Transmission1

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 ?
Cheers

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.

From there depending on what they're using you can get a radio that'll work.

DP1400 don't work with enhanced privacy or cap+, some don't even do digital.

Scott.

If you can't read from the radio directly, one of the USB SDR sticks is probably going to be the fastest way to find the frequencies. If its digital, if you pipe it through DSD+, you'll get the talkgroups and colour codes too.

If they're only being used on analogue, just about any of the cheap chinese HTs should work.

If its DMR/TRBO, one of the chinese DMR sets will work as long as there's no fancy encryption in use (TYT MD380 etc)

You can check the OFCOM WTR site to see if you can find a radio licence issued to the company.

Use Closecall

Would close call work with digital thou ? Great idea if it would work, buy a cheap ubc72xlt find your freq and then sell on..done the same before for finding a freq that eluded me for years !!

It should do..... it's still a transmission :-/

You Sure ? unless I am reading this wrong ?

viewtopic.php?t=41189

My UBC 72XLT won't detect DMR nor will another frequency counter I have (Watson Super Searcher). All it shows is very random frequencies.

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. They sell for between 35 and 40 quid. Keep in mind that it will work distance wise relative to the power output of the transmitter that you're sniffing.

As others have said, obtaining the CPS is a sure way to find frequency TX/RX, TG, CC, SL

DSD is really only useful when you know the frequency - finding the frequency with DSD would involve transmitting and trawling from a start frequency until you come across it which is not very practical seeing as you'll be blocking the channel for other users

Closecall will detect a DMR repeater output - because although the timeslots are there the repeater output is still constant

it will not sadly - detect a repeater input or Simplex transmission

Regards

BB

the 436 / 536 / etc also struggle to receive simplex dmr until you put them into FM not NFM

Why not a simplex transmission? Simplex DMR is not divided into timeslots so if repeater output is detectable as a single unbroken tx, so should simplex.

I think you need to ask Motorola that question but as Bigbloke said it's not possible unless its a repeater output signal and there's not much you can change to make that happen sadly , closecall is what it is

It was more a statement than a question.

There is no difference between DMR repeater output and DMR simplex transmissions. They are both unbroken data transmissions, unlike repeater input tx from the slave station, which transmits in 27.5ms bursts under synchronisation from the repeater/timing leader.

I can't dispute what Bigbloke says about simplex transmissions and close call as I have no experience, but on the face of it, it isn't logical.

JohnB57 wrote: There is no difference between DMR repeater output and DMR simplex transmissions. They are both unbroken data transmissions, unlike repeater input tx from the slave station, which transmits in 27.5ms bursts under synchronisation from the repeater/timing leader.

There is a difference. Simplex and repeater input are both pulsed, they only use one timeslot out of two. Only tier 1 DMR radios may use continuous transmission mode according to the DMR specifications, and since tier 1 radios have to be band limited to the PMR446 band, there are not very many of them in use.
The repeater output, on the other hand, always fills both timeslots so it is continuous.

radiosification wrote:

JohnB57 wrote: There is no difference between DMR repeater output and DMR simplex transmissions. They are both unbroken data transmissions, unlike repeater input tx from the slave station, which transmits in 27.5ms bursts under synchronisation from the repeater/timing leader.

There is a difference. Simplex and repeater input are both pulsed, they only use one timeslot out of two. Only tier 1 DMR radios may use continuous transmission mode according to the DMR specifications, and since tier 1 radios have to be band limited to the PMR446 band, there are not very many of them in use.
The repeater output, on the other hand, always fills both timeslots so it is continuous.

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.