Hi,i need building/winding instructions for a 80-10M helical for my car
please with tappings for eacvh band. all help gratefully received.. PJ

On Feb 20, 9:49*pm, "PJ" wrote:
Hi,i need building/winding instructions for a 80-10M helical for my car
please with tappings for eacvh band. all help gratefully received.. PJ

Now that's a tall order! The taps are the hard part since that depends
on your construction.

But then, winding a helical for 80M is not going to be fun, either. If
memory serves, I think you need a half wavelength of wire wrapped
around a pole.

Eric

Eric wrote:
But then, winding a helical for 80M is not going to be fun, either. If
memory serves, I think you need a half wavelength of wire wrapped
around a pole.

Seems to me the wind loading is going to be
a severe problem. Let's say it is 8 feet long.
At 2 turns per inch, it would need to be about
3 inches in diameter. That's about 200+ square
inches of wind loading. It will probably require
a guyed fiberglass pipe as a coil form. I calculate
about 150 feet of wire is needed for the above design.
--
73, Cecil http://www.w5dxp.com

On Feb 21, 5:08 pm, Cecil Moore wrote:
Eric wrote:
But then, winding a helical for 80M is not going to be fun, either. If
memory serves, I think you need a half wavelength of wire wrapped
around a pole.

Seems to me the wind loading is going to be
a severe problem. Let's say it is 8 feet long.
At 2 turns per inch, it would need to be about
3 inches in diameter. That's about 200+ square
inches of wind loading. It will probably require
a guyed fiberglass pipe as a coil form. I calculate
about 150 feet of wire is needed for the above design.
--
73, Cecil http://www.w5dxp.com

What he wants to build is what outbacker sells.
Has taps with banana plugs to change bands.
I don't know of any plans to build one.
It wouldn't be that big a deal though. A bit
tedious finding the tap points, but it can be done.
You could calculate the various points to get in
the ballpark, and then clip to, or probe the wires
to fine tune the tap.
I'd probably start on the lowest band and go up to
the highest freq it will tune with whatever length
stinger whip it is using.
My plastic bug catchers are about the same thing,
but using a single lumped coil, vs the thinner helical
winding. It's best to concentrate the windings at the
top of the glass whip to improve current distribution.
Using an even space winding along the whole stick
is not quite as good in most cases.
MK

This Might be what you need

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=10335

Cheers Mike
VK6ZYX

wrote:
What he wants to build is what outbacker sells.

Why would he want to build an antenna that,
on 75m, is only 12% as efficient as a good
bugcatcher?
--
73, Cecil http://www.w5dxp.com

On Feb 23, 7:35 am, Cecil Moore wrote:
wrote:
What he wants to build is what outbacker sells.

Why would he want to build an antenna that,
on 75m, is only 12% as efficient as a good
bugcatcher?
--
73, Cecil http://www.w5dxp.com

I dunno. Probably weight, and being able to avoid the
usual industrial strength mount required for the heavy
antennas.
But using a helical stick is no sure route to disaster.
I've used a few that were so close to bugcatchers in
performance you could hardly tell the difference on the
air.
But... they were modified sticks, and not the usual you
buy at a store.
IE: if I want a 40m stick, I don't use a regular 40m version.
I use a 20m version and a longer stinger. I also try
to use one that has the bulk of the windings near the
top to improve current distribution. The helical whips
act the same as a lumped coil antenna in this regard.
You will have a more linear current distribution if you
wind most of the coil near the top, and then use a pretty
long stinger above it.
Being that in most cases ground losses are higher than
coil losses, often the ground loss swamps the coil
loss, and you end up not seeing as large a difference
as you would expect.
I often see the same comparing larger lumped coils.
IE: a 3 inch vs a 6 inch diameter coil..
In theory the 6 inch should be quite a bit better, being
less turns are needed, but often in the real world the
difference is hardly noticeable being the ground loss
is pretty high.
The worst helical whips are the ones that use no or a
very short stinger whip. If you want to use a thin helical
whip, you *must* use a pretty long stinger above the
glass whip if you want any kind of decent performance.
The 20m stick I used on 40m was very stout. But it
was 6 ft of 20m glass whip with the windings at the top,
and 5 ft of stinger. 11 ft total.
Made the car look like one of those RC cars... :/
But that antenna eventually became my present
lumped coil "plastic bugcatcher.
MK

Hi,i need building/winding instructions for a 80-10M helical
for my car
please with tappings for eacvh band. all help gratefully received..
PJ



If you really want a great performing mobile, and you want to build
it yourself, you might consider this:

http://faq.1and1.com/web_space__acce...ctories/3.html

Scroll down to the bottom and click on "80-10M mobile vertical".
The PDF that comes up will contain all the info you need to build
yourself an efficient, and tunable, 80-10M bug-catcher type mobile
antenna.

I built myself a custom version of this for my motorhome and it is
outstanding.


Ed K7AAT

I couldn't find anything about antennas there

73 Mike
VK6ZYX

TY Mike,ive seen this site before and if i cant get what im after ill build
one of these...Cheers...PJ




"Manjimike" wrote in message
...

'PJ[_3_ Wrote:
;618945']Hi,i need building/winding instructions for a 80-10M helical
for my car
please with tappings for eacvh band. all help gratefully received.. PJ

This Might be what you need

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=10335

Cheers Mike
VK6ZYX




--
Manjimike