SDS100/SDS200: No Sound/"Overpowering" System

[Dexter2]

Hi guys,

As many of you have seen, in my near two years of having this radio, I am starting to experience transmission with no sound during the middle of the transmission. It is rare, but more noticeable in recent months. Observing when this happens, not always but the signal bars drop out and NOISE increases greatly. Once or twice, the screen will show as a normal transmission, but there would be no sound shortly after. But, then for the rest of the time things would be fine.

Also, if you live close to a dispatch center for entire area whether it be county-level or city-level. Can that have an effect on how you receive other systems that you may have programmed?

 

[tvengr]

Is it on just one system or several?

 

[Ubbe]

the signal bars drop out and NOISE increases greatly.

If you got good signal strength from that system then enable the attenuator setting to it and see if it changes anything. The automatic gain controller will reduce the signal level if it sees a too strong signal, -60dBm or stronger, within a +/-7MHz wide frequency window that might reduce your signal below what can be received.

If it's just a "normal" interference you can try and set the IFX to the frequencies that are used in the site you are monitoring. It doesn't sound like the beginning of a cold solder joint issue but can't be excluded. It's a ticking time bomb in many SDS100 that had sloppy soldering of the J401 connector from the factory. Hopefully Uniden will treat csj faults as they did with the clock and display issues in other scanners and have them repaired on their cost even when the warranty have run out.

/Ubbe

 

[tvengr]

If it's just a "normal" interference you can try and set the IFX to the frequencies that are used in the site you are monitoring.

The setting of the filter may be helpful also.

 

[IAmSixNine]

Is this conventional or trunking? Analog or P25?
Stock antenna? Have you adjusted filters?

 

[Dexter2]

For the drop out and no more sound its just one system. Its a Trunking P25. I do think the battery is starting to deplete though, as when this change started happening, the radio seems warm more often and the battery life is significantly lower. In a given day, I would say I'd miss four transmissions due to the silence or dropped signal. The antenna is a Remtronix, not the original box antenna.

When I have more than one system turned on, it seems the "over powering one" seems to stay on that one the most, it cycles through the others real slow, but indeed stays on the others if a transmission comes in.

Attenuator is horrible, no matter what system I try it on. Everything goes blank every time. Not sure if its the density of the urban area, but filters do not really help, unless its turned Off or Wide Invert.

If you recall, that one P25 system, I used to speak about. It works with Squelch on 2, in VERY specific areas now. I have just left it on 1, just to "play it safe" and leave the radio alone.

 

[buddrousa]

Sounds like you do not have enough signal what are you calling a good signal.

 

[Dexter2]

Full signal bars and the word "DATA".

 

[tvengr]

Is there a new radio broadcast station that just went on the air or did a TV station recently change channels that you have to reprogram your TV? There is a possibility that your SD card is corrupted. Try reprogramming the favorites list. It could also be the cold solder joint problem.

 

[DudleyG]

The word "DATA" tells you that someone is transmitting DATA versus talking (voice) on the channel. For example, on a police talk group, the dispatcher might call a unit (voice) and tell them to go to 123 Main Street for a robbery. The dispatcher might also transmit the call plus additional information (DATA) to a machine installed in the cruiser that will show up on a screen and/or can be printed by the officer.

EMS units often use a verbal dispatch plus DATA (medical information) to send information to the EMS field units and sometimes even location/directions to the location.

Some police unit have machines installed in their cruiser where they can run operator license checks and registration tags via a terminal and get the results back. That will show as DATA with no sound coming thru the speaker.

I see the "DATA" with full bars often, but when people are talking you will see P25 and on a P25 Type 2, you will of see P25 Slot 1 or P25 Slot 2.

Also police and fire units can send messages between units that will show as DATA and you won't hear anything when that happens.

Sounds like you unit is working just fine to me.

 

[mc48]

The word DATA appears to show you that the scanner is receiving DATA from the system not that MDT DATA is being transmitted between units.

LNK appears when data is received on a voice channel in Receive/Hold Modes.

