SDS200 pop driving me crazy!

[Stecomp]

I have a slight whine and a very light pop sometimes. Tried a ground loop isolator with a Realistic speaker. Totally silent from that speaker, but I have to increase volume from 8 to 23. Is that normal? Also the isolator only works in one direction - normal too?

Are you using the front headphone jack or back ext speaker port? If you use the front one you can use a speaker without the isolater and any noise will be eliminated but as you say you need to crank the volume up. The back one should allow normal volume but the ground loop isolater is needed if you have any hum or pop.

 

[maus92]

I am using a Uniden ESP12 (unamplified) speaker with the isolater on the older one and just the internal one for now on the new one. If I plug the speaker in to the back of the 200 without the ground loop isolater the noise is magnified.

This is a known behavior. The curious thing is the headphone jack does not have the noise. Of course the headphone jack is totally useless in my operating environment.

 

[Ubbe]

Interestingly when I set Audio Off to infinite I get the pop at the beginning and end of each signal but set at 100 Ms only get it at the end.

Whenever you use that timer it will switch off the speaker amplifier, after the delay time when a transmission stops, and when a transmission starts it turns on the amplifier again. But the powering on of the amplifer needs it to settle and charge coupling capacitors and so on and will take a couple of 100mS until audio are produced. During that time the pop are not heard as the amplifier are not yet ready to produce any sound and are muted.

Any pop sound are the result of DC voltage differencies in the audio chain, usually when the squelch action mute and unmute the audio. As it is not heard in all scanners it's probably component tolerancies that are too widely spread or a high ohm area have solder fluid or laquer that are sligtly conducting if it's unpure.

I once had an audio device that had a terrible pop and it turned out to be a polarised capacitor that was installed the wrong way at the factory and where leaking DC current. My Icom PCR2500 receiver have two capacitors interchanged on the circuit board, probably the placement robot where feed with the wrong capacitor values, so that the PLL signal isn't filtered enough and gives a high hissing noise with all carriers. Not all PCR2500 have that fault so some production batches can have faulty components from factory.

/Ubbe

 

[Kaleier1]

The first SDS200 I bought had the pop at the beginning and end of each transmission from the internal speaker. It also popped every time a key beep occurred and when I turned the audio from off to on (0 to 1). I noticed it the second day I had it and it does drive you batty.

Another member here posted about it and no one had it before until he responded to my post about it. It also happens when you touch a key on the keypad. Audio mp settings did nothing to fix it nor did a different SDS car or resetting the scanner to factory settings. Long story short. I returned it for a refund and got another one and it doesn't have the pop.

Here is my post about it. The first few replies thought it was through an external speaker so don't apply. The other person here said they were eventually going to send their SDS200 to Uniden for repair. Don't know of they ever did.

 

[scnrfrq]

Are you using the front headphone jack or back ext speaker port? If you use the front one you can use a speaker without the isolater and any noise will be eliminated but as you say you need to crank the volume up. The back one should allow normal volume but the ground loop isolater is needed if you have any hum or pop.

I tried both jacks. The speaker jack has no noise but you have to increase volume from 8 to 23. The headphone jack provides even less volume. I'm happy just using the built-in speaker. I basically don't hear any noise in a normal environment.

 

[N8SHA]

Mine is running with an external Kenwood KS-3 speaker. I've tried other speakers with the same result. It seems to do it without the external speaker too. It's kind of difficult to discern because it's mounted in a rack.

This link is to an audio file I created while listening to one of our local WX channel, and turning the volume on and off (0 - 1 - 0) several times.

-Matt

 

[RF23]

Have you tried the attenuator on that frequency, perhaps together with different filter settings like Normal and Invert? You could also try the IFX setting on that frequency.

Do you have any $10 SDR dongle or other receiver that can be used to watch the whole frequency spectrum so that you really can see what's going on?

/Ubbe

Yes, I tried the local and global attenuator and various combinations of the filters and antennas with NO effect on the problem but it sure dropped the signal down. I really expected that to fix the problem but it didn’t.

I do have a couple of SDR dongles which I used for DMR and NXDN until the upgrades came out for the 436HP. I will give it a try as I may have some strong signals that I am not aware of, thanks for the suggestion.

 

[RF23]

I don't have the pop but, I do get the drop outs on 152.300 on my sds200 there is also, some type of security service I hear on that same frequency as well as severe weather watch when there are storms close by.

You are correct, it is Crawford Security and the two frequencies they usually use are their normal security frequencies but they are the official Civil Defense Weather Team for Butler County and have another County Repeater that can use such as the EMA Repeater. They are in direct contact with NWS and have radar apps that allow them to see Rotation, hail cores, rain fall rates, etc..

