No it’s not. The units you are talking about and I have two here - cost a fortune - $700+ and the electronics is pretty clever. When people have headphones clamped to their ears, any form of feedback is painful, and on a loudspeaker station the internal speaker lets local users hear everyone speaking quite loudly, apart from the local user themselves. Their microphone is processed and cancelled out inside the unit, so the local microphone goes down the line to everyone, but none of it comes out of their own loudspeaker. This sidetone adjustment works really well and makes these products possible. Radios do not have it, so everything goes wrong if your own voice is returned by the system and not cancelled. Feedback suppression is not a feature on any two-way radio I’ve come across, so the little speaker is VERY close to the microphone, meaning output does get re-transmitted unless you use remote earpieces, for example when it’s more stable - but speakers are bad news.
In my theatre systems, a few people attempt to use walkie-talkie type radios on speakers, wander near a headset user, and all ■■■■ breaks loose - and as I said, feedback inside a headphone generates considerable pain when volume levels are up. Full duplex, both ends, on speaker = instability.
Hey Paul;
I’m a bit of a newbie when it comes to radios, but my work for the past 30 years is in audio and electronics, specifically live audio. I design, build, operate, install audio systems for a living. I have built intercom systems, and I know how the nulling and sidetone circuits work.
What we’re talking about with these full-duplex radios are more akin to wireless Com, where they receive on one frequency and transmit on another. They’ve been around for years, but quality systems cost 10k or more. There’s a few cheapy products out there, but until recently, I hadn’t heard of Two-Way radios with this capability, so I was as skeptical as you!
Radios do not have it, so everything goes wrong if your own voice is returned by the system and not cancelled. Feedback suppression is not a feature on any two-way radio I’ve come across, so the little speaker is VERY close to the microphone, meaning output does get re-transmitted unless you use remote earpieces, for example when it’s more stable - but speakers are bad news.
I think what you’re missing is that the received audio is from the other radio, not from the local mic. The local mic is transmitting on frequency A, the speaker in that radio is receiving frequency B, not the audio from the local mic. If the 2 radios are far enough apart that the mic in one Radio doesn’t hear the speaker in the other Radio, then there should be no feedback. Of course, since each radio has dual-receive capability, you would need to turn down or mute the frequency that you’re transmitting on, if it doesn’t do that automatically.
In my theatre systems, a few people attempt to use walkie-talkie type radios on speakers, wander near a headset user, and all ■■■■ breaks loose - and as I said, feedback inside a headphone generates considerable pain when volume levels are up. Full duplex, both ends, on speaker = instability.
That’s just weird. Portable COM is always headsets, fixed (as in position) can sometimes be speaker boxes, but people need to wise up and not key their mics when they’re standing near a speaker box.
I appreciate that, Rick. My big quandry right now is between the only 2 (inexpensive) products that possibly will do full duplex, the Wouxun 8D/9D and the AnyTone AT-3318UV-D or -E.
The Wouxun SUPPOSEDLY can do full-duplex, but I don’t have any real proof of that, and I don’t know how well it works in that mode. I think it has a feature I do want, though, which was the subject of this thread, Channel Announce. It’s also cheaper than the AnyTone.
The AnyTone is subjectively a better quality product, and I have seen proof that it will operate quite well in full-duplex. However, it does not have Channel Announce, and it’s a little more expensive.
So, Rick, how would you feel about pulling out a pair of Wouxuns, trying the full-duplex operation, and posting a little video? I really need to know how well it does full-duplex and there’s no proof online that I have found so far… that would allow me to make my decision.
It does have Channel Announce in your choice of English or Chinese. Channel 001 is “Zero Zero One”, Channel 002 is “Zero Zero Two”, etc. It has full voice prompts for menu features as well.
As for videos, It’s a great idea. Unfortunately due to a backlog of current projects and time constraints, it may be some time before I have an opportunity to create one on this particular feature. I will consider adding it to a long and growing list of videos planned for the future.
Also, the KG-UV9D and 9D Plus are not the only radios with Duplex Work Mode. The KG-UV8E also has this feature, and it is a tri-bander.
From the user manual (Page 3): “Duplex Work Mode (TX on one area while RX on the other area simultaneously”. Area= Side, as in the Side A or Side B mentioned previously.
Understood and can totally appreciate that.
