go wrong probably will....

73's
Richard Clark, KB7QHC

That's a great idea.. A long wire along the trailer... It's a flatbed,
too, so I could use the stake posts to hold PVC pipes for antenna
supports... Hrm.. Now if only the AH-4 tuner for my 706 would do 160M, I
could just set up the wire and tune it, much like I did with the one on
the old truck.

I'll have to give that one some thought.

Thanks Richard.

de AI8W, Chris

stake posts around the perimeter and a wire around them... looks like a 160m
halo to me.

"SideBand" wrote in message
om...
Richard Clark wrote:
On Thu, 27 Jan 2005 22:37:24 GMT, SideBand wrote:


Thanks for the suggestion. Any other thoughts?


Hi Chris,

Is this a tractor/trailer rig? Put a monster whip up front and pull
it back to the trailer (where-ever) with a monster coil at the end and
make the trailer the -ahem- top hat.

Everything that could go wrong probably will....

73's
Richard Clark, KB7QHC

That's a great idea.. A long wire along the trailer... It's a flatbed,
too, so I could use the stake posts to hold PVC pipes for antenna
supports... Hrm.. Now if only the AH-4 tuner for my 706 would do 160M, I
could just set up the wire and tune it, much like I did with the one on
the old truck.

I'll have to give that one some thought.

Thanks Richard.

de AI8W, Chris

Power mount to raise it up when you're parked, otherwise leave it retracted,
lest a bridge give you a severe re-tuning incident.

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...

Mark:

Great idea...

In fact, the semi I'm planning to put this on is a '97 Ford LTLA9000.
Only 872,722 miles on it. Just had the motor rebuilt, so it'll be good
for at least another half a million. This was my first truck. I'm
planning on keeping it until I retire, then turning it into a motor home.

The vertload program is quite interesting. It shows I can make an
antenna with twice the efficiency of a base loaded antenna with similar
dimensions, and I can tailor it to the truck for where I can mount it,
and all of a sudden new mounting possibilities are popping up.

I took the fairings off the truck awhile ago, and the bolt holes on the
fuel tank straps are still there for the fairings. It would be quite
simple to weld up some angle-iron to make a mount for this, and keep the
feed point low to the ground, so I can have a longer whip (higher
efficiency! Yay!) on top of the load coil.

What I've got figured here is a 2 foot long, 1 inch OD copper "mast", a
1 meter (3 feet, 3 inches), 3 inch OD coil form, and a 78 3/4" whip,
which should be resonant close to 1.903 with a 3.81% efficiency. Total
overall height of the antenna is 3.61M, or 142 1/8", or 11' 10 1/8",
which leaves me a little over a foot and a half to play with. Good deal.

Reg's vertload program (THANKS REG!) doesn't show a 2:1 SWR bandwidth,
so I'll have to try it to see what the bandwidth will be. I really only
need it to handle the width of an SSB signal (3 kHz), with some "wiggle
room" to move up or down a few KC's for an SSB net I want to check in to
during the winter nights. I have an AT-180 tuner I can use to match it
down to "usable".

I'm going to play with the numbers a bit to see where I can move things
around to get even better efficiency, then I'm going to build the sucker
when I have it where I want it.

The really good news here is that I can build this thing for just a
little over $20.00, which is exactly where I want it to be. Of course, I
won't get around to building it until this summer, but it'll be ready
for next winter's nets..

I just wish Reg's program would show a 2:1 SWR bandwidth (or a 3dB point
bandwidth!).. that would be a godsend to those of us who would like to
build some of these for SSB use.

Just thought I'd share.. This is cool. If I'd known stuff like this was
out there, I would have been playing with mobile antenna building a long
time ago.

73 de AI8W, Chris

wrote:
SideBand wrote:

H. Adam Stevens, NQ5H wrote:

"SideBand" wrote in message
.com...


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...

It would be quite
simple to weld up some angle-iron to make a mount for this, and keep
the
feed point low to the ground, so I can have a longer whip (higher
efficiency! Yay!) on top of the load coil.....................

