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  #11  
Old 03-14-2017, 04:47 AM
paulears paulears is offline
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Default Re: Help me find some new radios

Simplex is where a radio uses the same frequency for transmit and receive. Duplex indicates two separate frequencies are used. Strictly speaking, radios that do this should be called semi-duplex, because they can only do one thing at a time, transmit OR receive. Full duplex is like a phone - you can speak and listen at the same time.

The purpose in (semi) duplex systems is that they enable you to use repeaters. If you apply for one of the licenses that allows their use, then your range will increase, reliability goes up because dead spots and impossible geography aren't so important, and of course range is always from the user to the repeater - if two users are on opposite sides of the repeater, they would not be able to hear each other, but the repeater hears both, and links them up.

Simplex is what all simple radio systems use - for a small area, it works fine, and is uncomplicated. Repeaters are expensive, need licensing, and often expensive aerial systems. Repeaters cannot work without duplex frequencies being in use.
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  #12  
Old 03-23-2017, 09:16 AM
Mr.X Mr.X is offline
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Default Re: Help me find some new radios

Thank you, Paul! Great info.

Two more questions...

1. If I have a number of channels on an analog radio with groups of people on each, then reserve channel #1 as an "all call" and have the radio set to scan channel #1 and the group's channel, is the scanning system reliable and fast enough that it will always catch any transmission on channel #1? I'd like to know more about how analog scanning works, since I've never used it.

2. Are there any FULL-duplex analog radios? I've seen a few digital ones, but don't know of any analog ones... (I'm not interested in repeaters or that functionality, just the ability to speak and listen at the same time)
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  #13  
Old 03-23-2017, 02:46 PM
paulears paulears is offline
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Default Re: Help me find some new radios

I've never come across anything that is full duplex in our price ranges, apart from a few radios that can do cross band, on two separate antenna connectors.

The thing to remember is that most business and amateur designed radios will scan their memory channels, they don't do it super fast - so the more channels in them, the more chance there is of missing a very quick call. Real scanners are designed to scan very fast - but even these when faced with hundreds of channels are not brilliant. My Yaesu radio in the van has 200 memory channels in use and is pretty hopeless as a scanner now - takes too long to do the cycle. My business radios with 6 channels work much better.
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  #14  
Old 03-23-2017, 04:14 PM
Mr.X Mr.X is offline
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Default Re: Help me find some new radios

I see. Don't they just scan channels that have been selected to scan? It sounds like you're saying they scan all channels even if you have it set to scan only 2...
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  #15  
Old 03-24-2017, 03:49 AM
paulears paulears is offline
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Default Re: Help me find some new radios

Scanners have lockouts to temporarily block the scan stopping, but most hand helds can be put into scan mode and scan whatever is in the channels. You can on most of them programme the scans to me limited - so you might have ten channels and the scan function does half, but that's rarely user programmable.

So they can do it - IF programmed. Lockout by the radio isn't usually possible because you don't want users accidentally locking the critical ones out and scanning the wrong ones. Scanners need radio control from the keypad - the last thing a PMR user wants.
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  #16  
Old 08-14-2017, 03:56 AM
Mr.X Mr.X is offline
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Default Re: Help me find some new radios

Back again...

I've now tried the TYT MD380, kinda geared towards the DMR world, the analog functions don't get much attention. There's a bug in the scanning function that is a showstopper, so I moved on.
Tried the Retevis RT23, and it's functions are spot-on. Has Dual-receive and voice prompts, has pretty much all the other features I want, but unfortunately, is a pretty cheaply-made product.
Are there any well-made products from say Kenwood, Moto or HYT that have these same features:
  • VHF & UHF in one unit
  • Dual Receive (2 channels can be received and you can choose which to transmit from
  • Voice prompt - the channel number or name is "spoken" by the radio
  • Free (or at least reasonably priced) programming software
  • Quality build like the Moto DTR
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