SDS200 Goes Silent

[pkrawetz]

I've read through several threads but couldn't find one that matches my scenario. I do have a similar issue where it just locks up on a channel (not necessarily a digital trunked channel) from time to time but this is different.

If I leave the scanner on for long periods of time, I noticed it goes silent even though it's scanning. Yes the volume is up and squelch is set to 1. I have both analog and digital trunked systems programmed. It doesn't lock up on any one channel. I have to shut off/turn on the unit in order to start receiving transmissions.

Firmware version:

• Main:Version 1.21.00
• Sub :Version 1.02.01

Any thoughts?

 

[tvengr]

Replace the SD card and program it again.

 

[pkrawetz]

@tvengr reformatting it won't work? What is the technical issue with the card?

 

[tvengr]

Have you tried reformatting the card? Sometimes, that will solve the problem. The fact that it fails after a period of time indicates the problem may be temperature related. I had one scanner which appeared completely dead. The formatter didn't even recognize the SD card. In the case of any strange problems, the SD card should always be suspected first and eliminated before doing any other troubleshooting. SD cards are a major cause of scanner failures.

 

[trentbob]

I agree with the SD card problem but I think you said your squelch was open as you leave it on1? Squelch should be set at 2.

 

[pkrawetz]

I agree with the SD card problem but I think you said your squelch was open as you leave it on1? Squelch should be set at 2.

If the squelch was on one and it caused an open channel it would lock on that channel.

 

[pkrawetz]

Have you tried reformatting the card? Sometimes, that will solve the problem. The fact that it fails after a period of time indicates the problem may be temperature related. I had one scanner which appeared completely dead. The formatter didn't even recognize the SD card. In the case of any strange problems, the SD card should always be suspected first and eliminated before doing any other troubleshooting. SD cards are a major cause of scanner failures.

It's 75 degrees here and the scanner is not in direct sunlight. Outside case is cool. I'll give the SD card a shot. Thanks for the suggestion.

 

[trentbob]

If the squelch was on one and it caused an open channel it would lock on that channel.

At a squelch of 1 a conventional analog frequency with no tone squelch would lock up, squelch is open at a setting of 1. A conventional Channel with a PL tone would stay quiet, a system would stay quiet but not necessarily work right especially with digital systems, with an SDS 200 the squelch has to be 2 or above.

 

[trentbob]

Just for fun, program Marine Channel 16 156.8 and place the squelch on 1 and see what happens. Then turn it to 2 and see what happens.

 

[tvengr]

If the squelch was on one and it caused an open channel it would lock on that channel.

Digital trunked systems will scan with the squelch open. Paul, the former Uniden rep, suggested leaving the squelch open when having problems receiving simulcast systems on older scanners. Conventional frequencies with CTCSS or DCS tones will not hang up with the squelch open. If a conventional frequency is using carrier squelch, the squelch normally needs to be set at 2 on an SDS200. The internal temperature of components in an SD card is what matters. I have seen solid state devices develop leakage currents and fail with an increase in temperature. Leakage currents can also set up a time constant after which a circuit will be cut off and fail. Turning the scanner on and off can reset the time. We had an audio console where the audio output on an IFB circuit failed after a period of time. I found a resistor missing from the circuit board which caused the input voltage on an op amp to gradually build up and cut off the device. You need to remember that the SD card controls almost everything in the scanner including the audio type. Everything you program into the scanner is stored on the SD card.

 

[Ubbe]

There have been several reports of SDS200's that stops receiving and works only after a Uniden repair.
The SDS200 have some component issue, or a firmware bug, that ignores the carrier detect or do not unmute as it should.

How the SD card scanners work are that they first load all frequencies from the SD card for the favorite files you scan and store them to its working memory in RAM. Then the scan function just scans those frequencies until it detects a carrier and stops scan and then checks the SD card what the credentials are for that frequency, analog and if its any subtone or digital and what mode and use that info to try and decode the audio. If it has problem reading the SD card info for a detected frequency it seems that the firmware code doesn't have enough error traps to get out of a bad read and show an error on the display, it just stops working without indicating that something has gone wrong.


/Ubbe

 

[GlobalNorth]

Noise floor can vary, based on location.

When I was in the metro Phoenix, AZ area; VHF-Air had to be set at a minimum squelch of 3 and sometimes 4 at night. 150 to 174 MHz VHF band required 3.

Try it and see what happens. It costs nothing and can eliminate a variable.

 

[trentbob]

Noise floor can vary, based on location.

