Date   
New HF+ Install Problem

Steve Jerome
 

Brand new install of a new HF+ and PC says 'Unknown USB Device - device descriptor request failed' under Device Manager.  tried uninstalling and restarting but with no joy.

I'm now stuck as to what to do !  WIN10 desktop, x64...

Thanks,

Steve Jerome

Re: Airspy noise figure

jdow
 

Given a choice I'd prefer to try liquid funnygas er Helium for the cold source.

{^_-} Just being imaginative and silly again.

On 20180312 09:15, David Eckhardt wrote:
Yes, there is nothing to compete with the hot/cold 'noise' source.  kTB is very specific.  However, knowing the information bandwidth introduces errors for our amateur receivers unless we rigorously measure that as well.  I've always preferred the hot/cold noise source, but don't keep LN2 around.  However, these days, most larger grocery stores carry dry ice.
Dave - WØLEV
On Mon, Mar 12, 2018 at 4:06 AM, Marcus D. Leech <mleech@... <mailto:mleech@...>> wrote:
On 03/11/2018 09:00 PM, David Rowe wrote:
Thanks Dave - sounds like you have a great experimental set up there for
NF measurements.  For anyone interested in NF measurements, I've blogged
on my humble experiments here:
http://www.rowetel.com/?p=5867
I mentioned your results in the post Dave, hope thats OK.
Cheers,
David
I'll point out that single-point noise-figure methods are rather
error-prone, which is why the industry has standardized on the Y-factor
method, in which
  you have TWO sources of known noise power distribution.
For noise figures above 3dB, you can usually use a high-quality terminator
at room temperature -- whose PSD will be -174dBM/Hz, and then a calibrated
  noise source, usually in the 20-35dB ENR range.  You take averaged
measurements of both, and use that to determine the noise figure of the DUT.
Once you start going to noise-figures below 2-3dB, it's better to have a
"cold load" as one of the noise sources.  Labs that care about noise figure
  measurements for "good" LNAs usually use an LN2-cooled load for the
"cold" load, and again a calibrated noise head for the "hot" load.
On 12/03/18 10:18, David Eckhardt wrote:
I have a calibrated noise source good to 18 GHz and several
precision attenuators (HP, both single value and switched).  Knowing
the noise output of the noise source, I attenuate until the noise
just goes into the 'noise', tangential noise.  The difference
between the noise source known output and the attenuation  is my
noise figure.
Dave - WØLEV
On Sun, Mar 11, 2018 at 10:27 PM, David Rowe <david@...
<mailto:david@...> <mailto:david@...
<mailto:david@...>>> wrote:
    Thanks Dave,
    Could you tell me a little more about how you measured NF?
    Thanks,
    David
    On 12/03/18 08:37, David Eckhardt wrote:
        I've measured both the R1 and my present R2.  They both come in
        around 4 dB.  I believe 7 to 8 dB is a bit much based on my
        experience with them.
        Dave - WØLEV
        On Sun, Mar 11, 2018 at 9:34 PM, <david@...
<mailto:david@...>
        <mailto:david@... <mailto:david@...>>
<mailto:david@... <mailto:david@...>
        <mailto:david@... <mailto:david@...>>>> wrote:
             Hi - I've been setting up a system to measure noise
figures
        of SDRs
             in real time, an extension of some similat tests we
        performed a few
             years ago:
https://www.rowetel.com/?p=5057 <https://www.rowetel.com/?p=5057>
        <https://www.rowetel.com/?p=5057
<https://www.rowetel.com/?p=5057>>
        <https://www.rowetel.com/?p=5057
<https://www.rowetel.com/?p=5057> <https://www.rowetel.com/?p=5057
<https://www.rowetel.com/?p=5057>>>
             I'm getting a NF of 7-8dB for a new Airspy R2 and Airspy
        mini.  The
             spec quotes 3.6dB.  Has anyone else measured the NF?
             I note the 3.6dB figure is exactly the same as the front
        end tuner
             R820 tuner.  However a system noise figure will always be
        poorer
             than the front end device.
             Thanks,
             David
        --         *Dave - WØLEV
        *
        */Just Let Darwin Work/*
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*

Re: Remote Flashing airspy HF+ connected to Raspberry pi. #firmware

Alexander
 

Hello! To you could accept a flow in SDRSharp# using Virtualhere without Spyserver involvement?

