1 Purchase, Install, and Configuration Guide
PLEASE READ THE ORDERING ANTENNAS SECTION BEFORE PURCHASING ANTENNAS
Please use this page as your initial starting point to learn about the system, how to order antennas, install, and configure your system for the first time.
The core components of the system will be the Raspberry Pi, the SDRduo, Reference and Surveillance Antennas, and the nearby station you end up selecting as your pilot signal. The local station emits waves to the surrounding area and the antennas pick up those waves, the SDR digitizes both the reference waves and reflected waves bouncing off of things, and the Pi processes them into something we use to log the data and send data to the cloud for post processing and aerial signature management. For more on Bistatic Radar and how it works please visit Offworld Labs
Before you purchase your antennas, you first need to decide what tower you will use. This will then determine the antenna shape you will need to purchase.
- Go to https://towers.retina.fm/ or if you already have your system installed use the “Find Towers” button in the configuration flow
- Figure out your latitude, longitude, and altitude above sea level by allowing tower finder to use your location or searching online
- Change the data source to the correct country or you will not get correct results
- Find a tower ideally somewhere between 3 and 20 miles of your house
- If the tower is too close, within a couple of miles, the SDR can be overwhelmed by its signal and that frequency will not be usable. Note: these are approximations. Your SDR will tell you the true power of the signal once the system is connected. There are many factors that affect signal including weather, your mounting location, directions and types of all of the antennas, and other miscellaneous factors.
- Prioritize a VHF tower over UHF ideally as it is easier to work with and better for capturing longer-range data
- If neither VHF nor UHF has decent options you can use FM as well, but you need to make sure you choose a station that has a steady stream of music coming from it as talk will have pauses in signal when there is nothing being said, a steady stream of sound is preferred. To do this select “Add Frequency” and add 88, 89, 90, etc., all the way to 108 to capture the full range of FM bands that may be in your area
- Locate 2-3 towers that could be usable and note their callsigns, frequencies, longitudes, latitudes, and heights above sea level. Note: It is also recommended that you confirm those callsigns still exist on the FCC website and that the signal is a steady, usable TV channel. High power (>15 kW) is preferred. https://www.fccinfo.com
Ideally try Option A first as it's simpler for first time users, but you can use this section as verification or in lieu of Option A if you prefer to get more technical
- Install your Pi and RSPduo per the install section
- Configure your Pi and RSPduo per the Configuration section. Follow the normal configuration process but skip the Tower Selection Section since you don't have your final antennas yet
- Enter into SDRconnect Mode described here
- Look for strong pilot signals (6MHz bandwidth "hill" that rises 20-30dB above the neighboring noise) at upper VHF (169 to 216 MHz), UHF (512-608 MHz), and FM (88 to 108 MHz)
- Cross reference these results against Option A's Tower Finder results
- Once you have chosen your station or have 2-3 options you are now ready to purchase your antennas
- Choose a surveillance antenna that meets the frequencies of the towers you have chosen. Directional antenna is recommended that ideally has up to a 10 dB gain
- Choose a reference antenna that also meets the frequencies of the towers you have chosen. Single pole or dipole antennas are recommended. You may need to buy an adjustable reference antenna if you can’t find one with the correct frequencies, or you could also use another directional antenna as a reference
- Make sure the Raspberry Pi is inside the protective case and the cooling fan and heatsink installed properly
- Connect the Raspberry Pi and RSPduo with the USB A to B cable. It does not matter which USB slot it is plugged into
- Confirm the SIM card is firmly mounted into the Raspberry Pi
- Choose a location indoors near a 120V outlet to store these devices and within range of Wi-Fi. If you have an outdoor waterproof storage case for the items you will still need to make sure you can route a 120V plug to the case safely. Choose a location as close to the surveillance antenna as possible to remove losses in signal power over the line
- You are welcome to power on the system at any time whether all cables have been connected or not the system is plug and play in any order
If you need to reflash your SIM card to reinstall your operating system for whatever reason follow these instructions to flash a 64 GB or larger card.