When I was in the metro Phoenix, AZ area; VHF-Air had to be set at a minimum squelch of 3 and sometimes 4 at night. 150 to 174 MHz VHF band required 3.

Try it and see what happens. It costs nothing and can eliminate a variable.

Of course very normal for your average analog receiver. My experience has been that the squelch on the SDS series doesn't work exactly the same as an analog scanner. Not much difference between two and three, but if you have some kind of a and I use this term loosely just as a description, not reality...

If you have some kind of a birdie produced by another power source in one of the many that you are using in your Shack, bumping it up to three or four might eliminate that but usually just moving wires around will do the same but.. your point is noted.😉

 

[n1chu]

I've read through several threads but couldn't find one that matches my scenario. I do have a similar issue where it just locks up on a channel (not necessarily a digital trunked channel) from time to time but this is different.

If I leave the scanner on for long periods of time, I noticed it goes silent even though it's scanning. Yes the volume is up and squelch is set to 1. I have both analog and digital trunked systems programmed. It doesn't lock up on any one channel. I have to shut off/turn on the unit in order to start receiving transmissions.

Firmware version:

• Main:Version 1.21.00
• Sub :Version 1.02.01

Any thoughts?

Sorry I don’t have any corrective action I can pass along but;
I have the exact same issue. One moment the SDS200 is scanning normally, the next, no audio. It happens infrequently… or at least that’s my impression. For all I know it’s happening more than that but I haven’t paid much attention to it as I usually have a portable amateur radio general coverage receiver scanning my local stuff since I’m in and out of the room where the SDS200 resides throughout the day. I turn the SDS200 on in the morning and turn it off at night (which would reset the radio if the problem was active). One thing I have not checked (or if I did I don’t remember) is if it stops on an active channel, produces no audio, and then continues to scan, or just continues to scan without stopping. I’m running the latest FW and Sentinel SW. I have returned the scanner to Uniden once for this issue and they returned it stating nothing other than they couldn’t get it to do what I claimed it did. (I figured I’d wait until complaints of the same nature piled up causing Uniden to do a deeper dive on the subject. But to date, that doesn’t seem to be what happened.)
I’ve come to realize the SDS200 is NOT the radio to use if its application requires a confidence that it will perform without missing comms (other than those already being missed because the scanner was listening to a busy channel). It’s for this reason I discounted its use in the town’s first responder’s command vehicles in town. I have two of these radios. They are from the first production run. I use them as personal devices. My monitoring practices are strictly as a hobbyist now that I am retired from the fire service. I run one in my personal vehicle without issue and the other at my house, where I have noticed the problem… I just live with it as the radio has many features I appreciate.

 

[pkrawetz]

So I played around with the squelch before wiping out my SD card. It's now set to 2 and seems to be working. I haven't had to reboot my scanner.

I'll keep monitoring this and if anything changes, I'll post back.

 

[n1chu]

I haven’t tried formatting (or replacing) my SD card. I’ll give that a try. Good to hear your issue has been corrected.

 

[W6QY]

So I played around with the squelch before wiping out my SD card. It's now set to 2 and seems to be working. I haven't had to reboot my scanner.

I'll keep monitoring this and if anything changes, I'll post back.

I came here looking for an answer to your exact question. My 2 week old SDS200 is doing the same thing. I am not sure about the Squelch issue though, mine was set at '4'. I'll set it down to 2, but don't see that as the issue. I'll try a new SD card though.

 

[n1chu]

“Replay” and “Record” are two options that don’t fare well with SD Cards when power is disrupted. The SD Cards are likely to become corruptive. I’m not suggesting that may have happened with your SDS200/100 but keeping it in mind is definitely to our advantage.

 

[W6QY]

I have tried a brand new SD card and I am having the same problem. I called Uniden today and the Tech support said it's an issue with the "Set Audio Off Time". (page 36 of the manual). They said to set it to Infinite. Looking at the description of this function, It doesn't seem that this would cause this issue, but I'll try it...??

 

[tvengr]

I called Uniden today and the Tech support said it's an issue with the "Set Audio Off Time". (page 36 of the manual). They said to set it to Infinite. Looking at the description of this function, It doesn't seem that this would cause this issue, but I'll try it...??

Set Audio Off Time was a workaround so you didn't have to listen to the hum between transmissions. The audio amp turns off at the set time after a transmission drops. The audio amp is supposed to turn back on at the start of the next transmission. Auto Shutoff completely turns the scanner off after the set time. That allows you to go to sleep knowing the scanner will not be on all night.