When the SDS200 first came out a user reported this same kind of problem and even made a short UTube video of it. Upman later came out with a firmware update that addressed this drop-out problem and the user confirmed it did solve the problem. I now think this dropout problem we are having may only be fixed by Uniden, since I have tried everything I can think of but I will try my SDS Dongle to make for sure unless others can suggest more things to try.

 

[Ubbe]

but it sure dropped the signal down.

The attenuator are a 20dB one so your 45dBm signal should drop to 65dBm. If it dropped more than that then it is some kind of overload problem.

As it is a VHF frequency, have you tried the easiest and chepeast solution using a FM broadcast trap filter? It has helped people with mixing products in the VHF airband. It's the sum of all signals that matters and attenuating one of them, perhaps in the FM broadcast band, could help to get below the critical level.

/Ubbe

 

[RF23]

The attenuator are a 20dB one so your 45dBm signal should drop to 65dBm. If it dropped more than that then it is some kind of overload problem.

As it is a VHF frequency, have you tried the easiest and chepeast solution using a FM broadcast trap filter? It has helped people with mixing products in the VHF airband. It's the sum of all signals that matters and attenuating one of them, perhaps in the FM broadcast band, could help to get below the critical level.

/Ubbe

That is interesting, I will have to remember that. I was using both the local and global ATT, filters, even no antenna trying to get some effect but it just did not matter. However, I do have a -30dB commercial FM tower less than a mile away so I will give the FM trap a try to. Thanks for the help!

 

[RF23]

Here is about a 2 minute audio clip of my “pops”, “clicks”, & “buzz” sounds that appear to be unique on my SDS100 and 200 scanners. None of my other scanners have them although most of these other scanners do have a moderate to pronounced squelch tail (on analog signals) which my SDS scanners do not have (thank Goodness)!

Once I viewed the audio file with Audacity I found the “pops & Clicks” were WAY more common than I thought and they are at the end of the transmission as well. The Buzz sound is the one that is almost always at the very beginning of the Transmission.

You will need to change the extension from "txt" to "mp3" to listen or view it with Audacity.

 

[Ubbe]

I only hear a normal FFSK system signalling at the beginning of transmissions and sometimes at the end. Maybe that digital signal can be heard as pop or buzz to an untrained ear.

Whistler scanners usually has some sort of delay, 200mS or maybe more, at the beginning of analog transmissions as it tries to see if it is a P25 signal in the carrier and first after the delay it unmutes the audio. Whistler has that hardcoded in some way in the firmware to always detect analog P25 signalling even if you set the channel to do only analog. In plain simplex transmission I often miss the first syllable and I have asked Whistler to look into it, but it's probably a legacy from the old GRE days and might be difficult for anyone else to remove it and still decode P25 when its needed.

/Ubbe

 

[scnrfrq]

The barely audible "whine" is from data being written to the display. Use the audio time off setting - mine is set to 500ms. TBH, I don't find this to be a big deal since my radios are used in a work environment where there are other much louder noise sources.

Using 500ms, the whine is gone. It still is slightly audible in the background of transmissions, but not bad. That's with an external speaker - with the internal speaker I don't hear it at all.

 

[maus92]

Using 500ms, the whine is gone. It still is slightly audible in the background of transmissions, but not bad. That's with an external speaker - with the internal speaker I don't hear it at all.

That is the way the audio cutoff functions - it's literally turning off the audio between transmissions, so you don't hear the whine generated by the internal electronics. It is still being generated though, that's why you can barely hear in the background during transmissions. Some people are super bothered / anal about the whine, but I use the radio constantly and the level is so low, I don't notice it - unless I try to notice it. Even then, meh, not a big deal. There is a mod that can be performed that cleans up the grounding internally, but I don't suggest doing it until the whine is driving you mad, lol.

 

[scnrfrq]

That is the way the audio cutoff functions - it's literally turning off the audio between transmissions, so you don't hear the whine generated by the internal electronics. It is still being generated though, that's why you can barely hear in the background during transmissions. Some people are super bothered / anal about the whine, but I use the radio constantly and the level is so low, I don't notice it - unless I try to notice it. Even then, meh, not a big deal. There is a mod that can be performed that cleans up the grounding internally, but I don't suggest doing it until the whine is driving you mad, lol.

I'm familiar with that mod, but I thought it was for a "hum". What I'm hearing is more of a slight whine for sure. Are they both the same thing then?

 

[maus92]

I'm familiar with that mod, but I thought it was for a "hum". What I'm hearing is more of a slight whine for sure. Are they both the same thing then?

Yes - basically semantics used to characterize the extraneous sound generated internally.

 

[RF23]

I only hear a normal FFSK system signalling at the beginning of transmissions and sometimes at the end. Maybe that digital signal can be heard as pop or buzz to an untrained ear.

