Projects:Foxhunting

Exact name	Foxhunting / Fuchsjagd
	Generated Design (experiment here)
Description	Find hidden radio transmitters
Has website
Persons working on	RealD Edit specify you're working on this project on your user page, here... and then on "edit with form" at the top.
Self-organized sessions	create self-organized session
Tags	Foxhunting, Game, foxhunting, fox hunting, foxoring, Fuchsjagd, Amateurfunk, find, hidden, radio, beacons, transmitter, 2m, 144Mhz, ARDF, Amateur Radio Direction Finding, Amateurfunkpeilen, hamradio, ham radio, Geofoxing, geocaching, SDR, software defined radio, RTLSDR, rad1o
Located at village	Village:TMS
	Other projects... Projects:watermeter readout: component handout; Projects:ESP32 LifeCycleManager; Projects:Demoparty; Projects:Yolocation; Projects:Arch Linux; ... further results
	refresh data

MCH2022 Foxhunting is over! Winner is Oh8etb who found all 5 foxes in under 1 hour. See you all at next camp!

How?

Go to the marked search points and start your receiver.
Find transmitter signal between 144.000 and 144.005 Mhz.
Go to place with strongest signal and find tag (Example tag here) with station code.
Log fox online. (URL on Tag)
Repeat until you have found all foxes.

The nearest transmitter may not be the strongest. Remember the place if you listen to several transmitters at once. This might be a good place to go back if you have found the stronger one.
Pay attention to the different beep patterns. From which direction is which signal coming?
Foxes beep (in different patterns). If you receive a constant signal this is not from a fox.
It is not necessary to cross heavy vegetation. Stay on the paths as long as possible!

One out of:

RTL-SDR/Hackrf/Rad1o with OTG capable Android phone with RTL-SDR driver and demodulator app (RF Analyzer with SDR driver seem to work). Bring a powerbank to recharge you phone during run. RTL Sticks consume surprisingly much power.
RTL-SDR/Hackrf/Rad1o with PC and installation of gqrx (Linux, Mac)/SDR# (Windows) or similar. Second person might be helpful to carry all the stuff. :-)
RTL-SDR/Hackrf/Rad1o with PC and installation of gnuradio if you want to create a receiver by yourself.
Any receiver for 144Mhz region with SSB (or CW) demodulation mode.

Directional Antenna recommended. For some antenna building ideas see the #FAQ: below.

Frequency range is 144.000000 - 144.005000 Mhz
Set demodulation mode to SSB (USB or LSB). Tune slightly next to the signal to hear a tone. Of course you can use CW mode but then the frequency has to fit exactly.
Set RF gain to manual mode. Start with a medium or smaller value.
Disable automatic gain control if possible.
It might be helpful to zoom into this small frequncy range
The spectrum should look like: File:Spectrum_Example.png

What is a fox?
- A radio transmitter transmitting different beep codes. Here they will have a very small range (50-150m).
I see a strong continous signal. Is this a fox?
- Probably not. Might be a harmonic of the local oscillator of your RTL stick. Disconnect your antenna; if the signal is still there it can´t be a fox.
I want to build my own transmitters. Where can I find instructions?
- Maybe here: http://www.df1fo.de/index.html#2mTX . Please be aware that you normally need an amateur radio license in your country.
I want to build my own directional antenna. Where can I find instructions?
- Yagis here: https://www.qsl.net/dk7zb/PVC-Yagis/3-Ele-2m.htm
- Tape Measure antenna: https://www.instructables.com/The-Tape-Measure-Antenna/
- ...
Can I borrow a directional antenna for 1 or 2 hours at this event?
- Yes. I can offer one with SMA and MCX connectors and one RTL-SDR dongle. Please contact User:RealD.