All folded dipoles are not the same.
If you have a modeling program, you may evaluate the diameters of dipole
and the spacing as well as the length.
Beyond that use your nano to find the actual feed impedance of the folded
dipole. A 1 wavelength jumper would be a good test cable. Remember make
short connection to the antenna. And close spacing between the dipole ends.
A 1/4 wave of 75 will match a 100 ohm antenna to 50 ohms. Don't forget the
velocity factor in measuring the coax, hint shorter.
The Utube shows a longer looking cable.
In reality the half wave cable Balun works.
An alternative is like commercial vhf uhf antennas. They are a half folded
dipole to match an unbalanced coax. One side is folded and connected to
the coax. The other side may be a single tube or a folded dipole with both
ends in the feed point connected to ground.
Good luck in your efforts. Keep an open mind and look at others for
options.
toggle quoted message
Show quoted text
On Mon, Nov 2, 2020, 8:32 AM AllassoPraise <allassopraise@...> wrote:
I saw in this video the other day at 1:40:
The presenter talks about using a length of 75 ohm cable inline to
match a (theoretically) 300 ohm folded dipole to (presumably) 50
ohms. Has anyone else ever heard of doing that?
It sounds like it might be easier than using the 1/2 wave phasing coax
balun method, especially at 1 to 2 GHz frequencies, where tweaking the
antenna can require a lot of adjustments to the 3" to 6" coax loop.
