DMR Decoded on DSD+ but not CS701

I'm using a discriminator tapped scanner and DSD+ to listen to a very small local public safety agency that uses a conventional TRBO VHF repeater, with no problems. Using DSD+ and the scanner I am able to hear audio just fine, and have identified the relevant frequency, time slot, color code and talkgroup of sheriff dispatch when near the PC.

I recently purchased a CS701, thinking this would give me a convenient way to monitor the same radio traffic on the go. So far, I haven't been able to get it to work. I'm struggling to imagine what could cause a CS701, which appears to be properly programmed, to not pass voice traffic on channels I can monitor just fine using DSD+ on the PC.

To program the CS701, in the Digital Contact tab, I set a Contact Name of Sheriff Dispatch, selected a Call Type of "Group Call" and entered the talkgroup number from DSD+ into the "Call ID" field.

I then created a Group List called Sheriff Dispatch under the Digital RX Group Call tab, and added the "Sheriff Dispatch" Contact to the "Contact Member" field.

In the "Channel Information" tab, I set the "Channel Mode" to "Digital," entered a Channel Name of "Sheriff Dispatch", entered the RX and TX frequencies (the same, since I'll only monitor anyway), and checked the "RX Only" box (though I've also tried unchecking this). Under "Digital Data," I set the Contact Name to "None" since I won't be transmitting (though I've also tried setting this to Sheriff Dispatch), set the Group List field to "Sheriff Dispatch," set the Color Code to the CC I found using DSD+, and set "Repeater Slot" to the time slot I found using DSD+.

I created a Zone, and put the channel Sheriff Dispatch in that zone. Then I programmed the radio. I powered up the CS701 and it displays "Sheriff Dispatch." When there is voice traffic on Sheriff Dispatch on DSD+, I hear it fine through the PC, but do not hear the voice audio through the CS701. When there is voice traffic on Sheriff Dispatch on DSD+, the green light on the CS701 lights up, and the signal meter on the screen goes to full scale. But no audio. Pressing the Monitor button (side button 1) does nothing.

Thinking this could be as simple as a bad speaker in the CS701, I programmed an analog frequency and transmitted on another radio. The CS701 passed that audio just fine.

Anyone have any ideas what could be the issue here?

So very puzzling that I hear voice audio just fine on DSD+, and the CS701 is clearly receiving the signal based on the green LED and signal meter, but audio isn't passing through the CS701's speaker. Of course, I double checked that the programmed Group Call number matches the numbers that follow "TG=" in DSD+, and that this is in fact a Group Call (DSD+ displays "Group Call; TG=###### RID=######## Slot=2").

Dan

Continuing to try to answer my own question here: Could the circumstances I described be caused by RAS? Any way to determine whether the system uses RAS?

Dan

If your radio is showing activity in the display but not decoding, 99% probability that the repeater is using RAS. You can always call the department and ask their radio tech.

You can't have the same tx and rx frequency. Change the tx to something else, make sure rx only is checked, and try again.

Essentially, the radio behaves totally differently for simplex versus repeater operation. With the same frequency for transmit and receive, the radio assumes simplex.

Um, Huh? If they are running RAS, the radio is NOT going to receive. If it DOES, please explain how, as this is another security issue with RAS.

Kirk said:

Essentially, the radio behaves totally differently for simplex versus repeater operation. With the same frequency for transmit and receive, the radio assumes simplex.

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Genius. Working great now. The repeater apparently isn't running RAS; I just had no idea the transmit and receive frequencies had to be programmed differently just to be able to hear a repeater I don't plan to transmit on anyway. Thanks!

on DSD+ but not CS701

just wondering if this can be done on a capacity plus system, any ideas?
my be off topic?

DanRollman said:

So very puzzling that I hear voice audio just fine on DSD+, and the CS701 is clearly receiving the signal based on the green LED and signal meter, but audio isn't passing through the CS701's speaker. Of course, I double checked that the programmed Group Call number matches the numbers that follow "TG=" in DSD+, and that this is in fact a Group Call (DSD+ displays "Group Call; TG=###### RID=######## Slot=2").

Dan

Click to expand...

