Transmitter Receiver project help -ADF

[nilesh.7650]

Hi, I am an Aerospace Engineering student and need help on a communication project.

The project is making a small ADF i.e. 'Automatic Direction Finder' which is used in aircrafts to locate the correct bearing to the airport.
I am not an expert at making electronic projects so I need step by step guidance for making it.

Here is a reference link to a PDF document containing circuit diagram and general explanation:
**broken link removed**

General Introduction:
Radio direction finder - Wikipedia, the free encyclopedia

At the first stage, how do i go about using a loop antenna?

 

[MikeMl]

The cited PDF takes forever to load; I gave up.

ADF based on VLF transmitters is dead. The VLF transmitters are being decomissioned by the FAA as we speak. I tore the ADF out all my aircraft years ago.
You might prefer a system based on VHF (108-136MHz), where the aircraft can follow a needle to the airport or navaid.

 

[KMoffett]

They've already dumped LORAN (Feb 18th) and now it looks like VOR (service reductions starting this year) may be on the way out...leaving only GPS.

ken

 

[mneary]

The document host must be on dial up. It didn't finish loading for me either.

 

[KMoffett]

1.71MB...loaded for me in about 20 seconds. Slow, but loaded.

Ken

 

[abilask]

Hi..Any one have simple ADF circuit ..Please share as it will helpful for my project work.



thanks in advance

 

[EI3HG]

A DF loop that could be used manually is quite simple.

Look up 'loop antenna' on a search engine for plenty of designs. (especially on HAM or DX forums.) Basically this is a number of turns of wire on a frame or inside a copper pipe (if the 'E ' field needs to be shielded) which forms a parallel resonant circuit with a capacitor usually a variable type. another single insulated turn is used to connect to the receiver.
There are more elaborate systems which can combine the signal from an omni-directional whip or wire antenna in such a way as to cancel with the loop's signal when it is oriented one way, but not when turned by 180 degrees. still a quite simple electronic circuit.

I doubt if the 'Automatic' part can be done simply. You are talking servo or stepper motors, and PIC controller. Certainly do-able, someone in to robotics could help here.

You need to break the project down in to parts. An RF hobbyist may not have the knowledge or inclination to build the servo and PIC part, and a robot expert may well not have much RF knowledge.

Best of luck

Andy