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Old 26th April 2012, 6:53 PM   #16
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If it is only two units, you can cheat a bit and get full duplex by programming the receive frequency on unit 1 to the transmit frequency of unit 2, then a different frequency pair for the other side of the link.
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Old 26th April 2012, 10:07 PM   #17
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If it is only two units, you can cheat a bit and get full duplex by programming the receive frequency on unit 1 to the transmit frequency of unit 2, then a different frequency pair for the other side of the link.
That doesn't give you full duplex. As standard hand-held radio radio can either transmit or receive, but not both at the same time. The result is that it doesn't matter if your running Tx and Rx on the same freq. or on a split as each set can't hear while transmitting anyway.

2.
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Old 27th April 2012, 8:09 AM   #18
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That doesn't give you full duplex. As standard hand-held radio radio can either transmit or receive, but not both at the same time. The result is that it doesn't matter if your running Tx and Rx on the same freq. or on a split as each set can't hear while transmitting anyway.

2.
I should have said that you do need to use radios that can be programmed to do that, obviously not going to be possible on your $20 cheapies.
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Old 27th April 2012, 4:54 PM   #19
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Does it really need to be full duplex or would hands free (ie. VOX) be ok?
100m sounds like it might be within the capability of bluetooth.

2.
The problem with VOX is it can slow down a conversation and it's a problem when both parties talk at once. I know, I know, you just need to have discipline however that's difficult when you've got to stay focussed on other tasks at the same time.

I guess I could simply buy 4 units and wire them up in pairs, does that sound feasible?
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Old 27th April 2012, 5:16 PM   #20
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The problem with VOX is it can slow down a conversation and it's a problem when both parties talk at once.
Oh yes! Definitely takes some practice.

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I guess I could simply buy 4 units and wire them up in pairs, does that sound feasible?
Best answer - it can be made to work.
If all radios are on close frequencies, then the close receivers are likely to be overloaded and they won't hear a weaker signal. There are tricks to getting around this. The most obvious is running the lowest power you can get away with for the distance/obstacles your dealing with.

Gecko suggested this and from memory he is a licenced HAM where the common method is to use radios on different bands. So instead of having radios with 100's of kHz separation between Tx & Rx, you can have 100's MHz (makes all the difference).

2.
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Old 27th April 2012, 5:40 PM   #21
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OK. I got a refund on the unidens. I'm still looking for viable alternatives. I found this review for the GME670 but I'm still a bit worried after reading the whirlpool thread posted earlier.
http://mike.musskopf.com/travel/tx670

The other option is to go for the Uniden UH710SX. Similar price but only 1w.
I'm sure 1w will be fine for my needs so I just need to know whether the Unidens will offer better sound quality over the GME to make it worth sacrificing the power.
Has anyone used the Uniden 710's?

Last edited by ccmarci; 27th April 2012 at 5:58 PM.
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Old 28th April 2012, 6:59 AM   #22
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Oh yes! Definitely takes some practice.

Best answer - it can be made to work.
If all radios are on close frequencies, then the close receivers are likely to be overloaded and they won't hear a weaker signal. There are tricks to getting around this. The most obvious is running the lowest power you can get away with for the distance/obstacles your dealing with.

Gecko suggested this and from memory he is a licenced HAM where the common method is to use radios on different bands. So instead of having radios with 100's of kHz separation between Tx & Rx, you can have 100's MHz (makes all the difference).

2.
Thanks for describing it more eloquently than I could at the time I also missed the comment about only wanting to spend ~$500 on it.

Without getting into some pricey kit, the cheapest way to do it is going to be buying 4 units and "pairing" them as suggested. Just try to keep them a few channels away from each other to avoid any interference.

(not a licenced HAM yet, although I am sitting my for my tests in a couple of weeks time, current task is figuring out where I can build a decent mast, and deciding on a callsign).
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Old 28th April 2012, 7:43 AM   #23
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OK. I got a refund on the unidens. I'm still looking for viable alternatives. I found this review for the GME670 but I'm still a bit worried after reading the whirlpool thread posted earlier.
http://mike.musskopf.com/travel/tx670

The other option is to go for the Uniden UH710SX. Similar price but only 1w.
I'm sure 1w will be fine for my needs so I just need to know whether the Unidens will offer better sound quality over the GME to make it worth sacrificing the power.
Has anyone used the Uniden 710's?
Well, I used to have great faith in the GME line until I bought a pair of 670s. When using them it was obvious there was something not quite right with the received audio, it was very 'muddy' i.e. hard to understand. The charge circuit didn't seem to behave properly either. Both units were the same and when compared with an older Uniden hand held it was chalk and cheese.

I still like GME as a brand, especially their dash mount radios, but watch out for the cheaper hand held gear, I think it's being built to a price.

- Rob.
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Old 28th April 2012, 11:03 AM   #24
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Thanks Rob,
I might go to prestige communications and see if they've got some 670's to test. I'd prefer these if the audio is good because they're 2w, maybe its improved?? I won't buy them unless i can test them.Office works have also got the uniden 710's at a good price. I'm sure if I buy from there they'll take them back if I'm not happy.
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Old 28th April 2012, 2:51 PM   #25
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does DSE have another higher power model you can upgrade to? The Uniden UH720SX are $150 each

http://forums.whirlpool.net.au/forum...rch&f=83&q=uhf
My bro and I have a few of these, DSE had the cheapest price too. We get at least 1km - nearly line of sight (as far as we've tested so far) and it is crystal clear.

Last edited by TERRA Operative; 28th April 2012 at 3:04 PM.
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Old 28th April 2012, 8:10 PM   #26
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I am sitting my for my tests in a couple of weeks time, current task is figuring out where I can build a decent mast, and deciding on a callsign).
Hmmm ... VK2GKO is available!

2.
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Old 29th April 2012, 5:10 PM   #27
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Right, some posts have gone bye bye as they are promoting illegal activity.

Anyone who posts up encouraging such behaviour will face the ban stick.
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Old 29th April 2012, 6:24 PM   #28
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so u deleted all my posts. Pfft there goes fredom of speach. good luck to the OP when there are post nazis arround
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Old 29th April 2012, 7:04 PM   #29
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so u deleted all my posts. Pfft there goes fredom of speach. good luck to the OP when there are post nazis arround
There has never been free speech here, you've confused OCAU for some kind of democracy
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Old 29th April 2012, 8:28 PM   #30
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so u deleted all my posts. Pfft there goes fredom of speach. good luck to the OP when there are post nazis arround
I'm pretty sure the OP wants quality advice that will assist him. Information which encourages him to break the law is not what I would call quality advice.
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