Training Morse code transmission with control using the FLdigi program

November

2022

Training Morse code transmission with control using the FLdigi program

morse

21 November 2022 16:21

Scheme of a simulator for monitoring the transmission of Morse code.

The simulator uses an Ultra Picokeyer electronic key and an Asus EEE PC with the FLdigi program.

Components of a CW Transmission Trainer

complete

Linux PC with line or microphone audio input
1. Ultra Picokeyer (see online store HamGatgets)
Y-shaped adapter from 3.5 mm jack to two 3.5 mm sockets.
Audio cable 3.5mm - 3.5mm 2 meters long.
Headphones
Iambic telegraph key MFJ

Ultra Picokeyer

An external electronic key was purchased as a kit on the HamGatgets website and soldered by me.
A key with memory has many capabilities, but here it is used only as a Morse code generator when closing the contacts of an iambic key.
cwkey2
cwkey3

The CW keyer has headphone/speaker jacks, horizontal iambic keyer connections, and a contact closure output for the transceiver.
cwkey4

Iambic key MFJ QRP

It was purchased assembled from abroad when payment via PayPal worked.
Now it can be replaced with a Chinese analogue.
paddle

Divider from one audio source to two audio consumers

Purchased from the OZON online store.
divider

The divider is connected to the sound output. One output goes to headphones, the other to a computer with the FLdigi program.
cwkey1

Setting up the FLdigi program to recognize CW keying

1) Disable the noise suppressor (squelch) - the button in the lower right corner must be released.

2) In the settings menu Fldigi - Configuration - Config dialog - Modem - CW - General:

Accept:

WPM tracking - enable
Bandpass filter - 99 Hz
RX WPM 18

*Range 8

Send:
*Default - 20 WPM

Lower limit - 15 WPM
*Upper limit - 35 WPM
Transmit (bottom slider - 18 WPM)

Click to enlarge in full screen:

Save changes and close window.

3) Set the bandpass filter to the frequency of sound vibrations.

Put the key into gear by squeezing one or both paddles. Click on the "waterfall".

4) Switch the signal graph display from WF mode to SIG mode (button in the lower left part of the window)
5) Using the parameters next to the WF/SIG button, adjust the input signal level to a normal level, without overload. Why, observe the scope of the graph at the bottom of the window.

Click to enlarge in full screen:

The first number is responsible for the threshold level, the second number is for the range (the difference between the maximum and minimum of the input signal).
The DIFF range was set to 20-31, because... at low values, a lot of garbage is output during pauses. Using the first parameter - the threshold level (amplification of weak signals) I achieved the absence of noise in pauses, while during transmission the signal should occupy the entire height of the signal window in SIG mode.
levels