What's the best vertical antenna for 2 meters?
There isn't any such thing as the "best" antenna. Or radio, microphone, band, or anything
else. There may be some that fit your needs and operating preferences better than some
others do.
I am probably looking to make my own and use something I can pull up into the tree and not a yagi.
Are J pole's, 5/8, isopoles, or anything else better than making a vertical dipole? Please share. If there's a site online that discusses the construction of what you're talking about, please share it as well.
Height makes far more difference than gain. The antenna you can get up highest is
probably going to work better than one you can't mount as high because it is heavier,
more awkward, etc.
For an omnidirectional antenna, gain is a function of overall radiator length (assuming the
antenna is properly designed. You can make it worse than that, but not better.) So any
antennas of about the same radiator length will have about the same gain. This means
there is little difference in practice between a ground plane, vertical dipole, or a J-pole,
as they are all basically half wave radiators. The ground plane on a coax connector
is simple to build, cheap, and works well. The biggest difference you will find among
these antennas is how well they decouple the feedline from the antenna: this is a
particular problem with a vertical dipole when the coax runs down along the lower
element (which is why a ground plane is preferred) but the J-pole is also prone to
this. The current flowing on the coax can partially cancel the radiation from the
antenna at the horizon and raise the angle of maximum radiation.
The IsoPole is a 2 x 5/8 wave design that will have about 3dB gain over a dipole. This
is similar to some of the "extended" J-poles, etc. that have about an 8' radiator. There
are several construction methods. Note that you can't use just a straight wire for the
radiator to get it to work at this length - you need some sort of phasing stub in the
middle.
I don't recommend going to any longer of a radiator, however, unless you can get it
very high in the air and ensure it is plumb, as it doesn't take much tilt to a 6dB omni to
where it is no better than a dipole in some directions.
On a separate note:
I am also in the process of testing a 5/8 wave versus a 1/4 wave antenna on the mobile and am not finding much difference most of the time. Sometimes I am even finding the 1/4 wave outperforms the 5/8 wave.
That's what most people find who compare them in practice. The top of the typical
vehicle (even a van) is nowhere near large enough for the 5/8 wave to achieve it's
advertised gain, an the longer whip is more prone to bending over at speed and
cross-polarizing the signals. By switching back and forth between two antennas
while driving through marginal coverage areas, I find that the 5/8 wave tends to
show a little gain over the 1/4 wave whip - perhaps the difference between 40%
copy and 60% copy. Most of that gain is due to the fact that the active radiator
is higher in the air.