Re: Airspyhf+ flashing

Mid Mid
 

hello every body this is my first post , i was having problems flashing my hf+ i tired at least 10 times with different OS almost all the tricks mention here except I  didn't do a voodoo spell  .. until (Alberto I2PHD) mention that he had to scratch the surface of the erase pins ..so here what i did
scratched the erase pin then used a my sharp pocket knife and pushed it a little on the Erase pins .. disconnect the USB .. a miracle  happen flash worked  !

thanks (Alberto I2PHD)

On Mon, Mar 12, 2018 at 6:22 PM, John Fonseca <fonsecanyc@...> wrote:
With the first HF+ I got (part of pre-order batch via Airspy.us) I had no problems flashing.  I just couldn't do it on my main desktop PC because the virtual com port system used by my RigExpert TI-8 interfered with the Bossa com port assignment.

However, I ordered a 2nd one that came last week and on the same laptop I use to keep the the original HF+ updated, using the same procedure, didn't work the first 3 or so times I tried it.  The HF+ would stay in normal mode after erasing it and Windows would never detect the Bossa com port.  I also tried flashing without erasing first and that also failed.  I kept trying it and on the 4th or 5th attempt it worked normally and I could do the update.

I'm not sure if this is happening for others having an issue with flashing and you just need to keep trying until it works.  As I said, I never had this problem with the original one.  That one worked on the first shot on the same Win10 laptop used for the 2nd one (and for subsequent updates on my original HF+).

John


Re: Airspy noise figure

David Eckhardt
 

Yes, there is nothing to compete with the hot/cold 'noise' source.  kTB is very specific.  However, knowing the information bandwidth introduces errors for our amateur receivers unless we rigorously measure that as well.  I've always preferred the hot/cold noise source, but don't keep LN2 around.  However, these days, most larger grocery stores carry dry ice. 

Dave - WØLEV   

On Mon, Mar 12, 2018 at 4:06 AM, Marcus D. Leech <mleech@...> wrote:
On 03/11/2018 09:00 PM, David Rowe wrote:
Thanks Dave - sounds like you have a great experimental set up there for NF measurements.  For anyone interested in NF measurements, I've blogged on my humble experiments here:

  http://www.rowetel.com/?p=5867

I mentioned your results in the post Dave, hope thats OK.

Cheers,

David
I'll point out that single-point noise-figure methods are rather error-prone, which is why the industry has standardized on the Y-factor method, in which
  you have TWO sources of known noise power distribution.

For noise figures above 3dB, you can usually use a high-quality terminator at room temperature -- whose PSD will be -174dBM/Hz, and then a calibrated
  noise source, usually in the 20-35dB ENR range.  You take averaged measurements of both, and use that to determine the noise figure of the DUT.

Once you start going to noise-figures below 2-3dB, it's better to have a "cold load" as one of the noise sources.  Labs that care about noise figure
  measurements for "good" LNAs usually use an LN2-cooled load for the "cold" load, and again a calibrated noise head for the "hot" load.





On 12/03/18 10:18, David Eckhardt wrote:
I have a calibrated noise source good to 18 GHz and several precision attenuators (HP, both single value and switched).  Knowing the noise output of the noise source, I attenuate until the noise just goes into the 'noise', tangential noise.  The difference between the noise source known output and the attenuation  is my noise figure.

Dave - WØLEV

On Sun, Mar 11, 2018 at 10:27 PM, David Rowe <david@... <mailto:david@...>> wrote:

    Thanks Dave,

    Could you tell me a little more about how you measured NF?

