Fishing rod for mobile whip

[VK1UU]

Hi all,

I am tinkering wiht the idea of building a centre loaded mobile 'whip' but need something sturdier than the old CB whip that am presently fiddling with (base loaded)

Are the new range of fishing rods suitable for use or does the graphite component upset the apple cart?

Obviously, an old fibreglass rod would be fine but I know nothing about fishing and browsing the cheap rods at Big W, I couldn't work out what was fibreglass, what was graphite, or even if it mattered (I suspect it does)

Thanks all.

Murray

[VK5IR]

Hi Murray

I'm not really sure what you're looking to do but David, VK5DWC runs a 9 ft (?) fishing rod from the back of his car and it works very well. He may be able to give you some advice. - http://qrz.com/db/VK5DWC

[VK3XL]

If you know anyone with a lathe you can turn up the brass connectors etc, you can use some fibre glass electric fence rods available from farm supplies. They are about 10mm dia and 1 meter long, so you need to join a couple together to make a decent size mobile antenna.

[VK4TI]

Hi all,

I am tinkering wiht the idea of building a centre loaded mobile 'whip' but need something sturdier than the old CB whip that am presently fiddling with (base loaded)

Are the new range of fishing rods suitable for use or does the graphite component upset the apple cart?

Obviously, an old fibreglass rod would be fine but I know nothing about fishing and browsing the cheap rods at Big W, I couldn't work out what was fibreglass, what was graphite, or even if it mattered (I suspect it does)

Thanks all.

Murray

Cheap Kmart rods with a clear tip , I bought some 12 ft rods recently @29.00 and apart from some carbon in the black gel , just strong cheap glass rods

[VK4GHZ]

Hi all,

I am tinkering wiht the idea of building a centre loaded mobile 'whip' but...

Murray, for what band(s)?
HF or something else?

[VK5KLV]

The fibreglass rods I have bought from rural suppliers (in my case, Landmark) are available in 10mm & 12mm diameter & are 1.5 m long. The rural suppliers also stock "pump rod connectors" which are made of hexagonal brass & have a half inch whitworth thread as used on many mobile aerials. It is possible to drill about half the length of the brass connector to 12mm & then use epoxy to fix to the fibreglass rod. This forms the basis for a very versatile mobile antenna system! Cheers, Les, VK5KLV.

[VK1UU]

Thanks all for the advice.

I'm fiddling with something for 20 (and maybe 40) at this point.

I didn't even know about the fibreglass rods at rural supplies, I'll check them out next.

All good fun, thanks again.

[VK2WX]

Murray,

My two cents worth.

About 40 years ago I made a mobile whip from a fibreglass fishing rod. Essentially it was top loaded with the bottom section helically wound and resonant on 20 metres (the top 9" were close wound to get resonance.) The top of the helically-wound bottom section of the whip terminated in a female fishing rod ferrule which took a 7" long by 1" dia. loading coil to make the whole thing resonant on 40 metres. The 40 metre loading coil used the male section of the ferrule to plug into the top of the whip. On the top surface of the loading coil was another female ferrule which took about 2ft of wire made from a coathanger which made the three-piece whip resonant on 80 metres.

Performance on 20 metres was excellent, even though to base of the whip was mounted on the back bumper bar of the car. I was based in London part of the time and used to work back into VK2 when the band was open. Working from VK9 (Papua) into North America at night was routine. My rig was an FT-200 with about 100 watts.

Performance on 40 metres was also good using the top loading coil plugged into the top of the whip. The former for the loading coil was cut from the bottom of the fibreglass blank. Working around VK was no problem. There was a bit of a problem with corona discharging from the top of the loading coil on tune up (very impressive in the dark at night!) but terminating the top of the coil with a blob of solder instead of a sharp wire, solved that.

Adding the top 2ft of coathanger wire to make the antenna resonant on 80 metres worked, but not too well. Although the antenna had a very low SWR, its bandwith was very limited and if you moved away from the resonant frequency, the SWR climbed quickly.

The three-piece, three band antenna -- helically would whip on 20 metres, plus the 40 metre top loading coil, plus the 2ft coathanger wire-- was cheap and efffective.

The main problem is (as you have found out) that fibreglass blanks are hard to come by. Also, brass ferrules, which were common 40 years ago, are almost impossible to find. There is one place in the US that stocks them but the metal is rather thin and a bit on the light side.

