Archive for the ‘Interface’ Category.

Remote SDRs – update

This is short update on my post about seting up the Multiband WEB SDR with remote receivers: https://e.pavlin.si/2021/12/11/multiband-sdr-with-remote-receivers/

The update is based on Armbian, Linux for ARM development boards. First download and write image (CLI) for your preffered board. After first boot, enter default credentials for Armbian (root/1234) and follow some basic setup:


create new password
select bash (1)
enter your new username
create pass for new user
enter real name
Set user language based on your location? Yes

Now enter following commands:

apt update
sudo apt install soapyremote-server
sudo apt install soapysdr-tools
sudo apt install rtl-sdr
sudo apt-get install soapysdr-module-rtlsdr

edit the file /etc/modprobe.d/blacklist.conf and add following lines:

sudo nano /etc/modprobe.d/blacklist.conf 
blacklist dvb_usb_rtl28xxu
blacklist rtl2832
blacklist rtl2830

reboot with

reboot

Now plug RTL SDR (could be more than one) and check if everything works with:

SoapySDRUtil --probe="driver=rtlsdr"

The output should be something like this:

#
Soapy SDR -- the SDR abstraction library
#
Probe device driver=rtlsdr
Found Rafael Micro R820T tuner
Found Rafael Micro R820T tuner

-- Device identification
driver=RTLSDR
hardware=R820T
origin=https://github.com/pothosware/SoapyRTLSDR
rtl=0

-- Peripheral summary
Channels: 1 Rx, 0 Tx
Timestamps: NO
Other Settings:
* Direct Sampling - RTL-SDR Direct Sampling Mode
[key=direct_samp, default=0, type=string, options=(0, 1, 2)]
* Offset Tune - RTL-SDR Offset Tuning Mode
[key=offset_tune, default=false, type=bool]
* I/Q Swap - RTL-SDR I/Q Swap Mode
[key=iq_swap, default=false, type=bool]
* Digital AGC - RTL-SDR digital AGC Mode
[key=digital_agc, default=false, type=bool]

-- RX Channel 0
Full-duplex: YES
Supports AGC: YES
Stream formats: CS8, CS16, CF32
Native format: CS8 [full-scale=128]
Stream args:
* Buffer Size - Number of bytes per buffer, multiples of 512 only.
[key=bufflen, units=bytes, default=262144, type=int]
* Ring buffers - Number of buffers in the ring.
[key=buffers, units=buffers, default=15, type=int]
* Async buffers - Number of async usb buffers (advanced).
[key=asyncBuffs, units=buffers, default=0, type=int]
Antennas: RX
Full gain range: [0, 49.6] dB
TUNER gain range: [0, 49.6] dB
Full freq range: [23.999, 1764] MHz
RF freq range: [24, 1764] MHz
CORR freq range: [-0.001, 0.001] MHz
Sample rates: 0.25, 1.024, 1.536, 1.792, 1.92, 2.048, 2.16, 2.56, 2.88, 3.2 MSps

Finally, use rtl_eeprom to change serial numbers and add newly created receivers to your WEB SDR.

Optionally: add firewall rule for the Soapy remote:

ufw allow 55132

Multi-Service Flight Tracker

(Photo by Dan Gitwood/Getty Images)

There are many flight tracking services around the web and most of them are based on ADS-B receivers placed by individuals. Few months ago I put together simple GP antenna, RTL-SDR and installed Pi-Aware software. It fed data to FlightAware. Soon after one of my mod-school friends asked if I could do the same for FLightRadar24. After some search I found this github repo: Balena ADS-B Multi-Service Flight Tracker. I had good experience with balena (for LoRa gateways) and followed the really excellent step-by-step instructons. Below are some details about my installation of this Multi-Service Flight Tracker.

The plane tracker is now feeding online (with short outages) since August 2019.

Here are links:

https://flightaware.com/adsb/stats/user/s54mtb

https://www.flightradar24.com/account/feed-stats/?id=24076

https://planefinder.net/coverage/receiver/102325

Continue reading ‘Multi-Service Flight Tracker’ »

Tiny, isolated USB to Xcvr interface (PTT, Audio, CAT, …)

I will descvribe here the USB interface between the redio station and the computer which I recently developed and tested. This post is a continuation of the first part, where I described a simple interface for controlling two digital lines using the USB / Serial Converter, where I presented simple interface to control two digital signals (e.g. PTT and CW). This time I will describe an interface that combines more functions:

  • Controlling several digital (switching) inputs and outputs,
  • Interface for controlling the station via the serial interface
  • Audio input and output interface (sound card)

I had some implementation issues with the microcontrollers and USB virtual com ports, which I have described in detail in the previous contribution, I decided it’s better using the tested solutions. The block diagram of the interface is swhown in following picture:

Block diagram of the interface

Continue reading ‘Tiny, isolated USB to Xcvr interface (PTT, Audio, CAT, …)’ »

Small USB to PTT/CW adapter

In this post, I will first introduce some of the basic technical background of the control of the transmit signal (PTT) and other signals (eg CW or linear activation). The second part will describe theĀ  interface development and the final product.

Standard DB9 male connector

Continue reading ‘Small USB to PTT/CW adapter’ »