Trunking Call-Flow
Key up a radio and watch the signaling move: affiliation, control-channel request, channel grant, talk path, teardown. Starve the channel pool and see queuing and busy behavior under load.
Core Architecture
A clickable map of the ASTRO 25 core: Zone Controller, UEM/UCS, KMF, gateways, RF site, and dispatch. Tap any element for its role and model family, plus the K/L/M core scaling tiers.
Field Technician Bench
Sweep an antenna and feedline against the −14 dB limit, then find the fault by distance. Plus R56 grounding, the measurements that matter, and the instruments you'll carry.
Fault-Injection Trainer
A fault hits the system; symptoms report in from users and dispatch. Read the pattern, commit to a diagnosis — failsoft, site trunking, a dead console, or RF — and check your reasoning against the answer.
Follow the Packet
Build a packet, then move it across site → core yourself — predicting at each device which layer it reads. A guided, step-by-step intro to encapsulation and routing, with QoS as its own follow-on lesson.
Radio or Network?
Trouble tickets that all sound like "my radio's broken." Gather clues, climb the OSI ladder, and isolate the layer the fault actually lives at — the instinct every field engineer earns the hard way.
The Transport Network
Click through the LAN-at-a-site, the WAN backhaul, and the gateways at each end — and flip on "show redundancy" to see the doubled-everything design that defines a mission-critical network. The architecture behind the trainers.
Roaming the System
Drag a subscriber across a multi-site coverage map and watch it automatically re-register on the strongest control channel — seamless within an RFSS, a SIP handshake across the ISSI to a foreign one. Flip on "island site" to see roaming fail when a site loses the core.
Simulcast & Voting
Talk-out: slide the transmitter timing and watch the overlap zone go from clean to distorted as sites fall out of GPS sync. Talk-in: adjust receiver quality and watch the comparator vote the best copy, packet by packet, as multipath fades the winner.
Encryption, KMF & OTAR
Trace a key through its life — generated in the KMF, loaded by KVL, kept current over the air with OTAR. Then rekey a fleet and watch who misses it: the powered-off radio, the stale one. The real vocabulary (TEK, KEK, CKR) and the fix for that garbled-audio fault.
The Capstone
The final trainer. Ambiguous faults that span RF, transport, call processing, simulcast, and encryption — where the first symptom misleads and two subsystems look guilty at once. Gather evidence across the whole system, then commit. One scenario hides two faults.
The Codeplug
Tap through a radio's codeplug field by field — Unit ID, talkgroups, NAC, control channels, the failsoft frequency — and learn what each one is and the exact symptom you get when it's wrong. Demystifies the CPS screen before you ever open it.
Inside the RF Site
A whole ASTRO 25 RF site lives in one rack. Tap the modules — base radios, site controller, combiner, multicoupler, voting receivers — to learn each one, and flip on redundancy to see the no-single-point-of-failure design that replaced the old QUANTAR stations.