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This is a continuation of the archived thread from https://www.physicsforums.com/threads/how-to-make-inductor-coils.570700/. Judging by the list of needed coils, I suspect the author was looking to build VHR AM Aircraft Receiver as described here: http://electronics-diy.com/vhf-fm-aircraft-transmitter-receiver.php. I am also interested in building this device and later interfacing it with a PC using Arduino development board (to set frequency and receive digital mono stream). Mainly I am interested in this project to listen to aircraft communications because I am learning to be a sports pilot as a hobby and also because I am a software engineer and have recently become interested in building hardware that can interface with a computer.
A few questions that I have:
A few questions that I have:
- Do coils get sold already wound or do I just need to buy a wire and wind it myself?
- According to https://www.physicsforums.com/threads/how-to-make-inductor-coils.570700/#post-3727829, I could use http://www.crystalradio.net/cal/indcal2.shtml to calculate the resulting inductance given number of turns, diameter of coil and wire diameter. Unfortunately, after trying to get the 0.15 uH by specifying the input parameters from the first post (1.5 - number of turns, 3/8=0.375 inches - diameter of coil, and various values from the tables for #26 wire), I get resulting induction ~0.04 uH, which is nowhere close to 0.15 uH. Where is my mistake?
- How can I interface a variable capacitor with Arduino? Is there any way to control capacitance between two inputs on Arduino digitally? Although I do not technically need Arduino or PC to listen to aircraft communications, building a digital device will be a good exercise for me to learn writing drivers and creating digital hardware.
- I am also not sure which components of the circuit correspond to various parts of the super-regenerative receiver pipeline as shown here: https://en.wikipedia.org/wiki/Superheterodyne_receiver#Design_and_principle_of_operation. From the description it's only clear that the implementation is mostly done by components on the left of the L3, but I have no clue what is needed for which purpose.
- Does this circuit provide protection against transmitting on the same frequency? I only intend to build a device for listening and would like to avoid interfering with any aircraft communications.
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