Low noise floor


Francesco Di Giovanni
 

Hi,

I have upgraded my Airspy HF+ Dual Port and Airspy HF+  Discovery to firmware to version 3.0.7.

Since then I have an  “improbable” low noise floor.

I suspect the frequency calibration file of both devices are now corrupted.

Both devices were connected to the pc when the firmware upgrade was done.

I have reinstalled SDR# and SDR Console v3, but it seems to me nothing changes.

 

There is a way to recreate a new calibration file?

 

Regards

Francesco – IN3XZP

 

 


Alan G4ZFQ
 

I suspect the frequency calibration file of both devices are now corrupted.
There is a way to recreate a new calibration file?
Francesco

This was asked in the Airspy group

https://groups.io/g/airspy/message/35064

If the problem persists try flashing again.

73 Alan G4ZFQ


David J Taylor
 

Hi,

I have upgraded my Airspy HF+ Dual Port and Airspy HF+ Discovery to firmware to version 3.0.7.

Since then I have an “improbable” low noise floor.

I suspect the frequency calibration file of both devices are now corrupted.

Both devices were connected to the pc when the firmware upgrade was done.

I have reinstalled SDR# and SDR Console v3, but it seems to me nothing changes.



There is a way to recreate a new calibration file?



Regards

Francesco – IN3XZP
==================================================

For frequency calibration see:

https://gist.github.com/jj1bdx/ce9eb3bd7320eed76396669a25f27e29

I would try with SDR# in the first instance.
You did cold-boot the devices after updating?
You did use the correct firmware for the two devices (BB or CD variants)?

David GM8ARV
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


Alan
 

Francesco,

If the noise floor is low then perhaps flashing again is required. I do not think loss of� calibration would not affect the noise level.

73 Alan G4ZFQ


Mike Millen
 

I would first check that the Pre-Amp, Attenuator and AGC settings are all the same as before.
The new firmware might have changed the default settings.

The frequency calibration will not affect noise levels.

Regards,
Mike - M0MLM

On 14/06/2020 10:02, David J Taylor via groups.io wrote:
Hi,

I have upgraded my Airspy HF+ Dual Port and Airspy HF+  Discovery to firmware to version 3.0.7.

Since then I have an  “improbable” low noise floor.

I suspect the frequency calibration file of both devices are now corrupted.

Both devices were connected to the pc when the firmware upgrade was done.

I have reinstalled SDR# and SDR Console v3, but it seems to me nothing changes.

There is a way to recreate a new calibration file?

Regards

Francesco – IN3XZP


jdow
 

hfplus_fw.exe is your secret weapon. But, you have to read FLASH.bat to see what it is doing and play with the sdrsharp config file to enable airspy hf debugging.

First figure out how hfplus_fw.exe works. Use that to set the offset to zero ppb the same way the FLASH.bat file does it. Tune a known precise source, GPSDO driven ideally, at VHF ideally but high HF will do if that's what you have. 10 MHz is too low to be really good but, enh, can work. Set SDRSharp to exactly the signal's frequency. Then adjust ppb until it is as precisely tuned as you can get. Generally that involves absurdly high FFT bin counts and zoom in AM mode. Once you have the PPB number feed that in to the hfplus_fw.exe tool. Then I unplugged and reinserted the airspy hf whether it needed it or not. Mine is as "right on" as it can get in an environment that changes temperature a lot.

I give you a strategy above. It is up to you to do your homework and figure out what to do. I want NO responsibility if you make a mistake. Figuring out how to do this is on your shoulders as it will increase your understanding of what you are doing, I hope.

{^_^{

On 20200614 01:58:18, Alan G4ZFQ wrote:
I suspect the frequency calibration file of both devices are now corrupted.
There is a way to recreate a new calibration file?
Francesco
This was asked in the Airspy group
https://groups.io/g/airspy/message/35064
If the problem persists try flashing again.
73 Alan G4ZFQ


jdow
 

PS to Alan - if the calibration is somehow fooed up reflashing will not fix it.

