TYT MD380 PMR PROGRAMMING

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TYT MD380 PMR PROGRAMMING

Postby T2tim » Tue Nov 10, 2015 11:17 am

I would like to program in the licence free digital 446 simplex channels for RX only but I do not know what colour code I should use or which admit criteria I should use in the software? or is it just a matter of trial and error? I would also like to program in some additional digital simplex PMR channels in on another UHF band for both RX and TX because I have a PMR licence, but again what settings to use seems like information that is hard to get hold of. getting the info for the Amateur service seems no problem whatsoever but it seems that anything else is nigh on impossible. if anyone could help me it would be much appreciated. unfortunately the seller did not program the radio to my requirements even though I requested it and now the retailer seems to be 'unavailable' which could be a warranty issue if something goes wrong down the line, but my main concern for now is actually getting the radio working.
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Re: TYT MD380 PMR PROGRAMMING

Postby Im_Listening » Tue Nov 10, 2015 10:42 pm

You won't need any colour code etc as they are analogue channels
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Re: TYT MD380 PMR PROGRAMMING

Postby Alfie » Tue Nov 10, 2015 10:49 pm

As said above pmr 446 are analogue so no colour codes etc needed.

You need to set up the following 8 channels in analogue mode (not digital) with no dcs/ctcss set and you will hear all traffic on the pmr 446 channels....

PMR 446 Channel 1 - 446.00625
PMR 446 Channel 2 - 446.01875
PMR 446 Channel 3 - 446.03125
PMR 446 Channel 4 - 446.04375
PMR 446 Channel 5 - 446.05625
PMR 446 Channel 6 - 446.06875
PMR 446 Channel 7 - 446.08125
PMR 446 Channel 8 - 446.09375

There are some other 446 channels that are digital but they are dpmr not dmr so your radio wont talk to them or monitor them. you can see all the analogue and digital 446 freqs in this link viewtopic.php?f=8&t=181
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Re: TYT MD380 PMR PROGRAMMING

Postby T2tim » Wed Nov 11, 2015 12:40 am

No I meant the digital simplex licence free channels which begin at 446.103-446.196 which is what I explained above. so you say that my radio wont read DPMR? and yet I have heard of loads of people using TYT 380's on the 446 licence free channels so how are they managing it? If what you say is true then they must be using some type of modification. someone I know who lives near me is monitoring it on his TYT 380 and he said he just progammed the channels in! strange.
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Re: TYT MD380 PMR PROGRAMMING

Postby Alfie » Wed Nov 11, 2015 12:50 am

T2tim wrote:No I meant the digital simplex licence free channels which begin at 446.103-446.196 which is what I explained above

sorry mate my mistake you clearly said "digital channels"

ok so its still bad news. dpmr and dmr are different though the same but the bad news is they dont work together. they use the same ambe codec but dmr is 12.5 steps where dpmr is 6.25 and a different kind of tdma i think (timeslot system).

the dpmr frequencies are also listed in the link i posted but as your radio is dpmr and 12.5 steps it wont do the 6.25 frequencies. for example the closest you can program to dpmr channel 1 446.103125 would be 446,1000, the next closest one would be 446.1125 which is well off.
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Re: TYT MD380 PMR PROGRAMMING

Postby T2tim » Wed Nov 11, 2015 1:46 am

ok thanks for that and I dare say digital is more critical with regards to channel steps than analogue. but it sounds as though it may still be possible to hear QSOs on some channels am I right? I must admit though iam still a little confused as to why you cannot individually program one channel to be more or less spot on with the software, as you can with chinese analogue radios with Chirp. because although they still dont have the correct step for the analogue 446 channels you can still program them in very close, almost exactly on channel frequency. after all, it wouldnt matter if you couldnt directly step from one channel to the next in the memory just as long as there was a way of doing it manually do you get me? or have I misunderstood? however, when I was using my legal 446 analogue radio the other day I heard somebody who sounded way off frequency on channel 1 446.006. but when I checked it with my scanner I was able to tune them in on 446.000! and they accused me of being off frequency! when it was infact them. they could still understand what I was saying but I couldnt understand them on my 446 radio so I had to work them in conjunction with my scanner, although iam surprised they sounded so off when infact they were only slightly off. my mate around the corner talks to me on 446.000 dead using his chinese HT and I can hear him perfectly on my legal 446 on 446.006. so I have no idea why I wasnt able to work them in the same way. they were using a TYT 380 and claimed that 446.000 dead was the closest they could get to channel 1. when they accused me of being off frequency I told them channel 1 was supposed to be 446.006 and not 446.000 dead! when they realised I knew my frequencies they sounded a bit worried lol
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Re: TYT MD380 PMR PROGRAMMING

Postby T2tim » Wed Nov 11, 2015 4:22 am

I know DMR radios only have 12.5khz shift but check this out from Ofcm who state that the licence free 446 digital channels can be either 6.25 or 12.5: http://stakeholders.ofcom.org.uk/binari ... MR4461.pdf although iam sure which is the most popular with users.
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Re: TYT MD380 PMR PROGRAMMING

Postby G4RMT » Wed Nov 11, 2015 8:52 am

I can answer this one. Radio channels usually are specified as a centre frequency and a deviation from that frequency in FM systems. Years ago we used 25KHz channels, and the centre frequency swung lower and higher as the channel contained content, as in voice or data. 25 was chosen because the equipment could cope with it in terms of performance and filtering to stop nearby channels in use interfering too much. As much of our radio use worldwide is historic, we have to cope with old equipment and old standards working alongside modern kit which is technically better. When the big brands could make equipment capable of working at 12.5KHz spacing, they did. In mixed systems, when people, bought new radios to work alongside old ones, the new ones, heard on the old ones were quieter, their deviation from centre being less. Icom, that I was using at the time, were a pain, because when their new radios H16 and U16 heard a wider old radio, instead of distorting a bit, they would simply cut out!

