Unsquelchable static significantly louder then signal

Fallynn · Nov 8, 2015

Hello everybody

I was hoping somebody could help me with a problem I'm having. I'm using SDR Sharp (v1.0.0.1379) with a NooElec dongle. I'm trying to listen to ham traffic in the area but the signals only come in when the “radio” section of the software is set to WFM. With any other setting, the signal is garbled. Which wouldn't be a problem except the squelch option is grayed out (Not available) when in WFM mode. Which, again, wouldn't be a problem except, for reasons I don't understand, the signal comes in very quiet yet the un-squelched static blasts in at a ridiculous volume. I've tried adjusting the gain, filters, audio output, and anything else that seemed like it might work.

If anybody has any suggestions, I'd be very appreciative.

Flatliner · Nov 8, 2015

Try another version of the software.

SCPD · Nov 8, 2015

If you are only getting it to work on WFM .. it is sorely mis-configured. :wink::wink:

That is my issue with a lot of this software, once you mess it up .. you had better have a backup to restore from or else you will be reinstalling it. I found that SDRConsole was far worse in this regard .. ie the whole garbled audio part. SDR# seems to be much better.

I use a 'backup folder' with a known good configuration .. and robocopy to restore it if needed. But I am getting much better at using the software so that is not really needed now. But .. it is there just in case.

Flatliner · Nov 8, 2015

It seems like every release since 1361 has been buggered in some way. Maybe go back to that.

Voyager · Nov 8, 2015

Fallynn said:
I'm trying to listen to ham traffic in the area but the signals only come in when the “radio” section of the software is set to WFM.

THAT is your issue. You are misunderstanding what WFM is. WFM is for FM Broadcast stations. They transmit continuously which is why there is no squelch option. You're trying to monitor several channel widths of ham channels while you want to monitor one, and you're hearing the squelch noise from the other channels with no activity. The solution is this:

You want to use NFM with a bandwidth of 16000 for 99.9999% of ham FM transmissions.

The only WFM ham use are by a few sporadic links across the USA which is actually True standard FM use (36 kHz bandwidth or so).

As they say... the correct mode for the correct reception (OK, paraphrased)

For reference:
Mode / EIA designation / Bandwidth / Deviation / Use

NFM_/_SNFM_/_11200 Hz (or less)_/_2.5 kHz__/_Most PS and Business between 150 and 470 MHz
NFM_/_NBFM_/_16000 Hz________/_5.0 kHz__/_Almost all HAM FM as well as almost all Low Band (30-50 MHz) users
FM__/____FM_/_36000 Hz________/_15.0 kHz_/_FM nearly everyone used in the 50's/60's - virtually extinct anymore.
WFM_/_WFM_/_180000 Hz_______/_75 kHz___/_FM Broadcast (88-108 MHz)

(Sorry that didn't format better)

For all but the last mode, select NFM in SDR# and use the BW as shown (I.E. 16000 for ham FM or Low Band FM)
Only for Broadcast FM will you want to use WFM, and use a BW of 180000 for that.

BTW, for DMR, use a BW of 7200, and for NXDN use 4800 or 9600 depending if it's Narrow or Wide NXDN respectively.

Fallynn · Nov 9, 2015

Voyager said:
THAT is your issue.

Yep. I kinda had a feeling that was it but as I said, it was the only thing that was audible. Even after making the changes mentioned above, it's still not working. I'm thinking the install might be corrupted. I'll reinstall and try again.

wyShack · Nov 11, 2015

You may also want to check the frequency calibration of your dongle. I have had this sort of thing happen when I was off frequency by 10 kHz or so. If you have time while there is traffic make sure you are tuned to the 'center' of the signal-zoom the display as needed. A good signal to use as a test is your local weather broadcast. it is also NFM and you can verify your frequency calibration. Using the weather broadcast (there is at least one in most areas between 162.4 and 162.6 MHz) gives you a continuous signal so you can tweak settings with a 'known' good steady signal.

Good luck

Voyager · Nov 11, 2015

+1 on the frequency calibration, and the specific method WY described. I bet that fixes your issue. I've found calibration values of somewhere between 30-65 are typical. But, they can be outside that range.

