mototrbo Frequencies

Scanning radio frequencies in Wales
gerald123
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Re: mototrbo Frequencies

Post by gerald123 » 16 Feb 2015, 14:02

on my sdr sharp i have got funcube dongle as source device.. input devise is virtual audio cable..and virtual audio cable output..to dsd 1.7 ..to pc speakers i am using a discone antenna in my garden up on a pole about 20 feet of the ground.................i can see very small spikes which are there all the time but nothing difirent.

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welshevo
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Re: mototrbo Frequencies

Post by welshevo » 16 Feb 2015, 16:08

no im puzzled a discone 20 ft off ground level should be finding frequencies from a far! your fun cube gain set to auto? or manual? and in sdr can you tune your dongle? normally up too 49db dont crank it all the way just small steps to see if that improves......the Trbo beacons are normaly every 2-3 seconds and every 10 seconds is a burst of data so will notice a thick line ! let me get home later and ill see what i can find out for you regards to whats up your ways..... im shocked !!!
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Re: mototrbo Frequencies

Post by gerald123 » 17 Feb 2015, 00:32

i forgot to say i have got the same set up for pager decoding with [ PDW software] using sdr sharp with pdw works great on that...... like you say i should be getting some sort of signal to decode

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Re: mototrbo Frequencies

Post by gerald123 » 17 Feb 2015, 01:18

i just spent about an hour and made a dipole antenna for 453 mhz and put it outside my bedroom window..i found a frequencie on 453 .464 and it did start decoding . what i am getting is this [ dmr cach err slot 2 bs data err1 cc=2 idle ] i did get some voice comming through but it only lasted about 10 seconds........but it sounded intermitant, i changed to my discone again it is not showing any spike. changed back to dipole every thing seems ok.so getting somewhere now i hope

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welshevo
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Re: mototrbo Frequencies

Post by welshevo » 17 Feb 2015, 08:10

im pretty shocked! about the Discone! but hey if your getting some DMR with the dipole! then use that! and good luck now your finding Trbo !! and enjoy if i can help any more just let me know :D
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Re: mototrbo Frequencies

Post by gerald123 » 18 Feb 2015, 16:13

i wounder if you could help me again.........i am getting audio but it is very intermitant i cant seem to find the right setting to make audio any better...i had someone speaking on 453.463 this afternoon but i could only make bits and peases out of what they were saying.

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Re: mototrbo Frequencies

Post by welshevo » 19 Feb 2015, 10:22

no problemo.... so im guessing in SDR# you have an audio output set to VB virtual cable? and DSD will decode ....if the speech in DSD is very broken (like a tv free view box losing signal, ) this could be a weak signal... or could be mode set incorrect on SDR# i found using NFM so much better and the voice was clear.... the other problem you could be having is your decoding a Encrypted signal... this will sound broken and in general terrible! haha let me know.....
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Re: mototrbo Frequencies

Post by digitalradiohacker » 19 Feb 2015, 13:40

Prestatyn shopwatch are using 455.475

Colour code 1
time slot 1
group 1
group 5
and group 10

No encryption

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Re: mototrbo Frequencies

Post by welshevo » 19 Feb 2015, 15:26

Digitalradiohacker? is that you Dave? M30DQ? if so ill pm you need to ask for your expertise and sales! haha
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Re: mototrbo Frequencies

Post by digitalradiohacker » 19 Feb 2015, 16:04

Sorry that isnt me though I do know Dave

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Re: mototrbo Frequencies

Post by gerald123 » 20 Feb 2015, 01:12

welshevo wrote:no problemo.... so im guessing in SDR# you have an audio output set to VB virtual cable? and DSD will decode ....if the speech in DSD is very broken (like a tv free view box losing signal, ) this could be a weak signal... or could be mode set incorrect on SDR# i found using NFM so much better and the voice was clear.... the other problem you could be having is your decoding a Encrypted signal... this will sound broken and in general terrible! haha let me know.....
thanks again.....i have checked all the settings in sdr and the way virtual audio cable is set up all seems ok ...i am using DSD+ i have tried to download dsd 1.7 and ca not seem to download it have you or anyone got a link to download DSD 1.7 just to see if it would work better .or would it make any diffirense.. i could try a antenna amplifier but i do not want to take a chance on damaging my funcube dongle. this is the only frequencie 453.463 i am picking up to decode on DMR {bnghd}