Whistler scanners usually has some sort of delay, 200mS or maybe more, at the beginning of analog transmissions as it tries to see if it is a P25 signal in the carrier and first after the delay it unmutes the audio. Whistler has that hardcoded in some way in the firmware to always detect analog P25 signalling even if you set the channel to do only analog. In plain simplex transmission I often miss the first syllable and I have asked Whistler to look into it, but it's probably a legacy from the old GRE days and might be difficult for anyone else to remove it and still decode P25 when its needed.

/Ubbe

OK, but I think you may have missed the one example of the buzz or blitz sound in this first audio example, so I have made another audio clip example (about 22 seconds long) with more examples of this buzz or blitz sound. Unlike the “pop or click” or even the aggravating squelch tails on some radios they are not ON TOP of the audio you are trying to listen to. This Blitz sound is at the beginning and on TOP of the audio so you cannot hear what is being said. This I hope is not normal!

This recording like the other one was made on my SDS100 feeding a Sony ICD UX560 digital recorder which at the end of each week is downloaded to Audacity and “Truncate Silence” is applied, this changes the 2-3 second maximum time between calls to only one-half second. No other digital manipulation has been used on this recording except to remove audio between blitz sounds to reduce the size of the file to meet the size requirements of the RR.com servers.

Again you will need to change the txt extension to mp3 to listen to it.

Sorry my first example was not better at showing this problem.

 

[Ubbe]

OK, but I think you may have missed the one example of the buzz or blitz sound in this first audio example, so I have made another audio clip example

I hear that blitz sound and it sounds as radio interference. Perhaps I can hear a faint voice in the background when the blitz is on, that would indicate that the sensitivty where lost almost completely.

Did you try with the CTCSS/DCS turned off completly and not even in search mode? If it happens almost every time when the transmission starts, on that analog conventional VHF frequency, it has to be someting strange with the subtone decoder in the scanner. If that doesn't help then it could be the automatic gain controller that overshoots when it goes from receiving nothing to a very strong -45dBm signal. Did you try and reduce the signal by "hiding" the SDS100s antenna, or use a paper clip in the BNC adaptor?

One interseting thing would be to look at a debug log to see what the scanner thinks it's receiving.

Creating Bug/Error Files for Uniden

I remember reading some instructions in one of these posts about how to capture error/bug information from the scanner, then sending it to Uniden, hopefully to help them address some of the issues with the SDS100. Can someone walk me through how to do that? Having issues with conventional P25...

forums.radioreference.com

/Ubbe

 

[N4DJC]

Well, mine has a very light pop at the beginning and end of each transmission. I don’t think it has anything to do with the display grounding issue, I got bored and fixed mine today. I’m not sending mine back, it’s not that noticeable plus the hum is gone. I would like to get to the bottom of the actual cause of the popping nonetheless. It sounds like it might be a capacitor but I have no way of checking it out.

 

[RF23]

I hear that blitz sound and it sounds as radio interference. Perhaps I can hear a faint voice in the background when the blitz is on, that would indicate that the sensitivty where lost almost completely.

Did you try with the CTCSS/DCS turned off completly and not even in search mode? If it happens almost every time when the transmission starts, on that analog conventional VHF frequency, it has to be someting strange with the subtone decoder in the scanner. If that doesn't help then it could be the automatic gain controller that overshoots when it goes from receiving nothing to a very strong -45dBm signal. Did you try and reduce the signal by "hiding" the SDS100s antenna, or use a paper clip in the BNC adaptor?

One interseting thing would be to look at a debug log to see what the scanner thinks it's receiving.

Creating Bug/Error Files for Uniden

I remember reading some instructions in one of these posts about how to capture error/bug information from the scanner, then sending it to Uniden, hopefully to help them address some of the issues with the SDS100. Can someone walk me through how to do that? Having issues with conventional P25...

forums.radioreference.com

/Ubbe

Sorry about taking so long to get back to you.

The CTCSS/DCS was one of the last things I tried but it made no difference. I made a spread sheet up with all the combinations of Antennas (outside, inside, no antenna), use of the various filters, Global ATT and Local ATT, AD/DC operations, Pulling the circuit breakers in the house, driving several miles away. This took several months of every day or so trying a different combination out but none of it made any difference that I could tell.

The Debug log is a good idea and I will give it a try. Unlike the drop out problem which occurs in a few seconds of the local Civil Defense transmitting on the main repeater the “Blitz” interference is unpredictable and does not happen every time. I think I posted about how frequent it occurs on one of my earlier posts, so it will be more difficult but I agree with you it needs to be done. I have tried everything else I can think of, and I had fun doing it too!