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Host an op

Unlike POTA and SOTA, there are no geographic restrictions for where you can host an op. If you are in a park or on a summit, you can include the POTA reference or the SOTA summit code when you go on the air, and the OTA bot will notice and link your op to those sites.

Other than that informal linking of codes, there is no relationship between APRS OTA and POTA or SOTA.

QSOs you make using the OTA bot will almost certainly be disallowed as contacts for POTA or SOTA, both of which prohibit the use of land-based repeaters.

Prerequisites

In order to host an op you need:

Configuration recommendations

Communicating with the OTA bot requires your APRS messages transmitted via RF to make their way to an iGate, which puts them on the internet-based APRS-IS backbone. The OTA bot then receives your message from APRS-IS. Messages back to you follow the reverse path.

An iGate will typically only broadcast an RF packet to your callsign if it has heard you on RF in the last 30 minutes.

Therefore, while hosting an op, you should configure your APRS beacon to be sent at least every 15 minutes. This will ensure that your local iGate knows you are there and will therefore transmit messages from the OTA bot via RF to your radio.

Point your app at your radio, not the internet

If you use a phone or laptop app to send your APRS messages, check which connection it is using before you go on the air. Most of these apps can talk either to a radio or straight to APRS-IS over your internet connection, and they look exactly the same while you use them. If the app is set to APRS-IS, your radio is not involved at all and the OTA bot will decline your op.

In APRSdroid, this is Preferences, then Connection Preferences, then Connection Protocol. Choose the setting that matches how your radio is attached, such as Bluetooth SPP for a Mobilinkd or similar TNC, rather than APRS-IS. Other apps name it differently, but most of them have the setting somewhere.

You can find out your path to the OTA bot using the PING command.

Plan ahead (optional)

You can announce your op up to 7 days in advance with the PLAN command. Your plan is posted to the website and to the project Discord, where chasers can see what is coming up, and when you go on the air near your planned time, your op takes the plan’s place. Planning is optional: going straight on the air works exactly the same. See Plan an op for the whole flow.

Go on the air

Starting an op is what you do to go on the air. It requires a two-part exchange with the OTA bot:

K7ABC-6OTAHOST op from the track at our high school
OTAK7ABC-6Send a position report within 5 mins to go on the air
K7ABC-64003.25N11131.50W((<>)) aprsota.org/K7ABC-6
OTAK7ABC-6K7ABC-6 is on the air from DN40fb. aprsota.org/K7ABC

HOST is the command that tells the OTA bot you are ready to go on the air. (If you know your Q-codes, QRV, meaning “I am ready”, does the same thing.) You then have 5 minutes to send a position report (aka beacon) of your current location. When the OTA bot notices your beacon it will send you a message telling you that you are now on the air. Your op will be posted to the website in two places, the page showing all ops that are on the air, and to your callsign page. It is also announced in the #on-the-air channel of the project Discord, along with your grid square and whatever description you sent with HOST. That same channel gets a second post with your totals when your op ends.

Anything after HOST is free text describing the op, and it is optional: a bare HOST goes on the air exactly the same way. The description is worth the extra words. It shows on your op’s card on the website and on the QSL card for every contact you make, and it tells a chaser something a grid square cannot.

K7ABC-6OTAHOST lakeshore op, HT and a signal stick

Beacon from the same callsign and SSID that sent the HOST. K7ABC-6 goes on the air by beaconing from K7ABC-6, not from K7ABC or K7ABC-7. An op is run by one station, so a beacon from the digi at home can’t stand in for the radio you are carrying. If the 5 minutes run out, the OTA bot tells you so you can try again:

OTAK7ABC-6No beacon received. Send HOST to try again.

When your op is on the air, you have done the equivalent of calling CQ, meaning you have notified chasers that you are ready to be contacted.

See the full HOST reference for its rate limits and every reply it can send.

You won’t be able to host an op without following rule #3.

