Simplex Duplex Repeaters

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Simplex Duplex Repeaters

Postby YorkshireBiker » Wed Nov 08, 2017 6:42 pm

Now as I understand simplex and duplex. Simplex is single use back to back, where as duplex is two frequencies operating via a repeater. Now my question is, is it possible to use a single input ( frequency ) on repeater ? I have seen a few posts not on here where they state using single frequency on repeater.
If so how easy is it to set up.
I know its a bit naughty without the correct licence
I doubt that the people I have seen posting would have a SRBR licence.
Many thanks
73s
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Re: Simplex Duplex Repeaters

Postby G4RMT » Thu Nov 09, 2017 6:08 pm

You're nearly right.

A repeater needs to transmit and receive at the same time - so it listens on one frequency, while re-transmitting it on another - Duplex, as two - frequencies. The other radios just transmit on one, and listen on the other - the reverse of the repeater. A repeater CANNOT receive and transmit on the same frequency.

However - it's usual to operate hand held on simplex - as they do on CB, much of Marine, Aircraft and Ham bands - everyone in range hears everything. However, there is nothing to stop the control station using duplex. Taxis often do this when they have a dispatcher. The cars use duplex, transmitting on channel A - the control (which could even be a hand held radio if you really wanted_ listens on A, but talks on B - which is what the hand holds receive. The benefit is that the controller can hear everyone and speak to everyone, the cars can hear control, but they CANNOT hear the other cars - only the dispatcher is listening that way around. Like a repeater, but not actually repeating.

The repeaters I run have the facility to select when they repeat.

I do a lot of event style work - the repeater has a mic plugged in and has the volume turned up. All the people with radios use two frequencies (duplex) and they can talk to the person in charge. That person tells them what to do, but it stops people ear wigging in to the others. This is important. Maybe the controller got called by a steward saying a suspect package had been found near gate 2. With volunteers, it's quite likely that hearing this, other radio users either take action the person in charge may not want. It's often where a general call produces too much assistance. Maybe control know that Fred is actually on his way to the location, so it's pointless for John and Jack to eave their posts when help is already close. If however, Jane sticks a call out saying she needs to speak to John, control calls john, tells him jane wants him - presses repeat and then transmits - Jane, go ahead with John - she asks the question, john replies, and then control switches off repeat.

It's one of the fundamentals of good communications to filter who gets what. Taxis often do this too, because they might not want one driver to respond, but for the greater good, have somebody else do something.

You need two frequencies to do this. Simplex means everyone gets everything. Some radios have a 'tall around' function - all this does is swap the radio's duplex frequencies around so when you are out of repeater range, but close, one of you presses talk around and you can talk to each other.

Just remember simplex - one and duplex two frequencies. The only repeaters that can use simplex are those awful parrot devices where they simply store your message and when you release the PTT, the play it out. They work, but are soooooooooooo slow!
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Re: Simplex Duplex Repeaters

Postby Davie Boy » Thu Nov 09, 2017 11:39 pm

G4RMT very informative post and accurate.... I have noticed a lot of ham simplex repeaters pop up of late....

https://www.ukrepeater.net/gateway_list.htm

Do I take it these are all so called parrot repeaters....? On the list they say gateway repeaters so could be the internet is involved....?
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Re: Simplex Duplex Repeaters

Postby m0lsx » Thu Nov 09, 2017 11:56 pm

YorkshireBiker wrote: Now my question is, is it possible to use a single input ( frequency ) on repeater ? I have seen a few posts not on here where they state using single frequency on repeater.
Many thanks
73s


There is something called a simplex or a Parrot Repeater. It involves using a recording device, so I may call you on lets say GB3Parrot & when I de-key, it transmits my message to you. And when you reply the Parrot listens & repeats it to me.
Parrots are occasionally fitted to the Birds (satellites) & you get under a minute per over.
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Re: Simplex Duplex Repeaters

Postby YorkshireBiker » Sat Nov 11, 2017 5:55 pm

Cheers people. That clears things up
73s
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Re: Simplex Duplex Repeaters

Postby G4RMT » Sat Nov 11, 2017 10:17 pm

To Davie boy - those frequencies you listed are digital gateways - They aren't repeaters, just access points into the various digital networks. Not really the same thing - you use them as if talking to people simplex, but your voice might hop out in New York, and you get an answer from a Taxi driver!
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Re: Simplex Duplex Repeaters

Postby Davie Boy » Sat Nov 11, 2017 11:31 pm

G4RMT wrote:To Davie boy - those frequencies you listed are digital gateways - They aren't repeaters, just access points into the various digital networks. Not really the same thing - you use them as if talking to people simplex, but your voice might hop out in New York, and you get an answer from a Taxi driver!


Thanks for that G4RMT.... I have used a local 446 gateway so as soon as I saw the word "gateway" I thought it might be something similar.... we have had three pop up around around nottingham but so far not heard any of them active....
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Re: Simplex Duplex Repeaters

Postby Alfie » Sun Nov 12, 2017 12:36 pm

You can by cheap little parrot repeaters my mate has one its only about as big as a small pmr446 :thumbup: you plug a pmr into it and it will receive and record on that channel and then re transmit the message on the same channel. so basically to use it you transmit your message then you wait for the repeater to repeat it to you and whoever and then the other users do the same.

I found one on google that looks similar here it is

Image
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Re: Simplex Duplex Repeaters

Postby m0lsx » Sun Nov 12, 2017 12:57 pm

Alfie wrote:You can by cheap little parrot repeaters my mate has one its only about as big as a small pmr446 :thumbup:


I did try a borrowed one up under my lifting kite. I wanted to know if it would make a good or usable emergency situation link. I used 446 for legal reasons. But in a emergency with 2 meters or 70cm. It would work great. Even at under 200 feet 446 gave me good coverage.
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Re: Simplex Duplex Repeaters

Postby Alfie » Sun Nov 12, 2017 2:18 pm

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