Signal Calculator

Carrier Measurement

Measure the S/N ratio of the steady carrier using the longest possible coherent measurement time (narrowest bandwidth) to obtain an average S/N. Ideally, use a similar time of day and duration to the intended messages.

S/N ratio of carrier:  dB   In bandwidth:  Hz, or measurement period:  seconds

Code Selection

Choose a code, symbol period, message length and decoder list size. Choose the constraint length K according to the capacity of your decoding computer. If you are confident of the clock accuracy of the PCs at both ends, choose a rate 1/16 code, otherwise rate 1/8 is a safer bet.

Select code:
  Rate 1/4 K = 19 (Maximum 31 characters on 32-bit Windows)
  Rate 1/8 K = 19 (Maximum 31 characters on 32-bit Windows)
  Rate 1/8 K = 21 (Maximum 12 characters on 32-bit Windows)
  Rate 1/16 K = 21 (Maximum 12 characters on 32-bit Windows)
  Rate 1/8 K = 25 (Large Linux computers only)
  Rate 1/16 K = 25 (Large Linux computers only)

Symbol period:  seconds     CRC bits:     Number of characters: 


Needs bandwidth or measurement period