If you try to go on the air by sending APRS messages via APRS-IS instead of sending them via RF, the OTA bot will decline your request to go on the air:

K7ABC-6OTAHOST op from the track at our high school
OTAK7ABC-6Must transmit via RF to host. aprsota.org/handbook/host-an-op

If you get that reply while you are sitting in front of a radio you know is transmitting, the usual cause is your app: point it at your radio, not the internet.

Exchanging Messages

As a host, the primary thing you’ll do during your op is make contacts with chasers.

Information about your op

You can do a few things to manage or get info about your op while it’s on the air. You can always see all of this on the website, but the website is a supplement to what you can do with just APRS.

Any position reports you send will be noticed by the OTA bot and plotted on the map of the op along with the locations of all the chasers you QSO with.

Send a message to the OTA bot containing “TIME” and receive a message back telling you how much time remains before your op goes off the air automatically (see below). If you know your Q-codes, QRT? does the same thing: QRT means “stop sending”, and followed by a question mark it means “shall I stop sending?”. The traditional meaning of the Q-code is not an exact fit for what the command does, but if you squint it’s close enough.

K7ABC-6OTATIME
OTAK7ABC-6Off the air in 35 minutes, max 95 minutes. STAY adds 30 mins

Read that as three facts about the same op. You go off the air in 35 minutes unless something extends you. The maximum is 95 minutes away, which is the 2 hour ceiling no op can pass. And STAY would move the first number by 30 minutes, to 65, still short of the ceiling.

The last part only appears while there is room to use it, and it always quotes what a STAY would really add. Near the end of a long op that is less than 30:

K7ABC-6OTATIME
OTAK7ABC-6Off the air in 9 minutes, max 25 minutes. STAY adds 16 mins

Here a STAY buys 16 minutes rather than 30, because 16 is all the room there is between going off the air and the maximum. Once those first two numbers are the same you are at the maximum, and the offer stops appearing because there is nothing left to add.

See the TIME reference for its rate limit.

You can also ask how many chasers are calling you, how many QSOs you have completed, your score so far, and the countdown timer. Send it from the station running your op.

K7ABC-6OTAINFO
OTAK7ABC-63 chasing, 12 QSOs, 11 pts, off in 22 min

See the INFO reference for its rate limit.

Talking to everyone on the op

Your chasers are not in a group chat. If the weather turns or you are moving to another summit, you can let everyone know by sending a BLAST. One message from you reaches everyone on your op, including the chasers still waiting on a QSL from you.

K7ABC-6OTABLAST moving to the north summit
OTAW1XYZ-5BLAST K7ABC-6: moving to the north summit

Chasers can also send a blast.

Finishing your op

Ops are time limited by a simple algorithm described below. You can end your op at any time by:

K7ABC-6OTADONE gotta go thx all 73
OTAK7ABC-6Op complete: 12 QSOs, 11 pts. aprsota.org/K7ABC

The reply is the end-of-op summary: how many QSOs you made, your score, and any chasers still waiting on a QSL when the op ended. You get the same summary if your op ends on a timer instead of a DONE.

DONE ends your op. (If you know your Q-codes, QRT, meaning “stop sending”, does the same thing.) See the DONE reference for the details.

An op will remain on the air:

This means that if the host doesn’t send a DONE:

The countdown timer for automatic ending of the op is shown on the website, and the method of ending the op will also be shown, meaning if it times out or if the host sends a DONE.

If nobody has come back to you, or the pileup has gone quiet but you want to keep going, send STAY and the OTA bot adds 30 minutes:

K7ABC-6OTASTAY
OTAK7ABC-6Staying on the air. Off the air in 34 minutes, max 55 minutes

It works whether or not you have completed any QSOs, and you can send it more than once. What it cannot do is get you past the 120 minute maximum, so in practice that is room for two extensions.

If your op goes off the air because you hit the 120 minute max time limit, you can always start another op and keep going.