I want to build some mobile antennas for 10 15 and 20 meters but I am
having trouble with the physical design of the coil. My biggest problem is
finding readily available material. A shopping list of things to get at the
Home Depot would be nice. Antenna would be mounted on my pickup tool box and
would like to keep them six ft long so they will fit neatly in the back of
the pickup when not in use. I tried this about a year ago and got the
antennas to work but the PVC loading coil forms came apart after a while.
Any help would be greatly appreciated.

wrote:

I want to build some mobile antennas for 10 15 and 20 meters but I am
having trouble with the physical design of the coil.

I've had good luck on those bands using relatively short
lengths of 1.5" diameter, 6 TPI, coil stock and just
tie-wrapping the coil to the middle of the fiberglas rod.
--
73, Cecil http://www.qsl.net/w5dxp

"Cecil Moore" wrote in message
. net...
wrote:

I want to build some mobile antennas for 10 15 and 20 meters but I am
having trouble with the physical design of the coil.

I've had good luck on those bands using relatively short
lengths of 1.5" diameter, 6 TPI, coil stock and just
tie-wrapping the coil to the middle of the fiberglas rod.
--
73, Cecil http://www.qsl.net/w5dxp

Thanks Cecil, I have some old fiberglass 11m antennas, the kind that has a
wire antenna heatshrinked to a fiberglass rod that would be pefect for
making this.

" wrote in message
...
I want to build some mobile antennas for 10 15 and 20 meters but I am
having trouble with the physical design of the coil. My biggest problem is
finding readily available material. A shopping list of things to get at the
Home Depot would be nice. Antenna would be mounted on my pickup tool box
and would like to keep them six ft long so they will fit neatly in the back
of the pickup when not in use. I tried this about a year ago and got the
antennas to work but the PVC loading coil forms came apart after a while.
Any help would be greatly appreciated.


I put together the 15m and 10m antenna today. 10 meter is OK,15 and 20 meter
units have a really high SWR, nearly fullscale on the meter which reads 5:1
max. I figure this may be normal as the impedance of the shorten antenna
should be getting pretty low at this point. 10 ohms or less would not sound
to unreasonable to me for a 6ft long 20m antenna.

I went to the Home Depot today and found some chimney sweeper brush handles
.. These are about 4 ft long each made of fiberglass and screw together. A
few of these in the back of the truck will allow me to put together nearly
any length antenna I need. Im thinking 40M may be a practical limit Dont
worry I dont drive and ham at the same time.

Worst problem I see with this is making an adapter for my ball mount. Will
probably cannibalize one of the handles for its attaching hardware and weld
a bolt to it to fit the ballmount

I went to the Home Depot today and found some chimney sweeper brush handles
. These are about 4 ft long each made of fiberglass and screw together. A
few of these in the back of the truck will allow me to put together nearly
any length antenna I need. Im thinking 40M may be a practical limit Dont
worry I dont drive and ham at the same time.


how much were the sweeper handles?

--
73 for now
Buck
N4PGW

"Buck" wrote in message
...

I went to the Home Depot today and found some chimney sweeper brush
handles
. These are about 4 ft long each made of fiberglass and screw together. A
few of these in the back of the truck will allow me to put together nearly
any length antenna I need. Im thinking 40M may be a practical limit Dont
worry I dont drive and ham at the same time.


how much were the sweeper handles?

--
73 for now
Buck
N4PGW

Dont know the price was not marked on them so I didnt bother finding out
being it was late Sunday. I have since looked for them on the internet and
have seen some really outrageous prices $50 for 5ft. Hope the HD price was
not that bad.

Thanks Cecil, I have some old fiberglass 11m antennas, the kind that has a
wire antenna heatshrinked to a fiberglass rod that would be pefect for
making this. ....................................

You can use one of those for all those bands, just by changing the
top "stinger" whip. I use the small hose clamps to hold them, if the
stick doesn't have a slide in mounting part on top.
IE: if you had a 6 ft CB stick that used a short stinger, you can add
length to tune the lower bands. On one of mine, the stinger needed to
be about 2 ft longer to tune 20m using the CB stick. So if you had
various
stingers to clip on, you could work all the bands from 20-10.
On those upper HF bands, even the simple CB stick/extended stinger
will work quite well. A cb/10m stick using a longer stinger to tune
20m,
is more efficient than most 20m sticks using more turns of wire, and a
shorter stinger.
I have one antenna that I've used for nearly 15 years that was built
from a
firestick CB antenna. I added a large coil in the middle, and it works
all
bands 80-10. I change coil taps on the low bands, stinger length on the

upper bands.
I also have one I made from a 6 ft 20m stick. It's also converted to
all
band use, and has the performance of a bugcatcher, being it uses a
large
coil on the lower bands. But...it's as light as a fishing rod n reel...
I use a 5 ft stinger, and the normal driving height of the antenna is
11 ft.
That antenna is exactly center loaded in the driving mode. If I add a
3 ft
mast, it's 14 ft tall, with the coil at the 8 ft level. But I use that
when parked.
Bit tall for driving... :/ Anyway, you can build a pretty good antenna
dirt
cheap if you look around. I've never spent more than junk parts and
chump change for a mobile antenna.
MK

wrote in message
oups.com...
Thanks Cecil, I have some old fiberglass 11m antennas, the kind that has
a
wire antenna heatshrinked to a fiberglass rod that would be pefect for
making this. ....................................