- Mount your surveillance antenna as high as possible for best signal reception. It is recommended at least 10 ft off the ground, but the higher the better. If mounting on the roof use things like a chimney for stability.
- Your reference antenna is ok to be mounted indoors if it is smaller, but is also recommended to be as high as possible as well for best results
- Connect your coax cables and route them as directly as possible to the location of your RSPduo
- Connect your reference coax cable to the RSPduo antenna port 1 and your surveillance antenna to the antenna port 2 using the SMA to coax adapters. Your reference antenna may already have an SMA connector on it
- It is recommended you also get 2-4 ferrites for your system: install a ferrite at each end of the surveillance coax and, optionally, a ferrite at each end of the reference coax. To install a ferrite run the coax through the ferrite core, then loop it back around once or twice through the core again for a total of 2-3 passes through the core before connecting the coax.
Use a grounding block in your system to ground it both to the earth using a rod and to your home service entrance earth grounding location.
- Confirm with your local authority on what is required and who is qualified to install it
- Often a copper #10 or #8 awg wire is required to properly ground a system from lightning strikes
Limitation of Liability — Grounding. Offworld Labs is not responsible or liable for any death, injury, property damage, fire, or equipment failure resulting from improper, incomplete, or non-code-compliant grounding, bonding, or earthing of this antenna system. Proper grounding in accordance with all applicable electrical codes and local authority (AHJ) requirements is the sole responsibility of the installer and/or owner.
Once the Raspberry Pi is powered on and all of the components plugged in successfully use your phone or computer and open up Wi-Fi connections. Your node should be broadcasting its own Wi-Fi connection SSID: "node-setup" that you can connect to:
- Connect to it and follow the steps to connect it to your router. Alternatively if using ethernet it should automatically detect it is connected to your router and connect online at that point. Note: The network "node-setup" will disappear after it successfully connects to your router.
- Go to http://owl.local/
- Accept the terms of service and the usage of cloud services
- Update your OS to the latest version, this can take up to an hour sometimes
- Download the latest RETINA package, this can also take up to an hour sometimes
- Input your house in Latitude and Longitude coordinates and meters above sea level. Use the spectrum analyzer button optionally to get exact dB of the tower powers near you. If the system has trouble starting up the spectrum analyzer give it a couple seconds, if not you may need to restart the configuration and try the button again
- Go to the Find Towers button and confirm the towers you had found before are still the best candidates. If there is a better tower there unaccounted for in your original search you are still welcome to try out that tower and frequency and see if it works for detection.
- Choose the tower and it’s accompanying frequency you would like to use and select Save & Continue
Congratulations, if you've made it this far you are all done and your system is now capturing data! Your data will be captured and uploaded to the offworld labs servers and made publicly available each day for anyone to post-process. Here are some other helpful tips to help you monitor your system:
To monitor the system and the data it is picking up:
- Go to the Home dashboard. Once configuration is complete owl.local becomes a small dashboard to work from.
- Click the Passive Radar button for you to see the real time data coming in
- From the Passive Radar screen at the top right you can also click the Controller button to access other data captured so far.
To validate if you are capturing aerial phenomena above you like planes you will need to open up 2 screens side by side:
- Open up the Max-hold map from the controller screens
- Navigate another tab to your home owl.local page and open up the ADS-B Map of your area Confirm that, when a plane flies by at a certain distance, you then see an expected track on the max hold table at the same distance and time
You can always experiment with different Frequencies and this is actually encouraged. The VHF tower 30 miles away may perform worse than an FM station 10 miles away, it all depends on your situation and setup. To compare performance you have two options:
- Compare frequencies and pilot signals you are receiving using SDRconnect mode and manually check different frequencies and gains. Follow the SDRconnect Mode section walk through here
- Use the Validating Your Data method described above to compare different performances and see how far out you can capture real data
All data is made publicly available here: https://dash.retina.fm/ Navigate to the Data Explorer tab on the left and you will see all the data available for that day from every node
We will define a wiki on data, it's format, and how to interpret it in a new page to be linked
If you run into issues with your system or downloading data:
- Troubleshooting steps can be found here
- Or if you still have questions or issues please reach out to info@offworldlabs.com