    Thanks,

    David

    On 12/03/18 08:37, David Eckhardt wrote:

        I've measured both the R1 and my present R2.  They both come in
        around 4 dB.  I believe 7 to 8 dB is a bit much based on my
        experience with them.

        Dave - WØLEV

        On Sun, Mar 11, 2018 at 9:34 PM, <david@...
        <mailto:david@...> <mailto:david@...
        <mailto:david@...>>> wrote:

             Hi - I've been setting up a system to measure noise figures
        of SDRs
             in real time, an extension of some similat tests we
        performed a few
             years ago:

        https://www.rowetel.com/?p=5057
        <https://www.rowetel.com/?p=5057>
        <https://www.rowetel.com/?p=5057 <https://www.rowetel.com/?p=5057>>

             I'm getting a NF of 7-8dB for a new Airspy R2 and Airspy
        mini.  The
             spec quotes 3.6dB.  Has anyone else measured the NF?

             I note the 3.6dB figure is exactly the same as the front
        end tuner
             R820 tuner.  However a system noise figure will always be
        poorer
             than the front end device.

             Thanks,

             David




        --         *Dave - WØLEV
        *
        */Just Let Darwin Work/*







--
*Dave - WØLEV
*
*/Just Let Darwin Work/*









--
Dave - WØLEV
Just Let Darwin Work

Re: Airspyhf+ flashing

John Fonseca
 

With the first HF+ I got (part of pre-order batch via Airspy.us) I had no problems flashing.  I just couldn't do it on my main desktop PC because the virtual com port system used by my RigExpert TI-8 interfered with the Bossa com port assignment.

However, I ordered a 2nd one that came last week and on the same laptop I use to keep the the original HF+ updated, using the same procedure, didn't work the first 3 or so times I tried it.  The HF+ would stay in normal mode after erasing it and Windows would never detect the Bossa com port.  I also tried flashing without erasing first and that also failed.  I kept trying it and on the 4th or 5th attempt it worked normally and I could do the update.

I'm not sure if this is happening for others having an issue with flashing and you just need to keep trying until it works.  As I said, I never had this problem with the original one.  That one worked on the first shot on the same Win10 laptop used for the 2nd one (and for subsequent updates on my original HF+).

John

Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

Stepan Synek
 

Hello Witham,
I have similar observation with my other brand SDR. (Elad FDM-S1, SDRPlay rsp 2) 
I have two monitors connected to my Lenovo notebook. Sometimes the picture displayed on the second screen affects the reception noise “spikes”) on the SDR. I had thought that LCD monitor creates some RFI, but switching off this monitor did not help.
It also differ depends on antenna type and frequency... One day I have “spikes” the other day they are gone with the same setup. (????)
Maybe to add bunch of the ferrite clamps to the monitor cable could help, but I haven’t found time to verify it yet.
Please continue with your lab tests :-)
regards
Stepan 

Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

Siegfried Jackstien
 

hmmm ... their dac and adc could make a nice sdr backend with high quality

dg9bfc sigi


Am 12.03.2018 um 13:45 schrieb Ken Alexander:

I'd be interested to know if anyone has ever tried one of these.  It's a "USB decrapifier", meant for audio systems.  It isolates computer's USB power from (in our case) the Airspy and replaces it with cleaned-up power from its own linear power supply.  Kind of expensive at US $99 compared to ferrites and better cables.  I've had my eye on them and just wondering.






From: jdow <jdow@...>
To: main@airspy.groups.io
Sent: Monday, March 12, 2018 12:58 AM
Subject: Re: [airspy] USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

Put some ferrite on every lead that goes out of the Pi. Any one of them can
radiate and create problems. Try using a longer cable for the HF+ and placing it
further away from the Pi. You are in the near field for at least the HF noise.
So doubling distance from the noise source will bring as much as a 9 dB
improvement. It will help at much as 6 dB at VHF. A 5 meter cable would not be
out of line. But don't go beyond that without careful testing with a powered USB
extension.

