UHF repeaters

Hey Andrew,
A repeater picks up the radio signal from your UHF and retransmits this with a lot more power, and over a greater distance than what the radio would do by itself. Repeaters work when you have selected duplex on the radio, which causes it to transmit 30 stations over that selected. Eg Ch1 on duplex will receive on Ch1 but transmit on Ch31, Ch2 receives on Ch2 but transmits on Ch32 and so on. The repeaters are channel specific, so they will only receive 1 channel and transmit on 1 channel. Eg. the Hurstville repeater in Sydney only recieves Ch31 and only transmits on Ch1. (I can pick up and transmit to this Sydney repeater with a handheld out at Katoomba).When the radio is set to simplex (instead of duplex) it transmits and receives on the same channel and works like a normal 2 way radio. The repeaters are usually located in regional high spots, as UHF's work best on the line of sight principle.The other thing it is useful foris transmitting to the other sides of hilly terrain. Repeaters are not set up to, and do not transmit to each other at all. In terms of use Ch1-8 (duplex channels) will transmit to a massive number of people, so day to day conversation may be difficult on these channels. They seem to be more chat type channels.

Repeater are not manned, but automated radios that simply repeat a signal in real time. You access them via the duplex function on your radio (ie channel 1 duplex really transmits to the repeater on channel 31 but still receives on channel 1).

Repeater are not linked and cannot pass messages. Your radio works in the same way as far as conversations go when you use a repeater except that you can talk over greater distances.

Selcall is similar to dialling a phone number - you send a call to the number of the radio you want via tones. Only the more expensive sets feature selcall.

You should avoid channels 1-8 in the areas where they are used unless you have them in duplex mode. More importantly avoid channels 31-38 as simplex conversations on those channels will be rebroadcast on channels 1-8 if a repeater is in range.

TKS Slunnie and Nigel, you have clarified a couple of points for me too, Ed B

Lots of good info there!! Just one thing to add - when I turn my set on the display shows my selcall number for 5 seconds. Yours may do the same. That's the number you give other people with selcall in order that they can call you personally - similar as others have said to calling on a phone.

With regards to Bills post, my GME TX4400 shows the selcall number on powerup, but my older TX4200 doesn't. If you have a GME you call tell if it has selcall ability as it will have a call button on the top of the mic. If you have a GME TX4200 you can find out your selcall number by pressing the call button on the mic then press the squelch button. It will then display your selcall number. This may work on other models too.

Since 2001 the UHF channels 21 and 22 are reserved to data communication. Np voice should be transmuitted on 21 and 22.
Actually it is used for farmers in the outback/remote to monitor/control theri water pumps. This is the primary use but it
can be used for other purposes using data transmissions.
Guy

Thanks to every one. This sort of response shows the value of a forum like this. Goes to show how much collective stored info is out there. What'd we do before the internet? Long live positive replies.