Very low volume

[Ve3uky]

I have another post on the forum regarding the same issue, but specific to an IF frequency question. I'm confident that I am using the correct IF frequency and this question is more general. I'm experiencing extremely low voice volumes. The sound that I get is also garbled.

I have to assume that it's a software setup issue, but I haven't been able to solve it and it's consuming my life at the moment.

Has anyone had similar experiences that they have found a solution for?

Any help would be greatly appreciated.

[Max]

I have another post on the forum regarding the same issue, but specific to an IF frequency question. I'm confident that I am using the correct IF frequency and this question is more general. I'm experiencing extremely low voice volumes. The sound that I get is also garbled.

I have to assume that it's a software setup issue, but I haven't been able to solve it and it's consuming my life at the moment.

Has anyone had similar experiences that they have found a solution for?

Any help would be greatly appreciated.

You mentioned in the other post that the SSB sounds garbled. Makes me think that you need to Invert the spectrum? I believe that on some radios you may need to invert on some bands and not on others?

If the inversion is not set correctly then SDRC will tune in the wring direction versus the external radio. This should be easy to check by, for example, seeing at what end of the band is the CW section?

You also have not (I don't think) posted any screenshots so that makes it even harder to diagnose for us:

https://www.sdr-radio.com/screenshot

ATTACH don't (insert picture/image to the post) and also do NOT crop the screenshot as generated by SDRC.

73

Max

[Ve3uky]

Thanks Max. I've tried inverting the spectrum, but I didn't realize that the spectrum can be inverted on some bands but not others. I'll try that again. If it doesn't work, I'll take some screen shots and forward them.

73
Joe

[Ve3uky]

Hi Max

I've attached a screen shot. Not sure if this is adequate. Should I be shooting a screen shot of another tab?

Joe

[Ve3uky]

Here's one of the Receive tab.

[Ve3uky]

Hers is what I'm hearing on SDRC along with the same conversation heard from the radio.

[Max]

Hers is what I'm hearing on SDRC along with the same conversation heard from the radio.

Hi Joseph

Two things. Firstly in the recording it definitely sounds like you are attempting to listen with the wrong sideband. Out of interest, I assume that in SDR Console you have tried to tune in the same signal but with LSB selected instead of USB? If it comes good, then the spectrum is inverted.

Another thing makes me think that the spectrum is inverted. In the first screenshot you posted, the signal at 14320kHz, that definitely looks like an LSB signal. You can see the energy concentrated to the high side of the signal. You should see the reverse with a USB signal, as the higher energy contained in the lower frequencies of the audio, with a USB signal, this would show with the high energy concentrated to the low (left) of the signal. So again that makes me think that the the spectrum is flipped. Another thing is that in the second screenshot you have an SSB signal showing outside the band at 14360kHz. Again, an indication that something is not right with the spectrum calibration.

But first, to confirm, I'd try changing mode to LSB on SDRC and see of you can decode the signals. If so, it definitely needs inverting. With the IF output at 70Mhz I'd be surprised if, as per my earlier statement, the need to invert would vary by HF band. This might only happen if the band you are receiving is on the other side of the IF, so if it were 144MHz for example, but I think the TS-570 is HF only so probably does not apply. I think you can disregard this as an issue.

The other thing from your recording...... hard to tell when listening to it "scrambled"...... is that the filter bandwidth sounds narrow. You have not shown the filter bandwidth selected in the RX DSP panel because you have the filter panel collapsed. Obviously it would ideally be 2.5kHz ish for SSB.

Another thing regarding the RTL-SDR settings in the Home tab. I would turn the AGC OFF and wind the RF Gain right down, possibly to zero, and then wind the RF up slowly until you get a good signal. The RTL SDR front end is easily overloaded. I would imagine the signal from the IF tapping is pretty high level, so the AGC might just be throttling the RTL right back.

One last thing is I'd update SDRC to the Beta version v3.4. I don't totally recall when Simon updated the API for the RTL-SDR V4 as it took place some time during 3.3. Most likely not an issue but just mentioning. On the V4 for the HF Upconverter setting you should leave it on HF Upconverter - Enable. I forget what the previous options were on there for RTL-SDR, but I see you have it set to "Quadrature". No need for that on the V4. I don't think this affects anything, but mentioning just in case it does.

73

Max

[Ve3uky]

Hi Max. Thanks so much for the comprehensive response. I'll take another in-depth look at it tomorrow and let you know what I find. Very much appreciated.

Joe

[jdow]

He also seems to have the audio gain control set lower than necessary.
{^_^}

[Ve3uky]

Hi Max. Well I started up SDRC today to find that there was absolutely no voice to be heard from the software. I'm thinking that either I'm getting an intermittent IF signal from the radio, or the SDR-RTL is problematic. I receive broadcast AM and FM signals on the dongle, so I'm guessing that it's likely an IF signal issue. I'm going to do some research to see whether this is a known problem with the TS-570 and to find a way to test the IF tap to see if the signal is intermittent. Thanks for your help. When I figure it out, I'll let you know.