UHF radio transmission

Submitted: Saturday, Jun 29, 2002 at 00:00
ThreadID: 1378 Views:1873 Replies:4 FollowUps:2
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I understand the principle of simplex and duplex transmission but how does this work in practise?

If I select duplex on my UHF, it stops scanning.

If I press the start talking button on the handset I'm (apparently) in simplex.
How do I transmit in duplex?

Do I select duplex and then transmit in whatever channel the unit stops at?

Do I selecet a channel then go to duplex and then transmit?

And if someone is transmitting in duplex and I'm in simplex, can I hear them? And speak with them?


Thanks in advance....
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Reply By: Colin- Saturday, Jun 29, 2002 at 00:00

Saturday, Jun 29, 2002 at 00:00
My GME set has separte buttons for DUP and SCAN. To transmit in Duplex, turn off Scan and select required Duplex channel (1-8) then transmit. Duplex only works on these channels. Most sets will display "dup" if selected and if you are on channels 1-8. If another person transmits in Simplex on any channel and is within range you will here them regardless of what 'mode' tou are in !!
Hope this is correct and helps.
AnswerID: 4514

Reply By: Member - Jim - Sunday, Jun 30, 2002 at 00:00

Sunday, Jun 30, 2002 at 00:00
For duplex to work you have to be in range of a repeater.

For instance if there was a repeater nearby on Channel 1, when you select duplex on you radio you are actually transmitting on Channel 31 to the repeater, the repeater retransmits your signal on Channel 1.

Of course if you are using Channel 1 in its normal simplex mode, say to talk from car to car you will hear everything coming from the repeater, thats why you don't normally travel in convoy using channels 1-8 or for that matter 31-38.

To answer the last part of your question, say you were using Channel 2 on simplex from car to car and you heard another conversation coming through from a repeater you may be able to talk to them if they are withing range as they are listening on Channel 2 but transmitting on Channel 32 through a repeater. There is a good chance that they could be out of your normal transmit range although they sound to be loud and clear.

Clear as mud isn't it

Regards, Jim

AnswerID: 4524

Reply By: Bill - Sunday, Jun 30, 2002 at 00:00

Sunday, Jun 30, 2002 at 00:00
Tony I think the best suggestion I can give is to get the handbook out and go through all of the scenarios with the radio and handbook in front of you. Selecting duplex won't stop scanning. You select duplex for particular channels (1-8). Scanning then goes on as normal and if there is someone on a duplex channel you will hear them. You can transmit on the channel your radio stops on or you can switch scan off and choose any channel you wish. If your radio has group scan you can select a "Priority Channel". The radio then checks the channel chosen for priority and any transmission on that channel is heard. Also if you press the talk button your radio will go to that channel immediately. In normal scan you transmit where the radio stops or as previously said you can turn scan off and select a channel manually.
AnswerID: 4537

Follow Up By: Tony - Monday, Jul 01, 2002 at 00:00

Monday, Jul 01, 2002 at 00:00
Bill, Thanks for the reply. I have had the book out and it is particularly short on detail. It's almost as short as "If you want to talk, push the talk button; if you want to scan, push the scan button; if you want to use dimplex, push the duplex button". It also tells me that if I transmit, the receiver will stay locked on that channel so that I can continue a/any conversation. That's good. What it doesn't tell me is that when the conversation is finished, I have to then push the scan button to re-start scanning. On a scale of one to ten, the book is about 4, hence the quesion. Tony
FollowupID: 1939

Reply By: Nigel - Wednesday, Jul 03, 2002 at 00:00

Wednesday, Jul 03, 2002 at 00:00
What brand/model or radio do you have?
AnswerID: 4593

Follow Up By: Tony - Wednesday, Jul 03, 2002 at 00:00

Wednesday, Jul 03, 2002 at 00:00
GME TX 840 B
FollowupID: 1959

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