Date   

Re: ARRL review of the SDRPlay RSP2

Joe M.
 

Not that I want to defend them (especially against you),
but maybe they wanted to cite the "worst case scenario".

I have to wonder how they choose what to review.
They have stated they will not accept requests to review items.
That leads me to believe it's more political than logical.

Joe M.

On 9/14/2017 3:31 PM, jdow wrote:
And what set me off from the test results page.
===8<---
FM two-tone third-order dynamic range: Not specified
20 kHz spacing: 29 MHz, 50 dB†; 52 MHz 49 dB†, 144 MHz, 50 dB; 440
MHz,
40 dB†. 10 MHz spacing: 29 MHz, 61 dB, 52 MHz, 64 dB; 144MHz, 57 dB;
440 MHz, 59 dB.
Measured with maximum RF gain setting.
===8<---
Note that last line. The damn fool reviewer had no idea how to use an
SDR properly.

{+_+}


Re: ARRL review of the SDRPlay RSP2

jdow
 

A little fairness might be called for here - they have to find authors to write worthwhile articles on SDRs that include more technical detail and less naive puttering around. Without that they cannot educate. Without education their readership will remain crouched back in their mental caves afraid of the monsters out there they don't understand. Look at how long after Morse Code was removed from commercial service that the ARRL finally suggested to the FCC that a Morse Code requirement for ham licenses might be just a tad out dated. Look at the famn dool signal descriptions they use. If a signal is generated directly at RF it is listed with a different designation than if it is generated at audio as an IF and translated through bog standard "super-heterodyne" principles to the output frequency. Somehow going through an signal generation at audio frequencies has a magical effect on the transmitted signal even though the receiver cannot tell any difference. Go figure.

{^_^}

On 2017-09-14 10:47, David Eckhardt wrote:
I have yet to read the review, but I approach it with a grain of salt.  Does anyone remember what a major task it was to drag ARRL into the modern age of solid state?.  I do.  It was painful.  Some of us participated in dragging them into that 'modern' era kicking and screaming as they did.  Transistors were well entrenched in the designers bag of tricks before ARRL ever published a single useful article involving transistors.
In 1985 and my article published in the ARRL handbook of that year (the 1296 transverter), they didn't know how to represent a stripline or transmission line is a schematic diagram.  I, yes, I, taught them how to draw a simple transmission line in schematic representation.  We'd been using that representation in the professional world for almost two decades by that time!
And the ARRL MISdirection for decades on "grounding" ! ! !    Their most recent pubilcation on grounding and bonding has FINALLY cleared them of all the errors of the past in this respect!
ARRL isn't perfect, and at times, I think they should keep out of technical, but they can't.  Our hobby REQUIRES a minimum understanding of the technical and radio theory behind the front panels of our radios.  Realize ARRL is the amateur radios operator's lobby group.  Their function is to maintain our frequencies and, occasionally, ask for and procure more.  Forgive them for their ineptness in evaluating the SDR technology (which has been with us, professionally, for well over 1.5 decades).  They'll learn, but behind the power curve.  Some of us may have to step up to the plate as we have in the past and hold their hand. What else is new?
Dave - WØLEV
PS:  I am a life member of ARRL.
On Wed, Sep 13, 2017 at 6:00 PM, <wageners@gmail.com <mailto:wageners@gmail.com>> wrote:
Here you go:
http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf
<http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf>
Stefan
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*


Re: ARRL review of the SDRPlay RSP2

jdow
 

And what set me off from the test results page.
===8<---
FM two-tone third-order dynamic range: Not specified
20 kHz spacing: 29 MHz, 50 dB†; 52 MHz 49 dB†, 144 MHz, 50 dB; 440 MHz,
40 dB†. 10 MHz spacing: 29 MHz, 61 dB, 52 MHz, 64 dB; 144MHz, 57 dB;
440 MHz, 59 dB.
Measured with maximum RF gain setting.
===8<---
Note that last line. The damn fool reviewer had no idea how to use an SDR properly.