Hope that's given you a few ideas. When I have time I want to rebuild the whole system and get mobile on HF again.

Rgds es 73,
de Jim VK3OX

[VK1UU]

Thanks Jim,

Sounds like you've had some fun from the car.

As you pointed out, the mechanics of it can be as difficult as the electrical side, sourcing ferrules and other threaded bits and pieces.

If I work at my normal rate, I may have something on the air by Christmas this year. hi hi.

73s.

Murray

[VK3XL]

Murray, try to get hold of a program called "mobile.exe" I think it came out on a cd in the back of the ARRL Antenna book a few years ago. It will allow you to design center loaded whips with ease. I have made a set of whips using a power line spreader (12mm dia fiber glass rod 2.5m long) cut in half and brass connectors made to suit joining them back together. I then made removable centre loading coils for 10, 15,20, 40 and 80 meters. You will need access to a lathe or someone who has one, or be able to adapt what you can buy from your local hardware or farm supplies to replicate what I did.

The set up works very well for me, If you dont have any luck finding "mobile.exe" let me know and I will see what I can do.

[VK1UU]

Thanks Mike,

I've had a bit of a google at work but the thought police have blocked a few things.

I'll have another look tonight at home.

73s

Murray

[VK5TM]

"Mobile.exe" is on the ARRL 22nd Antenna book cd.

You can get it here, scroll down to near the bottom (Mobile.zip)

http://www.arrl.org/arrl-antenna-book-reference

[VK2FXXX]

Try your local tip shop for old 27mhz antennas. I found one about 7 ft long for $5.
It will eventually go on top of a 3 ft copper mast, and I will go with interchangeable loading coils .
See this article: http://www.qsl.net/k5lxp/mobile/HFMast/HFMast.html
and this site: http://www.k0bg.com/
Have fun!
Brendan.

[VK3XL]

i found mobile.exe in my software saves, and found also that it will not run under windows 7 in 64 bit mode, so you will need to have a 32 bit version of windows or run it in xp virtual machine within windows 7 etc (however the hell that is done I dont know) just lucky I have a netbook wit xp on it....

[VK1UU]

Yep, already noted another op indicating mobile.exe doesn't work on Win7 64. I'll have to crank up the old laptop.

On a side note, I have had some success with a base loaded helical for 20m I made based on a stripped down CB aerial.

73s

p.s. thanks for the link Terry

[VK4TI]

i found mobile.exe in my software saves, and found also that it will not run under windows 7 in 64 bit mode, so you will need to have a 32 bit version of windows or run it in xp virtual machine within windows 7 etc (however the hell that is done I dont know) just lucky I have a netbook wit xp on it....

To run a virtual machine there are several options , microsoft have virtual machine , yuo can find that on their site or use virtual box etc , install , start and load the os of you choice be it linux or some version in winblow , not rocket science .

[VK1UU]

Hi Mike,

I got mobile.exe working, all good. It designs the coils fine but what about the whip part? I assume they are helically wound above and below the coil? Or maybe not, does it assume solid sections above and below?

Murray

[VK3XL]

Solid sections above and below the center loading coil.... I think you will find that a center loaded whip is more efficient than a hellicaly wound whip. Though efficiency and hf mobile antennas are not terms that are used together very often.
I have used the braid off some old rg213 or rg8 coax stretched over 12mm fibre glass rods then covered with shrink tubing

[VK4GHZ]

I have used the braid off some old rg213 or rg8 coax stretched over 12mm fibre glass rods then covered with shrink tubing

This is exactly the method I have used in the past, to create a 6m 1/4 wave whip out of an old 27 MHz whip.
The RG213 braid starts immediately above the ferrule with a short flexible wire link soldered to the ferrule at one end, and the braid at the other.
(you could even solder the braid around the entire circumference of the ferrule, if you can generate the heat and avoid disturbing the adhesive that fixes the f/g rod into the ferrule)
Heat shrink over the top, and once you have trimmed to the correct length, you can pop one of those helical end caps on.

Works well.
Cheap and cheerful for simple applications.

[VK1UU]

Solid, that makes sense, thanks Mike.

I know what you mean, "efficient hf mobile antenna", bit of an oxymoron.

73s