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Humming/pulsing artifact on the SDS200


Hai Nguyen Ly
 

Evening all:
I just received, unpacked and programmed an SDS200 and am mostly enjoying monitoring with the rig. One issue that I can’t seem to pin down is a humming/pulsing sound being emitted from the speaker of the unit. This noise is also apparent when connecting headphones/speakers to the scanner and detracts quite a bit from the monitoring experience. If any of you could please let me know if you can replicate this issue, I'd really appreciate it. I really hope that I don’t have a defective unit and that this is a problem that can be corrected in firmware.

Hai


Joe M.
 

How are you powering the unit?

Joe M.

On 2/8/2019 11:15 PM, Hai Nguyen Ly kc1blt@... [SDS200] wrote:
Evening all:
I just received, unpacked and programmed an SDS200 and am mostly enjoying monitoring with the rig. One issue that I can’t seem to pin down is a humming/pulsing sound being emitted from the speaker of the unit. This noise is also apparent when connecting headphones/speakers to the scanner and detracts quite a bit from the monitoring experience. If any of you could please let me know if you can replicate this issue, I'd really appreciate it.. I really hope that I don’t have a defective unit and that this is a problem that can be corrected in firmware.

Hai

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Posted by: Hai Nguyen Ly <kc1blt@...>
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Ubbe .
 

Some owners report the same thing. It could be related to the SD card so try to turn off the recording function if that are enabled. It is probably some sort of audio coupling between modules over a common voltage source.

You can follow the discussion and Unidens response at www.radioreference.com

/Ubbe


Hai Nguyen Ly
 

Thanks for this. Could you please verify the Radio reference URL? The one provided doesn’t resolve for me. Also, if this is an issue with the recording function and the SD card, as a basic check, shouldn’t removing the card resolve the problem?

Best regards:
Hai Nguyen Ly

On Feb 9, 2019, at 6:41 AM, blarren@... [SDS200] <SDS200@...> wrote:

 

Some owners report the same thing. It could be related to the SD card so try to turn off the recording function if that are enabled. It is probably some sort of audio coupling between modules over a common voltage source.

You can follow the discussion and Unidens response at www.radioreference.com

/Ubbe


Hai Nguyen Ly
 

I am using the provided AC adapter.


Hai Nguyen Ly

On Feb 9, 2019, at 6:41 AM, blarren@... [SDS200] <SDS200@...> wrote:

 

Some owners report the same thing. It could be related to the SD card so try to turn off the recording function if that are enabled. It is probably some sort of audio coupling between modules over a common voltage source.

You can follow the discussion and Unidens response at www.radioreference.com

/Ubbe


Hai Nguyen Ly
 

Thanks again for responding. I found this Radio Reference thread on the issue.
Temporarily removing the MicroSD card causes the hum to disappear when powering up the unit, so this may be slightly related. I don’t currently have recording enabled on my unit and playback has also been disabled, however the hum is still present. Based on the above thread, different units may experience the issue at varying levels, but my guess is that this may be related to how sensitive one’s hearing is to the noise. It’s super apparent if the rig is connected to external speakers.
I’ve tried connecting the scanner to battery power in hopes that this may be related to the AC circuit, however this too did not resolve the issue.

Hai

On Feb 9, 2019, at 6:41 AM, blarren@... [SDS200] <SDS200@...> wrote:

Some owners report the same thing. It could be related to the SD card so try to turn off the recording function if that are enabled. It is probably some sort of audio coupling between modules over a common voltage source.

You can follow the discussion and Unidens response at www.radioreference.com 

/Ubbe



Ubbe .
 

Sorry about the link, Yahoo let me use a link function but I would probably have refrained from using it.

As I understand it has nothing to do with external devices or interferencies. It is a plain internal problem in the scanner that probably depends on differencies and tolerancies during manufacturing. In some cases the robot that places component on the circuitboard have been loaded with one component of the wrong kind or inverted so that a capacitor are placed with the wrong polarity. Then the voltage are not decoupled enough and that migh create a ripple from one module to couple into another module depending of how that capacitor will behave running in the wrong polarity.

I have one Icom R2500 where a crucial capacitor in the VCO have a value more than ten times less than it was supposed to be and do not filter PLL noise enough which will give white noise in the audio even when monitoring signals at full strenght. One of these days I'm going to try and fix that, after ten years of use.

/Ubbe


Joe M.
 

Try a 12V source to see if it is still
there. If not, it might be the adapter.

Joe M.

On 2/9/2019 7:43 AM, Hai Nguyen Ly kc1blt@... [SDS200] wrote:


I am using the provided AC adapter.


Hai Nguyen Ly

On Feb 9, 2019, at 6:41 AM, blarren@... <mailto:blarren@...>
[SDS200] <SDS200@... <mailto:SDS200@...>> wrote:

Some owners report the same thing. It could be related to the SD card
so try to turn off the recording function if that are enabled. It is
probably some sort of audio coupling between modules over a common
voltage source.

You can follow the discussion and Unidens response at
www.radioreference.com

/Ubbe


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Joe M.
 

I see you tried the battery already. Try a different SD card.

Joe M.

On 2/9/2019 8:34 AM, Hai Nguyen Ly kc1blt@... [SDS200] wrote:


Thanks again for responding. I found this Radio Reference thread on the
issue.
https://forums.radioreference.com/threads/sds-200-speaker-noise-again-like-the-536hp.383186/page-10
Temporarily removing the MicroSD card causes the hum to disappear when
powering up the unit, so this may be slightly related. I don’t currently
have recording enabled on my unit and playback has also been disabled,
however the hum is still present. Based on the above thread, different
units may experience the issue at varying levels, but my guess is that
this may be related to how sensitive one’s hearing is to the noise. It’s
super apparent if the rig is connected to external speakers.
I’ve tried connecting the scanner to battery power in hopes that this
may be related to the AC circuit, however this too did not resolve the
issue.

Hai

On Feb 9, 2019, at 6:41 AM, blarren@... <mailto:blarren@...>
[SDS200] <SDS200@... <mailto:SDS200@...>> wrote:

Some owners report the same thing. It could be related to the SD card
so try to turn off the recording function if that are enabled.. It is
probably some sort of audio coupling between modules over a common
voltage source.

You can follow the discussion and Unidens response
atwww.radioreference.com <http://www.radioreference.com/>

/Ubbe



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