{+_+}

On 2017-09-14 11:06, John Scherer wrote:
Ya, like the "Bottom Line" call out on the first page?
"Building on the success of theRSP1, the SDRplay RSP2 adds a number of useful features"
On Thu, Sep 14, 2017 at 1:34 AM, Shirley Dulcey KE1L <mark@buttery.org <mailto:mark@buttery.org>> wrote:
I have to dissent from the opinions here. Although the ARRL review is
not perfect, there is a lot of useful information there. In
particular, the lab tests show the excellent sensitivity of the
Airspy, as well as its dynamic range limitations (which are in line
with expectations for a device with a 12 bit digitizer, which other
comments have correctly pointed out was not mentioned in the review).
They also provide a useful table of the differences between the R1 and
R2.
On Wed, Sep 13, 2017 at 8:00 PM,  <wageners@gmail.com
<mailto:wageners@gmail.com>> wrote:
> Here you go:
>
> http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf
<http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf>
>
>
> Stefan
>
--
*John Scherer*
(619)354-4142
1552 Regulus Street 92111
WebsiteGB <https://www.qrz.com/db/N0CTL> email <mailto:jrsphoto@gmail.com> Twitter button <https://twitter.com/johnscherer> Google button <https://plus.google.com/+JohnScherer/posts>


Re: ARRL review of the SDRPlay RSP2

John Scherer
 

Ya, like the "Bottom Line" call out on the first page?

"Building on the success of the RSP1, the SDRplay RSP2 adds a number of useful features"

On Thu, Sep 14, 2017 at 1:34 AM, Shirley Dulcey KE1L <mark@...> wrote:
I have to dissent from the opinions here. Although the ARRL review is
not perfect, there is a lot of useful information there. In
particular, the lab tests show the excellent sensitivity of the
Airspy, as well as its dynamic range limitations (which are in line
with expectations for a device with a 12 bit digitizer, which other
comments have correctly pointed out was not mentioned in the review).
They also provide a useful table of the differences between the R1 and
R2.


On Wed, Sep 13, 2017 at 8:00 PM,  <wageners@...> wrote:
> Here you go:
>
> http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf
>
>
> Stefan
>






--
John Scherer  
(619)354-4142 
1552 Regulus Street 92111  
WebsiteGB   email    Twitter button   Google button 


Re: ARRL review of the SDRPlay RSP2

W0LEV
 

I have yet to read the review, but I approach it with a grain of salt.  Does anyone remember what a major task it was to drag ARRL into the modern age of solid state?.  I do.  It was painful.  Some of us participated in dragging them into that 'modern' era kicking and screaming as they did.  Transistors were well entrenched in the designers bag of tricks before ARRL ever published a single useful article involving transistors. 

In 1985 and my article published in the ARRL handbook of that year (the 1296 transverter), they didn't know how to represent a stripline or transmission line is a schematic diagram.  I, yes, I, taught them how to draw a simple transmission line in schematic representation.  We'd been using that representation in the professional world for almost two decades by that time!

And the ARRL MISdirection for decades on "grounding" ! ! !    Their most recent pubilcation on grounding and bonding has FINALLY cleared them of all the errors of the past in this respect! 

ARRL isn't perfect, and at times, I think they should keep out of technical, but they can't.  Our hobby REQUIRES a minimum understanding of the technical and radio theory behind the front panels of our radios.  Realize ARRL is the amateur radios operator's lobby group.  Their function is to maintain our frequencies and, occasionally, ask for and procure more.  Forgive them for their ineptness in evaluating the SDR technology (which has been with us, professionally, for well over 1.5 decades).  They'll learn, but behind the power curve.  Some of us may have to step up to the plate as we have in the past and hold their hand.  What else is new? 

Dave - WØLEV

PS:  I am a life member of ARRL.

