The NDB/ADF...
07-24-2007, 04:04 PM
#1
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The NDB/ADF...
How does it work? Yes, I've heard and taught a thousand times about frequencies, wattages, classes, errors, and navigating with them. But what does it DO? It seems like they just pump a whole bunch of electrical power out over one frequency, and the ADF senses where its coming from via the loop/sense combo. Is that even remotely correct? And why is it NON-directional as opposed to OMNI-? It transmits in all directions...
Thanks!
Thanks!
07-24-2007, 06:39 PM
#2
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Originally Posted by PFGiardino
How does it work? Yes, I've heard and taught a thousand times about frequencies, wattages, classes, errors, and navigating with them. But what does it DO? It seems like they just pump a whole bunch of electrical power out over one frequency, and the ADF senses where its coming from via the loop/sense combo. Is that even remotely correct? And why is it NON-directional as opposed to OMNI-? It transmits in all directions...
Thanks!
Thanks!
You are correct in that it transmits a constant signal in all directions, and the ADF determines from which direction the signal is strongest, and points to it.
07-24-2007, 08:33 PM
#3
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DF to ADF
The basic concept is that a loop antenna oriented perpendicular to the incoming radio wave will get an induced current flow clockwise in one half and counter-clockwise in the other half, thus producing a "null" signal. Turning the antenna 90 degrees will get a maximum signal. The "A" in ADF came along when they got the radio to do this automatically instead of manually, solve the pesky "180 degree ambiguity", and provide the result on a compass card.
08-02-2007, 02:20 PM
#5
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Most of my coworkers scoff at using an ADF even in the F-141. However, all the students I've taught who could use an ADF properly rarely had any trouble with VOR or localizer orientation. Conversely, students who had lots of trouble or never used the ADF tended to get lost easier when using the nav systems. I had one student who had a bit of trouble early on, but once he learned the ADF he rarely got turned around. Even though the system is on its way out, it can develop good skills.
08-04-2007, 05:02 PM
#6
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Try the following link: http://selair.selkirk.bc.ca/Professi...-adf-works.htm You'll need Shockwave installed on your browser to get it to work. It's an animated tutorial showing explaining how an ADF works. I've had some students who just couldn't grasp how a lot of the navigation equipment works, but after they see THIS website they finally understand.
09-07-2007, 06:54 PM
#7
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Originally Posted by cfii2007
And they are really good for picking up AM radio stations to listen to on a long flight.
09-09-2007, 06:09 AM
#8
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Originally Posted by mccube5
They are good enough. Certainly not winning any points for clarity, but it was coming in loud and clear last week when the Yanks were beating up on the BoSox!
09-12-2007, 11:21 AM
#9
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VOR uses a circular array of antennas inside that conical tower you see on the ground. A reference signal is transmitted in ALL directions, and another is transmitted from the rotating array...Basically a phase comparison that changes
depending on where you are in relation to the transmitter.
The VOR receiver compares the phase shift, and positions the needle accordingly...
depending on where you are in relation to the transmitter.
The VOR receiver compares the phase shift, and positions the needle accordingly...
09-12-2007, 02:12 PM
#10
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Originally Posted by tomgoodman
The basic concept is that a loop antenna oriented perpendicular to the incoming radio wave will get an induced current flow clockwise in one half and counter-clockwise in the other half, thus producing a "null" signal. Turning the antenna 90 degrees will get a maximum signal. The "A" in ADF came along when they got the radio to do this automatically instead of manually, solve the pesky "180 degree ambiguity", and provide the result on a compass card.
KI6ETY here, if ya are.
