Option for detecting an aviation band radio signal?

I am working on a project where I need to determine when a radio transmission happens on an air band frequency. I am currently using a handheld radio, with a voltage detection module hooked to the headphone output, I watch for the voltage to go non-zero and that triggers a counter. For each individual transmission, the counter is increased by 1.

Using a handheld radio is an expensive way to do this. It's also pretty kludgy. What I would like is to have some sort of smaller and simpler receiver that I can specify the frequency on, and which could send a high/low or on/off type signal to the arduino, from which I can count the transmissions.

I have not been able to find many options. Any ideas? Thanks!

Depends what you mean by expensive I guess.

There is https://www.rtl-sdr.com/about-rtl-sdr/

Or you can get cheap Chinese/Russian made handhelds like https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR12.TRC2.A0.H0.Xbaofeng.TRS0&_nkw=baofeng&_sacat=0 for around $20-30

Frequency bands are allocated for specific purposes. Some bands such as the aviation bands require a license to transmit on that band. So small, cheap transmitters are simply not available. Some bands don't require a license so thousands of people can use them. Those are the bands we usually use for Arduino projects because the transmitters and receivers only cost a buck or less.

The cheap transmitters and receivers are prohibited by law from being easily re-tuned into another band.

Honestly, the handheld radio is the easiest and cheapest way to get a tuneable receiver on the aviation band. With anything else you would be working hard to tune in a specific frequency without picking up any other nearby frequency.

You may be able to hack this software-defined radio Software Defined Radio Receiver USB Stick - RTL2832 w/R820T : ID 1497 : $22.50 : Adafruit Industries, Unique & fun DIY electronics and kits or something similar, if it can receive the band you want. The product page has a link to a hack. Have no idea if the device or that page will help you. But it looks like it would be fun to play with.

DaveEvans: You may be able to hack this software-defined radio https://www.adafruit.com/product/1497 or something similar, if it can receive the band you want. The product page has a link to a hack. Have no idea if the device or that page will help you. But it looks like it would be fun to play with.

That would work perfectly for you. But it won't work for an Arduino because the SDR software can't run on it, only a PC.

Paul

You dont say which Airband frequency you want to listen to, nor which handheld you are using that is 'expensive'.

Is there an RX LED on your receiver? Most do have one. It will come on when a signal breaks the squelch circuit. Since you don't want to use your radio, find a scanner that has one. You could monitor it with an LDR or photodiode.

Paul_KD7HB: That would work perfectly for you. But it won't work for an Arduino because the SDR software can't run on it, only a PC.

The software supposedly also runs on Linux, so maybe an RPi could handle it. (I know, I know, this is an Arduino forum.... :) )

The RPI runs an arm version of Linux , which isnt compatible with PC versions of Linux which use x86 binaries, so pretty unlikley the SDR code will run.

greghughespdx: Using a handheld radio is an expensive way to do this. It's also pretty kludgy.

On this point, I must disagree. Except that you don't need a transmitter, so a scanner will do. Both of those are specifically designed for good selectivity and sensitivity for the signal you want to receive. Generally a "kludge" is something that is used for a purpose that it was not designed for (among other aspects). Additionally, a scanner has a built in detector and squelch circuit which saves you from having to re-invent it.

mauried: The RPI runs an arm version of Linux , which isnt compatible with PC versions of Linux which use x86 binaries, so pretty unlikley the SDR code will run.

Check this out! https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-scanner/overview

Probably a long ways from that to what the OP wants, tho'.