{^_^}

On 20180311 12:38, ea5ehs@... wrote:
> Hello David,
> I decided to go de Orange Pi UNO way for different reasons; low cost, Gigabit
> ethernet outside the usb bus, only one usb 2.0 port.
> My theory about the usb qrm from cables is that there is a RPI USB design
> allowing for this. I have tested one Rpi2B and two Rpi3B with identical results.
> QRM is only generated when an active data connection is on, ie when a client
> connects to spyserver and start sdr#.
> When I connect the airspy HF+ to a usb port of my Laptop and rin SDR#, no noise
> is generated with any of the six tested cables' using the same antennas.
> I was considering the Tinkerboard SBC but as I'm runing on solar power, every mW
>   of power consumption counts. Tinkerboard seems to draw more power than Rpi an
> Orange pi. Rpi3+airspy accounts for 630mA at 5V during an active connection. I
> have also taken additional power saving measures like turning off the on Board
> leds and the HDMI.
>
> Best Ni
> EA5ZL
>
>






Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

Ken Alexander
 

I'd be interested to know if anyone has ever tried one of these.  It's a "USB decrapifier", meant for audio systems.  It isolates computer's USB power from (in our case) the Airspy and replaces it with cleaned-up power from its own linear power supply.  Kind of expensive at US $99 compared to ferrites and better cables.  I've had my eye on them and just wondering.






From: jdow <jdow@...>
To: main@airspy.groups.io
Sent: Monday, March 12, 2018 12:58 AM
Subject: Re: [airspy] USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

Put some ferrite on every lead that goes out of the Pi. Any one of them can
radiate and create problems. Try using a longer cable for the HF+ and placing it
further away from the Pi. You are in the near field for at least the HF noise.
So doubling distance from the noise source will bring as much as a 9 dB
improvement. It will help at much as 6 dB at VHF. A 5 meter cable would not be
out of line. But don't go beyond that without careful testing with a powered USB
extension.

{^_^}

On 20180311 12:38, ea5ehs@... wrote:
> Hello David,
> I decided to go de Orange Pi UNO way for different reasons; low cost, Gigabit
> ethernet outside the usb bus, only one usb 2.0 port.
> My theory about the usb qrm from cables is that there is a RPI USB design
> allowing for this. I have tested one Rpi2B and two Rpi3B with identical results.
> QRM is only generated when an active data connection is on, ie when a client
> connects to spyserver and start sdr#.
> When I connect the airspy HF+ to a usb port of my Laptop and rin SDR#, no noise
> is generated with any of the six tested cables' using the same antennas.
> I was considering the Tinkerboard SBC but as I'm runing on solar power, every mW
>   of power consumption counts. Tinkerboard seems to draw more power than Rpi an
> Orange pi. Rpi3+airspy accounts for 630mA at 5V during an active connection. I
> have also taken additional power saving measures like turning off the on Board
> leds and the HDMI.
>
> Best Ni
> EA5ZL
>
>





Re: Airspy noise figure

Marcus D. Leech <mleech@...>
 

On 03/12/2018 01:36 AM, jdow wrote:

And LN2 is incredibly fun to play with when you have spare left over in the bottom of the flask.... Just be seriously freaking careful with the stuff lest you lose appendages. (Chocolate cake frozen in an LN2 cooled testing "oven" freezes so fast it thaws as good as fresh.)

{^_-}
One might be able to improve results for lower-noise devices with mere dry-ice for the cold-load. I've seen it done. The uncertainty would be higher
than with LN2, but better than at ambient....

Re: Airspy noise figure

jdow
 

On 20180311 21:06, Marcus D. Leech wrote:
On 03/11/2018 09:00 PM, David Rowe wrote:
Thanks Dave - sounds like you have a great experimental set up there for NF measurements.  For anyone interested in NF measurements, I've blogged on my humble experiments here:

  http://www.rowetel.com/?p=5867

I mentioned your results in the post Dave, hope thats OK.

