Hi Some more info about wolf
http://freenet-homepage.de/dl4yhf/wolf/index.html 73 de LA5VNA Steinar Andrew O'Brien wrote: > from http://www.scgroup.com/ham/wolf.html > WOLF > > WOLF (Weak-signal Operation on Low Frequency) is a proposed new signal > format and protocol designed specifically for the LF bands. It can be used > for beacons and for two way communication. Unlike existing formats, which > are optimized for a particular S/N (and corresponding speed), WOLF can > operate over a wide range of signal levels. For example, a WOLF beacon > transmits a 15-character message repeatedly. If the received signal would be > adequate for conventional CW, copy will be displayed in 24 seconds. At a > level barely enough for 0.4 WPM QRSS, copy will appear within two minutes. > Even if the signal is another 10 dB weaker, the message can still be > received. It will take from 20 minutes to several hours, depending on the > stability of the Tx and Rx. Of course, it is also necessary that the > propagation path remain open over the required interval. > > I hope that WOLF will permit a QSO to be completed in an hour, if one > station receives a signal that is 10 dB weaker than would be needed for > QRSS, and the other station's signal is 6 dB below the QRSS threshold. I > believe that it is also feasible to "hear" a LOWFER beacon across the > Atlantic, during an overnight run (very accurate time and frequency control > is required). > > At this time, I have implemented only a crude "off-line demo". In transmit > mode, this command line program writes a .wav file which contains the > specified message. A simulation is performed by mixing (using an audio > editor) a small amount of this signal with a large amount of noise (recorded > off the air or synthetic, as desired). The resulting file is read by the > program in receive mode, and attempts to decode the message are made at > various intervals. For an on-the-air test, the transmit output file is > played (with a media player or editor), feeding the audio into an SSB > transmitter. There are also various ways to drive a PSK transmitter. The > receiving station records the Rx output as a .wav file, which is then > supplied to WOLF for decoding. > > There have been a few successful WOLF transmissions; simulated results have > also been quite encouraging. I used the procedure developed by Lyle Kohler; > see his description and results > <http://www.computerpro.com/%7Elyle/weaksigs/weaksigs.htm>. Lyle's tests > found that conventional CW could be received with the signal attenuated up > to 18 dB below the reference noise level. For 0.4 WPM QRSS, the limit was > -30 dB. BPSK at MS1000, ET1 was the most robust mode tested, showing > intermittent copy after many minutes at -33 dB. WOLF occasionally shows good > copy at -45 dB, and seems quite robust at -40. > > -- --------------------- > > and http://www.mlecmn.net/~lyle/wolf/wolf4beginners.htm WOLF for beginners > > > -------------------------------------------------------------------------------------- > > Andy K3UK > > > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.169 / Virus Database: 270.7.0/1682 - Release Date: 20.09.2008 > 10:24 > >