So a critical feature is the deviation, and many radios, like cheap Baofengs and others have a WFM/NFM mode that reduces deviation on transmit, while ignoring it on receive, being wide enough to hear the old 25KHZ deviation equipment perfectly well. The benefit is that they don't really care if a signal is slightly wrong, frequency wise. Many can work perfectly well 12.5KHz wrong! Two higher spec radios 12.5KHz apart will NOT hear each other. once we get to 6.25KHz channels, it gets worse. They may be able to be set to centre channels on that spacing, but the killer is the receivers. If they are high quality and correctly filtered, then you can squeeze in four channels into one old 25KHz channel, all working totally separately. Poor receiver performance means most cheap equipment will hear them overlapping.

Dialling in 400.000 or 400.006 in a typical scanner will make no difference at all. Everyone worries about frequencies, very few people consider deviation. I've still got loads of old equipment designed in the 25KHz days that sounds fine on Chinese radios. Really it shouldn't! I use the old Icoms as a test of deviation. Use a cheap programmable Chinese radio and say one two three four on the indicated frequency. Ten feet away the Icom is all choppy and horribly distorted. The radio has the deviation set too high. This is why cheap radios are difficult on crowded business radios where strong signals right next door, channel wise. They leak into the next channel quite badly. If your radios leak into the next frequency slot, that's bad in busy locations. In rural ones, signal strength dropping off means the problem is less.

Aviation and marine systems have had their channel spacing changed over the years, slotting in new channels in between, but this bleeding into the next channel nuisance was minimised by careful control of where ground stations were. Both AM and FM systems suffer from channel width, even though AM is usually thought of as always being 'just' the centre frequency being modulated in depth, but AM has a width too, it just remains constant.

Two people on slightly different frequencies can communicate quite happily if their equipment is wider band than perhaps it ought to be, but consider how annoying it will be if somebody nearby uses the channel right next to yours? You would be cross, perhaps accusing them of deliberately blocking you. However, if they had good spec radios, they may never even be aware you are there?

Frequency AND width of your channel are what is important.

Don't forget that digital radio of the dPMR variety is two narrow channels in one 12.5KHz bigger one. They talk about the centre frequency, but on an analyser, it's two narrow ones either side of the centre, which is why receiving this mode will be difficult on general equipment. An SDR can receive DMR because it's one stream of data, containing two channels sequentially, on exactly the same frequency.
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Re: TYT MD380 PMR PROGRAMMING

Postby T2tim » Wed Nov 11, 2015 1:34 pm

so in theory you could be receiving two licence free DPMR channels at once on a DMR radio with 12.5khz step? and yes the difference between 446.000 and 446.006 on a scanner is going to be very small but obviously it made a big difference when I was trying to receive the bloke on the TYT on my legal 446 radio. I guess iam right in thinking that most DPMR users on the licence free channels will be using 16- 6.25 channels instead of 8 -12.5 channels though as detailed by Ofcom. meaning that on some occasions I would hear two conversations at once on my TYT if I programmed the channels in am I right? and even then some channels would be more off than others. I guess the channel spacing is the main difference between DMR and DPMR. but am I right in thinking you may still be able to receive something? assuming two channels beside each other are not being used at the same time? or perhaps even better if they are using 12.5? although I would be surprised if the licence free equipment had the facility to switch between 6.25 and 12.5 anyway. (on the basis that the Ofcom info states: either eight channels at 12.5 spacing or sixteen channels at 6.25 spacing) thanks for your advice
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Re: TYT MD380 PMR PROGRAMMING

Postby G4RMT » Wed Nov 11, 2015 4:13 pm

Digital PMR446 is a bit different from the mode 1 implementation of the ETSI standard used outside the 446 band. 446.1-446.2 digital services are split into 8 12.5KHz channels and/or 16 6.25KHz channels in pairs. This, I think is just OFCOM deciding that as the band is license free, there is little sense developing a band plan for DMR and another for dPMR - the two systems have to co-exist in the same space. If they gave 50KHz to system one and 50KHz to system two, and then like VHS and Betamax, one became more popular, they'd have to change to maybe 75%/25% of the 100Hz band. It's license free, so has been allocated for digital services with low power, so while interference is possible in busy environments, the users will have no idea what is happening because they cannot hear it! It will work, or not work - they won't hear the interference, it will just cut out!

The dPMR446 system uses a different version of the ETSI standards allowing each radio to access all 16 of the individual channels available. DMR based versions would have 16 'channels' on a knob, but position 1 would be Freq 1, slot 1, with position 2 being Freq 1, slot 2 - position 3 on the dial would be Freq 2, slot 1 and so on. Users would have no idea, or need to know.

You can see that they've offset the actual channel frequencies away from the centre of each pair, making the individual channel centre frequencies a bit weird on the surface.
CH Frequency (MHz)
1 446.103125
2 446.109375
3 446.115625
4 446.121875
5 446.128125
6 446.134375
7 446.140625
8 446.146875
9 446.153125
10 446.159375
11 446.165625
12 446.171875
13 446.178125
14 446.184375
15 446.190625
16 446.196875

Trying to listen on a radio not designed to cope is going to be quite interesting. Most scanners can't cope with digital anyway, but scanners that can manage DMR won't be able to do dPMR. Front ends designed to cope with listening to 25 and 12.5KHz channels struggle with discriminating between two narrow ones. I'm sure somebody will bring one out that switches between these different standards, but there isn;t one at the moment, is there?

I wonder what people will think of a 32 channel radio that has the solid but very computerised digital audio AND the old hissy but easy to listen to analogue? How many will buy digital, but use the analogue channels, like they did with HD TV?
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