DIY DF device

I guess one of these newfangled TCAS systems that monitor for nearby
transponder squalks are out of the question since you would have to take
your eyes out of the skies to look at the little led's!

Hey go to the listed web page and look at the display. It only takes a quick
glance at the display to get an idea where its coming from. If you've let
another plane get so close to you that you can't glance at the display to
see where neigboring traffic is then you weren't flying your plane. Sure
there will be times when you miss one transmission and view a second but
they will be few and your still looking all around for traffic anyway. Your
main advantage is most of the time you will start your scan where the
display indictes it originating from and if you don't see it contiunue on
from there.

Last I looked the last word in this newsgroup was "homebuilt" to me that
screams "EXPERIMENT", go for it try a new project and enjoy the process and
journey!
As far as antennas you need 4 each 1/4 wave antenna's which is no biggy
unless your driving around in one of these 200+ mph monsters and are
concerned about drag. One idea for antennas since this is a receive only
concern is to use an electically shortened antenna say take a piece of pc
board and etch an inductor/antenna on it and cover it with a layer of
foam/fiberglass suitable shaped aerodynamically, should be able to get away
with only a 4-6 inch antenna especially since you really don't want a long
range system anyway.
Good luck and go play with it


John






Bill Daniels wrote:


"Ron Wanttaja" wrote in message
...
On Mon, 12 Apr 2004 18:27:05 GMT, "Bill Daniels"
wrote:

I'd like to have one of these in the aircraft. That way if I'm
listening
in
on approach, I'd have an idea of the relative bearing to another
aircraft
that is transmitting. For example, another aircraft reporting over the
same
fix - it would be nice to know which direction to look. A circular 8
LED display would be fine.

Ummm. Personally, I think it's better to keep one's attention OUTSIDE
the
cockpit at a time like this. It takes a finite amount of time to remove
your attention from the exterior, focus on a panel-mounted dial. By the
time you've realized the guy is reporting the same location and look at
your readout, he's probably let loose of the mike button and the LED is
dark.

Sure, you could set up some sort of latching system, but on busy days, as
soon as one guy quits transmitting someone else punches the button.
Inaccurate data is far worse than no data at all. If you're close and
maneuvering, the relative positions are probably changing rapidly,
anyway.

Ron Wanttaja

I'd still like to have the DF on the comm radio. When somebody is
talking,
I'd like to know what direction they are coming from. So, maybe instead
of LED's we need a 3D aural display so the voice seems to come from the
direction of the transmitter.

Bill Daniels

On Tue, 13 Apr 2004 09:47:20 +0000, John wrote:

I guess one of these newfangled TCAS systems that monitor for nearby
transponder squalks are out of the question since you would have to take
your eyes out of the skies to look at the little led's!

Don't know much about TCAS, but I believe the system has an voice warning
that actually tells you how to maneuver. In any case, most aircraft
current with TCAS have two pilots. TCAS also is tracking transponder
squawks, not radio calls made at 1 minute intervals.

Hey go to the listed web page and look at the display. It only takes a quick
glance at the display to get an idea where its coming from. If you've let
another plane get so close to you that you can't glance at the display to
see where neigboring traffic is then you weren't flying your plane.

But isn't that what the system is for...helping you spot traffic that's
close to you? If I'm two miles from the airport and someone transmits from
the pattern, there's already a relatively narrow arc they can be in.

Here's an experiment for you: Next time you're in a busy traffic pattern,
glance down at, say, the oil temperature gauge, note what the reading is,
then go back to your visual traffic scan. *Every* time there's a
transmission on the radio. Then decide whether looking at a panel-mounted
instrument is a good idea.

My home drome is a very busy uncontrolled airport with a single 3,000-foot
runway. I've been in the pattern with ten other aircraft....don't know how
busy the radio was then, 'cause that was in my NORDO days. But my guts get
a little loose at the prospect of one of those ten other people fiddling
with a gauge on his panel when he should have his eyes open for traffic.

Last I looked the last word in this newsgroup was "homebuilt" to me that
screams "EXPERIMENT", go for it try a new project and enjoy the process and
journey!

And if the LEDs aren't bright enough in the sunlight, go ahead and paint
the windows black. After all, it's just an "experiment."

Actually, I'm not too worried in this case. I think Ken has an interesting
project on his hands, but will find that it probably isn't all that useful
once it's in his airplane. I doubt we'll be faced with a flood of these
things. And he doesn't fly around here. :-)

Ron Wanttaja