On 6/16/2012 2:19 PM, Ian Jackson wrote:
In message , Boomer
writes



The worst antenna I hear on the air comes from people using G5RVs.
Their signal is just totally lame when they use the recommended 80
foot dipole on 75 meters. If they would just extend that same antenna
to 120 feet they would do so much better.

The full-size G5RV is 102' (not 80'), and works pretty well as a
shortish halfwave on 80m. The half-size is 51', and is intended for 40m
and above. However, although maybe not the antenna of choice, with a
tuner and 450 or 600 ohm twin feeder it should be possible to make even
an 80' dipole work fairly effectively on 80m.

One amateur (local to me), who I believe has limited space, reckons that
a straight, short dipole works better than a squeezed-in, dog-legged
full-size dipole. I think his is 85', and it certainly works well on 80m.





On 160m, I had better luck using a full size "Z" dipole than
I did shorter dipoles that were loaded with high Q coils.

I sort of agree with him about the G5RV, but it's the feed that
is the problem, not the length of the radiator. Generally too much
feedline loss with the way most people run them. Same problem with
many of the various commercial Windoms that they sell.

I prefer the full length dipoles because it's easy to feed them in
a low loss manner. On the low bands, it's very hard to beat a dipole
fed with coax for overall system efficiency. Maybe nearly impossible,
being as I've never found anything more efficient so far.
I suppose a tuned feeder of ladder line would be as good, "IE: the Cecil
method" but not nearly as convenient.
I never could match coax performance using ladder line and a tuner.
Close, but not quite.. No matter how careful setting the tuner using
the very minimum of inductance.

I guess that's why I'm such a coax fan... May not be good for multi-
band use with a single dipole, but for single or limited band use, very
hard to beat.

I remember one year I got stuck using some kind of Windom for 80 and 40
at field day.
It was terrible... I swore never, ever again..
But sure nuff.. The next year they tried to stick me on a windom again.
But I was ready.. I brought everything I needed to make a dipole
on site. Which I did. I then whipped out a coax switch so I could
A/B the two antennas, just to prove I wasn't barking at the moon.
When you switched to the coax fed dipole, *everything* jumped up
at least full 2 S units on his rig. His eyes got big as saucers.
He never really suspected he was losing that much.
Needless to say, I stayed on the coax fed dipole.
The RF mayhem of field day is no time to be using lossy compromise
antennas.. I never could see that, when you have enough room to
use just about anything.