New to radios

Wireman121

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I'm new to radios and just learning. I have acquired a few older Motorola PR400 UHF radios. I was looking to get them working around Essex County, preferably with the ability to communicate expanded as far as Wayne, East Hanover, Montclair, and Parsippany. Looking into how repeaters work, trying to understand how setting up multiple repeaters, I assume at different frequencies, would all work together to repeat on the same frequency without the need for the end user to make channel changes on the radio. I see an option for an LTR system, which appears may be the solution but documentation seems to be limited.

Looking to learn more than anything else, but having something setup for friends to talk to each other around the area would be cool.
 

Whiskey3JMC

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What exactly is your use case as far as communication goes? LTR systems (few and far between these days) aren't open for public use you know. If you're looking to just talk to friends perhaps you should consider FRS or GMRS instead, but pick up radios (and a license for the latter service) suitable for whatever service you choose
 
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mmckenna

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Looking to learn more than anything else, but having something setup for friends to talk to each other around the area would be cool.

What are you licensed for? Like, actual FCC issued license?

There is not anywhere that you can use these radios without an FCC issued license. There is no "license free" frequencies.

Depending on -exactly- what model radio you have, you ~may~ be able to use them on GMRS, or on the amateur radio bands.

GMRS license is $35, license is good for 10 years, and the license covers everyone in your immediate family. All your friends would need to get their own license, they would not be covered by yours.
Trunking is not permitted on GMRS, so using LTR will not be an option.
Setting up your own repeaters is something you can do, but before you start down that path, understand that setting up a repeater isn't a "plug-n-play" sort of thing. You don't just buy a repeater off Amazon or e-Bay, plug it in, and go. There's a lot of knowledge, skill and -very- expensive test equipment involved if you want to do an even halfway decent job.
There are often existing 'open' GMRS repeaters in major urban areas that you may be able to use with permission.

Amateur radio is an option, but each and every user needs to have an FCC issued amateur radio license. Getting the license requires learning some technical material and taking a fairly simple multiple choice test. Repeaters are an option, and there very well may be repeaters in your area that you can use.

Usually it's recommended to research the radio service that you'd use before buying radios. It's a bit difficult (but not impossible) to come into this backwards.

Let us know what you've got and what your knowledge/skill level is, and we'd love to help you in the right direction.
 

Wireman121

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I have a bunch of UHF Motorola PR400 radios (old I know, but they're relatively cheap AND durable). I have no problem getting a license, I'm interested in it.

I have a lot of technical background and knowledge, but am very new to the radio scene. So I understand how things work fairly well, but when it comes to the technical terms, radio settings or different configurations, I'm not very knowledgeable and really only know what I do know from playing around with options and testing them out.

I am more than willing to learn with the right material. And I am more than happy to get a license. I guess I need some direction and maybe a hand holding.

In my head, I have an idea of how a repeater SHOULD work, but I doubt it actually works the way I'd want it to (I'd expect a bunch of repeaters to receive on the same frequency (say 450mhz for example) and then all transmit on the same (say 460mhz) frequency. I know that works with ONE repeater which then allows you to still utilize a radio to radio frequency communication at 460mhz while still maintaining the repeater at the 450mhz, but once you start adding more repeaters, how does the system function without the need for end user interaction?
 

mmckenna

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I have a bunch of UHF Motorola PR400 radios (old I know, but they're relatively cheap AND durable). I have no problem getting a license, I'm interested in it.

I have a lot of technical background and knowledge, but am very new to the radio scene. So I understand how things work fairly well, but when it comes to the technical terms, radio settings or different configurations, I'm not very knowledgeable and really only know what I do know from playing around with options and testing them out.

I am more than willing to learn with the right material. And I am more than happy to get a license. I guess I need some direction and maybe a hand holding.

Sounds like amateur radio may be something you find interesting. The entry level "technician" license isn't difficult to get. Amateur radio gives you a lot of room to experiment and talk to like minded people.

In my head, I have an idea of how a repeater SHOULD work, but I doubt it actually works the way I'd want it to (I'd expect a bunch of repeaters to receive on the same frequency (say 450mhz for example) and then all transmit on the same (say 460mhz) frequency. I know that works with ONE repeater which then allows you to still utilize a radio to radio frequency communication at 460mhz while still maintaining the repeater at the 450mhz, but once you start adding more repeaters, how does the system function without the need for end user interaction?

The only way a system like that would work is:
On the receive side, all the receivers would tie back to a central point where there would be a device called a signal to noise voter. The voter would choose the clearest received signal based on signal to noise ratio. The system would "vote" that signal and send it out to the rest of the transmitters.

On the transmit side, it gets tricky because all the transmitters would have to transmit on —exactly— the correct frequency and would need to be sending the signal out at the —exact— same time. This isn't easy.
The transmitters need to have their frequencies very tightly controlled so there is no variation. This is often done by using a frequency reference derived from a common source, usually GPS. If this isn't done, the transmit signals all vary a bit and tend to cancel out the transmit signals where they overlap and make a mess.
They also use the timing from GPS to make sure they all send the same signal at the same time. This has to compensate for delays in the arrival of the audio from the voter site due to how long it takes the signal to get to the transmitter.

Complex stuff and these "simulcast" systems are not commonly used in amateur radio as it's expensive. Usually the repeaters are all on different frequencies and operate independently. Some repeaters are part of larger systems where they are tied together, but usually using different frequencies so they don't have to deal with all the complexities of a simulcast setup.
 
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