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Re: #Airspy ADSB decoder and Raspberry Pi3 #airspy #bestpractice

David J Taylor
 

From: prog

The new RPi3 image is useless for ADSB without changing a few settings, so I added a new section in the quick start guide.
Here's a copy:


Raspberry Pi 3 Performance Tuning
===========================================

Thanks for the note.

When you say "new RPi3" image, is it correct that this would /not/ apply to "8 - Jessie"?

Linux 4.1.19-v7+ #858 SMP
Linux 4.1.18-v7+ #846 SMP (stretch)

Thanks,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
#Airspy ADSB decoder and Raspberry Pi3 #airspy #bestpractice

prog
 

The new RPi3 image is useless for ADSB without changing a few settings, so I added a new section in the quick start guide.
Here's a copy:

Raspberry Pi 3 Performance Tuning

The latest Raspbian distros come with a new default CPU governor that is not suitable for sustained high performance operation. The CPU will start at a very high frequency (1200MHz), get very hot, then throttle back to a very low frequency (600 MHz). The governor will keep swinging back and forth between these two extremes and the USB controller will drop whole packets, which could affect both the number of decodes and the MLAT timing.
The following settings will force the “performance” governor at a much more acceptable CPU frequency for sustained operation without causing excessive heat and without sacrificing the performance of the decodes.
If very high MLAT reliability is required, the following switches should be applied to the decoder:

sudo /home/pi/airspy_adsb -l 30005:beast -w 1 -d 2

This will run all the decoding in one core using signal 5 phases instead of 10.
Additionally, we recommend to put these lines in /etc/rc.local :

# /!\ RPi3 Only! /!\
echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor
echo performance > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor

Then append these lines to /boot/config.txt :

# /!\ RPi3 Only! /!\
force_turbo=1
arm_freq=800

Lastly, you can also disable the “FIQ Fix” that limits the number of USB interrupts. Less USB interrupts will create more latency when polling the samples out of the USB hardware with the risk of missing more buffers.
To disable the “FIQ Fix”, you can add the following parameter to the line in /boot/cmdline.txt :

dwc_otg.fiq_fix_enable=0
Re: AstroSpy - automatic csv logging #radioastronomy

Daniel Fox
 

I too have requested the same feature for Astrospy. Has I understand it, it
would be an easily added feature.

Dan

-----Original Message-----
From: main@airspy.groups.io [mailto:main@airspy.groups.io] On Behalf Of David
J Taylor via Groups.Io
Sent: Saturday, May 12, 2018 12:35 PM
To: main@airspy.groups.io
Subject: Re: [airspy] AstroSpy - automatic csv logging #radioastronomy

Dear Developers
Long ago we requested the feature for data logging out of AstroSpy and we
received the answer, that all the development power was focused on the release
of the HF+. Because the HF+ is now out and running, I would like to bring up
the question again.
Is it possible to extend AstroSpy for a periodically logging of the data into
a csv or other kind of file?

Many thanks for your support
HB9DRT, Joe
============================

This is something many would find useful. I have a need for a simple
programing interface to set frequency, and measure power. OK, you would need
one-off receiver/mode/bandwidth setting as well, but that /could/ be done
manually.

There is a sample plug-in available (Windows C# I think), so perhaps check
that and see whether the signal level is something which is available as an
output. There must be enough people writing plug-ins to at least state
whether it is possible or not without having to extend the present software.

Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv

?
smime.p7s

sdrsharp and Xamarin app #sdrsharp

pc.dus@...
 

Hello,

I would like to know if SDR# could be used in a Xamarin app?
I search a way to create an Android app, and it could be interesting to combine Xamarin and SDR#.

 

Regards,
Re: Airspy R2 LDO blown

Terry Gaff
 

That overall cost sounds reasonable, I think I'll go for those from Farnell as I'm not in too much of a hurry... (I have two Airspy R2s).
Many thanks indeed for the link, much appreciated.
Terry
Re: Airspy R2 LDO blown

Support@...
 

You're probably aware, but just incase...

Farnell list them for 38p each with a MOQ of 5 so £1.90+P&P+VAT (£1.90 + £3.95 + £1.17 = £7.02), but they're on back order till mid June. Quicker than 8 weeks though.
http://uk.farnell.com/texas-instruments/lp5907mfx-4-5-nopb/ldo-fixed-4-5v-0-25a-sot-23-5/dp/2492305?ost=LP5907MFX-4.5%2FNOPB&ddkey=http%3Aen-GB%2FElement14_United_Kingdom%2Fsearch
Re: Attic Dipole Question

Martin - G8JNJ
 

Hi Rob,

If it's for receive only an active dipole may perform better.

