OpComms Test Procedure

What follows is a complete set of instructions for completing a long-distance test (of any length) with the current Optical Communications transmitter/receiver node system.

Decide to Test

Step 1: Check the weather for the two test sites and make a fog prediction. Using the Automated Packet Reporting System check station KG6UWN for fog-forming factors upwind of Skyline: temperature and dew point within 5 degrees of each other, high humidity, and unfavorable wind direction (i.e. towards Skyline). Also check station EW4825 for the current conditions close to Skyline.
Optional: Check for METAR reports at local airports: KHAF, KMRY, KSNS, and KWVI.
Step 2: If Step 1 returns favorable results, book two Zipcars for an appropriate time window. Testing will usually run from 7pm until midnight, but allow room for a later return as you likely will not have cell reception at Skyline.

Get Organized

Before heading out to test, ensure that you have the following pieces of equipment:
1) Transmit/receive node. Ensure that the laser, photodetector, control board, and BNC connection between sensor and board are all present.
2) Tripod. Make sure the tripod matches the node you have chosen. The Rosencrantz tripod has a round plate with a hole in the center; the Guildenstern tripod has a large tri-lobed plate that is continuous.
3) Laptop. Ensure your code is up to date by pulling from the opcomms and opcomms-embedded Github repositories.
4) Keysight oscilloscope. Have Sasha or Elizabeth unlock an oscilloscope from the toolbox. Guard it with your life.
5) Test bin. Must contain toolbox, extension cords, power supplies, and motorized alt/az mount. Use a dry-erase marker to complete the Test Checklist posted on the lid of the bin. If all of the contents are present you may proceed
6) Radios. Each group will need one Baofeng transceiver, to be used by a licensed amateur radio operator. These radios live on the left side of the shelves above the EE workbench in MC and should be on their chargers when not in use. Tune both radios to a quiet radio frequency (good range: 445.000-447.000, try 446.200) and test communications down the hallway. While driving to your test locations, remember to periodically check in with the other group to confirm that the connection is good. 6) Headlamps. If you're testing over 10km (Skyline Boulevard and W6YX), you'll need a headlamp or flashlight for each group. There are 2 flashlights that live on the side of the toolchest in MC.

Set Up

Step 1: Set up tripod on a piece of level ground. Attempt to identify the approximate location of the communicating node and ensure you have a clear line of sight in that direction.
Step 2: Find a source of AC power and run an extension cord to your test site. Verify you have at least 2 outlets available, using a power strip if necessary.
Step 3: Attach motorized alt/az mount. Use the attached mounting hardware to screw through the tripod plate and into the bottom of the mount. Ensure that the mount is solidly attached. If you are using the Guildenstern tripod, make sure that all three feet on the base of the mount are in contact with the surface of the tripod plate (if not, rotate).
Step 4: Find the leather battery purse and plug it into the mount. Verify that all batteries (AA) are present and replace if missing. Hang or support the purse somewhere on the tripod. Step 5: Attach the transmit/receive node to the mount by sliding the black plastic adapter on the node into the mount's slot. Make sure that the angled and flat faces are oriented correctly and that the adapter block slides fully into the slot. Tighten the set screw on the mount, ensuring a firm connection (although do not overtighten, as the screw is bearing on plastic).
Step 6: Find the modular cable (phone jack) in the yellow toolbox and connect it between the mount and the control board.
Step 7: Find the photodetector's power supply in the test bin (2 parts: one large block that plugs into AC + one 3-pin cable that connects to the block). Plug one side into AC. Plug the other side into the unoccupied port on the sensor, by first aligning the pins, pressing firmly, and screwing down the retaining collar. Make sure the switch on the power supply block is switched on, and verify that the sensor has power (check for green light between power and BNC ports on the top face of the sensor).
Step 8: Set up and plug in the Keysight oscilloscope. The power cable can be found in the side pouch inside the main compartment of the Keysight case. Toggle the power switch to start the boot sequence. Find the BNC cable in the yellow toolbox and connect the downward-facing BNC port on the control board to Source 1 on the oscilloscope. Adjust the vertical scaling to 20mV/division and the horizontal scaling to 10us/division.
Step 9: Find the microUSB cable in the yellow toolbox and connect the control board to a USB port on your computer. Open Arduino and connect to the board (Teensy 3.1), ensuring that a serial port appears in the Tools menu. Upload the code to the board and open the serial monitor when this is complete.
Step 10: Remove the lens cap from the node and ensure that the switch cover on the laser is flipped such that the button is continuously depressed.
Step 11: Straighten up the area. Close the toolbox and store it in the test bin. Place the test bin and oscilloscope case underneath of the tripod.

You're done! Let's test!

Pack Up

In general, store cables wrapped and secured with twist ties. Any component with a labeled place in the toolbox should return there.

Step 1: Place the lens cap on the transmit/receive node and ensure the clips lock it into place.
Step 2: Turn off oscilloscope and unplug it. Pack the BNC Cable back into the yellow toolbox. Disconnect the power cable from the oscilloscope and pack it into the side pouch in the Keysight case. Snap the front cover onto the oscilloscope and zip it and the side pouch inside the carrying case.
Step 3: Disconnect your computer and store the MicroUSB cable in the yellow toolbox.
Step 4: Switch off and disconnect the photodetector's power supply. Store in the test bin.
Step 5: Disconnect the modular cable (phone jack) and store in the yellow toolbox.
Step 6: Disconnect the mount's battery purse and store in the test bin.
Step 7: Hold the transmit/receive node firmly and loosen the set screw to remove from the mount. Leave the sensor BNC cable and laser power wires connected.
Step 8: Unscrew the motorized mount from the tripod plate. Make sure to screw the mounting hardware back onto the bottom of the mount for storage. Store in the test bin.
Step 9: Collapse tripod.
Step 10: Check the area for forgotten components. Ensure you have the test bin (with toolbox), transmit/receive node, laptop, oscilloscope, and tripod.

Head home. If you're driving back from Skyline Boulevard, you probably want to stop at Secret Safeway and get some ice cream :)

At Home

Step 1: Store test bins, tripod, and transmit/receive nodes on the shelves above the EE benches in MC.
Step 2: Ask Sasha or Elizabeth to lock the oscilloscopes to the toolchest.
Step 3: Return radio transceivers to their chargers.
Step 4: Upload your photos and data to Google Drive, in a folder with today's date and the test location.

You'll also probably want to debrief to interpret test results and figure out next steps. If the test was significant, write a blog post about it.