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welshevo
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Re: mototrbo Frequencies

Post by welshevo » 20 Feb 2015, 13:01

something is definatley wrong.... stick with DSD 1.5 as this is the most stable? as 1.7 hasn't long been released i think? regardless of versions of DSD ... SDR# should be pretty much full of various peaks on the graphs with analogue, DMR, even tetra wave forms... especially using a Dipole? i have a friend who lives in rhondda and they confirmed plenty of DMR and analogue up by him! and hes using a standard 25-1500 MHz mag mount cheapo antenna out of his window! have you tried the Zoom settings, and bandwidth settings etc? take a read through of this and see if any of it can help you out??
(http://www.atouk.com/SDRSharpQuickStart.html) you probably already have done or know what to do but always worth checking it out...

hope this helps you a bit more.....
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Re: mototrbo Frequencies

Post by bigbloke » 28 Feb 2015, 11:12

Wrong section to be discussing this perhaps chaps ? Mods: suggest a topic move ?

But lets be constructive!

I'm assuming your using windows - DSD plus produces superior decodes than the legacy DSD

There are many issues that affect DSD+ with RTL SDR sticks

the usual culprits are:

* Wrong inputs / outputs set up in DSD - use the DSD plugin for SDR#

* incorrectly configured virtual audio cable - I use VBCable - I found it much easier and more reliable

* configuration changed in dsd+ sdr# plugin but not applied (under the configure menu there is an apply button does not appear on some screen resolutions - notably widescreen ones - you might just see the top of it )

* A badly tuned DSD+ installation (download DSDtune - capture a raw DMR audio sample [Press R during a trbo conversation] run dsd tune using the raw input file as the source not your FCD and it will give you some starter settings - input those into the DSD+ plugin settings configure page )

* Use of realtek audio input codecs (I know of 8 machines now with this problem - it varies between no slot 1 only slot 2 , or signalling but no clear voice or vice versa - no known resolution yet

Some people (myself included) get better decode by using Wide FM but constraining the bandwidth to 12.5 KHz - makes no sense but ... its better here - admittedly that is on at R820T RTL-SDR tuner chip.

If you have a radio with discriminator out or 9600 packet out it is FAR better to tune up DSD+ using that and then try and sort out sdr# this is because the discriminator / packet output of a
traditional radio is much, much cleaner than that you get from SDR# (I compared this with the scope in DSD+)

Hope that gives you some food for thought / things to check

regards

BB
Last edited by bigbloke on 28 Feb 2015, 11:58, edited 3 times in total.

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bigbloke
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Re: mototrbo Frequencies

Post by bigbloke » 28 Feb 2015, 11:48

gerald123 wrote: i can see very small spikes which are there all the time but nothing difirent.
put a multimeter on your discone antenna cable and check for a short circuit between the inner and the outer at the radio end of the plug- there should be none

Then using something like a car jump lead connect the disc of the discone to the cone of the discone then using your multimeter, make sure you DO get a
short between the inner and the outer of the coax at the radio end - if you dont - broken cable / dodgy antenna plugs or antenna fault

regards

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Last edited by bigbloke on 28 Feb 2015, 11:55, edited 1 time in total.

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Re: mototrbo Frequencies

Post by bigbloke » 28 Feb 2015, 11:54

welshevo wrote:the Trbo beacons are normaly every 2-3 seconds and every 10 seconds is a burst of data so will notice a thick line !
the 2-3 seconds is only true for a capacity plus (multi site / frequency) system - not a standard trbo / DMR

sync bursts can be more than a minute apart

regards

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