If it's also for transmit, these notes may be of interest.

http://www.g8jnj.net/Loft%20antenna.pdf

Regards,

Martin - G8JNJ
Re: Attic Dipole Question

jdow
 

Folding it back is not likely to work all that well. In the limiting case you get effectively 34.5' long transmission line on each side of the dipole. There are some people who push a fractal antenna design. You can search for "fractal antenna" to see some of the designs involved. It may be difficult to setup your wire that way, though.

You may be able to layout the antenna in a zigzag pattern. something like a resistor schematic symbol, that allows the antenna to extend only 64' but consume 133' of wire.

In any case the antenna's resonance will change for the same wire length. (Roughly speaking it's now resonant in the 80 meter band.) So if the resonance is important for your use (transmitting chiefly) you'll want to fiddle with it to get a good resonance. Modeling it in an antenna modeling program might give you a good starting point for lengths.

{^_^}

On 20180512 20:42, Rob Jaczko wrote:
Hello,
I've had to relocate my 133' 80-6m dipole to the attic after coming down outside in a winter storm.
The run of attic along the roof peak is 64' inside. I've extended the dipole end to end for 64' and doubled back parallel to the first run to secure the remaining 69'.
Q: Would it be better to use a zig zag pattern along the inside roof pitch to secure the remaining 69' or is it just as effective to loop back parallel as I have done.?
I'm using this as a receiving antenna for an Airspy R2 and Spyverter combo.
Any sagely advice welcome - Thanks, Rob - WA1UMU Boston MA
Re: W10 Update - MPX Output, RDS spy, Virtual Cables and UAC

jdow
 

I suppose you could turn that setting on and turn off access for all the "Apps" loaded on the machine individually if you wish to maintain your privacy.

{^_^}

On 20180512 15:26, jdow wrote:
Ah, that sounds like Microsoft - making the world safe for malware.
{+_+}
On 20180512 03:41, Patrick wrote:
Hi there !

Yesterday, after W10 April update (v1803), I noticed that both RDS spy (via MPX Output plugin) and DSD+ did not work.

Here is the explanation a kind guy sent me : in Win 10 1803 Build 17134.1, Microsoft have made a significant (undocumented) change in sound card handling with the April Update.
You will now need to select PC Settings -> **PRIVACY** -> Microphone and *TURN ON* "*Allow apps to access your microphone*".
The "Allow apps to access your microphone" now means "Allow apps to use sound devices for input". If "Allow apps to access your microphone" is turned off, Windows will not pass audio to *any* application.

I applied the trick and DSD+ immediatly worked. So it looks like the virtual cables are OK (VB cables)

But the problem remains when running RDSspy for LIVE LISTENING only. *Decoding is 100% OK when playing a file.*
It seems the culprit is the MPX Output (ticking / unticking, setting its level from min to max has no effect on the 'Peak Input signal level' in RDS spy (its shows 'silence').
As said before, if using exactly the same settings, everything is OK when playing a recorded file.

Any idea ?
(please use simple words, my english being limited when it comes to technical purpose)

Thanks a lot
Re: W10 Update - MPX Output, RDS spy, Virtual Cables and UAC

jdow
 

With the notations on the pictures it was not immediately obvious that was the issue you were talking about.

