May I suggest you're reading more into KK5F's comments than he actually
said?
He certainly did not say the Outbacker and similar antennas do not work. As
you point out, they are in use every day to make contacts. Mike said of
those antennas and similar designs that "...contacts can still be made using
the poorest of antenna systems."
That is very true! Mobile antennas, "ground coupled" antennas, indeed any
antenna that is small in terms of wavelengths is, by nature, very, very
inefficient! It's not unusual to see less than 5% of the RF applied to them
be radiated. Often it's much less than 1%.
What those antennas offer is the ability to operate mobile in motion or to
operate anywhere the equipment can be carried with very little setup time.
For that convenience they give up a huge amount of efficiency. Often that's
a good trade-off.
To be really efficient without an extensive ground system (the fabled 120
radials, etc.) an end-fed antenna needs to be at least 1/2 wavelength long.
I'm not about to try to mount a 66 foot whip on my car so I can mobile
efficiently on 40 meters! I'll take the drastically lower efficiency of a
more reasonable antenna size and I'll make a lot of contacts even though my
effective radiated power (ERP) will be very low. The same is true in a lot
of portable situations.
And, as Mike observed, these small antennas are not cheap. They can be among
the most expensive antennas one can buy short of a big tower. That
well-crafted portable design usually comes at a hefty price in addition to
very low efficiency. But, when properly done, it makes for an easy-to-set-up
portable radiator that many find worth the cost for the convenience.
If one goes to just a little more effort to get a larger radiator up, the
improved signal from the greatly-increased efficiency are enormous. Like
Mike, I certainly would suggest a center-fed half-wave antenna for the use
that was stated: portable work while camping. If that's too much to deal
with, next I'd suggest an end-fed wire, 1/2 wave long if the tuner will
handle the high impedance, or as close as the tuner will handle - longer is
better - with a 1/4 wave "counterpoise".
Either of those will produce a much, much stronger signal than a smaller
antenna, no matter whether it's a homebrew whip or a expensive commercial
product.
But that doesn't mean that you can't make contacts with a lot less antenna.
I often wince when I see people spend money on something that's expensive
without understanding why it's expensive. In the case of antennas, no amount
of money will make a small antenna work as efficiently as a larger antenna.
If the radiation efficiency is the primary goal, a wire tossed into a tree
with a 1/4 wave "counterpoise" near the ground will outperform any portable
"whip" antenna I've seen anywhere at any price.
I'd be very astonished if Terry at Outbacker didn't agree!
Ron AC7AC
-Original Message-
Just a quick word to say totally disagree with KK5F's comments about
the Outbacker antennas.
I and many of my club mates use them on a daily basis and they certainly
do work.
I am mobile at work and consistantly get excellent reports using my
Outbacker on 40 and 20 mtrs over a 500-800 mile path from my Mitsi
outlander with 100w and a TS 50.
I also have had many DX contacts on 20 and 15 mtrs while driving around
Western Australia.
Just cos you have had no luck dont paint the antenna black. Many many
people use them daily and get excellent results, including Police, Army,
and Emergency Services.
It even may have saved a life once as it has the RFDS ( Royal flying
doctor service) tap and I was able to call for help with a heart attack
patient.
I also have a Tarheel 200HP and that works well too.
I'm surprised you made such a categoric statement about how bad the
Outbacker was.
I will send your comments to Terry at Outbacker ( only 10 miles from
here ) for his consideration.
Maybe he will contact you.
probably not.
73
Keith
--
Keith
VK6XH / VK6DXR
Secretary
Northern Corridor Radio Group Inc VK6ANC
Chairman WIA VK6 Advisory Committee.
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