Cheers,

David
I'll point out that single-point noise-figure methods are rather error-prone, which is why the industry has standardized on the Y-factor method, in which
  you have TWO sources of known noise power distribution.
For noise figures above 3dB, you can usually use a high-quality terminator at room temperature -- whose PSD will be -174dBM/Hz, and then a calibrated
  noise source, usually in the 20-35dB ENR range.  You take averaged measurements of both, and use that to determine the noise figure of the DUT.
Once you start going to noise-figures below 2-3dB, it's better to have a "cold load" as one of the noise sources.  Labs that care about noise figure
  measurements for "good" LNAs usually use an LN2-cooled load for the "cold" load, and again a calibrated noise head for the "hot" load.
And LN2 is incredibly fun to play with when you have spare left over in the bottom of the flask.... Just be seriously freaking careful with the stuff lest you lose appendages. (Chocolate cake frozen in an LN2 cooled testing "oven" freezes so fast it thaws as good as fresh.)

{^_-}

Re: Airspy noise figure

jdow
 

That may be with a strong enough signal the AGC becomes active. It's an unusual AGC that does not adversely affect noise figure.
{^_^}

On 20180311 15:07, David Eckhardt wrote:
I've measured both the R1 and my present R2.  They both come in around 4 dB.  I believe 7 to 8 dB is a bit much based on my experience with them.
Dave - WØLEV
On Sun, Mar 11, 2018 at 9:34 PM, <david@... <mailto:david@...>> wrote:
Hi - I've been setting up a system to measure noise figures of SDRs in real
time, an extension of some similat tests we performed a few years ago:
https://www.rowetel.com/?p=5057 <https://www.rowetel.com/?p=5057>
I'm getting a NF of 7-8dB for a new Airspy R2 and Airspy mini.  The spec
quotes 3.6dB.  Has anyone else measured the NF?
I note the 3.6dB figure is exactly the same as the front end tuner R820
tuner.  However a system noise figure will always be poorer than the front
end device.
Thanks,
David
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*

Re: #SpectrumSpy #spectrumspy

Martin Smith
 

Or possibly qspectrumanalyzer ( https://github.com/xmikos/qspectrumanalyzer )

Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

jdow
 

At a guess he means "Blitzwolf" not a name that sounds like the silly CNN announcer. "Blitzwolf USB Cable" turns up a large Panamax boatload and a half of references on Giggle er Google.

{^_^}

On 20180311 13:44, Patrick wrote:
Hi Dave,
Could you please provide the reference of the shielded cable you mention ?
Thanks.
2018-03-11 21:39 GMT+01:00 D R via Groups.Io <robsond90=yahoo.co.uk@groups.io <mailto:robsond90=yahoo.co.uk@groups.io>>:
Hi David,
I'm currently using Wolfblitz shielded cables I bought on Banggood, and I've
found them to be very good indeed.  I've been running an ELAD S2, an RSP1A
and an HF+ simultaneously without a trace of PC/USB noise on any of them,
whereas previously it took a ton of ferrite to get rid of about 90% of it -
on supposedly "good quality" cables.  No ferrite is needed on the new cables.
I think they are only made with microUSB or Type-C connectors at the device
end, so I had to get a couple of microUSB to Type B adapters for the S2 and
RSP1A, but they don't appear to have compromised the end to end shielding. They aren't expensive when bought direct, and are well worth a look.
Regards,
Dave
--------------------------------------------------------------------------------
*From:* David Ranch <airspy-groupsio@...
<mailto:airspy-groupsio@...>>
*To:* main@airspy.groups.io <mailto:main@airspy.groups.io>
*Sent:* Sunday, 11 March 2018, 16:44
*Subject:* Re: [airspy] USB cable quality and QRM in a spyserver setup with
an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus
#bestpractice #raspberrypi
Hello EA5ZL,
Thanks for taking the time to write this up and it's quite illuminating to
see how poor some of those cables are.  I too have run into cables that LOOK
like their quality made with built-in ferrites on both ends, etc. only to
find their crap.  I wish we could find a reliable source of "RF tight"
cables that both consistently good and aren't outrageously priced.
Anyway.. I look forward to your results on the OrangePi to see if it's any
better.  Btw.. why the OrangePi vs. say a Tinkerboard or a Pine64 or other? There are SO many SBCs out there now but it's impossible to beat the
community and support found with the Raspberry Pi boards.
--David
KI6ZHD

