Hello, can someone explain to me which radio masts the analog fire alarm system uses?
In Bavaria, many, if not most, fire departments have digital radio, but alarms are still sent using analogue technology. How does this work if the digital radio masts/base stations aren't even analogue?
Where does the detector receive the signal from or from which source are the signals sent to the radio receivers when an alarm occurs?
LG
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Funny, with us in BW it’s as much different as possible: alarming has been digital for a long time, but radio is still analogue in the 4-meter band. The “Florentine” for the 2-meter band has now also been largely replaced by tetra mobile radios.
In analog radio, you need less masts than in digital, because the lower frequencies have a higher range. As a rule, you have a control station (ideally centrally located in the radio area), as well as several relays distributed in the area to be covered (called “Repeater” in the digital radio), which span a DC-wave network.
Because of the different requirements (e.g. due to the lower Reichweote of the digital radio signal), the digital radio masts are rarely at the same location as the analogue ones. For your alerting, the old, existing analog infrastructure is likely to be used further, while the digital radio has been built up in parallel.
Simple:
The DC-wave radio network of the BOS (4-meter band) is still active and is used for alarming. Consequently, the alarming has hardly changed anything to anything.
Digital radio receivers are now so slow in the free state, but only gradually (because expensive). It’s not different from the aid organizations.
The radio masts for the analog 4m radio still exist. Of these, however, there are not as many as digital radio masts as the 4m radio has a much greater range than the tetra radio.
If this mast is then used only for the purpose of the fire brigade and other aid organizations or it is also used differently. And how does it work that I only get the alarm in my county if the 4m mast has such a wide range? How can you handle it?
There’s nothing to be regulated. Each county has its own frequency on which it sparks. And exactly at this frequency are also the receivers of the sirens or the one you wear on the belt. Each receiver or group has its own number (loop) which is communicated in the form of sounds – just as with the phone. If a group or a siren is addressed, the number is communicated twice in succession by sound, so that the receiver switches on readiness. If the double tone required for triggering then the siren will run. The term “selective call”.
The sites were chosen at that time, which is covered by the entire county and a certain amount beyond it. Great, you have to look relatively. Digital radio masts have to stand every few kilometres, depending on topography, and at the 4m radio the reach of the former also ran via the 4m radio also the normal radio traffic, many older vehicles have also installed an analog radio in addition to the digital radio.
The range beyond the county area can vary greatly, which can already be over after a few kilometers, but sometimes even with favorable positions, it goes 10 km and more to the next counties. And since different counties with a sufficiently large distance from each other have been used and still use the same radio channels at the 4m radio, since there are simply not enough different channels, it is possible to hear and also turn around the radio traffic from the Alpine region in Oberfranken with favorable weather conditions and thus reflections in the atmosphere.
Thank you.
That’s not true. You can only listen to amateur radio, CB radio, Freenet and PMR – everything else is prohibited in criminal proceedings (operating radio, taxi radio, flight radio, etc.). And for listening, you don’t need a radio, but a scanner that is often included in an amateur radio. But he has nothing to do with the radio itself.
I’ve heard when I buy an amateur radio as a layman, then I’m not allowed to listen to everything everywhere. I’m surprised a huge mess wasn’t the rule at the time. For example, it is punished for someone and the fleet has an amateur radio and hears everything with me simply unimaginable. Thanks for the answers👍
Legal was allowed and can never be heard anywhere.
but yes, with the famous scanners that you did not have before of course and if so, then only for taxi radio you could hear everything, fire brigade, rescue service and also police.
Thanks to you for the technical and detailed answer now I finally know what’s behind the “Pepser”. I remembered one question: can radio amateurs legally listen to the alarms? And at the time, they could also hear the complete radio from the police or was somehow better protected. Because especially at POL I can’t imagine that anyone who buys an amateur radio just got everything. (I know you could hear the firefighter radio at that time)