{o.o}

On 20180513 02:14, Patrick wrote:
<< I fail to see a problem. If you are worried about the -18 dB vs -24 dB discrepancy, ignore it. Neither has a notation for reference level. Obviously they are using different reference levels. Add or subtract 6 dB as appropriate in your head if it bothers you. >>
You fail to see a problem ? It seems you did not have a look at the 'LIVE' pic !
0% and 'silence' mean RDSspy does not decode at all, though it decodes when playing a recorded file or listening via a spyserver (no matter 18, 24 or even 27% then !). This was the purpose of my post.
2018-05-13 0:26 GMT+02:00 jdow <jdow@earthlink.net <mailto:jdow@earthlink.net>>:
Ah, that sounds like Microsoft - making the world safe for malware.
{+_+}
On 20180512 03:41, Patrick wrote:
Hi there !
Yesterday, after W10 April update (v1803), I noticed that both RDS spy
(via MPX Output plugin) and DSD+ did not work.
Here is the explanation a kind guy sent me : in Win 10 1803 Build
17134.1, Microsoft have made a significant (undocumented) change in
sound card handling with the April Update.
You will now need to select PC Settings -> **PRIVACY** -> Microphone and
*TURN ON* "*Allow apps to access your microphone*".
The "Allow apps to access your microphone" now means "Allow apps to use
sound devices for input". If "Allow apps to access your microphone" is
turned off, Windows will not pass audio to *any* application.
I applied the trick and DSD+ immediatly worked. So it looks like the
virtual cables are OK (VB cables)
But the problem remains when running RDSspy for LIVE LISTENING only.
*Decoding is 100% OK when playing a file.*
It seems the culprit is the MPX Output (ticking / unticking, setting its
level from min to max has no effect on the 'Peak Input signal level' in
RDS spy (its shows 'silence').
As said before, if using exactly the same settings, everything is OK
when playing a recorded file.
Any idea ?
(please use simple words, my english being limited when it comes to
technical purpose)
Thanks a lot
Re: Airspy R2 LDO blown

Terry Gaff
 

Guys,
Many thanks for your information and links etc.
I checked the PPTC device and there is continuity across it, so that's a good thing. However, take a look at the attached pic, I think it leaves one in no doubt as to it's health. So, I guess I'll order a couple of these...somewhere :).
Many thanks for now.
Terry
Re: Attic Dipole Question

Mike Millen
 

Given the choice of the two, I think I'd zig-zag the length, rather than double it back.

Doubling back is liable to cause cancellations and reduction of signal strength at some frequencies.

HST, for receiving only, you may well find that a 64' dipole is just as effective as the 133' version.
Resonance is not so important for receiving.

If you really want 133', is there any way you can get the wire out of the roof to continue into the garden at each end?

Let us know what you find.

Mike - M0MLM

On 13/05/2018 04:42, Rob Jaczko wrote:
Hello,

I've had to relocate my 133' 80-6m dipole to the attic after coming down outside in a winter storm.
The run of attic along the roof peak is 64' inside. I've extended the dipole end to end for 64' and doubled back parallel to the first run to secure the remaining 69'.
Q: Would it be better to use a zig zag pattern along the inside roof pitch to secure the remaining 69' or is it just as effective to loop back parallel as I have done.?
I'm using this as a receiving antenna for an Airspy R2 and Spyverter combo.

Any sagely advice welcome - Thanks, Rob - WA1UMU Boston MA
Re: W10 Update - MPX Output, RDS spy, Virtual Cables and UAC

Patrick
 

<< I fail to see a problem. If you are worried about the -18 dB vs -24 dB discrepancy, ignore it. Neither has a notation for reference level. Obviously they are using different reference levels. Add or subtract 6 dB as appropriate in your head if it bothers you. >>

You fail to see a problem ? It seems you did not have a look at the 'LIVE' pic !
0% and 'silence' mean RDSspy does not decode at all, though it decodes when playing a recorded file or listening via a spyserver (no matter 18, 24 or even 27% then !). This was the purpose of my post.

2018-05-13 0:26 GMT+02:00 jdow <jdow@...>:

Ah, that sounds like Microsoft - making the world safe for malware.
{+_+}

On 20180512 03:41, Patrick wrote:
Hi there !

Yesterday, after W10 April update (v1803), I noticed that both RDS spy (via MPX Output plugin) and DSD+ did not work.

Here is the explanation a kind guy sent me : in Win 10 1803 Build 17134.1, Microsoft have made a significant (undocumented) change in sound card handling with the April Update.
 You will now need to select PC Settings -> **PRIVACY** -> Microphone and *TURN ON* "*Allow apps to access your microphone*".
The "Allow apps to access your microphone" now means "Allow apps to use sound devices for input". If "Allow apps to access your microphone" is turned off, Windows will not pass audio to *any* application.

I applied the trick and DSD+ immediatly worked. So it looks like the virtual cables are OK (VB cables)

 But the problem remains when running RDSspy for LIVE LISTENING only. *Decoding is 100% OK when playing a file.*
It seems the culprit is the MPX Output (ticking / unticking, setting its level from min to max has no effect on the 'Peak Input signal level' in RDS spy (its shows 'silence').
As said before, if using exactly the same settings, everything is OK when playing a recorded file.

