More than 3 SDRs

[Erich Varga]

Hello,

may you have a hint for me. As soon i put more then 3 SDRs to autoRx, i see on the 4th  sdr on the top of the webpage that the Stick catches a frequency but i got no results.

If i change back to 3 all works fine.

The SDRs are connected to an active USB Hub with 3A PSU.

Rgds 

OE3OSB-13 ;)

[Brian Hougesen]

Hi.

I had the same issue, with or with out active HUB.

Even if i use a active HUB, it still pulls down on the PI power.

As soon as SDR4 kicks in, it crashes.

Im testing the Beta release with a Airspy mini and it works very well. Ive had 8 virtual tuners running with out a problem.

Thats the way to go, if you want more than 3 tuners.

Cheers

Brian

OZ1SKY

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[Rubens Luciano]

I don't know if it's related or not, but I have issues also when I tried to use 4 usb cameras with the raspberry 4.

Problem was solved using this command after boot :

sudo sh -c 'echo 1000 > /sys/module/usbcore/parameters/usbfs_memory_mb'

Don't remember exactly but the issue was related to increase the memory buffer of the usb ports.

Abraços,

Rubens

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[Ron McMurdy]

Attempting to repurpose a Kerberos SDR receiver with 4 SDR's to do multiple receivers.  It has worked on and off for some time.  It appears with only 3 SDR's enabled it works close to 100% of the time.  However, when the 4th SDR is enabled it starts to act up.  It will scan and then acquire radiosondes as they come within range.  Lately it will, after a few minutes, stop updating.  It shows decoding in the list of receivers but they don't update and have been timing out.  It may or may not start receiving again or may just sit there until a reboot or restart of the auto_rx is completed.  The other issue occurs when all 4 are decoding and then one sonde drops out.  The software may or may not resume scanning.  We have 2 almost identical systems running at different locations and both are showing the same traits.  Running on Pi4's with the Kerberos 4 SDR sound card.  The power to the sound card is a separate power supply and voltage is good and stable at both locations.  We get ranges out to 495 mi when working, but I have resorted to a cron to reboot the computer 30 minutes prior to their launch in order to best achieve a good session.  This is hit or miss and lately has not helped keep all 4 receiving and/or scanning. 

The locations both receive the local DFM17 as well as a mix of other sondes.  Here is a list of what is normally received.

(This table was with only 3 SDR's enabled and worked flawlessly throughout the launch period)

DFM17 403.601 MHz  22032187  1678.5  14.9  -1181.1  71.6  -1  106.2  -0.2  61.5  6.1  4.8 V

RS41-NG  404.001MHz  U0940663 13488.5  8.4  -2007.9  44.2  31.6  162.4  -0.1  148.1  7.7  BT 07:59:53 2.6 V

MEISEI  404.401 MHz  IMS100-1005788  90341.2  15  1397.6  -459.4  -1  228.7  3.4  202.9   -1.0 V

RS41-SGP  404.301 MHz  U1820237 21348.1  45.3  -2362.2  7.7  85.9  305.6  0.0  178.6  7.7  BT 08:05:07 2.6 V

DFM17  403.601 MHz  22031895  988.8  12.5  -2696.8  75.6  -1  104.6  -0.2  50.1  5.14.8 V

RS41-SGP  404.301 MHz  U1811225  22861.5  34.4  -4606.3  4.1  18.6  307.0  -0.0  186.3  8.8  BT 08:19:06 2.5 V

Equipment:

PI4, 

auto_rx version 1.5.10 

IOS in pi: 2022-09-22-raspios-bullseye-arm64-lite.img

Any help would be appreciated.

W5QLD

Ron

  

[Mark Jessop]

I've never had any success with more than 3 RTLSDRs unfortunately. It may be a driver limitation as mentioned in a previous email.

For covering a wider bandwidth, I would now recommend trying the Airspy approach discussed here: https://github.com/projecthorus/radiosonde_auto_rx/wiki/Network-SDR-Decoding-Instructions

A single Airspy Mini can cover almost all of the radiosonde bands.

73

Mark VK5QI

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