Just really sucks being here in Canada where shipping and returns are so expensive, otherwise I could just buy some radios from any place that allows returns, try out the functions and return them if they don’t work as expected.
Of course, ideally I’d be much happier if there were still brick-and-mortar stores where I could see and try out new gear before buying, but that’s just not the way things work anymore…
My bad. Yes it was. The KG-UV9 or KG-UV8 (all suffixes) claim to work full-duplex, as do the AnyTone.
However, I have not had any ringing endorsments on either for proper full-duplex operation. A little more support for the AnyTone, but most people say the only HT that can REALLY do full-duplex is the Kenwood TH-D72a. That’s a big step up in cost, and it has a whole bunch of features I don’t need and would be very happy to not pay for, like all the GPS functions, text messaging, EchoLink, etc. It also doesn’t have channel announce, so I’m probably SOL on ever finding the perfect fit, no matter what the cost.
For anyone following along at home, I bought the Kenwoods, then promptly returned them. They have locked out many frequencies, have no channel announce and they’re too expensive!
I’ve given up on full duplex for radios, and I settled on the Baofeng UV6.
It’s disposably cheap, has no buttons for users to mess with, works on VHF and UHF, has dual watch, channel announce, and will even announce frequencies if you want. It’s pretty much exactly what I was looking for, and it’s so cheap you can literally buy 10 of them for the price of one Kenwood.
LOL! Aren’t those the same as the Retevis RT21 that I said you would like four pages ago?
But in all seriousness, I - like you - now have a fleet of DTR radios for serious work and a couple of cheap disposable radios that cannot be programmed from the front panel. They don’t hold a candle to our DTRs as far as range and clarity are concerned, but they are cheap and can be programmed to our business frequencies. I now have two RT21 radios, a Retevis RT5 and a Wouxun UV899 (that I really love more and more every day.)
I toss the RT5 into my pocket with one of those Retevis mini-antennas when I need a backup to our rental radios on a film set. (Motorola HT750s) It makes for a very compact package. The RT5 and the UV899 actually get better reception than the Motorola radios, but then again, they are not rental radios that have been dropped 50 times over the years.
I have been following the thread on Radio Reference about mobile antennas for the DTRs and it is fun to see how they have come up with a thousand explanations, but are finally starting to realize that a) external mobile antennas just do NOT work, and b) why would you need one with a DTR at 900MHz. Fun times my friend. Some day we should get together and compare all our radios and ranges.
I was actually in your town last summer for a quick IATSE training course but it was just in and out sadly.
No, not quite.
Here are the differences as far as I can tell:
RT21
Freq: UHF OR VHF
Power: 2.5W
Single channel receive
Channel Announce only
UV6 Freq: UHF AND VHF
Power: 4W/5W
Dual Watch/Dual Transmit
Channel Announce + Frequency Announce
Some day we should get together and compare all our radios and ranges.
I was actually in your town last summer for a quick IATSE training course but it was just in and out sadly.
Send me a note next time. I’ll PM you my contact info.
Original Firmware cables are unobtainable so they sold quickly for a good price. As you know, I’ve learned how to make my own, though, so not so valuable to me. See my forum for details. I should probably build up some more but I don’t know if people would buy a non-Moto product…
I have 9 DTR550’s left. Also some chargers, batteries, speaker/mics, earbuds, beltclips, and some replacement lenses. PM me if you’re interested.
Thanks - sorry I missed that in the earlier post - I assume it turned out not to be full duplex? I couldn’t find any mention of it in the manual?
Without some for of nulling, full duplex is very dangerous, especially if you try to use speakers. I’ve got quite a decent wired and wireless system, and if a radio user goes too close to anybody with a wired live mic, the leakage (which in the wired pack is cancelled out) makes the entire thing feedback, so I think your decision not to pursue it is a very sensible one. Feedback into headsets and earpieces is painful!
My understanding is that it’s the ONLY HT still in production that can properly do full duplex audio.
Without some for of nulling, full duplex is very dangerous, especially if you try to use speakers. I’ve got quite a decent wired and wireless system, and if a radio user goes too close to anybody with a wired live mic, the leakage (which in the wired pack is cancelled out) makes the entire thing feedback, so I think your decision not to pursue it is a very sensible one. Feedback into headsets and earpieces is painful!