On Wed, Sep 13, 2017 at 6:00 PM, <wageners@...> wrote:
Here you go:

http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf


Stefan




--
Dave - WØLEV
Just Let Darwin Work


Re: Airspy R2: Interferences with antenna disconnected

jdow
 

The conversation sort of branched out to more general terms. That is why I did not specifically mention AirSpy in favor of "unit under test".

{^_-}

On 2017-09-14 03:32, Ruben Navarro Huedo (EA5BZ) wrote:
Joanne: it is published in the quickstart page.
A firm update is needed.
No problems with 10MSPS


Re: Airspy R2: Interferences with antenna disconnected

jdow
 

Ah so quite different environments are involved for you and me. The original issue was at 137 MHz. (And I mis-read it because I use NOAA on 162.5 MHz for voice weather reports. And I can remember an era when there was a chance to hear that across the Atlantic - a slim chance but a chance nonetheless.) So a simple low pass filter would remove the harmonics of 160 kHz. For your case you were working down in the frequency regime where a low pass filter would not normally turn the trick. And, indeed, if it is in the power supply it is difficult to remove. Although I have eliminated cross-talk through the power supply between receivers in a 31 receiver box for the Navy using a very large synthetic (Miller Feedback) capacitor. It was a last minute panic solution during acceptance testing when the power supplies came in with disgustingly high output impedances above about 10 Hz. The synthetic capacitance created was something like 10 Farads. It very nicely tightened up the power supply output impedance.

Those pesky electrons do what THEY want to do unless you really ride herd on them, don't they?

{^_^} Joanne

On 2017-09-14 03:30, Jake Brodsky wrote:
Sorry about that, it was a default signature. PE means Professional
Engineer. I work with A/D circuitry in industrial environments where
electrical noise is a serious problem. Try using a 16 bit A/D near a
medium voltage variable frequency drive and you'll get a taste of what
my day can be like.
If the 160 kHz noise gets through because it was differentially coupled
from a noisy switching supply, then a common mode choke won't do much at
any frequency. I'm presuming you know how to select proper ferrite
materials. Once it is in the power supply, all bets are off.
Jake Brodsky
On 9/14/2017 3:36 AM, jdow wrote:
PE means WHAT? Yes, 160 kHz will get through. But harmonics of 160 kHz
won't. If the device internals regenerate the harmonics of 160 kHz and
its really low frequency harmonics then it has a serious design flaw.
That could be revealed by running a proper test - cap the input with a
proper shielded 50 ohm terminator.

It's also noteworthy that that some ferrites work best at HF for
attenuation while others work best at VHF and UHF. Furthermore some
ferrites are designed for low loss while others are higher loss
designed for EMI reduction. Proper ferrite choice (typically clip on
barrels) makes a difference.

Then if the 160 kHz is still present it's time for the designer to
diagnose where the problem comes from at 137 MHz.

{^_^}   Joanne


Re: ARRL review of the SDRPlay RSP2

jdow
 

Ethernet noise should also be considered if the Ethernet port is used.

And the ARRL should publish some good articles about SDRs, how they work, how their performance for noise and interference differs from standard receivers, how to set one up for optimum performance, and for God's sake inform the members that if they hear or the S-Meter indicates more noise with the antenna connected than with a dummy load connected the receiver's input. ANY excess gain over this setting costs you overload performance for a trivial signal to noise increase. This is true for ANY band. But for VHF and above you have to consider some additional receiver features. From 0-100 MHz you can generally safely use this setup trick.

{^_-}

On 2017-09-14 00:58, Chris van Lint wrote:
Well Said !!
At 05:51 PM 14/09/2017, you wrote:
Agreed 100%.

I have almost every SDR receiver that's ever been made, many of the big annoyances such as USB noise, EMI shielding are ignored. I was a member of the ARRL once but for now see no earthly reason to re-join. The ARRL should stick to checking QSL cards and stop pretending to be a technical authority.

