SDS100/SDS200: Sensitivity on DMR

[rocky28965]

While getting a TRX-2e programmed to my liking, I was running it side by side with a SDS200e.
The were both sharing the same external antenna and initially the Uniden was outdoing the Whistler.
Now it's the reverse.
I currently have them set up to scan three DMR Tier 3 sites.
I am watching them remotely on two monitors.
These are not busy sites.
During the last three hours only one site has been active and mostly with private calls.
I have only the control channels programmed into the radios.
With the Whistler I have added wildcards, while the Uniden is set on ID Searching.
Mostly they are even but there are several occasions where the Whistler has been active for maybe 30 seconds, the Uniden is still scanning.

 

[ka3jjz]

Keep in mind that Tier 3 (trunking) is not supported by the Whistler models. All the Whistler scanners can do is decode the signal. Unidens can trunk, however. Whistler never paid for the license for trunking, which is why you don't pay for that mode

Mike

 

[Ubbe]

To be clear, Whistler doesn't do control channel trunking on DMR but instead do voice channel trunking and supports all DMR types including TierIII.

You will have to program all voice channels for a site into a TRX scanner or it will only catch the conversations that are setup on the other slot of the control channels frequency.

/Ubbe

 

[rocky28965]

Thanks for the help guys, as a keen learner I do appreciate it.

I don’t have access to a list of the voice channels or who the users are, but I am compiling an ever growing list of them, which will be eventually programmed into the radios.

This post was more about the SDS200 and why it isn’t pulling in all of the same channels as the Whistler.

One particular site has two frequencies, one being the control channel and the other acting more like a DMR One Frequency, although it shows as DT3 under Digital Type in the logging window.

It is this frequency the SDS200 won’t decode a private call from.

If it’s not a private call it will decode it.

It will decode private calls from the control channel.

The log from the Whistler does give me all that info, but I’m just curious why the Uniden wont decode it.

Which leads to another question:

As the majority of the calls on this channel are private, can you enter TGID for a private call into the SDS200?

 

[Ubbe]

As the majority of the calls on this channel are private, can you enter TGID for a private call into the SDS200?

IDSearch include private calls. You can also program a TG as a zero and a dot and will show as i0 in the programming with a text tag as Private Call, if you do not want to use IDSearch that opens up for all TG's to be monitored.

Information about Private Calls are only briefly sent out on the control channel and if you are scanning other sites/systems or are monitoring a TG it could miss that control channel info. A whistler scans all voice channels and will always see that private call and starts monitoring it.

/Ubbe

 

[rocky28965]

Here is another query with the SDS200
Looking at the Proscan History Logging screen.

The private calls are shown in the Talk Group column with a small "i"in front.
Example i1085335
Also in the Channel column as TGID: i1085335 (SRC) i1085339 (DST)
Is the number 1085335 a TGID?

 

[Ubbe]

Uniden doesn't bother to change the display during private calls so it will look as if a TG are being used. Private call do not use any TG, it is only user iD's in work. Source and destination SRC DST tells which user that currently transmits and which that receive.

/Ubbe

 

[rocky28965]

Just getting back onto this thread.
I've tried three Uniden radios, now and none will match the Whistler scanning the same sites.
Tried with and without talk groups.
They are better on the MotoTRBO but not so on the DMR One Frequency sites.
Odd really, as I initially found all these sites on a search with my SDS200e
I must be doing something wrong here.

 

[Ubbe]

Search that locks on to a carrier, or programmed as conventional, works fine with Uniden scanners. It is when you program a frequency as trunked using a control channel that it can fail more often than a scanner like TRX that also do carrier scan of voice channels.

Using only the control channel to detect DMR conversations needs a perfect decode function, something that seems to not be the case in Unidens scanners. We have high hopes for the promised firmware for most Uniden scanners that has an improved decode performance.

/Ubbe

 

[rocky28965]

Does the squelch setting make difference on DMR?
I've been using 4.

 

[buddrousa]

Turning the Squelch UP is the same as turning the Volume DOWN.
If you turn the Volume down too much can you hear it?
You can get the Squelch set too High that the Receiver does not receive a signal.
The Problem with Digital is weak signals sound just as good as strong signals.

 

[Ubbe]

Does the squelch setting make difference on DMR?
I've been using 4.

It's like what buddrousa says, it sets the signal strength where the receiver will accept a signal. If you use NFM, or the auto setting uses it from the bandplan, the squelch can close on digital signals if they are weak. FM makes the squelch work better in those cases. If you set squelch to 0 it will not interfere at all with the signal and the receiver are always listening, but that also makes it scan super slow at about 4ch/s but can be used as a test to see if the squelch are the problem.

Usually a setting of 2 are normal so 4 are a bit tight but you might prefer that for analog signals to not receive noisy transmissions, but unfortunately there's the same squelch used on digital signals so it could clip those and make it difficult to decode digital transmissions.

/Ubbe