Without the use of compiler effects on satellites, it is difficult to work. After all, when span, the frequency changes, especially quickly in the middle of the orbit.

There are two ways to compensate for the frequency changes due to the Doppler effect - manual when two independent transceivers (or one with Duplex function) are used and automatically using programs such as GPredict, SATPC32 или Orbitron.

In this article I will try to configure automatic correction of the frequency of transmission and reception in Linux.

For work, you need a configured CAT interface (which was done in past articles about package radio communications Xastir и радио слабых сигналов WSJT-X.

Then, two programs will be required:
* gpredict * to calculate the compensation of the Doppler effect. The issuance of control signals will occur through the TCP-IP port.
Service Rigctld ** will receive commands from GPREDICT and control the transceiver through a COM port.

Settings:

1, I install rigctld (входит в состав пакета libhamlib-utils) и gpredict

 SU -

apt update

apt install libhamlib-utils gpredict

2. I launch the Rigctld service of one of the teams in the terminal window

a) only at the reception (if there is no transceiver on the table, we only want to check the change in the frequency of transmission and reception)

rigctld -m 1 -t 4532&

b) for receiving and transmitting using a sequential port /dev /ttyUSB0 and a real transceiver.

rigctld -m 122 -r /dev/ttyUSB0 -s 38400 -t 4532 -C stop_bits=1&

Where
-m 122 - номер модели трансивера библиотеки HamLib (в данном случае 122 - YaESU FT-857) from List "Supported RaDIOS "
Or -m 1 -a dummy model.
-r /dev/TTYUSB0 is a sequential port through which the transceiver is being controlled using CAT commands.
-s 38400 - скорость порта в байт/с, установленная в меню трансивера, с которой будет идти передача команд.
-t 5432 - номер свободного порта TCP-IP локального ПК, через который будет работать служба rigctld и gprEdict.
-C stop_bits=1 - число стоп битов (если нужно, попробовать указать 2)

& в конце переводит службу в фоновый режим Linux.

3. I turn on the calculation of frequencies to compensate for the Doppler effect and control the transceiver in GPREDICT.

Menu Edit - Parameters - Interfaces - Add New
(Edit - preferences- InterfaCes- Add New)

First, we add to the dough only to the reception

Name: rxonlysat
Host: Localhost
Port: 4532
Radio Type: RX Only
Ptt Status: No
Vfo up/down: select Main ↑ Sub ↓
LO Down: 0
Lo Up: 0

Where
4532 - Port for connecting GPredict и rIGCTLD
vfo - indicates which direction the frequency will change.
If the first VFO Main is 433 and the second VFO Sub - 144, then the frequencies should change main ↑ sub ↓
Если первый VFO MAIN - 144 и второй VFO SUB - 433, то частоты должны меняться SUB ↑ MAIN ↓
Если первый VFO A - 433 и второй VFO B - 144, то должно быть указано A ↑ B ↓
Если первый VFO A - 144 и второй VFO B - 433, то должно быть указано B ↓.A ↑

The transfer is the same, but indicated the type of radio "radio type": FT 817/857/897 (aUTO) ,
PTTT STatus: Read PTT или none. влияет на чтение состояния прием/Transfer by clicking on tangent.

4. The selection of a satellite and the start of work.
   To work through a linear relay, you need to call the context menu under the triangle in GPREDICT - "Radio control".

   • Choose the corresponding satellite in the left side of the window and start its maintenance - the "path". To use the CAT transceiver - "use."
   • Disconnect the frequency lock (squeeze the "l" button),
   • tune in to the station and press the "l" button (Lock),
   • The frequencies of receiving and transmitting will change synchronously in different directions (compensation for the doppler to the transmission up and down).
   • Now click for SSB to the tangent transfer key and speak or answer CQ in CW.

5. Observation and control of satellite escort. for viewing frequencies that GPREDICT calculates. You need to click on a small triangle on the right side of the window and select the "Radio Management" menu item.
   

Then press the “Way”, “Encabe” and “L” buttons.

Note:
The path - accompaniment of the satellite (calculation)
Задействовать - включение управления радио.
L - блокировка связи частоты приема и передачи.

Satellite frequencies will begin - uplink и Downlink с учётом эффекта Доплера:

6. With neglected servicerigctld последняя передает на трансивер команды по изменению частот приема и передачи на основе расчета эффекта Доплера в программе GPrEdict.

Sources:

https://github.com/Hamlib/Hamlib/wiki/Supported-RaDIOS
https: //manpages.ubuntu.com/manpages/trusty/man8/rigctld.8.htmL.
*https: // sourceforge.net/projects/gpredict/lists/gprEdict-Discussion

Useful links:

https: // www.amsat.org/wordpress/wp-content/uploads/2014/01/Work_FM_SaTS-20131010.pdf
https: // www.amsat.org/wordpress/wp-content/uploads/2015/09/XW-2CAS-3-SaTS.pdf
*https: // ukamsat.files.wordpress.com/2017/03/camsat-cas-4a-and-cas-4b-news-release.pdf

Related publications

Разбивка жесткого диска для установки Linux Mint на старый ПК с BIOS в режиме GPT

Обновление Linux Mint 21.3 Virginia до Linux Mint 22.3 Zena

Removing the Xanmod kernel from a Linux operating system

Устранение отклонений при установке драйвера видеокарты nVidia

Установка клиента Telegram в Linux несколькими способами