Hi Wolf
Any news about new version of WSQ ?
LA5VNA
On 13.02.2014 00:03, wolf_dl4yhf wrote:
> Hi Nicolas,
>
> Am 12.02.2014 23:52, schrieb [email protected]:
>> quick brown fox jumps over the lazy dog
>>
>> dl4yhf
>> ...-.-
>> cq cq ddl4yhfd4yh e k
>> *F4DTL Nicolas*
>
> *Ok, I was inspired for that sentence when reading the WSQ help pages
:-)*
>
> btw Murray ZL1BPU has answered my questions regarding notch filter,
guess he won't mind relaying his entire message here.
> Note the last sentence.
>
> Cheers,
> Wolf.
>
> -----
>
> Wolf,
> I can read the rsgb_lf_group reflector, but not post to it (problem
getting them to change my login). I am pleased to note your interest in
WSQ2. I can hopefully answer your questions about it works.
> First, there is no notch filter, so if there are interfering
carriers, you'll need to QSY. Not ideal, I know, but with no error
correction with a puncturing function there would still be no way to
recover from all the errors. The source code is available, so if you
want to try, you could add a notch filter.
> The important reason behind not using FEC is TYPING SPEED. We
designed it for 5WPM. WSQ2 is intended to be a QSO mode, like CW. If
there are errors, you ask for repeats. In our experience (we also tested
WSQ with FEC), for the same text speed, there is little difference
between reception quality of 0.5 baud with no FEC, and 0.25 baud with
standard NASA convolutional coding FEC. The big difference was that the
FEC version was of course much slower. Yes, the FEC version had slightly
fewer errors at around --24dB SNR, but it dropped out at --25 just like
the non-FEC version.
> Exactly the same situation applies when you compare DominoEX4 with
THOR8. Similar sensitivity, but double the speed. It's all about the
integration time -- the slower symbol rate has an impulse noise
rejection advantage as well as a sensitivity advantage.
> You have to realize that WSQ2 is designed as a real-time QSO mode, it
is not for beaconing or propagation measurement. Sure, you need slightly
more signal than for WSPR, but you can have a real QSO with a real
person. FEC, and especially block modes, don't lend themselves to this
level of operating freedom.
> If anyone on the rsgb reflector has any questions about the mode,
please point them in my direction.
> 73,
> Murray ZL1BPU
>
>
>
|