Do you have BOTH timeslots programmed in the 701?

Voyager said:

Do you have BOTH timeslots programmed in the 701?

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Yes. Both timeslots are used (two different groups). Both a programmed as separate channels in the 701, and both are working great now. I just had to get a different transmit frequency programmed in there, even though transmit is disabled. Thanks.

tyytor said:

just wondering if this can be done on a capacity plus system, any ideas?
my be off topic?

Click to expand...

Yes. Or, sort of.

To monitor a group on a Capacity+ system with a CS700/CS701:

1. Program a separate channel for each voice frequency and time slot on the system (e.g. excluding the frequency/time slot used by the control channel). The names have to be different (so call them, say "Dispatch 1", "Dispatch 2", and "Dispatch 3," in the case of a two-frequency Cap+ system (e.g. both time slots on frequency 1 are voice, slot 1 on frequency 2 is voice, and slot 2 on frequency 2 is control so we ignore that one) where you want to monitor the group you know is called "Dispatch".

2. Program each of those voice channels to monitor your desired group ("Dispatch").

3. Set up a Scan List called, say, "Dispatch," that includes each of the 3 channels you just programmed.

4. Go back to each of the channels you just programmed and set each of those channels to scan the Scan List "Dispatch" that you just made. Turn on auto-scan.

5. Write the radio.

6. On the radio, select any of the channels Dispatch 1, 2 or 3. Doesn't matter which. It will automatically start scanning Dispatch 1, 2 and 3, looking for the DIspatch group whenever it is active on any of those channels. You really don't need the control channel for this.

Does it work? Yes. Perfectly? Not really, because there is a delay as it scans through those channels, especially since the CS700/701 aren't very fast at scanning. Thus, you may miss the first part of some transmissions before you begin to hear audio. Obviously this will be worse on busier systems with more channels in use, since the CS700/CS701 has more active channels to sample before stopping on the talkgroup you're interested in. This isn't the same as actually monitoring the control channel and having your radio follow instructions to instantly switch to a voice channel that just became active with the conversation you're interested in. But it's close.

I'm using the above on a Cap+ system with 6 channels (3 frequencies, 2 slots on each, 1 is control, so I really only scan 5 channels). Again, occasionally I can tell it's clipping a bit off the first part of a transmission, but it's a lot better than nothing.

Dan

DanRollman said:

Yes. Or, sort of.

Click to expand...

To clarify, if the Cap+ system you're interested in is running RAS, or basic or enhanced privacy, ignore everything I wrote above - it won't work. What I wrote above works only on a Cap+ system that does not use RAS or privacy.

Dan

DanRollman said:

1. Program a separate channel for each voice frequency and time slot on the system (e.g. excluding the frequency/time slot used by the control channel).

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Actually, Capacity + Systems rotate the control channel, so you need all the channels/slots programmed in.

It's Connect + systems that use a dedicated control channel.

Voyager said:

Actually, Capacity + Systems rotate the control channel, so you need all the channels/slots programmed in.

It's Connect + systems that use a dedicated control channel.

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Of course you are right about that. It is a Connect + system I monitor using the instructions above. My mistake.

Voyager said:

Actually, Capacity + Systems rotate the control channel, so you need all the channels/slots programmed in.

It's Connect + systems that use a dedicated control channel.

Click to expand...

Connect+ can rotate also.

DanRollman said:

Of course you are right about that. It is a Connect + system I monitor using the instructions above. My mistake.

Click to expand...

Even on a Connect+ system the non-control channel time slot can be used for voice.

Remember if you are listening to a repeater there are two time slots. In simplex mode there is only one time slot. The MotoTrbo has software that allows them to have two time slots in simplex (one radio becomes the master and manages the time slots). The 701 only sees one time slot in simplex and won't decode the output of a repeater when in simplex. It is a Motorola "enhancement" to the DMR standard.
BB.

Connect Plus will only have the control channel (s) on slot one. It can rotate depending on how it is programmed in the XRC/XRT9000 controller.
Capacity Plus -idle channel- (s) will be any channel available for voice calls.
IP Site Connect beaconing will be one or both voice slots (or NONE) depending on how the site connect is configured at each site.