I'd ground that angle iron as well as possible. Myself, I tried angle
iron
one time, and it didn't work too well. I did run an extra grounding
strap to
body/frame. But it wasn't enough...I think the problem was from a lack
of
metal area directly underneath the antenna. That seems to be fairly
critical.
When I moved it from that angle iron support behind the back window,
and moved
to the side toolbox, the low band performance was much better. The top
of that
utility bed toolbox is a pretty good platform, and is a few inches
wide, and
naturally, pretty well grounded. Maybe use real wide angle iron??
I think you will find the bandwidth to be fairly narrow. And swaying of
the
antenna vs body of the truck will vary the SWR a lot at that low freq.
If it's
rigid, or guyed some way, it will be more stable. Should be plenty
enough for
SSB bandwidth, but for multiple freq's, I'd add extra taps on the coil,
to allow
you to move around. I have three or four 80m taps on my coil...
BTW, I was thinking about coil length vs wire size, and I may have been
a bit
off. An 80m coil of insulated 14 gauge would probably be about a
foot...
But 16 or 18 gauge would probably be a bit shorter. About wire size...
In the past I had made coils using larger dia wire thinking it really
mattered..
It does make a slight improvement, but I'd say slight...Hardly worth
the extra
weight...I made one using thick 14 gauge, and I can't tell a heck of a
lot of
difference compared to 16 or even 18 gauge. I think my present coil is
16 gauge
wire. That antenna is *light*. About like a fishing rod and reel. Using
thick
wire will make the coil much heavier, and then you have to worry about
it overly
swaying, unless guyed. So I don't use overly thick wire anymore. If I
make a 160
antenna, it will probably be 16 gauge...Maybe even 18...
If you mount the antenna low, it does increase ground loss, but I think
getting
the coil that much higher from the base *should* override the increased
ground
loss. Or as good as I can calculate anyway...I've never actually
mounted one
real low yet to compare..I do have hitches...Maybe I could try an
experimental
antenna on my bumper/bumper hitch...Would give me about a 3 ft longer
base under
the coil, compared to it's current mount on the toolbox.
Yea, vertload is pretty handy...I think probably the "Reg" program I
use the most
out of his vast collection. But I've been running these "plastic
bugcatchers" for
years...Since about 1990 I guess...I like the light weight. I've got a
"real"
80 m bugcatccher coil, and just that coil alone probably weighs 5 times
the total
weight of that 10 ft antenna I have. It's heavy and requires heavy
hardware to
support it. But heavy hardware doesn't "talk" any better than light
hardware..:/
MK

wrote:
It would be quite
simple to weld up some angle-iron to make a mount for this, and keep
the
feed point low to the ground, so I can have a longer whip (higher
efficiency! Yay!) on top of the load coil.....................

I'd ground that angle iron as well as possible. Myself, I tried angle
iron
one time, and it didn't work too well. I did run an extra grounding
strap to
body/frame. But it wasn't enough...I think the problem was from a lack
of
metal area directly underneath the antenna. That seems to be fairly
critical.
When I moved it from that angle iron support behind the back window,
and moved
to the side toolbox, the low band performance was much better. The top
of that
utility bed toolbox is a pretty good platform, and is a few inches
wide, and
naturally, pretty well grounded. Maybe use real wide angle iron??
I think you will find the bandwidth to be fairly narrow. And swaying of
the
antenna vs body of the truck will vary the SWR a lot at that low freq.
If it's
rigid, or guyed some way, it will be more stable. Should be plenty
enough for
SSB bandwidth, but for multiple freq's, I'd add extra taps on the coil,
to allow
you to move around. I have three or four 80m taps on my coil...
BTW, I was thinking about coil length vs wire size, and I may have been
a bit
off. An 80m coil of insulated 14 gauge would probably be about a
foot...
But 16 or 18 gauge would probably be a bit shorter. About wire size...
In the past I had made coils using larger dia wire thinking it really
mattered..
It does make a slight improvement, but I'd say slight...Hardly worth
the extra
weight...I made one using thick 14 gauge, and I can't tell a heck of a
lot of
difference compared to 16 or even 18 gauge. I think my present coil is
16 gauge
wire. That antenna is *light*. About like a fishing rod and reel. Using
thick
wire will make the coil much heavier, and then you have to worry about
it overly
swaying, unless guyed. So I don't use overly thick wire anymore. If I
make a 160
antenna, it will probably be 16 gauge...Maybe even 18...
If you mount the antenna low, it does increase ground loss, but I think
getting
the coil that much higher from the base *should* override the increased
ground
loss. Or as good as I can calculate anyway...I've never actually
mounted one
real low yet to compare..I do have hitches...Maybe I could try an
experimental
antenna on my bumper/bumper hitch...Would give me about a 3 ft longer
base under
the coil, compared to it's current mount on the toolbox.
Yea, vertload is pretty handy...I think probably the "Reg" program I
use the most
out of his vast collection. But I've been running these "plastic
bugcatchers" for
years...Since about 1990 I guess...I like the light weight. I've got a
"real"
80 m bugcatccher coil, and just that coil alone probably weighs 5 times
the total
weight of that 10 ft antenna I have. It's heavy and requires heavy
hardware to
support it. But heavy hardware doesn't "talk" any better than light
hardware..:/
MK


Sage advice.

The mount strap for the fuel tank is mounted directly to the truck
frame, so grounding isn't really going to be that big of an issue. I
have the cab and the sleeper strapped together with 3" strap, the doors
strapped to the cab with 1 1/2" strap, and the sleeper strapped to the
frame with 3" strap. All the "strap" is tinned copper flat braid.

I know ground losses will be greater, but having the antenna longer will
hopefully more than overcome that..

I could, also, tilt it back along the sleeper, but that gets it too
close to the sheet metal, and I'll get coupling losses from that.

I've also changed my mind on using a SS whip on the top. 1" copper pipe
would be better, and easier to guy/stabilize. I can fashion standoffs
from the cab/sleeper junction out of PVC, too, if necessary.

This is going to be fun.. Maybe I should set up a switched cap/inductor
at the feed point so I can force the antenna on to other nearby
frequencies. A wheatstone bridge could take care of the controls...

Thanks for all the pointers.

73 de AI8W, Chris