Re: Airspyhf+ flashing

jdow
 

Um, bring up the device manager. Unplug the unit. Wait a minute or so. Device manager should self update it's display. Plug in the unit. If it is erased it should come up as a serial port after device manager thinks a little bit. Try rescanning for equipment changes. (Highlight one of the device classifications, any one. Then the Action menu will over "Scan for hardware changes".) If none of them shows a new device is found you're into needing Youssef or somebody to help. If a device comes up with a yellow question mark it suggests it is something the system does not recognize. That is also a job for Youssef and company. It should come up as a BOSSA serial port, in an ideal world after it has been erased.

DO NOTE: After erasure UNPLUG IT. Then plug it in. Then try to flash it. Some steps on the initial flashing process may seem silly. They are not.

{^_^}

On 20180311 12:47, Mark Taylor wrote:
Hi,
Thanks for all the ideas:  Here's what I've done.  Cumulative and stopping with each step to try.  So far no luck.
- Scraped the erase pads and re erased the unit, being careful to hold it for a full 1 second.  Took all external devices off my laptop.  Checked the computer that Port 10, 11, 12 wasn't in use.  (In fact no ports were listed.) Same as previously.
- Changed cable.  Same as previously.
- turned off virus protection, internet, and firewall.  Same as previously.
I think those were the relevant suggestions I hadn't tried before.
Repeated this on 2 other computers with same responses - 1 laptop and 1 desktop.  Originally on a MSI laptop, then a Lenovo laptop, then a HP desktop.
It's pretty clear that the flash software isn't finding the unit even with downloading the flash software to 3 machines.
Other suggestions?
Thanks
Mark
On Sun, Mar 11, 2018 at 9:55 AM, Alberto I2PHD <@I2PHD <mailto:@I2PHD>> wrote:
Just a small note based on my personal experience. At first, shorting the
two "Erase" pads as shown in the photo did not work...
Then I realized that maybe the pads could have been covered by a transparent
layer of protective (and insulating...) paint.
I disconnected the unit from the USB port, and gently scraped the top of the
two pads so to expose the bare solder.
Then I reconnected the unit to the USB port, and repeat the shorting procedure.
This time everything worked as it should, and was able to correctly flash
the firmware.
--
/*73 Alberto I2PHD*
Credo Ut Intelligam/

Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

jdow
 

Put some ferrite on every lead that goes out of the Pi. Any one of them can radiate and create problems. Try using a longer cable for the HF+ and placing it further away from the Pi. You are in the near field for at least the HF noise. So doubling distance from the noise source will bring as much as a 9 dB improvement. It will help at much as 6 dB at VHF. A 5 meter cable would not be out of line. But don't go beyond that without careful testing with a powered USB extension.

{^_^}

On 20180311 12:38, ea5ehs@... wrote:
Hello David,
I decided to go de Orange Pi UNO way for different reasons; low cost, Gigabit ethernet outside the usb bus, only one usb 2.0 port.
My theory about the usb qrm from cables is that there is a RPI USB design allowing for this. I have tested one Rpi2B and two Rpi3B with identical results.
QRM is only generated when an active data connection is on, ie when a client connects to spyserver and start sdr#.
When I connect the airspy HF+ to a usb port of my Laptop and rin SDR#, no noise is generated with any of the six tested cables' using the same antennas.
I was considering the Tinkerboard SBC but as I'm runing on solar power, every mW  of power consumption counts. Tinkerboard seems to draw more power than Rpi an Orange pi. Rpi3+airspy accounts for 630mA at 5V during an active connection. I have also taken additional power saving measures like turning off the on Board leds and the HDMI.
Best Ni
EA5ZL

