I have one sitting in the back of the Pathy still waiting to be used. I have one in the backyard and regularly work Cape York to Tassy if only the birds stop picking the insulation off.
BigL said:coaxial ground plane its called. A colinear is a type of phased array, they have what looks like coils in the middle, these coils change the phase and in doing so results in gain.... +dBTathradj said:From the pl259 connector to the end of the braid acts as
a ground plane for the inner that is exposed which is the radiator
element.
Buffs can correct me at the moment as I am mentally flat,
I think it is called a co-linear ground plane.
BigL said:468 / MHz = 1/2 wave length (ft)
Measure and cut a length of wire to your half wave length answer
Cut the wire in half and then feed each piece of wire with your coax, + one side, - the other
you now have a half wave dipole which can be run vertical, horizontal or even at 45deg... whatever you like
the higher you can get it the better
all answered for you in the aboveGreenhornet_au said:BigL said:468 / MHz = 1/2 wave length (ft)
Measure and cut a length of wire to your half wave length answer
Cut the wire in half and then feed each piece of wire with your coax, + one side, - the other
you now have a half wave dipole which can be run vertical, horizontal or even at 45deg... whatever you like
the higher you can get it the better
Hi BigL,
I am not that bright with many things so I ask questions to confirm what I don't know.
As I understand it...
468 divided by the frequency = a half wave length in Feet ? (why 468 ? please)
468 is a constant derived from a RF wavelength or 0.5 lambda
Convert that to Centimeters to measure 1/2 wave length of wire. (is that acceptable)
yes 468/Mhz/3.2808x100 = cm
Fold in half and cut it, to get a 1/4 wave length x2,... feed one 1/4 side from the shield, and the other 1/4 side from the core.
correct
Preferably check the SWR.... how do I tune the antenna ? If I want to or need to.
what ever your calculations work out, add a couple of inches to each 1/4 wave side, that way your antenna should be resonant below your desired frequency, then you just trim maybe 5mm from each element side until the SWR is acceptable, anything <=1.5 SWR is fine. Best to start with wire to long than too short for obvious reasons
Is there a preferred spacing between the two 1/4 wave elements at the feed point ?
1/2 inch is fine
Would it be worth going up to 1/2 wave elements ?
no, because your feedpoint wont be around 72 ohm which is what your aiming for
If hanging it vertically in a tree, which end up is best ?
either end if you get it high enough, like greater that 1/2 a wavelength high, otherwise id have the positive side up
Is this a suitable antenna for uhf CB and vhf Marine, for a temporary base camp, I hand the girls uhf walkies and everyone goes for a wander,
so a base set would be a bit different for the kids to use. Generally I give everyone a cheap Baofeng 3.7Vdc GT-1's programmed to uhf CB,
at $20ea I am not worried if they are drowned or dropped.
If it would work, I could get the girls to make an antenna each, set up and test their work :lol: :lol: :lol: (camping STEMM classes)
i dont see why not... wire antenna is a lot easier to get high up a tree than whips ect
A 27mhz setup to follow a bit of skip would astonish them, a must do.
See how uneducated I am?
Cheers.
BigL said:all answered for you in the above
Jaros said:Most 2mtr conversations are done via repeaters placed strategically all over the place. I spoke on 2M a while ago to 2 fellas whoe were about 50Klms away not using a repeater and they were surprised how clear it was. My 2 mtr aerial is above the rooftops around us because of all the tin roofs around the house-including mine.
I haven't tried the online gear.I dunno it's not as tech as doing it yourself.
Cheers.
Jaros. VK4NLS.
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