"Jerry Martes" wrote in message
news:qCc_f.2174$wH1.1885@trnddc03...

"Richard Clark" wrote in message
...
Hi Ken,

What did you compute as being the Velocity Factor for the shield being
covered with thick PVC?

The problem with this modified Franklin Array is that you are cutting
for half-wave dimensions once, for two Velocity Factors along the same
length. Only one is going to be correct, and it is going to impact
the theoretical application of the other.

You might want to try again using bare wire, twin lead fashion.

73's
Richard Clark, KB7QHC

To Ken

Hi Ken, I'd always take Richard's advice before mine. But, I wonder if
you realize how difficult your task is. It is a very difficult project
to
develop the design of any array of radiators thats about 5 wavelengths
long.
And, it *is* a project, not just a matter of precise measuring and
cutting.
I'd think that 3 dB improvement over the antenna that was designed for
optimum performance shows that you are doing something right.
This project is a great learning opportunity for you.

I'd suggest that you get a directional coupler and get some idea of the
match of the array while it is being made longer. If you can manage to
keep
the VSWR under 2:1 with 6 or 8 elements, at your operating frequencies,
you
will be way ahead of me.

Jerry KD6JDJ


Thanks to both of you for your help. I took the antenna down and by-
passed the 40' of LMR 400. Still, my Rssi with the OEM antennas was
only 3db better on the big antenna. Thinking maybe the radome was an
issue, I took it off and saw about another 2db improvement.

I had fun building the antenna and I learned a lot. I just bought a pair
of OEM high performance (9dbi gain) antennas off of eBay. Someone
suggested running the router up my tower in an enclosure. Neat idea...

Ken KG0WX