Re: Airspy noise figure

Marcus D. Leech <mleech@...>
 

On 03/11/2018 09:00 PM, David Rowe wrote:
Thanks Dave - sounds like you have a great experimental set up there for NF measurements. For anyone interested in NF measurements, I've blogged on my humble experiments here:

http://www.rowetel.com/?p=5867

I mentioned your results in the post Dave, hope thats OK.

Cheers,

David
I'll point out that single-point noise-figure methods are rather error-prone, which is why the industry has standardized on the Y-factor method, in which
you have TWO sources of known noise power distribution.

For noise figures above 3dB, you can usually use a high-quality terminator at room temperature -- whose PSD will be -174dBM/Hz, and then a calibrated
noise source, usually in the 20-35dB ENR range. You take averaged measurements of both, and use that to determine the noise figure of the DUT.

Once you start going to noise-figures below 2-3dB, it's better to have a "cold load" as one of the noise sources. Labs that care about noise figure
measurements for "good" LNAs usually use an LN2-cooled load for the "cold" load, and again a calibrated noise head for the "hot" load.





On 12/03/18 10:18, David Eckhardt wrote:
I have a calibrated noise source good to 18 GHz and several precision attenuators (HP, both single value and switched). Knowing the noise output of the noise source, I attenuate until the noise just goes into the 'noise', tangential noise. The difference between the noise source known output and the attenuation is my noise figure.

Dave - WØLEV

On Sun, Mar 11, 2018 at 10:27 PM, David Rowe <david@... <mailto:david@...>> wrote:

Thanks Dave,

Could you tell me a little more about how you measured NF?

Thanks,

David

On 12/03/18 08:37, David Eckhardt wrote:

I've measured both the R1 and my present R2. They both come in
around 4 dB. I believe 7 to 8 dB is a bit much based on my
experience with them.

Dave - WØLEV

On Sun, Mar 11, 2018 at 9:34 PM, <david@...
<mailto:david@...> <mailto:david@...
<mailto:david@...>>> wrote:

Hi - I've been setting up a system to measure noise figures
of SDRs
in real time, an extension of some similat tests we
performed a few
years ago:

https://www.rowetel.com/?p=5057
<https://www.rowetel.com/?p=5057>
<https://www.rowetel.com/?p=5057 <https://www.rowetel.com/?p=5057>>

I'm getting a NF of 7-8dB for a new Airspy R2 and Airspy
mini. The
spec quotes 3.6dB. Has anyone else measured the NF?

I note the 3.6dB figure is exactly the same as the front
end tuner
R820 tuner. However a system noise figure will always be
poorer
than the front end device.

Thanks,

David




-- *Dave - WØLEV
*
*/Just Let Darwin Work/*







--
*Dave - WØLEV
*
*/Just Let Darwin Work/*

Re: USB cable quality and QRM in a spyserver setup with an Airspy Hf+ and Raspberry PI3. 6 microUSB cable test. #airspyhfplus #bestpractice #raspberrypi

smswk
 
Edited

that seems very strange to me.
After testing USB cables (with and without ferrite chokes), Filters and reading application notes
for a couple of months my only solution seems to be a good USB Filter
like the Wuerth EPLE + blocking the USB shield to pcb ground with
a 1M Ohm resistor in parallel with a 4n7 Cap. 

To stop and restart the Software had no effect (and if so it would have surprised me)

vy 73`s de
Stefan

Re: Airspyhf+ flashing

jdow
 

Hm, it belongs in several places. c:\windows\system32\wbem, c:\windows\syswow64\wbem, and a couple others with REALLY long names. The first one of those should be on your path for executables. (The command line "path" command should have the c:\windows\system32\wbem entry.)

