FAQ for the Burning Man 2009 "Papa Legba" Test Network


  • Who is doing this? This is an activity of the OpenBTS project. The entity legally responsible for the test is Kestrel Signal Processing, Inc.. The actual on-site engineers are David Burgess and Harvind Samra.
  • Is this legal? Yes. We have an experimental license, WD9XSP, and a consent letter from Verizon authorizing us to operate in their KNKN224 block A cellular spectrum. We are also coordinating operations with Commnet Wireless to prevent interference.
  • How much does the service cost me? Nothing.
  • What do you do for emergency calls? Nothing. We are an experimental service and do not support emergency calls.
  • Where is your camp? We are Papa Legba, placed at 4:30 & H. Look for the WD9XSP tower. Drop by for a sticker and a tour.

Black Rock City, LLC

  • Does BM-Org know about you? Sorta. The technical side of the organization is supportive and coordinating network service for our backhaul. Other parts of the organization are still finding out about us.

Commnet Wireless

  • Are those your trucks and towers at Frog Pond and in Gerlach? No. That's Commnet Wireless, a commercial cellular carrier who is providing cellular service at Burning Man this year.
  • Are you going to interfere with each other? No. Commnet will be operating in the block B spectrum under license KNKN225. We will be in block A. We have exchanged contact information to resolve any unforeseen problems on-site.
  • What is you relationship to Commnet? None. Please do not get us confused.


Service Capabilities

Papa Legba's primary service is on-Playa text messaging, the delivery of text messages between handsets within BRC. We will also have limited support for speech service.
  • Can I call the "real world"? If you do get full speech service, you will indeed be able to call out of BRC.
  • Can the "real world" call me? If you have speech service, you will be able to receive inbound calls from VoIP carriers through the +883 iNum country code.
  • Can I use my own VoIP PBX to route calls to my cellphone while I'm at Burning Man? Yes, as soon as we know our public IP address.
  • Can I text the "real world"? You can send text to many internet-based IM services, like Gizmo or Skype. You can also send text to e-mail addresses.
  • Can the "real world" text me? You can receive text from many internet-based IM services, but probably not from cellular carriers.

Using My Phone

  • Will my phone work with the Papa Legba network? All current-market phones that work with AT&T or T-Mobile will also work with Papa Legba, even if they are locked. You can use your existing SIM, too.
  • How will you know my phone number? You will tell Papa Legba via SMS. When your handset first contacts the network, you will receive a text message asking you to respond with your 10-digit phone number. If that process is successful, you will receive another message informing you that you have been provisioned in the network. That's it.
  • My phone shows service but I can't make a call. Why not? Only the first few hundred subscribers will get full speech service. Everyone else will just get SMS. There are two good reasons for this:
    1. We don't have enough equipment for everyone to get normal speech service.
    1. Widespread speech service would change the nature of BRC in ways a lot of people would not like.
  • How do I know my phone is on your network? You will see a network ID of "001 01", "Test" or "PpaLgba", depending on your handset brand and model.
  • How can I force my phone to use one network or the other? That depends on your phone model. We are still working on a collection of instructions:
  • Will my carrier charge me for every text message I send or receive on the Papa Legba network? No, the Papa Legba network is a separate isolated network from your normal carrier's network, and no charges will apply as no SMS is being sent or received through your normal carrier.
  • Will putting a Papa Legba sticker on my phone make it work better? Probably.


  • What band and technology are you using? GSM850.
  • What are your specific frequencies and powers? Our frequencies will be 870-880 MHz downlink and 825-835 MHz uplink. We will operate our downlink at 20 W EIRP. In the uplink, the typical GSM handset has a maximum power of 1 W, although we will use closed link power control to minimize handset power to the greatest degree possible.
  • What RF equipment are you using? See OpenBTSBM2009RF.
  • What network software do you use? We use Asterisk for our speech PBX and provisioning functions. We use a custom server for SMS. All interfaces are based on SIP/RTP. The GSM stack itself is OpenBTS.
  • What is your GSM configuration? We will operate 3 or 4 BTS units. Each will be a single ARFCN. Each will be configured with channel combinations V, 3xVII, 4xI. That will give each BTS unit 4 speech channels and the ability to transfer 300-400 text messages per minute.


  • Why "Papa Legba"? Papa Legba is a voodoo deity who mediates human contact with the spirit world. Like Papa Legba, our radio equipment stands at a crossroads between seen and unseen worlds.
  • How much did this cost? The BOM cost for the full system is about $16k. We have sponsors, though:
    • Martin Pelayo is providing our 70' tower.
    • John Gilmore funded part of the development of our SMS air interface and actually wrote the SMS server himself.
    • Voxbone is providing funding and most of our VoIP connectivity.

PapaLegbaSticker.jpg (160.9 KB) David Burgess, 09/17/2009 05:42 PM

注:FAQ for the Burning Man 2009 "Papa Legba" Test Network(原文出处,翻译整理仅供参考!)