DM4401 on post and control room: base antenna, power supply, speakerphone
The DM4401 is not only put in the car: it turns into a full-fledged stationary station of a security post or control room. The same power is 25-45 W, but with a mast antenna and stationary power supply - and the coverage area is much wider than the car.
Antenna: baseline to mast
For a stationary post, take a basic antenna - for example, BC-100 (VHF only, just the range of station 136-174 MHz). It is raised on the mast or wall of a building: height here decides more than power. In the DM-series, the BNC connector - the adapter for the antenna cable is laid immediately.
Power supply: not from the socket "as it happens"
The station operates from the network via power supply of 13.8 V with a current reserve: the configuration 45 W on the transmission consumes a lot, so the cable is taken to 20 A (HKN4191), as in the car. The duty post is useful reserve: when the network disappears, the station connected to the battery continues to keep in touch.
Speaking and pedaling
Through the PMLN5072 set, an external speaker, ignition (in the car) and a pedal are connected to the rear 26-pin connector - the dispatcher responds without removing the tangent. At the post, this is the usual “loud communication” mode: the conversation is heard by the whole room, the answer is by pressing the pedal.
Dispatch: what the number gives
In digital DMR mode, the dispatcher sees the GPS coordinates of the machines (GPS is built into the DM4401), calls subscribers individually and in a group, and sends text messages. The analogue channel is reserved for the old park, such as the handheld GP340. If there are several jobs, the network increases repeater – technical guide Repeater DR3000: its own tower.
Frequent questions about the post
Is there enough power 45 W for the village? In most cases, yes, but the area is decided by the height of the antenna: the base antenna is raised on the mast, and not put on the window sill.
Is it possible to power the post from the 24V board? It is possible, through a lowering converter 24 → 13.8 V with a current reserve - the station in the transmission consumes a lot.
What do you need for a speakerphone on the post? PMLN5072: external speaker and pedal are connected to the rear connector, the dispatcher works without a hand microphone.
Will the dispatcher see the car on the map? Yes: the DM4401 has built-in GPS, digitally transmitting coordinates to the control room.