Your_account · Nov 15, 2015

Using the weather broadcast (there is at least one in most areas between 162.4 and 162.6 MHz)

there is nothing...

Search in Google for VOLMET in your Area!

wyShack · Nov 15, 2015

to find the NOAA weather station in your area try:

NOAA Weather Radio All Hazards

If you are in the US odds are you can hear one or more...

73

Voyager · Nov 15, 2015

Also make sure the settings (aside from Calibration) are correct in your configuration.

thndr143 · Oct 8, 2017

Voyager said:
THAT is your issue. You are misunderstanding what WFM is. WFM is for FM Broadcast stations. They transmit continuously which is why there is no squelch option. You're trying to monitor several channel widths of ham channels while you want to monitor one, and you're hearing the squelch noise from the other channels with no activity. The solution is this:

You want to use NFM with a bandwidth of 16000 for 99.9999% of ham FM transmissions.

The only WFM ham use are by a few sporadic links across the USA which is actually True standard FM use (36 kHz bandwidth or so).

As they say... the correct mode for the correct reception (OK, paraphrased)

For reference:
Mode / EIA designation / Bandwidth / Deviation / Use

NFM_/_SNFM_/_11200 Hz (or less)_/_2.5 kHz__/_Most PS and Business between 150 and 470 MHz
NFM_/_NBFM_/_16000 Hz________/_5.0 kHz__/_Almost all HAM FM as well as almost all Low Band (30-50 MHz) users
FM__/____FM_/_36000 Hz________/_15.0 kHz_/_FM nearly everyone used in the 50's/60's - virtually extinct anymore.
WFM_/_WFM_/_180000 Hz_______/_75 kHz___/_FM Broadcast (88-108 MHz)

(Sorry that didn't format better)

For all but the last mode, select NFM in SDR# and use the BW as shown (I.E. 16000 for ham FM or Low Band FM)
Only for Broadcast FM will you want to use WFM, and use a BW of 180000 for that.

BTW, for DMR, use a BW of 7200, and for NXDN use 4800 or 9600 depending if it's Narrow or Wide NXDN respectively.

All FM repeaters on VHF use Wide FM, and SDRSharp doe NOT allow the squelch function to be used (greyed out) This has to be fixed

spongella · Oct 9, 2017

Good idea by previous posters to start with the NOAA channels which are narrow band FM. See if you can get the squelch to work properly (maybe not the squelch though) on some of the weaker NOAA channels.

Also look at your spectrum display, perhaps even though you have selected narrow band FM your bandwidth might be too wide or narrow (as previously mentioned). You can adjust this manually by placing your cursor on one edge of the blue window that surrounds the signal until you see the cursor change to a double-sided on, then widen or narrow the bandwidth until the signal sounds acceptable by moving the cursor left or right.

Let us know how you made out.

KevinC · Oct 9, 2017

spongella said:
Good idea by previous posters to start with the NOAA channels which are narrow band FM. See if you can get the squelch to work properly (maybe not the squelch though) on some of the weaker NOAA channels.

Also look at your spectrum display, perhaps even though you have selected narrow band FM your bandwidth might be too wide or narrow (as previously mentioned). You can adjust this manually by placing your cursor on one edge of the blue window that surrounds the signal until you see the cursor change to a double-sided on, then widen or narrow the bandwidth until the signal sounds acceptable by moving the cursor left or right.

Let us know how you made out.

Seeing how the thread is almost 2 years old and the OP hasn't visited since I doubt you'll get a response. :wink:

spongella · Oct 9, 2017

Oh my....

bama9999 · Oct 9, 2017

thndr143 said:
All FM repeaters on VHF use Wide FM, and SDRSharp doe NOT allow the squelch function to be used (greyed out) This has to be fixed

Pretty sure that's the wider regular FM, as compared to narrow-banded FM, and not WFM which as has been mentioned, is used in FM broadcasting.

KevinC · Oct 9, 2017

Closing.

Unsquelchable static significantly louder then signal

Fallynn

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Flatliner

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SCPD

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Voyager

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Fallynn

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wyShack

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Your_account

Completely Banned for the Greater Good

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