Today's Message Index:
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1. 08:36 AM - Re: MkIII antenna location (b young)
2. 01:04 PM - finally a bit of flying weather (Larry Cottrell)
Message 1
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| Subject: | MkIII antenna location |
Boyd
Sorry, but now I am confused. As near VERTICAL as possible?
do not archive
Mike what you are describing is a quarter wave antenna with an X shaped
ground plane. A di pole ( di meaning two) is a radiating element with
one ground element usually mounted in a straight line, and in our case as
vertical as possible.
_________________ co _________________ < horizontally polarized
antenna
where co is the coax feed point.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Yes vertical: radio signals can be vertical OR horizontally
polarized.
Example.
1 most antennas on cars and trucks are vertically polarized,
the broadcast antenna is mounted vertically, meaning that for best
reception the receive antenna should be mounted vertically.
2 back in the old days when everyone had a T V antenna on the
roof they were horizontally polarized. The broadcast antenna were
horizontally mounted and the receive antennas were mounted with the elements
in a horizontal position.
3 in satellite communications there is another,,,, circular
polarization,,,, because satellites are generally rotating to remain
stable a combination of both.
When an antenna is transmitting there are 2 different types of energy that
come off the antenna. Static pulses, and magnetic pulses. If both tx
and rx antennas are in the same orientation the receive antenna will
capture more of the energy.
My picture above for an aircraft antenna should have been
l
l
l
l
l
l
l
co coax feed point of a vertically polarized antenna.
l
l
l
l
l
l
l
I hope this graphic works.
There are some exceptions,,,, working with ham radio on the H F bands,
when the signal is skipped off the ionosphere the static and magnetic
pulses are mixed up a bit. And a vertical transmitter and horizontal
receive antennas or visa versa seem to work well.. But for line of
sight transmitting on vhf frequencies they do not
The antenna in my aircraft has the radiating element goes from the left
bottom of the nose cone, up the left side, then horizontal across the top.
I never said it was perfect I said it works. It does not show, and
creates no drag. The center part of a dipole antenna has the largest
current flows as compared to the end. Thus it creates the largest static
and magnetic components. So it is still considered vertical. I probably
could have coiled the top of the antenna to keep it more vertical.. But
that creates its own set of problems as well. The need for a balun or
matching network.
Again more than you probably needed or wanted to know
Boyd Young
Message 2
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| Subject: | finally a bit of flying weather |
http://share.findmespot.com/shared/faces/viewspots.jsp?glId=0siAoTNYTZD
6KPbiDncNLfKZruRqx5nUO
The above link is to my spot tracking page. I prefer to use the hybrid
feature since it shows roads. There isn't much reason to have good sat
pictures here so you won't be able to get in too close.
The wind and weather finally moderated a bit or at least enough that I
felt like flying for the first time in almost a month. My interest was
to find a "two track" down into the Canyons that frame the Owyhee River
that would allow me to take a quad from this side of the river. If I go
the way that the roads are good I end up driving about 100 miles before
I can even get on my quad. This way it is only about 50 miles of two
track, and 15 hwy. It is very difficult here however because the roads
are not signed, and the land is so featureless as to not be much help.
So my plan was to press in GPS readings at the turns. Here in ranch
country all the roads lead to water, generally a stock pond, so it can
be a bit confusing actually trying to get somewhere.
I flew 103 miles in an hour and 34 minutes. I used 4.7 gallons of fuel
for 21.9 mpg average speed was 62 MPH There was a pretty good headwind
and it was a bit bumpy over the canyon coming back home.
My feet were cold by the time I got back on the ground, but it was nice
to get out for a while.
Larry
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