Flight Test Radio Protocol

Owned by Daniel Puratich
Last updated: 2023-03-25
4 min read

The Spirit

WARG at flight tests is beginning to leverage simple license free band walkie talkie radios for communication beyond yelling distance. This is needed as pilots operate the aircraft from a distance and visual observers are used as the drone is operated further from pilots. In the flight tests of the W23 leading up to competition 2023 in May we have discovered a need to clarify communication standards as many members handling radios do not have relevant experience in this area.

This document is to help standardize things and is adapted from mariner & pilot experience of WARG members. Please do not edit this document without discussion with Team Leads in Discord.

 

The Law

  • Avoid radio use when possible

    • If it is easier to talk loudly than use the radio simply talk loudly as it is much easier

    • Also easier to communicate with multiple people by talking loudly

    • Radios are preferred over phones at distance however due to convenience

  • Ensure radio operation is understood from a basic perspective before giving a radio to a member

    • Radios can relatively easily be misused so we should ensure members know how to operate the radio we hand them.

    • Accidental button presses (notably “open/hot mic”) faults are annoying, please avoid

    • Ensure radios are properly setup as well before testing at great distance

      • Preferably use fancy earpieces for improved clarity as well

    • Ensure “operators” are aware radios are half-duplex

      • You cannot transmit and receive at the same time

    • It is important when speaking to talk directly into the microphone and to speak loudly especially in the often windy conditions we endure at flight tests

    • Microphone button needs to be held down hard in order for it to fully register! Halfway pressing the button will result in unintelligible transmissions.

  • Keep transmissions short

    • Sometimes transmissions cutout partially which makes it tough to communicate which portion needs to be repeated

    • 15 seconds and below is preferred

    • Simply perform multiple shorter transmissions, allowing your recipient to acknowledge or ask you to repeat for each increment

  • Start conversation by stating the first name of who you want to talk to and then your first name

    • This should be a very quick opening that is simple and easy!

    • Point of discussion: Inclusion of the phrase “this is” between the names and use of “over”

      • Dhruv: wants E.g. Dhruv: “Daniel this is Dhruv, over”, Daniel: “Dhruv this is Daniel, go ahead, over”

      • Daniel: it’s unneeded extra words, keep it simple eg “Dhruv, Daniel, …” This phrase is included in some standards I was able to find. These extra words make sense when you are communicating with unknown names, however, because there are four of us using the radios at most it seems sensical to save on words.

      • Ryan: Alternatively, source to destination (e.g. “Earth to Moon, [message]”)

    • Exception if people have the same name or otherwise is to implement last names

    • This makes things very clear who you are talking too and who you want to acknowledge your communications

    • Avoid general announcements when possible

      • Generally very few people (4 or less) at the flight line will have a radio so general announcements are useless anyways

      • In the rare case of a general announcement use a general term for who you are talking for such as “all”.

        • Point of discussion: (require this to be prefaced with “WARG”)

          • Daniel: I think this isn’t necessary because we will be the only people on this channel. It’s not like we’re making an SOS call or something like nobody’s gonna misinterpret it that isn’t in WARG even if they cop our transmission. It’s extra words.

          • Dhruv: Awaitting perspective

  • A conversation ends when a final transmission is acknowledged and there is no further discussion, at this point anyone can start a new conversation

    • Point of discussion: (Optional or Require) End of conversation marked with “Out” (and acknowledgement after that ?)

  • Acknowledge all transmissions oriented toward you

    • This can be done by replying with a transmission verbally or by simply tapping the microphone button twice (as this makes an audible tone on the radio)

      • A reply can be something simple like “affirmative” or a longer transmission with a message to keep a conversation going. This type of reply replaces the double tap though the double tap is often prefferred because it is very quick and easy.

      • Point of discussion: Double tap feels like it can get screwed up (e.g. someone is trying to talk but is not transmitting any voice).

    • This indicates you heard the transmission to any sender

      • Even if you don’t have anything to say it is important to acknowledge the transmission so the sender knows their message was understood.

    • If you heard, but did not understand the transmission state “say again”

      • In poor connection qualities hold your radio higher in the air and repeat yourself as well as avoid standing behind obstacles (create LOS if possible)

  • If your transmission is not acknowledged assume it was not received

  • When initially setting up radios or after an operator has moved their radio a considerable distance considering performing a radio check

    • This can be done by stating “[Conversation Start (communicating who you are and who you want to radio check with)], Radio/Signal Check”. The reply should be “Reading you strength [number from 1-5, 1 is barely intelligible, 3 is okay, and 5 is excellent]”. If a reply is heard be sure you acknowledge it.

  • If you hear a transmission not for you not being acknowledge multiple times you can attempt to relay a message between parties.

    • This situation has not occurred and therefore hasn’t been documented well yet. Apply common sense.

    • This specifically applies if one or both of the transmissions you hear are of poor quality

  • Channel conflict case

    • We haven’t had this yet so it also hasn’t been discussed, but if another party (non-WARG-ians) are using the same channel we decide to pick we probably need to a protocol for one of us handling arbitration and channel hopping.

  • Do not use naughty words

    • Assume all transmissions are public and everyone is listening (because they are)

 

Inspiration