DIPOLE FOR PMR446 HELP NEDED

Licence free two-way radio services that now includes both FM and digital channels. Discuss models, modifications and other similar worldwide standards such as FRS and GMRS.
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Mikel
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Re: DIPOLE FOR PMR446 HELP NEDED

Post by Mikel »

Forgot to say this dipole calculator is handy, saves you having to work out the dimensions:

http://www.csgnetwork.com/antennaedcalc.html
................................................................................................2W0NBF.........................................................
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Merkin
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Re: DIPOLE FOR PMR446 HELP NEDED

Post by Merkin »

Thanks 4 this info Made the simple dipole that Mr Weetabix posted. Works better than the magmount that came with my wouxun KG-UV980P with 40 watt easy to make contacts over the west country and cardiff and guys up north on hills like Merthyr. :)

Used some bike spokes 160mm each side showing and terminal block and only in the attic so far with some old CB coax rg58 directly above me, only a few meters away so not much loss easy to make works :thumbup:
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friendly1uk
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Re: DIPOLE FOR PMR446 HELP NEDED

Post by friendly1uk »

Keeping within the prm446 confines.... It's like getting a ferry, to range test mobile phone's to shore. It's interesting consumer advice, but it's not testing yourself in any way. Unless it's staying awake.

Making your own antenna is an actual hobby. An achievement. A measure of your own abilities. 80 miles with that, and I'm interested in you, not where you shop.

A rated rubber duck might make a good radiator for a dipole. Just a few watts up one, should have enough hearing you, to need a masthead 70cm pre-amp. To hear them back. Is it a 771? that ought to do the trick. A well reviewed item indeed. Probably 70cm gear we claimed for 446. As 70cm is just a tiny bit too long. They are often sold as suited up to 440. A 70cm £10 magmount uses a magnet little bigger than a coin. It's like a whip and coax(and plug)in one piece. Just waiting for radials instead of a roof. A 90 degree mending plate might complete it. Magmount to one leg of the plate, and cable tie the other leg and coax to a mounting pole. Stripping the outer sheath to ensure a ground to the plate. The plate where the wires twist or solder on. 10 minute job on a really good day.
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LeakyFeeder
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Re: DIPOLE FOR PMR446 HELP NEDED

Post by LeakyFeeder »

Wow!!!! no wonder Judge Rinder isnt on the telly...he n his mate Rumpole reside on this forum...

viewtopic.php?f=4&t=59465
paulears
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Re: DIPOLE FOR PMR446 HELP NEDED

Post by paulears »

Three years ago after hearing all sorts of antenna advice I bought a pile. I’ve got an extension at the home where I work from and have small workshop in one of the rooms where I do repairs. I found one of my old handhelds with a decent bar type signal strength meter and constructed a metal ground plane with a hole in it that I could poke a radio up from below. In my radio room I set up a quarter wave for 2m, which would also work as a ¾ wave for UHF. I moved the receiver contraption further and further away till I got a noisy signal with the stock antenna, added a switched attenuator and tweaked the attenuator and generator to get me right on the change from 5 segments to 6. This was my ‘datum’. I couldn’t say exactly what signal strength was but I could increase or decrease the attenuator to get the same level when I tried different antennas.

The results were bizarre! All the clever antennas had questionable performance as frequencies changed. Some were good in the ham bands but rubbish only a bit higher on UHF and some were worse than the stock antennas. There were no firm conclusions at all, apart from maybe the simple ones like quarter waves were actually the best. Some advertising claims were silly and some simply must have been faulty!
The video is here https://youtu.be/LVzlFTIMV5A

You can spot some antennas have two good VSWR points in the ham bands and others are so good at a match you wonder how this result is achieved. Looking at the attenuation needed to achieve the signal strength at the receiver they often seem to fight. Also odd that some are simply terrible at UHF and one even has 449 in a big dip. You have to draw your own conclusions as what you have is just a collection of data. Some results just look very wrong!
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