Need Major Help

[cbrrider06]

I need major help. I have a nx-800. When I program this unit it will not decode digital transmissions. All I want the radio to do is monitor. I input the freq. select nxdn as type and so forth. write the info to the radio, everything goes good but it will not decode any help will be helpful. Also what I am listening to is not a trunking system.

[jhampton2000]

So a few obvious questions to check out first:

- Can you program your NX800 to decode other analogue channels ok?

- You say digital: Are you 100% certain that what you're trying to listen to is NXDN?

- Is it Narrow NXDN (12.5Khz) or Very Narrow (6.25kHz)?

- Have you selected a specific RAN decode channel for the frequency?

- Have you added a specific GID for the zone?

Jim

[cbrrider06]

Thanks for the quick reply. Here are some answers to your questions. Analogue channels work perfectly. Yes it is nxdn ( there was a article in the local paper about it). the 12.5 and 6.25 tried it both ways. As far as the RAN i have no idea i selected none, is that a specific issue

[fireandems13669]

it may be encrypted in which case you will be unable to decode.

[jhampton2000]

So it sounds like you have the settings I would have expected to set....if you set RAN to none it should receive all NXDN signals on that channel irrespective of the RAN used (so a bit like Carrier squelch on a frequency carrying one of more PL tones).

I have no idea what happens if you listen to an encrypted NXDN channel without any encryption set on the receiver.....I expected it to unmute but with 'scrambled' voice....maybe I'm wrong.

Perhaps fireandems13669 can confirm if the receiver perhaps remains muted unless the correct encryption key is set on an encrypted freq, or perhaps he can say what happens if the receiver is set with encryption on but with the wrong key - does that unmute at all (and the voice sounds garbled maybe?)?

Jim

[cbrrider06]

It sounds similar to P25 undecoded.

[jhampton2000]

>It sounds similar to P25 undecoded.
Sorry, I'm not quite sure what you mean by this....

There are some raw samples of common digital formats here:

For NXDN 6.25 (which sounds like a train going through a tunnel) and 12.5 (sounds like a vehicle engine running)
NXDN_multi.mp3 - Download free. Direct Link - General Files

For P25 - note the 'tail' on the transmission
Info about file NXDN_multi.mp3 - General Files

For DMR (MotoTRBO) - similar t P25 but different 'tail'
Info about file NXDN_multi.mp3 - General Files

I haven't (yet) tried listening to say a TRBO channel using a NXDN radio before...I assume it sounds just like listening to one of these raw samples on an analogue scanner.

Jim

[cbrrider06]

In listening to your samples what I am hearing sounds like 12.5 nxdn.

[cbrrider06]

If anyone could possibly take some screen shots of what the info should look like in programming mode.

[ramal121]

If a NX radio transmits with encryption and the receiving radio has the correct RAN but no (or wrong) encryption key then yes the speaker will unmute and only digital garbage will be heard. I believe if the receive RAN is set to "none" (or the monitor button is pushed) you'll still hear just digital hash. If the bandwidth is different the speaker will never unmute for anything (different baud between 6.25/12.5).

[fireandems13669]

Must be different radios do different things. The Kenwoods I have used Mute the encrypted traffic if the proper key is not there. Regardless if they have the proper ran code .

[jhampton2000]

So I'm still a bit stuck with this. I must admit I'm still not clear on exactly what you're hearing via the speaker on your NX800.....digital garbage, a P25-like signal or nothing at all?

Can you upload an audio sample of exactly what you hear via your speaker and also what the raw signal sounds like via a scanner?

[maxkelley]

The Kenwoods have an option under encryption to select whether you want to hear the garbles from receiving an encrypted signal or not.

[fireandems13669]

IDK if you mean the Kenwood P25. But in the NXDN Software under Encryption you do not have that option.
Radio will show that that a transmission is taking place with the green light on but it is muted.

[mmckenna]

Originally Posted by fireandems13669

IDK if you mean the Kenwood P25. But in the NXDN Software under Encryption you do not have that option.
Radio will show that that a transmission is taking place with the green light on but it is muted.

MaxKelly is correct. The 2.83 firmware we are running on our NexEdge radios has a muting option. I don't have the software in front of me, but as he said, you can program it to mute encrypted traffic if you don't have the right key, or unmute for all traffic, even encrypted traffic that you don't have the key for. Not sure why you'd want this, but it is an option.

[fireandems13669]

In newer firmware that option doesnt appear

[mmckenna]

Which firmware are you running?