Noise Levels and FT8 - My new 6600 seems to have poor hearing

Kevin Rich

Michael N3LI

Kevin Rich

Michael, thanks for the offer. I am on a work related call until about 11:30 Mountain and then have some time if you are still available.
 

KJ7G

Kevin Rich

Thanks Boris. I use a similar setup to compare the two radios. I am sharing the same antenna with the MFJ-1708SDR and I just tried those settings and don't see much change. I am decoding at least 50% less and usually 75% less or higher than the SDRPlay.  I have tried the AGC at off, slow, med, and fast and adjusted the level in all modes and used -8, 0, +8, +16, +24 on the preamp all while keeping the levels in WSJT-X between 30dB and 40dB which is the same as I run wiht the other rigs.

I am aware that the MFJ-1708 is not the greatest product on the market but even when I remove it form the path I get the same results and no better decodes. 

Michael N3LI

Mike-VA3MW

I can't comment on the SDRPlay, even though I own one and wasn't seriously impressed with any of the software it comes with.

However, this morning I was copying 6M FT8 signals on my 6600 down to -24db and while I don't have different model receiver to compare with, my settings are full gain (my noise floor is -140db when looked at on the waterfall), AGC-T set as required.  

The same is true for 160M, but the preamps are off and I can hear very very well.  In fact, it is pretty annoying when you call a guy in Turkey on 160M and he can't copy you to answer you.

Make sure that WSTJ is setup correctly and has the right number of Bins/Pixel.  If you only see from 0-1200hz in the WSJT waterfall, those are the only signals you are going to copy.  This is a common problem for not copying all the signals.  

The SDR technology in the Flex is radically different than that of the SDRPlay and not subject to the same overload issues.  Not all SDR technology is created equal.  In fact, and this is a very key point our Dynamic Range increases with more signals in the pass band.  

If you want to dig under the covers on SDR overload, this is a great article.  https://community.flexradio.com/flexradio/topics/adc-overload-myths-debunked.  Our CTO Steve Hicks authored it.

Mike

Kevin Rich

Michael, 

Thanks for sharing your settings, mine were already nearly identical with the exception that I have WSJT-X radio configured for FlexRadio 6xxx using the network server for CAT control and RTS/COM5 for PTT.

In the latest decode interval I have 20 decodes on the SDRPlay RSP2 and 4 on the 6600.

-Kevin

Mike-VA3MW

Something is not right.  Can you stop and restart DAX?  Is your radio on a Local LAN or is any part WiFi?  

There is something contributing to your bad audio on the DAX channel or RF signal making it to the radio.

Can you swap the feedlines from the SDRPlay and the Radio?  

Screen shots of the SmartSDR screen would be very helpful.

KJ7G

Michael N3LI

Michael - I've had the same problem with me hearing them better than they hear me. I can see my signal's hitting the area. 

Ohh, the trials and tribulations of owning a great radio.... 8^)

WX7Y

Mike-VA3MW

This is 20m for me right now on a HF6V at 44 degrees north (north of Toronto).

The Radio is a 6600.

Larry Loen WO7R

Kevin Rich

Mike - Thanks for the reply. I have swapped them and also have had the antenna feedline directly connected to the 6600. I have stopped and started several times. The 6600 is receiving and decoding and I have made QSOs. It just doesn't decode as many signals and the ones it does decode are much weaker. 

I have operated the 6600 with Ethernet connected to the local LAN and SSDR connecting to the rig from a laptop running wireless. I have also connected the laptop and 6600 with just an Ethernet cable between and eliminating any LAN issues. The is now discernible difference when connected either way. I have also tried operating from two separate PCs. Both of the systems are the same hardware and OS (Windows 10) as the laptop I use with other rigs and the SDRPlay. If I turn the NR *off* on the SDRPlay I get similar results from my noisy QTH. 

I'll snap a couple of pics of the SSDR and post them shortly.   

Kevin Rich

Mike - here a couple of pics of the setup showing them both. Taken within a few minutes of each other. It doesn't seem to matter where I adjust the preamp on the 6600. The results are about the same. I changed it to +8 in this image to match what you had. I just seem to have a huge amount of noise at this QTH. 

Being new to Flex and SSDR I am sure I am probably missing some simple setting. Happy to send other pictures or describe other settings if it will be helpful to the folks reading this.

Mike-VA3MW

I have converted this to a support ticket.

Kevin Rich

Thanks Mike. Apologies is this was the wrong area to post this in.

-Kevin

KJ7G

Larry Benoit

David Decoons, wo2x

Kevin Looks like you do indeed have a lot of noise (noise floor around -108). I get hit with power line noise here which has similar signature on panadapter. I run the WNB on when that happens and run the level at 93. If you would like to do a TeamViewer session I can take a look and see if there is anything that might have been overlooked. 73 Dave wo2x

Michael N3LI

Okay, now try the NR on the Flex. Really low though, like 1 or 2. 

Michael N3LI

Oh, and turn off any sound enhancements on the channels. They can sometimes wreak havoc 

Kevin Rich

Dave, 

I will have to get TeamViewer setup and would be fine having you take a peak if we can coordinate a time that works for both of us. 

73, 

Kevin

Roger_W6VZV

Wow, a noise floor of -140!  Mine is about -108 or so.  Noisy suburban neighborhood, I guess.

David Decoons, wo2x

I'll be available tomorrow except 1 p.m. to 3 p.m. Eastern (conference call).
Drop me an email at my call at ARRL dot Net and I'll send you my cell.

73
Dave wo2x

Kevin Rich

Thanks Larry and Michael.  I confirmed the settings and tried other DAX channels to no avail. I also confirmed there are no sound enhancements. 

Neal Pollack, N6YFM

You should not use, and should not need, NR or noise blanker on digital modes.
I am wondering if he got a bad circuit board or something?  But more likely audio level distortion getting in on the receive side.   I have an Icom 7300 and an SDR Play, and my Flex 6600 hears things the others can not.

Neal

Neal Pollack, N6YFM

You should not use, and should not need, NR or noise blanker on digital modes.
I am wondering if he got a bad circuit board or something?  But more likely audio level distortion getting in on the receive side.   I have an Icom 7300 and an SDR Play, and my Flex 6600 hears things the others can not.

Neal

George KF2T

Bill W2PKY

What is the noise level on the 6600 with the antenna disconnected and preamp set to +8?
How about SDRPlay, is there a big difference between the antenna connected & disconnected?
If my noise level was 100 dbm I would not hear anything either.