"David" nospam@nospam wrote in message
...

Which antenna is better: 5/8 wavelength vertical or a J pole?

Frequency of operation is 145 MHz = 2 metres.

The 5/8 wavelength vertical has a loading coil. There are losses in the
coil.

The J pole has a quarterwave matching stub. The matching stub provides an
out of phase current which means that there is a cancelling field close to
the radiating element. Also the J pole is end fed, which means the
transmitter is not connected directly to a maximum current point.

Does the J pole have a disadvantage because of the cancelling field from
the matching stub and the fact that it is end fed?

Also consider gain and angle of radiation.


I would not say any of the simple veticals are better. While I have not
tried them from fixed locations, expirimenting with several differant mobile
antennas over the years it seems that one type is not really that much beter
than another.

Depending on the direction and height of the repeaters almost any antenna
can be better going into one repeater and worse going to another. Several
of us got together and put several antennas (one at a time) on the same
mount of a car. Depending on the particular repeater, there was not one
overall winner. The car also had a 40 meter loaded whip that we tried and
it was actually better into some of the repeaters.

About the only antenna overall not suited was a colinear about 6 feet long.
It worked well enough while parked, but at highway speeds it whipped around
so much the mobile flutter made it almost unusable.

"Ralph Mowery" wrote in message
m...

"David" nospam@nospam wrote in message
...

I would not say any of the simple veticals are better. While I have not
tried them from fixed locations, expirimenting with several differant
mobile antennas over the years it seems that one type is not really that
much beter than another.

Depending on the direction and height of the repeaters almost any antenna
can be better going into one repeater and worse going to another.
Several of us got together and put several antennas (one at a time) on the
same mount of a car. Depending on the particular repeater, there was not
one overall winner. The car also had a 40 meter loaded whip that we tried
and it was actually better into some of the repeaters.

About the only antenna overall not suited was a colinear about 6 feet
long. It worked well enough while parked, but at highway speeds it whipped
around so much the mobile flutter made it almost unusable.

My experience with mobile vertical whips has been similar, I guess at least
in my case the location of the antenna was always a compromise and car
body's are not designed to be ideal ground plans.
I did get quite good at knowing where some of the good lobes were and
positioning the car accordingly.


--
Peter VK6YSF

http://members.optushome.com.au/vk6ysf/vk6ysf/main.htm