{^_^}

On 20200614 01:58:18, Alan G4ZFQ wrote:
I suspect the frequency calibration file of both devices are now corrupted.
There is a way to recreate a new calibration file?
Francesco
This was asked in the Airspy group
https://groups.io/g/airspy/message/35064
If the problem persists try flashing again.
73 Alan G4ZFQ


jdow
 

Look at settings. A bad ppb value will not do what you see.
{^_^}

On 20200614 02:02:07, David J Taylor via groups.io wrote:
Hi,
I have upgraded my Airspy HF+ Dual Port and Airspy HF+  Discovery to firmware to version 3.0.7.
Since then I have an  “improbable” low noise floor.
I suspect the frequency calibration file of both devices are now corrupted.
Both devices were connected to the pc when the firmware upgrade was done.
I have reinstalled SDR# and SDR Console v3, but it seems to me nothing changes.
There is a way to recreate a new calibration file?
Regards
Francesco – IN3XZP
==================================================
For frequency calibration see:
 https://gist.github.com/jj1bdx/ce9eb3bd7320eed76396669a25f27e29
I would try with SDR# in the first instance.
You did cold-boot the devices after updating?
You did use the correct firmware for the two devices (BB or CD variants)?
David GM8ARV


Alan
 

PS to Alan - if the calibration is somehow fooed up reflashing will not fix it.
Yes, but David probably got it right.
Either a bad flash or the wrong file may well give a low noise floor. I think calibration would not unless set to a possibly impossible value.

73 Alan G4ZFQ


jdow
 

I've had screwed up programming because I intentionally risked it to see what happens. 0 ppb seems to be the result. (I have two and tried to see what would happen if I left both plugged in. The results were unsatisfactory. But, I recovered using the kind of steps I mentioned at 29.990 MHz using a very precise frequency synthesizer.)

{^_^}

On 20200614 02:29:42, Alan via groups.io wrote:

PS to Alan - if the calibration is somehow fooed up reflashing will not fix it.
Yes, but David probably got it right.
Either a bad flash or the wrong file may well give a low noise floor. I think calibration would not unless set to a possibly impossible value.
73 Alan G4ZFQ


Simon Brown
 

Hi,

 

The logfile shows you some information, note that I’m running a version which may not be publicly available.

 

05:22:29.212: Radio Airspy HF+> Connecting

05:22:29.212: Radio Airspy HF+>   Address ...: C852A9804D343FEF

05:22:29.212: Radio Airspy HF+>   Bandwidth .: 768000

05:22:29.212: Radio Airspy HF+>   Frequency .: 144250000

05:22:29.212: Radio Airspy HF+>   airspyhf_open ...........: 0

05:22:29.212: Radio Airspy HF+>   airspyhf_version ........: R3.0.8-BB

05:22:29.213: Radio Airspy HF+>   advanced ................: 1

05:22:29.213: Radio Airspy HF+>   airspyhf_set_samplerate .: 768000, status 0

05:22:29.213: Radio Airspy HF+>   airspyhf_set_freq .......: 0

05:22:29.214: Radio Airspy HF+>   airspyhf_set_..._iq .....: 0

05:22:29.214: Radio Airspy HF+> Previous values

05:22:29.214: Radio Airspy HF+>   AGC ...........: 1

05:22:29.214: Radio Airspy HF+>   Attenuation ...: 0

05:22:29.214: Radio Airspy HF+>   Gain Visual ...: 10

05:22:29.214: Radio Airspy HF+>   Preamplifier ..: 1

05:22:29.215: Radio Airspy HF+> -

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Francesco Di Giovanni
Sent: 14 June 2020 09:29
To: main@SDR-Radio.groups.io
Subject: [SDR-Radio] Low noise floor

 

Hi,

I have upgraded my Airspy HF+ Dual Port and Airspy HF+  Discovery to firmware to version 3.0.7.

