NXDN Basics (What the SDS100 Needs)
NXDN is a digital voice format used by many businesses and industrial systems. For the SDS100, there are two common cases:
- NXDN One-Frequency (conventional): You program a single frequency and listen to traffic on it.
- NXDN Trunked: You program a site (multiple frequencies) and the scanner follows conversations across channels.
- Confirm NXDN upgrade is enabled: MENU → Settings → Upgrade (NXDN should show enabled).
- Confirm whether your target system is one-frequency or trunked (wrong system type is a common setup failure).
Step-by-Step: NXDN One-Frequency (Upgrade Required)
You need: one frequency. If known, RAN and Talkgroup IDs can refine what you hear, but you can often start without them and let the scanner display them during active traffic.
- Create a Favorites List (if needed): MENU → Manage Favorites → New Favorites List.
- New system: Open that Favorites List → Review/Edit System → New System → NXDN One Frequency.
- Department: Edit Department → New Department (name it).
- Channel: Edit Channel → New Channel → enter the frequency.
- Scan and observe: Start scanning and watch the display for NXDN parameters (RAN / TGID) when traffic appears.
- Refine: Once you know the talkgroups you want, avoid the noise and name items cleanly.
If you see traffic but it’s silent, jump to troubleshooting below—encryption is common on some systems.
Step-by-Step: NXDN Trunked (Upgrade Required)
You need: the correct trunking type, site frequencies, and LCNs for the site you can receive.
- Get the system details: Use RadioReference to collect site frequencies and LCNs for your nearest site.
- Create a Favorites List and then New System → choose the NXDN trunk system type offered by the SDS100.
- Add a site and enter all site frequencies.
- Enter LCNs for each frequency. This mapping is required for proper tracking.
- Validate with traffic: Start scanning; if it won’t follow conversations, re-check the LCN mapping first.
- LCN Finder (if available): If you don’t have LCNs, use LCN Finder where supported during active traffic to determine mapping.
Sentinel vs Manual: Which is Better for NXDN?
- Sentinel (recommended): Fastest way to pull correct system/site data from the database, then write clean Favorites Lists.
- Manual (on-radio): Great for quick one-frequency NXDN in the field, or small edits after you’ve built the list in Sentinel.
If you’re using a PC, start with the Sentinel guide, then come back here for NXDN-specific details.
Troubleshooting: NXDN “No Audio” and Other Common Issues
- Encryption: If the talkgroup is encrypted, you may see activity but you won’t hear intelligible audio.
- Wrong system type: Make sure you didn’t program a trunked system as one-frequency (or vice versa).
- LCNs: For trunked systems, incorrect or missing LCNs prevent proper following.
- What’s enabled: Check Quick Keys, Avoids, and that the Favorites List/System/Department is enabled to scan.
- Signal quality: NXDN needs a clean signal. If decode is broken, try a small move or better antenna placement.
Frequently Asked Questions
Does the SDS100 need the NXDN upgrade to listen to NXDN?
Yes. The Uniden SDS100 requires the optional NXDN upgrade key to decode NXDN (including conventional NXDN and NXDN trunked systems).
What information do I need to program NXDN one-frequency on an SDS100?
At minimum, you need the frequency. If known, RAN and Talkgroup ID help you narrow what you hear. If you don’t know them, you can often start with a basic setup and let the scanner display NXDN parameters when traffic is active.
Why won’t my SDS100 follow NXDN trunked conversations?
The most common cause is incorrect LCN mapping or incomplete site frequencies. NXDN trunking requires correct Logical Channel Numbers (LCNs) for the site you receive. Verify the site frequencies/LCNs and use LCN Finder where supported.
I see NXDN activity but hear no audio—what’s the usual reason?
Common causes are encryption on that talkgroup, wrong system type (trunked vs one-frequency), wrong site or LCNs, or the scanner isn’t set to scan the right items (Quick Keys/Service Types/Avoids).
Can the SDS100 monitor encrypted NXDN talkgroups?
No. If an NXDN talkgroup is encrypted, the SDS100 will not decode intelligible audio. You may see activity, but you won’t hear clear voice.