Any idea ?
(please use simple words, my english being limited when it comes to technical purpose)

Thanks a lot
Re: W10 Update - MPX Output, RDS spy, Virtual Cables and UAC

jdow
 

Ah, that sounds like Microsoft - making the world safe for malware.
{+_+}

On 20180512 03:41, Patrick wrote:
Hi there !
Yesterday, after W10 April update (v1803), I noticed that both RDS spy (via MPX Output plugin) and DSD+ did not work.
Here is the explanation a kind guy sent me : in Win 10 1803 Build 17134.1, Microsoft have made a significant (undocumented) change in sound card handling with the April Update.
You will now need to select PC Settings -> **PRIVACY** -> Microphone and *TURN ON* "*Allow apps to access your microphone*".
The "Allow apps to access your microphone" now means "Allow apps to use sound devices for input". If "Allow apps to access your microphone" is turned off, Windows will not pass audio to *any* application.
I applied the trick and DSD+ immediatly worked. So it looks like the virtual cables are OK (VB cables)
But the problem remains when running RDSspy for LIVE LISTENING only. *Decoding is 100% OK when playing a file.*
It seems the culprit is the MPX Output (ticking / unticking, setting its level from min to max has no effect on the 'Peak Input signal level' in RDS spy (its shows 'silence').
As said before, if using exactly the same settings, everything is OK when playing a recorded file.
Any idea ?
(please use simple words, my english being limited when it comes to technical purpose)
Thanks a lot
Re: W10 Update - MPX Output, RDS spy, Virtual Cables and UAC

jdow
 

I fail to see a problem. If you are worried about the -18 dB vs -24 dB discrepancy, ignore it. Neither has a notation for reference level. Obviously they are using different reference levels. Add or subtract 6 dB as appropriate in your head if it bothers you.

{^_^}

On 20180512 05:08, Patrick wrote:
Because a pic probably explains better ...
PLAYBACK.JPG
LIVE.JPG
Attic Dipole Question

Rob Jaczko
 

Hello, 

I've had to relocate my 133' 80-6m dipole to the attic after coming down outside in a winter storm. 
The run of attic along the roof peak is 64' inside. I've extended the dipole end to end for 64' and doubled back parallel to the first run to secure the remaining 69'.
Q: Would it be better to use a zig zag pattern along the inside roof pitch to secure the remaining 69' or is it just as effective to loop back parallel as I have done.?
I'm using this as a receiving antenna for an Airspy R2 and Spyverter combo.

Any sagely advice welcome - Thanks, Rob - WA1UMU Boston MA
Re: Airspy R2 LDO blown

Andrew Sutcliffe
 

I'd measure the pptc first and if it is open then pop the unit in a sealed airtight bag and put in the freezer for a couple of days - then remove it and allow 24 hours for it to return naturally to room temp and try again.

S>

At 10:55 AM 12-05-18, you wrote:
On 12/05/2018 10:30, jdow wrote:
On 20180512 02:12, Laurie wrote:
Digikey?

https://www.digikey.co.uk/product-detail/en/texas-instruments/LP5907MFX-4.5-NOPB/296-39064-1-ND/5143093
Minimum order?
Minimum order is 1 but they do charge £12 shipping for orders under £50.

Laurie

--
Re: Spyverter Compatibility #hardware

Cinnabar
 

The NESDR SMArTee has a 4.3V bias-t.

I've just spotted on the Spyverter specs that volatage requirement is as follows:
  • Bias-tee voltage: 4.2v to 5.5v
I was only worried as none of the NooElec devices are listed as compatible on the official website, whereas several other devices are. Sounds like it should work though.

Thanks!
Re: Spyverter Compatibility #hardware

atouk
 

The Spyverter is compatible with pretty much everything.  If the device has a it's own 5v bias-t, then great, if no, then there's an external micro-usb for power.


On 5/12/2018 12:49 PM, Cinnabar wrote:
Hi,

Does anyone know if the Spyverter is compatible with NooElec SDR's?

The specific combination I've got in mind is to use the Spyverter with NESDR SMArTee.

Thanks in advance!
Spyverter Compatibility #hardware

Cinnabar
 

Hi,

Does anyone know if the Spyverter is compatible with NooElec SDR's?

The specific combination I've got in mind is to use the Spyverter with NESDR SMArTee.

Thanks in advance!
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