Since then I have an  “improbable” low noise floor.

I suspect the frequency calibration file of both devices are now corrupted.

Both devices were connected to the pc when the firmware upgrade was done.

I have reinstalled SDR# and SDR Console v3, but it seems to me nothing changes.

 

There is a way to recreate a new calibration file?

 

Regards

Francesco – IN3XZP

 

 


Simon Brown
 

Just FWIW,

 

My noise floor is ~S0.

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Francesco Di Giovanni
Sent: 14 June 2020 09:29
To: main@SDR-Radio.groups.io
Subject: [SDR-Radio] Low noise floor

 

Hi,

I have upgraded my Airspy HF+ Dual Port and Airspy HF+  Discovery to firmware to version 3.0.7.

Since then I have an  “improbable” low noise floor.

I suspect the frequency calibration file of both devices are now corrupted.

Both devices were connected to the pc when the firmware upgrade was done.

I have reinstalled SDR# and SDR Console v3, but it seems to me nothing changes.

 

There is a way to recreate a new calibration file?

 

Regards

Francesco – IN3XZP

 

 


Francesco Di Giovanni
 

Hi, thanks to all for the suggestions.
do you think if I return it to the distributor (Astroradio) will they fix it?

If not, I will try with a signal generator referenced to an external GPSDO.
This will solve the oscillator calibration but not the lack of sensitivity.

73
Francesco - IN3XZP


jdow
 

Have you made sure you are set to AGC mode? Is there a chance a nearby lightning strike damaged the AirSpy?
{o.o}

On 20200614 08:26:28, Francesco Di Giovanni wrote:
Hi, thanks to all for the suggestions.
do you think if I return it to the distributor (Astroradio) will they fix it?
If not, I will try with a signal generator referenced to an external GPSDO.
This will solve the oscillator calibration but not the lack of sensitivity.
73
Francesco - IN3XZP


Francesco Di Giovanni
 

I have set the AGC control to on. In MGC mode I must insert almost 24 dB of attenuation, otherwise the audio is distorted by overload.

73 
Francesco - IN3XZP


Simon Brown
 

Hi,

 

PLEASE show the logfile! Start the radio, grab the logfile: https://www.sdr-radio.com/support#Logfile

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Francesco Di Giovanni
Sent: 16 June 2020 14:28
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Low noise floor

 

I have set the AGC control to on. In MGC mode I must insert almost 24 dB of attenuation, otherwise the audio is distorted by overload.

73 
Francesco - IN3XZP


Francesco Di Giovanni
 

Hi Simon,
attached I send you the log file.

73
francesco - IN3XZP


jdow
 

The following looks like you have a settings problem.
19:36:36.621: Radio Airspy HF+> AGC: Low
19:36:36.621: Radio Airspy HF+> AGC On .........: 0
19:36:36.621: Radio Airspy HF+> Threshold Low ..: 0
19:36:36.621: Radio Airspy HF+> -
19:36:36.622: Radio Airspy HF+> ATT 0 dB, status 0
19:36:36.622: Radio Airspy HF+> -
19:36:36.622: Radio Airspy HF+> LNA Off, status 0
19:36:36.622: Radio Airspy HF+> -

Turn on the AGC for best results with HF+ and accept that the S-Meter probably is more meaningless than usual.

On 20200617 10:44:49, Francesco Di Giovanni wrote:
Hi Simon,
attached I send you the log file.
73
francesco - IN3XZP


Francesco Di Giovanni
 

another screenshot

73
Francesco - IN3XZP


Simon Brown
 

Hi,

 

The logfile tells me you have R3.0.6 installed. Get the very latest firmware, install it. If signals are still very weak then I would look at the antenna connector, if all looks good then the unit may be poorly .

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of Francesco Di Giovanni
Sent: 17 June 2020 18:59
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Low noise floor

 

another screenshot

73
Francesco - IN3XZP