Simon Brown, G4ELI
www.sdr-radio.com <http://www.sdr-radio.com/>

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of jdow

Nowhere did they determine how many bits of digitization the units under test used. For SDRs this is an important parameter.

The ARRL and its membership remains as dumb and mired in cave dwelling as they were decades ago when I dropped out.

{^_^}   Joanne



Re: ARRL review of the SDRPlay RSP2

Shirley Dulcey KE1L
 

You're right, I misspoke. But it does usefully compare the RSP1 and
RSP2. I attribute the incorrect naming of the rig to sleepiness when I
posted. I do stand by the assessment of the review being less useless
than some other posters believed it to be.

On Thu, Sep 14, 2017 at 9:59 AM, Peter via Groups.Io
<philobarb=yahoo.com@groups.io> wrote:
Errr...

Not sure which review you were reading, Shirley ...
the one under discussion looks to me to be a comparison of SDRplay RSP1 and
RSP2 ...
I didn't spot any references to Airspy in it !

I'm also unsure as to whether the test was about SDRplay or SDRUno ...
certainly no other software seems to have been used in the testing
(other than some passing references to add-on decoders and VB audio cable ).

But, I can't knock everything ARRL does - they do have a handy Antenna
Handbook - cheap when 2nd-hand.

Pete.

On Thu, Sep 14, 2017 at 01:34 am, Shirley Dulcey KE1L wrote:

I have to dissent from the opinions here. Although the ARRL review is
not perfect, there is a lot of useful information there. In
particular, the lab tests show the excellent sensitivity of the
Airspy, as well as its dynamic range limitations (which are in line
with expectations for a device with a 12 bit digitizer, which other
comments have correctly pointed out was not mentioned in the review).
They also provide a useful table of the differences between the R1 and
R2.



Re: ARRL review of the SDRPlay RSP2

Peter
 

Errr...

Not sure which review you were reading, Shirley ...
the one under discussion looks to me to be a comparison of SDRplay RSP1 and RSP2 ...
I didn't spot any references to Airspy in it !

I'm also unsure as to whether the test was about SDRplay or SDRUno ...
certainly no other software seems to have been used in the testing
(other than some passing references to add-on decoders and VB audio cable ).

But, I can't knock everything ARRL does - they do have a handy Antenna Handbook - cheap when 2nd-hand.

Pete.


On Thu, Sep 14, 2017 at 01:34 am, Shirley Dulcey KE1L wrote:
I have to dissent from the opinions here. Although the ARRL review is
not perfect, there is a lot of useful information there. In
particular, the lab tests show the excellent sensitivity of the
Airspy, as well as its dynamic range limitations (which are in line
with expectations for a device with a 12 bit digitizer, which other
comments have correctly pointed out was not mentioned in the review).
They also provide a useful table of the differences between the R1 and
R2.



Re: Airspy R2: Interferences with antenna disconnected

Ruben Navarro Huedo (EA5BZ)
 

Joanne: it is published in the quickstart page.

A firm update is needed.

No problems with 10MSPS


Re: Airspy R2: Interferences with antenna disconnected

Jake Brodsky <ab3a@...>
 

Sorry about that, it was a default signature. PE means Professional
Engineer. I work with A/D circuitry in industrial environments where
electrical noise is a serious problem. Try using a 16 bit A/D near a
medium voltage variable frequency drive and you'll get a taste of what
my day can be like.

If the 160 kHz noise gets through because it was differentially coupled
from a noisy switching supply, then a common mode choke won't do much at
any frequency. I'm presuming you know how to select proper ferrite
materials. Once it is in the power supply, all bets are off.

Jake Brodsky

On 9/14/2017 3:36 AM, jdow wrote:
PE means WHAT? Yes, 160 kHz will get through. But harmonics of 160 kHz
won't. If the device internals regenerate the harmonics of 160 kHz and
its really low frequency harmonics then it has a serious design flaw.
That could be revealed by running a proper test - cap the input with a
proper shielded 50 ohm terminator.

