Would appreciate insight on efficiency of PSK31 on various HF band.

Would 300 to 1000 km generally achievable if suitable band are chosen, according to day night and sun spot cycle using low power QRP and simple 3 meters vertical antenna?

Please fill in the table like below. I only have VHF FM license. No experience on HF nor digit modes. Assume 5 watts, vertical antenna of about 3 meters, retransmission allowed. May be aiming for says 70% chance of the message transmitted success rate.


Best sun spot cycle, 300km day, 400km night

Worst sun spot cycle, 200km day, 300km night

Present sun spot cycle, 250km day, 350km night

..... other frequencies.....


=========== answer my own question

http://www.voacap.com/hf/ I found this site which answer my question. One can enter two QTH and it predicts propagation, received signal in dBW, SNR for time and months

  • $\begingroup$ I have closed this question as it is very difficult to give a definitive answer, and it's yet another example of a "range" question. I consider it to be 'too broad', and I don't think it would be possible to write a useful answer to it. $\endgroup$
    – Scott Earle
    Commented Oct 4, 2018 at 8:26
  • $\begingroup$ voacap.com/hf I found this site which answer my question. One can enter two QTH and it predict propagation, received signal in dBW, SNR for time and months $\endgroup$
    – EEd
    Commented Oct 4, 2018 at 19:13
  • 1
    $\begingroup$ @ScottEarle pointed out that there are other answers to this question. If this question were somehow reworded so that it could be reopened, it might be closed as a duplicate. I suggest that you try the search feature here and see if you don't find something useful. $\endgroup$ Commented Oct 5, 2018 at 3:01

2 Answers 2


This question is far too general to merit definite answers. There are free propagation prediction tools that can help you understand the possibilities. I recommend PropView, a component of the DX Lab Suite. With this tool, you can evaluate propagation paths between geographic locations based on solar weather conditions, operating mode, transmitter power, etc.


Transmission distance isn't limited by mode. It is limited by frequency, and sometimes power. Even given frequency and power, you can only give broad generalities on distance, because band conditions can make propagation vary in both directions by orders of magnitude.

Having said that, psk31 is a narrower bandwidth than many modes, which allows power to be concentrated, and digital modes frequently can be readable with a higher signal to noise ratio than phone modes, both of which effectively increase distance. But neither of these is unique to psk31.

  • $\begingroup$ I edit my question, would a few hundred km ok, with suitable chosen freq band, 5W and 3 meters simple ant $\endgroup$
    – EEd
    Commented Oct 4, 2018 at 0:32
  • 3
    $\begingroup$ Mode does make a difference. For example FT-8 vs SSB - about a 20 dB difference. $\endgroup$
    – Glenn W9IQ
    Commented Oct 4, 2018 at 0:40
  • $\begingroup$ I didn't say mode didn't make a difference, I said these properties are not unique to psk31 $\endgroup$
    – user10489
    Commented Oct 5, 2018 at 11:09

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