I need a thin 18 foot long piece of metal
- Thread starter Retro6
- Start date
Horizontal won't work efficiently as you are out of phase with everyone's else using a vertical.
Fishing pole or a portable mast is an option depending which is the cheapest.
https://www.sotabeams.co.uk/antenna-supports-and-hardware/
The last section to two are pretty thin so the wire will need to be light weight, common to buy a slightly longer unit and not extend the last section.
Unfortunately CB is line of sight so unless you are above the roof line in an elevated position it's pretty short range.
Fishing pole or a portable mast is an option depending which is the cheapest.
https://www.sotabeams.co.uk/antenna-supports-and-hardware/
The last section to two are pretty thin so the wire will need to be light weight, common to buy a slightly longer unit and not extend the last section.
Unfortunately CB is line of sight so unless you are above the roof line in an elevated position it's pretty short range.
Them were the days.... don't forget a carpet of aluminium foil to extend the ground plane
Soldato
- Joined
- 13 Apr 2013
- Posts
- 14,109
- Location
- La France
I can’t remember the make, but I had a quarter wave job with a coil winding in the centre mounted to a 2 metre square of 2mm thick steel sheet that was on my teenage bedroom floor at one point.
My dad had one rule regarding my CB radio use : “I don’t care as long as it never interferes with the TV.”
I've never used CB
so my only experience of that sort of thing is a quarter wave mag mount for 2m on a baking tray to access the local repeater.
Because they are lousy as homebase antennas. They never work with almost zero performance. CB mobile whips only really work on a vehicles body because the vehicles frame acts as a large ground plane to where it becomes an important part of the antenna.
Last edited:
Its still alive. It really picked up during covid and its still going now. Its more alive than Ham radio at least for the upper bands. During the day on upper side band you can make worldwide contacts on it.
Whilst not in stock, this kind of thing?
5-18 ft Long Telescopic Extension Pole // Multi-purpose Extendable Pole with Universal Twist-on Metal Tip // Lightweight and Sturdy // Best Telescoping Pole for Painting, Dusting and Window Cleaning : Amazon.co.uk: DIY & Tools
5-18 ft Long Telescopic Extension Pole // Multi-purpose Extendable Pole with Universal Twist-on Metal Tip // Lightweight and Sturdy // Best Telescoping Pole for Painting, Dusting and Window Cleaning : Amazon.co.uk: DIY & Tools
www.amazon.co.uk
Last edited:
Just engineered this for you 
www.aluminium-online.co.uk
12mm diameter, 1mm wall thickness. Goes up to 6m long = 19.6ft
Now, worst case for loading this pole - unless you hang something heavy off it or wangle it round like a madman - is probably going to be no worse than its own self weight in a cantilevered position.
Mass of pole = p*A*L = 2700kg/m3 * 3.8e-5m^2 * 6m = 0.61kg
Unit length loading = 0.61kg * 9.81 N/kg / 6m = 1 N/m
Bending moment as cantilever M = w*l^2/2 = 1 * 36/2 = 18Nm
Section modulus = Wel = 87mm3
Bending stress = M/Wel = 205N/mm2
Not incredibly clear but I'm quite sure the yield stress of that pole will be 240N/mm2, so you've got 17% safety margin.
Disclaimer - actual pole may not be fit for purpose for a multitude of reasons not covered by this very quick, very desk-based calc.
Aluminium Round Tube 12mm x 1mm | Aluminium Online
Shop Aluminium Round Tube 12mm x 1mm at Aluminium Online. Next-day delivery available across the UK. Select your width, height and thickness for your
www.aluminium-online.co.uk
12mm diameter, 1mm wall thickness. Goes up to 6m long = 19.6ft
Now, worst case for loading this pole - unless you hang something heavy off it or wangle it round like a madman - is probably going to be no worse than its own self weight in a cantilevered position.
Mass of pole = p*A*L = 2700kg/m3 * 3.8e-5m^2 * 6m = 0.61kg
Unit length loading = 0.61kg * 9.81 N/kg / 6m = 1 N/m
Bending moment as cantilever M = w*l^2/2 = 1 * 36/2 = 18Nm
Section modulus = Wel = 87mm3
Bending stress = M/Wel = 205N/mm2
Not incredibly clear but I'm quite sure the yield stress of that pole will be 240N/mm2, so you've got 17% safety margin.
Disclaimer - actual pole may not be fit for purpose for a multitude of reasons not covered by this very quick, very desk-based calc.
Soldato
- Joined
- 2 May 2011
- Posts
- 12,523
- Location
- Woking
What do you do with these radios? Just chat?
Thats the problem its always easier said than done because all the weight is at one end. I attempted to do something with an old Antron99 antenna that I have but there is no chance of that happening, once those things are assembled and you grab the end of it its quite heavy at that end even with two hands, combine that with it leaning plus it will need to go on a pole to clear the bottom of the antenna...Just engineered this for you
Aluminium Round Tube 12mm x 1mm | Aluminium Online
Shop Aluminium Round Tube 12mm x 1mm at Aluminium Online. Next-day delivery available across the UK. Select your width, height and thickness for your
12mm diameter, 1mm wall thickness. Goes up to 6m long = 19.6ft
Now, worst case for loading this pole - unless you hang something heavy off it or wangle it round like a madman - is probably going to be no worse than its own self weight in a cantilevered position.
Mass of pole = p*A*L = 2700kg/m3 * 3.8e-5m^2 * 6m = 0.61kg
Unit length loading = 0.61kg * 9.81 N/kg / 6m = 1 N/m
Bending moment as cantilever M = w*l^2/2 = 1 * 36/2 = 18Nm
Section modulus = Wel = 87mm3
Bending stress = M/Wel = 205N/mm2
Not incredibly clear but I'm quite sure the yield stress of that pole will be 240N/mm2, so you've got 17% safety margin.
Disclaimer - actual pole may not be fit for purpose for a multitude of reasons not covered by this very quick, very desk-based calc.
It always comes back to needing a lightweight long piece of metal cut to the wavelength.
I actually tried a random wire with an UNUN and it was pants horizontal. I've been trying for years to get a solution for a half decent antenna for CB outside but I just end up going around in circles and my theory is that if a coaxial flowerpot 18 foot half wave can work then a tuned piece of 18 ft metal should work the same vertically the only other option is to shorten it with loading coils but then it ends up having the performance of a mag mount on a biscuit tin. Its such a pain in the rear.
Thanks for the link I will check it out now.
Last edited:
Pretty much but its a lot more fun because you can chat about anything you like freely, lots of banter on CB as well plus you also have SSB/AM modes where you can talk to people all around the world and its amazing to be able to talk to somebody in America for example with point to point radio when conditions allow which is pretty much most days at the moment.
If you're working DX on CB then the aerial polarisation is utterly irrelevant. It's only when you're chatting to locals that it's really an issue.
If you're going to try and run an end fed halfwave vertical, what are you doing for a counterpoise?
If you really are adamant you want a vertical, get a fishing pole and use it to support a vertical dipole (fed in the centre).
If you're going to try and run an end fed halfwave vertical, what are you doing for a counterpoise?
If you really are adamant you want a vertical, get a fishing pole and use it to support a vertical dipole (fed in the centre).
Soldato
- Joined
- 2 May 2011
- Posts
- 12,523
- Location
- Woking