It's also noteworthy that that some ferrites work best at HF for
attenuation while others work best at VHF and UHF. Furthermore some
ferrites are designed for low loss while others are higher loss
designed for EMI reduction. Proper ferrite choice (typically clip on
barrels) makes a difference.

Then if the 160 kHz is still present it's time for the designer to
diagnose where the problem comes from at 137 MHz.

{^_^}   Joanne


Re: ARRL review of the SDRPlay RSP2

Hans J Albertsson
 

You guys really don't like the ARRL, do you?

I noted that they say they tested twotone imd in 400Hz bw with rf gain set to optimise dynamic range. NF was tested with rf gain maxed. Is this in any way counter to what you guys say?

Being a newbie even in terms of analog receivers I'm looking for useful information.

Hans J. Albertsson
From my Nexus 5

Den 14 sep. 2017 09:59 skrev "Chris van Lint" <chrisvanlint@...>:

Well Said !!

At 05:51 PM 14/09/2017, you wrote:
Agreed 100%.

I have almost every SDR receiver that's ever been made, many of the big annoyances such as USB noise, EMI shielding are ignored. I was a member of the ARRL once but for now see no earthly reason to re-join. The ARRL should stick to checking QSL cards and stop pretending to be a technical authority.

Simon Brown, G4ELI
www.sdr-radio.com

-----Original Message-----
From: main@airspy.groups.io [ mailto:main@airspy.groups.io] On Behalf Of jdow

Nowhere did they determine how many bits of digitization the units under test used. For SDRs this is an important parameter.

The ARRL and its membership remains as dumb and mired in cave dwelling as they were decades ago when I dropped out.

{^_^}   Joanne




Virus-free. www.avast.com


Re: Airspy R2: Interferences with antenna disconnected

Spencer
 

Barkhausen stability criterion was a problem years ago. The result was
of poor design was called a snivit.


Spencer W1GAK
Silver City New Mexico


Re: ARRL review of the SDRPlay RSP2

Shirley Dulcey KE1L
 

I have to dissent from the opinions here. Although the ARRL review is
not perfect, there is a lot of useful information there. In
particular, the lab tests show the excellent sensitivity of the
Airspy, as well as its dynamic range limitations (which are in line
with expectations for a device with a 12 bit digitizer, which other
comments have correctly pointed out was not mentioned in the review).
They also provide a useful table of the differences between the R1 and
R2.

On Wed, Sep 13, 2017 at 8:00 PM, <wageners@gmail.com> wrote:
Here you go:

http://www.sdrplay.com/wp-content/uploads/2017/09/QSTRSP2review.pdf


Stefan


Re: ARRL review of the SDRPlay RSP2

Chris van Lint
 

Well Said !!

At 05:51 PM 14/09/2017, you wrote:
Agreed 100%.

I have almost every SDR receiver that's ever been made, many of the big annoyances such as USB noise, EMI shielding are ignored. I was a member of the ARRL once but for now see no earthly reason to re-join. The ARRL should stick to checking QSL cards and stop pretending to be a technical authority.

Simon Brown, G4ELI
www.sdr-radio.com

-----Original Message-----
From: main@airspy.groups.io [ mailto:main@airspy.groups.io] On Behalf Of jdow

Nowhere did they determine how many bits of digitization the units under test used. For SDRs this is an important parameter.

The ARRL and its membership remains as dumb and mired in cave dwelling as they were decades ago when I dropped out.

{^_^}   Joanne




Virus-free. www.avast.com


Re: ARRL review of the SDRPlay RSP2

Simon Brown
 

Agreed 100%.

I have almost every SDR receiver that's ever been made, many of the big annoyances such as USB noise, EMI shielding are ignored. I was a member of the ARRL once but for now see no earthly reason to re-join. The ARRL should stick to checking QSL cards and stop pretending to be a technical authority.

