Scanning on a DM-1801

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freddyokel
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Scanning on a DM-1801

Post by freddyokel »

I've been scanning my local Shopwatch on my DM-1801 and I can't work out what I'm doing wrong.
It's in 'Monitor mode' and picks up the occasional conversation and shows the colour code and radio id of whoever's talking.
But... I'm only getting audio and id's about 20% of the time. The rest of the time I just get the green receive light.
I've tried picking up DMR on UK Simple Light (UK General as was) and this seems to work 100% of the time.

Anyone got any ideas? I'm probably being stupid as I'm really new to DMR.
deadite66
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Re: Scanning on a DM-1801

Post by deadite66 »

first thought was what's the signal strength like?

i'm using a rtlsdr blog dipole with mine.
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SDRPlay RSP1A + MARI-1 Marine Dipole, 24/7 Monitoring with rtl_airband
Airspy HF+ + CrossCountryWireless Loop
Retevis RT90 (opengd77) + Diamond x50
Yupiteru MVT-9000MKII, Baofeng DM-1801 (with opengd77)
freddyokel
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Re: Scanning on a DM-1801

Post by freddyokel »

Both the overs I hear which the radio reports CC and G (ID) for and the ones I don't are full signal as far as I can see.
Once a conversation starts, I can hear all the participants talk until they're finished.
It's just that during down time, the green light will come on (and the signal meter rise to maximum) with nothing reported on the radio whilst at the same time on the same frequency, my UV-5R will blast out the normal digital noise you'd expect.
At the time I'm pretty much sitting at ground zero for the Shopwatch area.
jhampton2000
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Re: Scanning on a DM-1801

Post by jhampton2000 »

So just checking back if I have understood what you say is going on here:
1. Every time the DM-1801 displays a GID/UID, Green LED is on, and you hear voice traffic?
2. There are times when the green LED is on but no GID/UID or voice heard?
3. Each time the Green LED is on for the DM-1801 you hear digital noise on the UV-5R when tuned to the same channel

I believe you will be observing (2) when there is control data being passed on the DMR repeater channel (such as portables registering with the repeater, repeater checking which radios are on the net, syncing the network etc). There wont be any voice with this. One way to check is listening to the signal pattern via (3): for data traffic it is a constant and regular buzzing noise pattern like a lorry engine. For voice traffic there is an irregular 'noisy warble' in the digital noise, with a data buzz noise at the end of transmission. Check out the sample on the right side of this page...there is voice transmission at about 13secs at the end of the 14sec clip https://www.sigidwiki.com/wiki/Digital_ ... adio_(DMR)
freddyokel
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Re: Scanning on a DM-1801

Post by freddyokel »

I'll have to have a listen when I'm in town again, but yes this is exactly the situation I'm getting.
I was thinking I was missing some voice traffic because every conversation I hear seems to start with 'Yes, receiving. Over' or something like that.
I'm guessing then that they're maybe starting with some kind of phone like dialing. Is this a DMR thing?
jhampton2000
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Re: Scanning on a DM-1801

Post by jhampton2000 »

Yes, they could be using multiple forms of alerting such as text messages over DMR or alerts via the control room
moj
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Re: Scanning on a DM-1801

Post by moj »

also what area are you in Freddy , it might help if any others on the group already know whats system is being used by your local etc ?
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Werthers
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Re: Scanning on a DM-1801

Post by Werthers »

I wish I had bought the Anytone 868 when it was going for 80 quid but now its a lot more and looks to cheap for my liking in terms of quality although they do have nice audio. I know some hams that have them.

I just find them a bit over priced for what they are and I'm not keen on the cheap display look. I would pay 70 maybe 80 quid tops for one as they have a good DMR scan feature.

I don't think my Hytera PD785's would be much use for DMR scanning unless there is a CPS hack or some kinda other software/firmware.

I have looked into the DM-1801 I've been looking for a simple way of scanning DMR. The DM-1801 did spark my interest.....
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