DAT appears when data is received on a control channel in Receive/Hold Modes. Easier to Read SDS100/200 Digital Scanner Manual (marksscanners.com)

 

[Dexter2]

Appreciate all of your replies. DATA and bars disappears when once a transmission appears. Usually when there is talking it shows as P25 Slot 1 or 2. But now, out of the blue it will go silent during talking and it still will flash/or show the P25 slot. When the transmission is over the DATA and signal bars come back as normal. Then the next transmission will either be gargled or normal it all depends in that moment. Its just I'm noticing more "missed/gargled" transmissions.

Nothing I'm aware of by the TV or channels.

 

[Dexter2]

When it goes silent after a transmission starts, it sounds like faint air blowing.

 

[tvengr]

Which P25 system is giving you problems? What is your city, county and state so that we can lookup the proper system and site info in the database. If you attach the favorites list with that system, we can check your programming for problems. Go to the File tab in Sentinel and Export to hpe file (Favorites List). You will need to right click on the exported file and Send to Compressed (zipped) folder to be able to attach it. Click on Attach files and Open the zipped folder.

 

[Dexter2]

I started over and reformatted my SD.

 

[tvengr]

I don't see any problem with the programming. In the sites, I suggest you try different filters. Invert and wide invert often work well. If that doesn't help, we can try IF exchange. In the Profile Editor, under Miscellaneous tab, bottom right, try adding the frequencies for the 3 site control channels to start.

 

[Dexter2]

That's why I for one minute think its a particular radio issue, then the next I think its just a system issue because no other favorite list has this problem and when I travel to two very specific places the radio works fine with this system.

I live close to a command center, which also uses 800 frequencies. Which is why I originally asked could it be like an overpowering system? I can "factory reset" the radio with settings fresh out the box and not one issue with that system.

My antenna to me seems bent, others say no and it doesn't screw on any other way. That's another reason why I thought could it be a mixture of antenna connection and some internal hardware problem. But, if that was the case I wouldn't receive other systems without tweaking any Filter or setting.

On the other hand, the Attenuator seems like the radio is dead in the water, no matter where, when, or what system I try it on.

 

[Ubbe]

But, if that was the case I wouldn't receive other systems without tweaking any Filter or setting.

Filter settings are frequency dependent. A 750MHz frequency could require one filter and 850MHz another filter setting or IFX.

On the other hand, the Attenuator seems like the radio is dead in the water, no matter where, when, or what system I try it on.

The attenuator will reduce the signal by 20dB. If you have a signal at -95dBm it will be reduced to -105dBm which usually are below the level where the scanner are able to decode a digital signal. You seem to have very low signal levels. Depending of the quality of the hardware filters in the scanner they could attenuate 5dB-10dB when used so try the Off setting which will restore the sensitivity if there's no interference problems.

/Ubbe

 

[a417]

The word "DATA" tells you that someone is transmitting DATA versus talking (voice) on the channel. For example, on a police talk group, the dispatcher might call a unit (voice) and tell them to go to 123 Main Street for a robbery. The dispatcher might also transmit the call plus additional information (DATA) to a machine installed in the cruiser that will show up on a screen and/or can be printed by the officer.

20 years ago or more, before the prevalence of cellular data systems integrated into modern vehicles, maybe so. Limited bandwidth, limited distance, extra hardware, tons of fuss. Not so much anymore. It's better now for each vehicle to have a commercially supported infrastructure (Verzion, ATT, Sprint) pumping data at fastest consumer speeds available, and the system to VPN in to the department for it's data needs.

It's a lot easier to troubleshoot a 5G sim card on a tablet than it was to bust out the RSS for the MDT modem mounted in the unit and try to figure out what the hell was going on.

 

[Dexter2]

Filter settings are frequency dependent. A 750MHz frequency could require one filter and 850MHz another filter setting or IFX.
The attenuator will reduce the signal by 20dB. If you have a signal at -95dBm it will be reduced to -105dBm which usually are below the level where the scanner are able to decode a digital signal. You seem to have very low signal levels. Depending of the quality of the hardware filters in the scanner they could attenuate 5dB-10dB when used so try the Off setting which will restore the sensitivity if there's no interference problems.

/Ubbe

It appears to be low signals but not consistently. The TG constantly flickers when a transmission comes in most of time with Squelch on 2, like in my previous threads. Now, with the silence, it seems when a transmission comes in (only on this system) it starts off fine, then the signals go to one or two bars and P25 Slot disappears, but I can still see the UID being they're literally talking, I just can't hear it.