What is the Adventure Radio Protocol?

This morning, Ron (W6AZ), sent me a link to a Ham Radio Crash Course live stream where Josh (KI6NAZ) interviewed my good friend George (KJ6VU) about his proposal for a new Adventure Radio Protocol.

We covered the Adventure Radio Protocol in Ham Radio Workbench episode 191 and I think it’s a brilliant step forward to make emergency communications via VHF/UHF portable radios easier, clearer and attract more attention. It also leverages CTCSS tones which are a standard feature even on the least expensive HTs on the market (and has been for decades).

George explains, in detail, what the protocol is and how it works on his dedicated website AdventureRadio.info. Here’s an excerpt from the front page:

Adventure Radio Protocol

By George Zafiropoulos KJ6VU

The Adventure Radio Protocol provides a common radio frequency and signaling standard to make it easier for radio operators in the field to find and communicate with each other.  The signaling protocol that uses CTCSS sub audible tones allows operators to signal the type of traffic on the adventure radio frequency and enable 24/7 monitoring without the need to listen to all traffic on the channel.


We propose to use 146.580 MHz FM for the nationwide US adventure radio frequency.  This frequency is chosen because it is already in use in various regions of the US for hiking, backpacking, SOTA, overlanding and other outdoors activities.  We also want to avoid using 146.520 to remove outdoor activity traffic from the national calling frequency.


CTCSS sub-audible tones are used to signal the type of traffic on the adventure radio frequency.  The following CTCSS tones are assigned for various types of traffic.  The Adventure Radio Protocol reserves all CTCSS tones between 67.0 Hz and 151.4 Hz to be assigned over time for various purposes.  Radio operators can use any CTCSS frequency above 151.4 Hz for any purpose and are not governed by the AR protocol.

    • 67.0 Hz   Emergency calling.
    • 77.0 Hz  Ping – Keying up will cause any automated monitoring station to respond to let you know there is a system on the air.
    • 88.5 Hz   SOTA/POTA and other operating events.
    • 100.0 HZ   General backcountry conversations.
    • 123.0 Hz   Trigger automated messaging from local repeaters.

Click here to gather all of the details on AdventureRadio.info.

I highly encourage you to check out the Adventure Radio Protocol and make your local club aware that it’s coming down the pipeline as this functionality will need to be added to repeater controllers to broaden the reach.

This protocol has the potential to make emergency communications via handheld VHF/UHF radios so much more effective and automated than it is today!

For more detail check out these episodes:

HRCC Livestream (Yesterday)

Click here to view on YouTube.

Ham Radio Workbench Episode 191 (October 3, 2023)

Click here to read all of the show notes and listen at the HRWB website.

16 thoughts on “What is the Adventure Radio Protocol?”

  1. I don’t know how well that will go over in this area, Kingman, AZ, as 146.58 has been the local simplex frequency for decades. That may also be the issue in other areas as well. To just blanket say, we’re proposing this frequency because its being used for X,Y,Z in some areas could be problematic. I think it would be better to suggest frequencies based on the area you are planning to be in.

  2. Watched this last night and was absolutely mesmerized by the creativity of this initiative! It’s brilliant! George had an answer for every one of Josh’s questions. It’ll make POTA, SOTA, emergency coms, hiking, backpacking, etc significantly safer and could add a Radio dimension to many new activities. We as Hams are indebted to those with these extraordinary ideas. As Josh mentioned, it will be up to us, though, to test and implement this protocol on our own radios. So let’s get going.

      1. Check out the Ham Radio Workbench episode in this post. George explains that this new protocol builds on the wilderness protocol and doesn’t rely on only certain times of the day to call and potentially be heard–where the person calling and the person receiving must be on the air at the same time and be heard by one another. This one actually uses sub-audible tones to trigger automation from local repeaters. For example, to trigger an email alert for locals to tune to the repeater and listen for a message, etc. It basically attracts much more attention.

  3. I regularly use 146.58 along with five other simplex frequencies to manage road rallies. I need to assign frequencies on nearby stages as far from each other to reduce desensing from nearby transmitters. The advent of digital comms on 146.42-50 and 147.42-48 simplex channels have already severely limited my options; removing 146.58 is not an option. I need this channel!

  4. I’m new to the hobby but the photo for this article caught my eye, I own an FT-60 but I’m not aware of any built-in mode or feature for SOTA that would put ‘SOTA’ on the display like it is in that photo. Does anyone know what the deal is there?

    1. Hi, Jacob, That’s just my name for the stored frequency. That’s a simplex frequency SOTA activators tend to use, so I labeled that frequency memory as “SOTA.”

    2. He probably labeled 146.580 in memory as SOTA. Should be listed in manual as alpha-numeric labels, or something to that effect. It’s a handy deal to program your radio, esp if you have a lot of memories programmed. Easier to manage, rather than remember all the freq of the memories.

  5. @Lee Chambers / how can we learn more about your road rallies and simplex frequency use? You struck my curiosity

  6. I get the intent here, and overall think it’s a good idea. However, there is so little VHF/UHF activity in my area that the best bets would be 146.52 and the local SARNET-FL repeater. Anything else stands a < 1% chance of being heard.

    I do really, really like the idea of 67 Hz CTSS tone for emergency calls though, regardless of the RF frequency. Being able to leave on an HT with that tone set and then not hearing any other calls has a lot of appeal for people who sleep, hunt, or do anything else where you don't want to be disturbed but are OK with getting the occasional emergency call. It's a good half-step between "actively listening" and "power off."

  7. I know I’m behind the 8 ball here, but is CTCSS based squelch a common feature on the receive side for HT’s and mobiles? As far as I know, the Yaesu FT5D doesn’t support that, and it’s quite full featured.

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