sBitx Controls CW - drexjj/sbitx GitHub Wiki

Controls

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1: Escape

Terminates the current transmission and clears any unsent text in the queue.

2: Words per Minute

Sets the speed of the built-in CW keyer and decoder [1-50].

3: Pitch

Sets the transmit tone frequency [100-3000], adjusting this will move the pitch line on the Spectrum Display. The decoder is also centered on this pitch and will display received messages in the Console.

4: CW Delay

Sets the time in milliseconds to wait from end-of-transmission ("key up") until returning to receive mode.

5: CW Input

Sets the type of external key being used for input (STRAIGHT, BUG, ULTIMATIC, IAMBIC, IAMBICB) to the built-in electronic keyer. Straight key is self explanatory. A "cootie" key can also be used in the straight key input mode - of course there is no electronic keyer assistance with dots, dashes and space timing.

BUG mode emulates a Vibroplex 'bug' The 'dit' contact produces a string of dits at the chosen WPM, the "dash" contact is completely manual and usually used just for dashes. Of course if you have a Vibroplex you don't need this function in an electronic keyer - this is for paddle users to get a taste for bugs.

The remaining three modes add the ability to "squeeze the paddle". Any of these modes can also be used with a single-lever paddle.

In ULTIMATIC mode when both paddles are squeezed, whichever one was squeezed last gets sent over and over, until that paddle is released or the other side is pressed.

In iambic modes, when you squeeze the paddles you get alternating dots and dashes. IAMBIC mode (aka IAMBIC A mode) and IAMBICB mode only differ when you release both paddles at the same time. In “A” mode, the keyer stops sending the current bit when you release the paddles. In “B” mode, the keyer sends the current bit plus the next alternating bit when you release the paddles.

If using an external electronic keyer, CW_INPUT should be set to STRAIGHT.

6: Sidetone

Sets the CW Pitch sidetone volume playback through the speaker [0-100] in 5 step increments.

7: Macros

CW Macros can be activated by clicking the on-screen button or pressing the corresponding function key on an attached keyboard. This will add the text from the macro to the end of the outoing text buffer and transmit the CW message at the selected Words per Minute. Macros can be 'stacked' in succession, and can be intermixed with keyboard text. CW Macros can be adjusted in ~/sbitx/web/ folder, for more information see Macro Customization.

Tips

Keys

If you don't have a key, the PTT button on your microphone can be used as a STRAIGHT key. The on-screen keyboard or an attached keyboard can be used to send CW. Note that text from a keyboard gets inserted into the TEXT field and is only sent when the 'ENTER' key is pressed.

CW Reverse Mode

CW Reverse ('CWR) mode is used when there are interfering signals near the desired signal and you want to change the interference tone. By switching to CWR, an interfering signal may sound much differently or be out of the passband altogether, potentially reducing or eliminating the interference.

This mode allows the operator to switch between receiving CW signals above or below the displayed carrier frequency, placing nearby interfering signals on the opposite side of the carrier frequency where they might be more effectively filtered out.

CW Reverse mode should be used carefully, as it can affect how the other station hears you if you do not zero beat the signal properly. If both stations are not in the same mode, the communication may be affected.

Hunting

  1. Adjust the Step to 1KHz
  2. Adjust the Bandwidth to 1KHz

The key is to have a wide bandwidth, if you use a small bandwidth like 200Hz while your step size is 1Khz, this will result in 800Hz of skipped frequency when you tune in the frequency.

Decoding

  1. Tune the signal so it aligns with the Pitch line at the center of the passband.
  2. Adjust the Words per Minute to roughly match the signal's speed. While the speed doesn't need to be exact (the decoder tries to adjust to the current signal) it helps with decoding if it is close.

Troubleshooting

Decoder

If you notice that you can hear the signal well but the decoder isn't working well it could be that your Words per Minute is not correctly set.

The CW decoder is not affected by the Bandwidth setting, that is purely for audio. The decoder uses a separate filter centered on the Pitch line.