SDS200 SDS-200 Speaker Noise Again like the 536HP

[ColdnFrosty]

A variable that has not been checked yet that can cause a “Hum” is improper outlet wiring in your house. Might consider trying one of those colored three light plug in testers in to your house outlets to see if they are properly grounded or not.

Just a thought.

Note that it has nothing to do with the power source. The hum is actually modulated by the scanning - causing the hum to change frequency with each channel it scans. There are several recordings that have been posted and they all reflect the same scenario.

 

[allend]

The in line external speaker ground loop 3.5 mm adapter I just got from Amazon today not only succeeded in lowering the hum dramatically to the external speaker, it also lowered the audio substantially. Even with the scanner volume turned all the way up, the sound was low and a bit distorted. Guess I’ll keep that adapter for a rainy day for some other use at some point in time.

Yes, exactly what happened to me, but it worked. But yes it dramatically dropped the volume power

 

[KB4MSZ]

Yes, exactly what happened to me, but it worked. But yes it dramatically dropped the volume power

Can you amplify it again externally without bringing back the noise?

 

[KevinC]

Yes, exactly what happened to me, but it worked. But yes it dramatically dropped the volume power

I wonder if it's loading down the circuit, thereby just attenuating the noise? This may end up damaging the audio amplifier if true.

ETA...
I don't think this device will work as I believe the jack on the SDS200 is mono and this has stereo input/output.

 

[ColdnFrosty]

So I bought this ground loop isolator on Amazon yesterday and had it delivered today. I absolutely do not hear anymore humming, hissing, or pulsing anymore. The only thing is that I have to turn up the volume knob more on the radio to get more of the sound results on the radio. I do get less speaker results but the noise is gone.

https://www.amazon.com/gp/product/B019393MV2

That device appears to have a stereo plug. Isn't the rear speaker jack a mono?

 

[KevinC]

That device appears to have a stereo plug. Isn't the rear speaker jack a mono?

According to a 2014 post all ext spkr jacks are mono...

https://forums.radioreference.com/threads/headphone-jack-on-the-bcd436hp.293463/#post-2208519

 

[ColdnFrosty]

According to a 2014 post all ext spkr jacks are mono...

https://forums.radioreference.com/threads/headphone-jack-on-the-bcd436hp.293463/#post-2208519

That could be why his audio is being attenuated.

 

[tkowalik]

I've spent a little more time with it and I've been able to reduce the noise (I'll quit calling it a hum because that's not really a good description) by about 90%. I took a video of what it sounded like initially and how it sounds by moving the plate all the way forward and applying modest downward pressure around the top left corner of the unit. I'll upload it if I can figure out how.

I'm just not brave enough to go beyond removing the upper and lower inner plates but it seems like it does indeed get much better when the top inner plate makes contact with the metal around the screen.

 

[budevans]

I've spent a little more time with it and I've been able to reduce the noise (I'll quit calling it a hum because that's not really a good description) by about 90%. I took a video of what it sounded like initially and how it sounds by moving the plate all the way forward and applying modest downward pressure around the top left corner of the unit. I'll upload it if I can figure out how.

I'm just not brave enough to go beyond removing the upper and lower inner plates but it seems like it does indeed get much better when the top inner plate makes contact with the metal around the screen.

Sounds like a ground or shielding issue.

 

[tkowalik]

Sounds like a ground or shielding issue.

I'm leaning to almost certainly a grounding issue based on what I'm hearing as I poke around it. Everything is pointing to something with the screen.

 

[weathermedic]

I

I've spent a little more time with it and I've been able to reduce the noise (I'll quit calling it a hum because that's not really a good description) by about 90%. I took a video of what it sounded like initially and how it sounds by moving the plate all the way forward and applying modest downward pressure around the top left corner of the unit. I'll upload it if I can figure out how.

I'm just not brave enough to go beyond removing the upper and lower inner plates but it seems like it does indeed get much better when the top inner plate makes contact with the metal around the screen.

I removed the black metal housing sleeve and placed some thin foam padding I had laying around on top of the silver metal housing as close to the front of the radio as possible. It has helped reduce the speaker hum dramatically. Still could use some more, as when I push down with my finger in that area, the noise almost completely disappears.

 

[radio3353]

ETA...
I don't think this device will work as I believe the jack on the SDS200 is mono and this has stereo input/output.

Would this solve that?
Adapter

 

[tkowalik]

I


I removed the black metal housing sleeve and placed some thin foam padding I had laying around on top of the silver metal housing as close to the front of the radio as possible. It has helped reduce the speaker hum dramatically. Still could use some more, as when I push down with my finger in that area, the noise almost completely disappears.

Exactly the same here. It doesn't even bother me anymore.

 

[budevans]

Would this solve that?
Adapter

Highly doubtful. It's never been an issue in the past. Using stereo head phones with monaural jacks goes back to the fifty's or sixty's.

 

[tkowalik]

Here's an attempt to upload the video.

 

[tkowalik]

edit: link works if I'm logged in but the video is still processing.

 

[allend]

Last one didn't work but here's the link:

www.metacafe.com/watch/11832143/sds200/

Link does not work

 

[Ubbe]

Can you amplify it again externally without bringing back the noise?

No, it's still the same relation between the noise and the signal and it is not a ground loop problem between speaker and scanner. But anything that reduces the signal to the speaker will also reduce the background noise that you hear independent of the volume control setting.

/Ubbe

 

[W2MB]

No, it's still the same relation between the noise and the signal and it is not a ground loop problem between speaker and scanner. But anything that reduces the signal to the speaker will also reduce the background noise that you hear independent of the volume control setting.

/Ubbe

Sounds like an internal component shielding and/or grounding issue. Not uncommon in digital and RF environments. Unfortunately, the real resolution may well be via design and/or component change. Basically, internal noise is getting into the receiver circuitry chain. Padding the audio would just be a mask. Firmware update may be able to address it via DSP filtering, but the real fix is hardware related. This is one reason why we see product revisions over time and is one of the pitfalls associated with being an early adopter.

 

[m42duster]

Sounds like an internal component shielding and/or grounding issue. Not uncommon in digital and RF environments. Unfortunately, the real resolution may well be via design and/or component change. Basically, internal noise is getting into the receiver circuitry chain. Padding the audio would just be a mask. Firmware update may be able to address it via DSP filtering, but the real fix is hardware related. This is one reason why we see product revisions over time and is one of the pitfalls associated with being an early adopter.

Agreed...but it could still be a component QC issue as well. So far, seems to be a 50/50 crap shoot on units w/o this issue. I see some posturing that this noise is normal, which doesn't surprise me. Uniden didn't make any changes in their export transceivers that were affected by CW buffering caused by a design flaw. Ignoring a FLAGSHIP scanner? We'll see.