[Lowfer] RE: PSK31 on LF

[Ed Phillips]

James Moritz wrote:
> 
> Dear Lowfers,
> 
> This mode has been used from time to time over this side of the pond on
> LF - I have done some operating using the PSK31 modulator/decoder
> functions of DL4YHF's Spectrum Lab software. It works quite well when
> there is little QRN, as others have said, with a barely audible signal
> producing correct copy. However, each static crash above a certain
> threshold corrupts a character, so it becomes unusable when conditions
> get noisy, producing mostly gobbledygook. Wolf also produced a "PSK08"
> mode for Spec Lab, essentially PSK31 slowed down by a factor of 4. This
> did pretty much what you would expect - it was 4 times slower and would
> work with about 6dB less signal; it was also somewhat better with QRN,
> presumably due to a longer integration time averaging out the QRN
> spikes.
> 
> The weakness of PSK31 for LF seems to be that there is no error
> correction used; each static impulse knocks out one bit, and so there is
> a 50% chance that the current character is corrupted. VE2IQ's "Coherent"
> PSK mode is better in this respect; with it's forward error correcting
> codes, it produces accurate copy with quite high levels of QRN.
> 
> Cheers, Jim Moritz
> 73 de M0BMU

	Results are to be expected.  QRN is bad news!  Is there any way to get
that PSK08 program?  I hope it runs on a sound card.

Ed