Fldigi v4.1.20 now available

The development team led by W1HKJ have announced the release of Fldigi v4.1.20.

Fldigi is a modem program for most of the digital modes used by radio amateurs today: CW, PSK, MFSK, RTTY, Hell, DominoEX, Olivia, and Throb are all supported. It can help calibrate a sound card to a time signal and do frequency measurement tests. As with all of the FL suite, Flrig supports PowerPC, Intel (i386) and Apple Silicon (M1) processors with individual downloads available for each architecture. Download the latest version of Fldigi here.

Version 4.1.20
  * Update release to both fldigi and flarq

  Cosmetic changes
    * Fix cosmetic issues reported by Bob, VK2YQA
    * Fix parse of macro 

  Gleam scheme
    * add fltk 'gleam' UI scheme

  xmlrpc id
    * add client ID to client requests
    * add client ID to server parsing

  cw tracking
    * adjust tracking filter constants to improve power detection

  Navtex modem
    * make single bit flip correction guess a little smarter
      The flip_smallest_bit code was written with the assumption that the
      discriminator has equal weights for mark and space, that we are equally
      likely to get things wrong in each direction, and that flipping the bit
      with the smallest absolute value is likely to get us what might have been

      However, in the face of selective fading and QRM, the assumption of
      symmetry proved to be wrong. This is "helped" by the 3/4 framing of
      SITOR-B, where every character has 3 marks and 4 spaces, resulting in
      the mark value consistently getting a lower envelope estimation than
      the space value, even when both are the exact same signal level!

      Make the bit flip guessing a little smarter by correcting towards the
      3/4 framing, but only if this character is only one off from a valid

      This seems to result in slightly better message decoding in marginal

  Smeter Pwr_meter
    * correction to xmlrpc procedure to get smeter and power out meter from flrig

  My Callsign
    * modify edit code to maintain cursor position

  Contest fields
    * Change to Rx text field parsing
    * Change to cut number parsing

  gpio ptt
    * fix for pi3/4 gpio h/w UDRC-II operation

  Add OFDM modes for NBEMS
   * OFDM-500F for HF SSB
     - survives HF NVIS/long path
     - 4-carriers of 62.5-baud 4PSK = 250 bps
     - 1/2 rate K=15 FEC with 4sec interleaver
   * OFDM-750F for HF SSB
     - survives HF NVIS/long path
     - 3-carriers of 125-baud 8PSK = 562 bps
     - 1/2 rate K=13 FEC with 3.2sec interleaver
   * OFDM-2000F for HF-SSB/FM
     - 8 carriers of 125-baud 8PSK = 2000bps
     - 2/3 rate K=13 FEC with 3.2sec interleaver
   * OFDM-2000 for HF-SSB/FM
     - 4 carriers of 250-baud 8PSK = 3000bps
     - NO FEC, meant for line-of-sight
   * OFDM-3500 for FM 9600-port
     - 7 carriers of 250-baud 8PSK = 5250bps
     - NO FEC, meant for line-of-sight
     - Requires Signalink made-after 2018 connected to the 9600-jack
   * OFDM-2000F CPU-load fix
     - FEC of previous mode too heavy for some CPUs
       . Reduced to: K=11 FEC with 1600msec interleaver
       . Other mode parameters unchanged
   * Added Vestigial-carrier based AFC to OFDM modes
     - Increases robustness and tolerance to drift
    * OFDM 2000F hold
     - commented out OFDM 2000 and 2000F modes for bugfixes
     - OFDM 500F, 750F, and 3500 are complete

Source: readme.txt, updated 2021-08-04