You can use one of those for all those bands, just by changing the
top "stinger" whip. I use the small hose clamps to hold them, if the
stick doesn't have a slide in mounting part on top.
IE: if you had a 6 ft CB stick that used a short stinger, you can add
length to tune the lower bands. On one of mine, the stinger needed to
be about 2 ft longer to tune 20m using the CB stick. So if you had
various
stingers to clip on, you could work all the bands from 20-10.
On those upper HF bands, even the simple CB stick/extended stinger
will work quite well. A cb/10m stick using a longer stinger to tune
20m,
is more efficient than most 20m sticks using more turns of wire, and a
shorter stinger.
I have one antenna that I've used for nearly 15 years that was built
from a
firestick CB antenna. I added a large coil in the middle, and it works
all
bands 80-10. I change coil taps on the low bands, stinger length on the

upper bands.
I also have one I made from a 6 ft 20m stick. It's also converted to
all
band use, and has the performance of a bugcatcher, being it uses a
large
coil on the lower bands. But...it's as light as a fishing rod n reel...
I use a 5 ft stinger, and the normal driving height of the antenna is
11 ft.
That antenna is exactly center loaded in the driving mode. If I add a
3 ft
mast, it's 14 ft tall, with the coil at the 8 ft level. But I use that
when parked.
Bit tall for driving... :/ Anyway, you can build a pretty good antenna
dirt
cheap if you look around. I've never spent more than junk parts and
chump change for a mobile antenna.
MK


I had taken an old CB 6ft antenna, the kind with the wire heatshrinked to
the side and put new wire and a loading coil in the middle. Works OK on 10
and 15 SWR is pretty high on 20 and I dont have a way to match it.
Experimented with a cane pole for a support and found I could get a
reasoable SWR on 20 if the antenna was about 14ft long, a couple more feet
and I wouldnt even need the coil. Next plan is to try to use something that
folds kind of like fiberglass tent poles and get away from the loading coils
all together. They are more of a bother than what they are worth for my
application since I dont ham while Im driving. I just wanted something I
could store neatly in the back of the truck which would limit eveything to
6Ft or less. Changed my mind about 5 times now on what I want and how to do
it, I guess that happens when you are going up the learning curve.

"Buck" wrote in message
...

I went to the Home Depot today and found some chimney sweeper brush
handles
. These are about 4 ft long each made of fiberglass and screw together. A
few of these in the back of the truck will allow me to put together nearly
any length antenna I need. Im thinking 40M may be a practical limit Dont
worry I dont drive and ham at the same time.


how much were the sweeper handles?

--
73 for now
Buck
N4PGW

Buck, when I saw them there wasnt a price on the handles so I went back
today to check. All of the chimney sweep items were gone. I checked and
found that these items are seasonal and wont be back out until August or
September, day late and a dollar short. It doesnt make sense to me, this is
the time of year that they should be out. I have never cleaned a chimney but
have had it done and you dont do it during the heating season.

Oh well, I still think these have great possibilities as antenna parts
barring they dont turn out to be super expensive.

Jimmie

There are quite a few ways you can match them. You can use a
coil at the feedpoint, IE: like the "dollar special" matcher in the
handbooks, or you can use an L tuner, or sometimes just a cap alone.
A few turns of the loading coil can be applied as part of the matching
too
if needed. Most of the "stick" antennas have the matching coil wound
at the base of the antenna. Most any old tuner would match it. Even a
cheap random wire tuner would work fine. You just reverse the
connections
for low Z use if you need to.
With the 6 ft stick I have, I put the coil at the top, and then added 5
ft of
stinger on top of the stick. So it came out center loaded, being the
coil
is a few inches long. The first one I built had the coil about 2.5 ft
above
the base. I still use it on the truck when I'm whacking a lot of low
trees.
I use the tall coil version when I more out in the clear. On my play
truck,
the mount is up on the cab at 64 inches from the ground. I hit trees a
plenty,
but have never hurt one of the antennas yet. The stinger just bounces
off
most of the time, and if I do hit the glass part, it just bends and
snaps
back. I don't use a spring. On the higher HF bands, even a loaded
antenna will still work real well. Even most hamsticks unmodified
will do ok. Both mine use fairly large coils. About 2.5 -3 inches
dia...
So electrically, about the same as a bugcatcher as far as performance
without all that heavy weight that the average bugcatcher entails.
I use the 3 ft mast at the base when parked, and on the low bands.
The coil is nearly 8 ft above the cab and the tip of the antenna at
about
19 ft. Kicks butt, even on 80m..
MK