{^_^}

On 20180311 05:41, EB4APL wrote:
HI,
The COM10 port issue is not definitive. Here one computer uses COM11, other COM13. None of them has anything installed on COM10.
I have noticed that the USB cable has influence in SOME flashing problems.
One problem that I had was due to my main computer not had the system program file "wmic.exe" , which is used by FLASH.bat,  in the right folder. I copied it to its standard location "Windows|System32" and the problem solved. Who knows what did the change.
Regards,
Ignacio, EB4APL
El 11/03/2018 a las 13:15, jdow escribió:
As a last resort temporarily remove all other USB devices that are not keyboards, mice, touchpads, or CDROMs. And based on something awhile back make sure nothing is sitting on COM10 serial port. There was a series of comments that suggested the ASHF+ device will look like a COM port and may try to land on COM10 by preference.

{^_^}

On 20180311 04:49, W8RMV@... wrote:
Mark Taylor,
You are not alone. I had the same message when trying to flash the latest version 1.6.2.  I have flashed the previous versions successfully & on the same computer (W10 64bit) & USB cable.  I took the cable & HF+ & connected it to my W10 64 bit Laptop & it flashed there, no problems.  I still haven't figured out why my desktop stopped cooperating.  I did notice that my virus protection on the Desktop warned me of a deep guard concern, but disabling the complete security suite, did not fix the flash issue.  And that was the first time my Virus protection did that.  All prior flashes did not trigger the protection.  I do not have that protection suite on my laptop.
--
73 Bob W8RMV

Re: Airspy noise figure

David Eckhardt
 

Oh, have at it.  If I can help anyone, I've succeeded. 

Dave - WØLEV

On Mon, Mar 12, 2018 at 1:00 AM, David Rowe <david@...> wrote:
Thanks Dave - sounds like you have a great experimental set up there for NF measurements.  For anyone interested in NF measurements, I've blogged on my humble experiments here:

  http://www.rowetel.com/?p=5867

I mentioned your results in the post Dave, hope thats OK.

Cheers,

David

On 12/03/18 10:18, David Eckhardt wrote:
I have a calibrated noise source good to 18 GHz and several precision attenuators (HP, both single value and switched).  Knowing the noise output of the noise source, I attenuate until the noise just goes into the 'noise', tangential noise.  The difference between the noise source known output and the attenuation  is my noise figure.

Dave - WØLEV

On Sun, Mar 11, 2018 at 10:27 PM, David Rowe <david@... <mailto:david@...>> wrote:

    Thanks Dave,

    Could you tell me a little more about how you measured NF?

    Thanks,

    David

    On 12/03/18 08:37, David Eckhardt wrote:

        I've measured both the R1 and my present R2.  They both come in
        around 4 dB.  I believe 7 to 8 dB is a bit much based on my
        experience with them.

        Dave - WØLEV

        On Sun, Mar 11, 2018 at 9:34 PM, <david@...
        <mailto:david@...> <mailto:david@...
        <mailto:david@...>>> wrote:

             Hi - I've been setting up a system to measure noise figures
        of SDRs
             in real time, an extension of some similat tests we
        performed a few
             years ago:

        https://www.rowetel.com/?p=5057
        <https://www.rowetel.com/?p=5057>
        <https://www.rowetel.com/?p=5057 <https://www.rowetel.com/?p=5057>>

             I'm getting a NF of 7-8dB for a new Airspy R2 and Airspy
        mini.  The
             spec quotes 3.6dB.  Has anyone else measured the NF?

             I note the 3.6dB figure is exactly the same as the front
        end tuner
             R820 tuner.  However a system noise figure will always be
        poorer
             than the front end device.

             Thanks,

             David




        --         *Dave - WØLEV
        *
        */Just Let Darwin Work/*







--
*Dave - WØLEV
*
*/Just Let Darwin Work/*







--
Dave - WØLEV
Just Let Darwin Work