![]() ![]() Paul on Animated LED Arrows Point The Way.hartl on Epoxy Blob Excised Out Of Broken Multimeter, Replaced With A QFP.Octavian Lupu on Snooping On Starlink With An RTL-SDR.Gravis on Adding A Third Wheel (And Speed Boost) To An Electric Scooter.Gravis on Epoxy Blob Excised Out Of Broken Multimeter, Replaced With A QFP.The Commenter Formerly Known As Ren on Epoxy Blob Excised Out Of Broken Multimeter, Replaced With A QFP.Josh on Adding A Third Wheel (And Speed Boost) To An Electric Scooter.Mark Garton on Simple Internet Radio Transplant.Since it was AM rather than FM, that’s likely the reason. Air band was rare for a long time, except for scanners that only scanned the airband. I think even the earliest tuned the low and high VHF bands, and maybe the UHF band. Get all the channels with precision, and scan through them. It was a big thing when synthesized scanner arrived, late seventies or early eighties. Qnd eqch scanner would cover only one band. Scanners appeared in 1970 or 71, six or maybe eight channels, a crystal needed for each. Some police band radios were tuneable but had the option of one crystal position, the best of both worlds. Crystal control always put you on the right frequency, but you needed to know it first, and you needed a crystal for each frequency, and they were a few dollars each. The former let you find signals, but since transmission is generally short, you might need to tune a lot. You had a choice, a tuneable radio or crystal control. People listened to police radio before there were scanners. Posted in Radio Hacks Tagged P25, police radio, police scanner, SDRTrunk, trunking radio Post navigation Not the first time we’ve seen an SDR dongle scanner, of course. With everyone spending more time at home these days, radio monitoring is a great way to live vicariously. You can, of course, get commercial equipment to monitor these radios, too, but what fun is that? P25 is the APCO ( Association of Public Safety Communications Officials) Project 25 standard used for public service trunking radios. That means that one channel might have several transmissions in a row from different talk groups and one talk group might hop to a new channel on each transmission. With trunking radio, a radio’s computer is set to be in a talk group and a control channel sorts out what channel the talk group should use at any given time. But most channels would be empty most of the time. In the old days, you might have a dozen channels for different purposes. shows you how to set it up for Windows or Linux and you can see the video below. However, P25 can unscramble trunked radio calls intercepted by a cheap SDR dongle and let you listen in. That means conversations might jump from channel to channel. However, it isn’t as easy as it used to be because nearly all radios now are trunked. Police scanners fans can hear live police, fire, and ambulance calls. There was a time when it was easy to eavesdrop on police and other service radio networks. ![]()
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