Radio Recommendations

hometownmedic5 said:
Not *ALL* transmitters. It’s a feature. MDC, GeStar, DTMF, etc are all types of this signaling, but if I turn signaling off in the programming, no such “chirp” is transmitted.
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I'm not talking about a unique identifier that is programmed into a radio for it to transmit every key-up. I'm talking about signal characteristics that are individual to each transmitter that occur each and every time it is keyed up, regardless of any "signalling" feature. It's basically like splatter but on much faster timescale and narrower bandwidth. You won't hear it, it happens too fast. Even an unmodulated carrier will show this upon initial transmit. If you have a good enough oscilloscope, you'll be able to see those characteristics happen and the"fingerprint" doesn't change when you change frequencies. Change hardware in the RF path and you will change the fingerprint.

I am WELL aware of MDC et al type radio identifiers. The chirp I'm referring to is NOT something that can be turned on and off and is absolutely NOT something programmed into the radio. You can clone two individual radios, turn off all signalling features and with a good enough oscilloscope, you'll be able to tell which radio was transmitting just by looking at the signal.

Every transmitter does this.
 
There are many radios that could be purchased that would work well on typical public safety and business bands. Some of those are HAM radios that are "freebanded" and there are many others that are "business band" radios that are actually type certified for use in those bands. HAM radios are NOT type certified for use in those bands, even if they might otherwise be compatible with all aspects of a transmitted signal that is required for use in the desired band. My recommendation therefore is NOT to use a HAM radio that has been modified to transmit outside the HAM bands.

The next issue to consider is that the entity that holds the FCC license that you'd be using a radio under may NOT have a sufficiently high number of mobile stations to legally allow you to operate a radio that is not issued to you by them. While it is true that the FCC isn't likely to enforce this, it IS a rule that they CAN enforce and they very well may if a complaint is filed with them about the license-holder allowing violations of the terms of the license. Then if the FCC does open an investigation, they very well could bring in the very high-tech equipment to determine who is not legally operating under the terms of the license. Significant fines and jail times are entirely possible.

Proceed at your own risk, you have been warned.
 
Akulahawk said:
Proceed at your own risk, you have been warned.
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Like has been said, it can be done. As someone legal responsible for a public safety radio system... I would you throw you under a bus in a heart beat. Depending on system contracts, the system warranties can be voided by unauthorized equipment. In my particular case the state could throw our system off the state system.

Also when it comes to the business class and HAM radios. You could probably squeak by for EMS. But I doubt they'd survive remotely long term in a fire service environment. Even a good fire service radio will fail in an extreme circumstance. High end non-fire service radios will at minimum suffer water damage quickly.

Part of the necessity for the radio is as a lifeline. You dont want one that isn't up to the task at hand, or you would be setting yourself up for failure... NIOSH reports often cited lack of radio or inappropriate radios as critical factors.
 
EMDispatch said:
High end non-fire service radios will at minimum suffer water damage quickly.
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High-end non-fire service radios could also very well be the same high-end fire service radios, just marketed to a different audience. But you do bring up a good point. There are business band, HAM radio, and Public Safety radios that have the same water resistance rating, so you very well could use them all in exactly the same wet environments. Now when you start considering "intrinsically safe" systems, no HAM radio that I'm aware of is rated for use in IDLH environments, not that some of them wouldn't be safe to use in those same environments.

Depending upon how the local system is set up, it may not be possible to use Business/HAM equipment on that system. The last system I worked in (EMS) didn't require radios to transmit an access code or unique identifier. The local system currently uses a trunked system and each radio must be specifically authorized to access the system. On the plus side, all radios in the system can interact with any other radio in the system, so Fire can talk to Sanitation which can talk to any LE agency, which can talk to various government offices which can talk to the Hospitals. Basically anyone can talk to anyone else if need-be. On the down side, if the radio system goes down, a whole bunch of agencies end up having a very difficult coordinating anything as few back up radios that are non-system exist here any more. The only major source of non-system comms are the HAMs and they regularly train for such an event.
 
It sounds like a good idea, but I didn't heard about somebody purchasing his own radio.
 
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