Simon Brown, G4ELI
www.sdr-radio.com

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of jdow

Nowhere did they determine how many bits of digitization the units under test used. For SDRs this is an important parameter.

The ARRL and its membership remains as dumb and mired in cave dwelling as they were decades ago when I dropped out.

{^_^} Joanne


Re: Airspy R2: Interferences with antenna disconnected

jdow
 

PE means WHAT? Yes, 160 kHz will get through. But harmonics of 160 kHz won't. If the device internals regenerate the harmonics of 160 kHz and its really low frequency harmonics then it has a serious design flaw. That could be revealed by running a proper test - cap the input with a proper shielded 50 ohm terminator.

It's also noteworthy that that some ferrites work best at HF for attenuation while others work best at VHF and UHF. Furthermore some ferrites are designed for low loss while others are higher loss designed for EMI reduction. Proper ferrite choice (typically clip on barrels) makes a difference.

Then if the 160 kHz is still present it's time for the designer to diagnose where the problem comes from at 137 MHz.

{^_^} Joanne

On 2017-09-13 15:07, Jake Brodsky wrote:
I second Doug's excellent advice. I would also like to add that just
because you inserted a few ferrites on the jacket does not mean that it
will attenuate 160 kHz all that well. There may be some differential
mode garbage on the USB power supply.
If you can find a Y USB cable where the power pins are available
separately, you might try powering your receiver with an external five
volt supply. If the 160 kHz noise changes, that is a strong indication
that the problem is in the power leads. This would indicate that you may
want to use more filtration on the power system. Your computer probably
doesn't have the cleanest 5 volt supply.
Jacob Brodsky, PE
Amateur Radio Station AB3A


Re: ARRL review of the SDRPlay RSP2

jdow
 

They tested IMD with the RF gain turned all the way up. With a conventional receiver this makes a vague sort of sense. With an SDR all that does is reduce the dynamic range. Once the RF gain is high enough that increasing it does not materially affect noise figure you stop raising the gain as all it does is reduce the receiver's dynamic range. As a result of this the units under test showed ridiculously low dynamic ranges. It might pay them to find some people who understand SDRs to define the tests properly. I'd suggest the folks who hang around Apache Labs and actually do tests and optimizations on SDRs.

Something else to consider is that conventional empty state or solid state analog receivers generally have higher dynamic range in the individual stages if you keep them running at their highest gain. It's an empty state and solid state thing. With a D/A in the picture and no fancy (and largely ineffective) AGC before the D/A all raising gain does is increase the noise level closer to the overload level. You cannot meaningfully test an SDR using analog radio tests as the ARRL did.

Nowhere did they determine how many bits of digitization the units under test used. For SDRs this is an important parameter.

The ARRL and its membership remains as dumb and mired in cave dwelling as they were decades ago when I dropped out.

{^_^} Joanne

On 2017-09-13 20:15, Jake Brodsky wrote:
What would you have done differently?
Jacob Brodsky, PE
Amateur Radio Station AB3A
On 9/13/2017 11:05 PM, jdow wrote:
Just as I was thinking that maybe by now the ARRL had grown some good
sense and some knowledge of radio more current than 1960 this comes
along and I give up on them yet again. They don't really have a
beginning of a smidgen of a flake of a clue how to properly test SDRs.
Tera-sigh!

{o.o}


Re: Airspy R2: Interferences with antenna disconnected

ab3a@...
 

I second Doug's excellent advice. I would also like to add that just
because you inserted a few ferrites on the jacket does not mean that it
will attenuate 160 kHz all that well. There may be some differential
mode garbage on the USB power supply.

If you can find a Y USB cable where the power pins are available
separately, you might try powering your receiver with an external five
volt supply. If the 160 kHz noise changes, that is a strong indication
that the problem is in the power leads. This would indicate that you may
want to use more filtration on the power system. Your computer probably
doesn't have the cleanest 5 volt supply.

Jacob Brodsky, PE
Amateur Radio Station AB3A

17281 - 17300 of 40990