APRS Tone Alert - What are they?

[Christian Arnaut]

Periodically, while my VR-N7500 is monitoring APRS, the radio will play four tones that increase in tonal frequency. What are these tones indicating?

When these tones are triggered, I am not receiving any direct APRS messages. Nor have I sent any messages and am awaiting an acknowledgment in return. 

I would love to know why these are occurring. Moreover, can they be muted?

[Marnoch Standen]

Don't know what tones your receiving but go to the memory for APRS and change the settings to mute. That will stop you hearing anything audio wise on that channel.

The issue with APRS is that radios use squelch and some don't setup them up to have a preamble to open the squelch on receiving Stations, so the messages can be cut short and miss what has been sent.

Make sure preamble is set to on.

Make sure the APRS channel is fixed in the app and you have turned off the 3 tx I'd tones at the end of a TX which is a feature that few uses. 

Marnoch (Min) Standen

G0JMS 

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[Marnoch Standen]

Further thoughts have you set a shutdown timer to ON in the app.

There is an auto timer that will turn off the radio is not operated like TX for a period of time.

Just  a thought.

Marnoch (Min) Standen

[Christian Arnaut]

To clarify. The audio tones I am hearing are what I would describe as alert tones. Something like 500/700/900/1100 Hz). These are not demodulated RF tones associated with an APRS RF burst. Yes, I already have channel 32 muted (the channel I have configured for APRS). No, I have no shutdown timers configured. 

Interesting. I'll keep digging. 

Christian

N1COW

[Marnoch Standen]

Interesting let us know what you find, nobody on here or FB have said about this before... Good luck.

Min Standen G0JMS

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[Christian Arnaut]

Some more information. Today, I had to drive to site that was about a 40 minute drive. As luck would have it, I did have the radio play the four alert tones. At the time of the alert, I had not sent a beacon (I had pushed that out to 10-minute intervals). But the message that did come at the time the alert played was an APRS Bulletin message. I found the bulletin message also logged on aprs.fi. 

I have another 40 minute drive ahead of me today. I'll continue to monitor and see if my theory is right. 

[Marnoch Standen]

Hi Christian

 

Thanks for the info and looking him up on QRZ he is a busy chap and runs an APRS relay station where he beacons every hour on TCPIP (Not RF) the 2 messages you see. Look into his RAW data.

If he has managed to add an alarm tone its past my knowledge ?

Happy hunting.

 

Min G0JMS

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[Christian Arnaut]

On my return trip today, I had the issue occur two more times and both were bulletin messages. FWIW, I am only monitoring on RF. IGate is disabled.

Also, adding the work 'bulletin' to my search string, I found that this issue was discussed on FB. The issue described in the link below describes the same issue I have. 

VERO VR N76/ Radioddity GA -5WB, BTECH UV-pro owners group | Local ham puts out "weather statements" on APRS | Facebook

[Marnoch Standen]

Looks like you have found the answer...

If the TX station sends out a 500mzh tone it can open the squelch on some radios that have this feature (Kenwood) the station you mentioned is sending messages into the APRS network by TCPIP and other igates will/can TX the message via RF...

Min Standen G0JMS

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