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please help me with Softrock Ensemble RX II interference source
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What happens if you disconnect the antenna?
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Do you still see the noise? On 20/05/2021 15:32, JonI via groups.io wrote:
I made a short 3 min video describing and showing this interference: |
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I mentioned this in the video- does not go away.? Thanks.
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On 5/20/21 3:01 PM, Nick wrote:
What happens if you disconnect the antenna? |
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Jon,
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Since it does not change when an antenna is removed that does suggest the noise is coming in over one of the connections. Can you run everything on battery and disconnected from the outside world? That is, run the Softrock from a 12V battery and use a laptop running on battery? Even a transformer based power supply will allow coupling of RF that can be difficult to filter out. The noise still could be coming over the air (not thru a wire). Can you make it better/worse by moving the Softrock around, putting your hand around the case, touching the ferrite transformers on the board? Things could be radiating RF through the AC lines, or ethernet cables, or broadband coax cables. WIFI routers and cable modems can cause RF havoc. Unplugging your cable/wifi system would be a simple test for that. And turn off the wifi on the computer you are using to run the Softrock. 73, Roger On May 20, 2021, at 12:15 PM, JonI via groups.io <ji425bt@...> wrote: |
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Thank, Roger.? Well, I did a lot of moving things around and unplugging items.? It is used with a desktop, so the only way of going off the grid is with the UPS I use for it when the power goes out.? I do have a separate lithium ion 12V battery I could use with the Softrock.? I may try this later just to see what happnes.
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I was fortunate to find a couple of more snap on RFI ferrite cores.? After placing them over every cable relating to the SDR, it appears that the broadband 30 Khz noise was greatly reduced. Not totally gone, but a lot better than it was.? I still have to be careful where I place my keyboard when not using it because I get a lot of interference if anywhere close to any of the Softrock cables.? And I have cores around the keyboard wires too. On 5/20/21 5:12 PM, Roger wrote:
Jon, |
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The important connection where the ground loop current is transformed into the interference voltage is from the SR audio output to the soundcard input.
Try using a VERY short audio cable, with good ground connection. I ended up using a separate short thick ground wire going in parallel with the audio connection. As for the QRM in the video, looks like the PC power supply to me. I only use linear wall warts with Softrock, it is difficult to find a quiet 12V small switching supply. 73, Mike AF7KR |
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Much of that interference has been reduced, but not all.? Big step was making sure to place ferrite snap cores around all the cables.? I tried both a linear based power supply and switching with no difference as each has the two ferrite cores.? What might be done about the PC supply (other than changing it as I don't have? a spare)?
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I'll see if I can give the short audio cord a try. Thanks, Jon On 5/21/21 3:20 PM, vbifyz wrote:
The important connection where the ground loop current is transformed into the interference voltage is from the SR audio output to the soundcard input. |
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I tried to tackle the remaining interference today.? So far, no success.? It of course disappears if I unplug the connection from the sound card to the SDR.
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When I tune into those frequency spans where I am hearing it, I noticed something today: it seems like an echo or reverb effect of some kind.? If I unplug the one of the audio into connections into the SDR and tap, it's like I can hear the taps echoing on whatever frequency where the interference appears.? Thus, I've been trying to see if there's some sort of audio processing enabled somewhere in the audio software, but so far nothing seems out of the ordinary.? Plus the fact that this behavior is only happening at certain frequencies. Two things I'm going to try today are to update the audio card drivers and maybe try something other than HDSDR.? It all runs under Win 7 and looks like some of the other programs need NET frameworks higher than the one I have for HDSDR. Jon On 5/21/21 3:20 PM, vbifyz wrote:
The important connection where the ground loop current is transformed into the interference voltage is from the SR audio output to the soundcard input. |
it seems like an echo or reverb effect of some kind. If I unplug the one of the audio into connections into the SDR and tap, it's like I can hear the taps echoing on whatever frequency where the interference appears.? Thus, I've been trying to see if there's some sort of audio processing enabled somewhere in the audio software, Jon, This seems like you have a microphone active? Or, I wonder if you have "Stereo Mix" or, "Listen to this Device" set in Sound Properties or somewhere. This gives an echo effect. It will not change with SDR software, certainly there is no way to make HDSDR produce this effect. 73 Alan G4ZFQ |
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Hi Alan,
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No, stereo mix/ mic, etc are not active.? I've turned off everything except what the card and SDR use.? Next step will be to switch out the SDRs since I have an identical one here.? See if it has these areas of interference too. On 5/23/21 12:07 PM, Alan G4ZFQ wrote:
it seems like an echo or reverb effect of some kind. If I unplug the one of the audio into connections into the SDR and tap, it's like I can hear the taps echoing on whatever frequency where the interference appears.? Thus, I've been trying to see if there's some sort of audio processing enabled somewhere in the audio software, |
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