Talk:HamRadio

Notes about the video meetings

Saturday 17 October 2020, 20:00 UTC

After some technical difficulties with Big Blue Button, we moved to Zoom and succeeded in doing the planned agenda:

• Brief walk-through of Simulation example: FSK

• Presentation of gr-RTTY-basics package

   https://github.com/duggabe/gr-RTTY-basics

   https://github.com/duggabe/gr-webserver

• Audio loopback demo
• Live Over-the-Air demo

The time (20:00 UTC) proved to be too late for participants East of Greenwich, so an earlier one was scheduled for 7 November.

Saturday 7 November 16:00 UTC

The meeting followed the agenda above. There was a minor audio difficulty with the loopback, but I proceeded to present the Over-the-Air demo successfully.

View the presentation on https://www.youtube.com/watch?v=_HmbRk-UG8Q

Saturday 12 December 2020 16:00 UTC

Subject: Transmit / Receive switching and station control
Presenter: Gavin Jacobs VE7GSJ
Agenda:

• Requirements for TX/RX switching
• VE7GSJ Solution (hardware & GNURadio Companion)
• Demo on 2m repeater

Files:

• GRC flowgraph: Media:Nb-fm-voice.grc
• Presentation slides: Media:2020DEC12.pdf

Thanks to Gavin for an excellent talk. It can be viewed at https://www.youtube.com/watch?v=rTp6vQk5MqE

16 January 2021 16:00 UTC

Subject: Using GRC to build radios: Make the flow graph work for you

Presenter: John Petrich W7FU

Agenda:

• Getting started with GRC
• Basic flow graph workspace organization
• Flow graph details
• Data flow problem solving
• Practical odds and ends for real radios
• Group discussion

Files:

• Media:Using_GRC_to_Build_Radios.pdf
• Media:HF_VHF_CW_SSB_transceiver_GRC_3.7.grc
• Media:NBFM_Transceiver_GRC_3.7.grc
• Media:SSB-CW_receiver_DSP_-_GRC_3.8_(annotated).grc
• Media:SSB-CW_transmitter_DSP_-_GRC_3.8_(annotated).grc

Thank you to John for a very informative presentation. It can be seen at https://youtu.be/j8OeK7c_zAU

27 February 2021 16:00 UTC

Subject: A Look at Project 25 (P25) Digital Radio

Presenter: Aaron Rossetto, NI

Agenda: In this presentation, I will introduce Project 25 digital radio, with a strong emphasis on its use in North American public safety trunked radio systems, and to describe experiments monitoring and decoding P25 traffic using GNU Radio code.

• What is Project 25?
• A brief introduction to trunked radio
• Diving into the P25 protocol
  • Modulation
  • Packet framing and encapsulation
  • Packet types
• GNU Radio and P25 decoding experiments

Here is the link to this meeting:

   https://seti.zoom.us/j/82159634190

20 March 2021 16:00 UTC

Remember that Daylight Saving Time will have started in the U.S.

Subject: Ground Station Test Transceiver

Presenter: Ray Roberge WA1CYB

Agenda:

• What is this Ground Station Test Transceiver ?
• Architecture – Three Sections
  • Receiver flowgraph
  • Transmitter flowgraph
  • Telemetry flowgraph
• GUI displayed with a ADALM Pluto SDR
• Over the Air results as received on a ETTUS B205mini on SDR-Console software
• Discussion on finer points of Packet telemetry
• Same flowgraph modified for UHD, Ettus B205mini and why you need to modify it
• QT display , GRC 3.8.2 / 3.8.0 minor issues noted
• Discussion

Files:

• Ground Station Test Transceiver.pdf
• Media:Ground_Station_Xcvr_Pluto.grc
• Media:Ground_Station_Xcvr_Uhd.grc
• These and other supporting files can be found at [1]

Questions and Suggestions for future meetings

Questions

• The Ham Radio chat room on Matrix is available for follow-up and continuing discussion.
  • server: https://chat.gnuradio.org
  • or via the Homeserver in a matrix app: gnuradio.matrix.ungleich.cloud
  • room: #HamRadio:gnuradio.org

• Questions about meetings also can be sent to "duggabe@dcsmail.net"

Suggested topics

• Transmit hardware to operate below 50 MHz.
• amateur radio satellite service
• FreeDV
• Contact ISS
• EME - moon bounce communications
• How to implement JS8, JS8-Call, and FT8 in GR
• An in-depth walkthrough of GQRX
• How ZMQ sockets work
• Spread-spectrum