what would i need ?

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Re: what would i need ?

Post by radiosification » 23 Sep 2017, 14:50

JohnB57 wrote: I believe you are incorrect in respect of simplex (tier 2) as there is no infrastructure available for the use of time slots and therefore no requirement or means for transmissions to "pulse". Any TS selected in CPS is thus ignored. However, if you are able to cite technical documentation that says I'm wrong, I'll be glad to have learnt something - I haven't been able to find any. And I do acknowledge your own background by the way.

edit.... Eating my words because simplex DOES, as you say, pulse, even though timeslots are not available. Anybody have any waveform images? Going back to Close Call, it seems that although you need to be near to the source, you can be too near.
No problem. I will explain for you so you understand why.
You're correct that the timeslot is ignored, but that doesn't mean it would transmit in both slots. It simply transmits half the time and the receiving radio listens without knowing which timeslot is being used, since there is no way to synchronise it. This means that if you program one radio to transmit on slot 1 on simplex and another to listen on slot 2, the listening radio will still hear the transmitting radio.

Why does it work like this? Well since the hardware is there to do TDMA anyway, it may as well be used in simplex too. It saves battery by transmitting on half the timeslots.

There is also a feature called DCDM on motorola radios which does allow correct timeslot use (so two conversations simultaneously) on simplex mode. It sends synchronisation data automatically on a set time period. This does use more battery but it allows 6.25KHz equivalency since both slots are used. Not all radios have this feature, and it is not enabled by default, so normally simplex use is just done ignoring the timeslots as described above.
This is a good site with an explanation of DCDM: https://cwh050.blogspot.co.uk/2012/12/dcdm.html

With regards to close call, I have found that it simply doesn't work on DMR simplex or repeater inputs since it seems to require a continuous signal to be able to detect it.
If you're interested in digital voice, check out my YouTube channel:
http://www.youtube.com/radiosification

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Re: what would i need ?

Post by bigbloke » 03 Oct 2017, 21:49

feedback deleted by edit - repeating what other posters had already said

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Re: what would i need ?

Post by bigbloke » 11 Oct 2017, 06:15

forgot to add

if your company uses RAS with DMR - no chinese radio will work

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Re: what would i need ?

Post by Radiotronics » 04 Nov 2017, 14:14

nordhavn wrote:
11 Sep 2017, 15:22
We use Motorola dp1400's at work . I have no idea what frequencies they are on I've asked if I can see the paper work that goes with them but not a lot of information on them . I believe they are mototbo . What would I need to listen to them or even transmit , would any of the cheap Chinese ones be OK ?
Here's the boring bit, but worth pointing out.

It sounds like you have been very open with your employer if you've asked them for the info on the radio system. That's good because meddling with a radio system - even adding an unauthorised radio to the system can result in dismissal in most companies.

Nevertheless, the fact is that they might not know themselves and it might be managed by radio comms company.

If they use a radio comms company who supply, program and manage their radio fleet they won't have given the underlying spec. to their client, your employer, unless they've specifically asked for it. And even then it's in their remit of duty of care not to release this information if it could be open to abuse in any way.

If you just want to listen in, then that's really no bid deal. But if you want to add to the system, then get it in writing before you do anything that could compromise your job. Worse still, the system might not actually belong to your employer and might be on rental or lease. If you tamper with any radio equipment or add unauthorised non-type approved equipment you could be liable to prosecution either by the company who owns it or by Ofcom under the misuse of radio communications equipment legislation.

So always ensure you're 100% transparent and always get it in writing that you're authored to do whatever you want to do.

That's the boring bit over.
normal wrote:
12 Sep 2017, 01:48
You can check the OFCOM WTR site to see if you can find a radio licence issued to the company.
Officially, access to the Ofcom WTR seems to have disappeared and does not appear to be returning any time soon. There are other sources of this info, including the relatively new monthly CSV download. But nevertheless, this does not give you all the information you need as it's just the frequencies - not the CTCSS or colour codes/talk groups etc. So whilst it gives you some info to listen in, that's all you really get from this source.
Scott_93 wrote:
11 Sep 2017, 17:06
Easiest option is to lay your hands on a copy of the mototrbo CPS and read from the radio ... Programming cable is a standard micro-USB cable, below the earpiece connector is a rubber flap, get a flathead under it and pull the flap out and you'll see the connector.
Indeed, this is by far the easiest way to read a Motorola DP1400 radio. You need a micro-USB cable with a thin plug. The type that comes with a Samsung or Sony smart phone usually fit ok. You can obtain the MOTOTRBO software from many sources online. It's good to note however, any radio with a firmware version below 2.0 requires MOTOTRBO v13.6 or below and radios with firmware version 2 and above require MOTOTBO v14 and above.

Another thing to note is that the DP1400 (and all MOTOTRBO radios) might have a programming password. If it does, there is absolutely no way to read, or even write, to that radio. Motorola have tightened up the MOTOTRBO security so, without that password, there is virtually no way to ready or write to that radio ever again.
Scott_93 wrote:
11 Sep 2017, 17:06
DP1400 don't work with enhanced privacy or cap+, some don't even do digital.
Here's a top tip. The Motorola DP1400 is available in two flavours, analogue only and analogue-digital hybrid. If it's an analogue only version, they must and can only be using it in analogue*. Look on the back of the radio, if the model number is MDH01JDC9JC2AN it's a VHF analogue-only DP1400, if it's MDH01QDC9JC2AN, it's a UHF analogue-only DP1400. If it's MDH01JDC9JA2AN (VHF) or MDH01QDC9JA2AN (UHF) it is a digital-analogue hybrid radio and you're none the wiser.

* Caveat: DP1400 analogue can be upgraded to a digital radio, but it's so expensive no-one ever does it.
humaxf1 wrote:
13 Sep 2017, 13:57
What you need to sniff DMR is a Surecom 401 PLUS (must be the plus version as it has a digital mode). It won't give you TG or CC or SL but it will display the frequency.
Scott_93 is right, there's no way it's a Cap+ and DP1400 does not support any additional enhanced privacy. And as humaxf1 said, you can read it using a cheap Surecom 401 PLUS. However as humaxf1 also correctly identifies is that it won't give you the Talk Group or Colour Code so still only 1/2 the info you need.

So the best approach is to, with the consent of your employer, contact whoever supplied the radios. Be 100% up front with them about what you intend to do.

You will most likely find that they'll be 100% happy with your listening in, and might even give you a hand by providing the programming info you need. And they might even help you to add more radios to the system. One thing is for sure, unless they have genuine cause for concern, they will unlikely be difficult and will usually help in any way they can.
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Re: what would i need ?

Post by radiosification » 05 Nov 2017, 11:48

Radiotronics wrote:
04 Nov 2017, 14:14
Another thing to note is that the DP1400 (and all MOTOTRBO radios) might have a programming password. If it does, there is absolutely no way to read, or even write, to that radio. Motorola have tightened up the MOTOTRBO security so, without that password, there is virtually no way to ready or write to that radio ever again.
I'm not sure about the DP1400 specifically but in the rest of the gen 2 radios they actually removed the write password option pretty quickly because (I imagine) so many people managed to lock themselves out of their own radios. So it is highly unlikely that the radios in question have a write password on them, as they would have to be running one of the specific firmware versions that did have that option. If they had been updated since then, that option would not be available.
If you're interested in digital voice, check out my YouTube channel:
http://www.youtube.com/radiosification

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