Bill, I think that what you describe is consistent with the following: Suppose that the the Tx Pct is set to 25%, some number of coordinated bands are active, and no bands are selected as Rx only. Then we will be transmitting 25% of the time and we also transmit on about 25% of the visits to any particular band (averaged over several 2-hour schedules).
On the other hand, suppose that, say, 6 coordinated bands are active, but 3 of the 6 are selected as Rx only. Then, overall, we’ll transmit only 25/5=12.5% of the time - but we will still transmit on 25% (averaged over several 2-hour schedules) of the visits to any particular non-Rx-only band. This behavior makes sense to me. The requested Tx Pct is still accurately reflecting the fraction of transmissions relative to the total number of visits to an active, non-Rx-only, band. Steve k9an > On Jun 9, 2015, at 12:02 PM, Bill Somerville <[email protected]> wrote: > > Hi All, > > there have been a few reports of failure to transmit while band hopping. > I believe I have got to the reason why this might be happening. > > If band hopping is enabled then WSJT-X will choose the coordinated band > according this table: > > ######################################################################### > > Coordinated hopping enables a sizable group of stations around the world > to move together from band to band, thereby maximizing the chances of > identifying open propagation paths. > > Band (m) 160 80 60 40 30 20 17 15 12 10 > UTC Minute 00 02 04 06 08 10 12 14 16 18 > 20 22 24 26 28 30 32 34 36 38 > 40 42 44 46 48 50 52 54 56 58 > The band-selection schedule repeats starting at UTC minutes 20 and 40, > for a total of three full ten-band sequences in each hour. If the > designated band for a given time slot has not been checked as active, a > random choice is made among the active bands. The algorithm for choosing > whether to receive or transmit guarantees at least one transmission on > each active band every two hours. If all ten bands are active, up to > three transmissions may be made on a given band in a two hour period. > ######################################################################### > > WSJT-X allows you to select which bands you want to join the coordinated > schedule on, depending on the phase of the day (Sunrise, Day, Sunset, > Night). It also allows you to designate bands as Rx only. > > Every two hours WSJT-X creates a transmit schedule based on the transmit > percentage that is set (it schedules again if the Tx percentage is > changed). This schedule is basically random but is manipulated to give > close to the expected number of transmissions per two hour period while > minimizing the number of consecutive transmit periods. > > So we are running to a fixed schedule and a fixed band plan for hopping. > > Before each period we first find the coordinated band, then we check if > it is enabled, if it is we will use that band next. This makes sense > because we want the herd effect of everyone who is band hopping to be on > the same band at once. If the coordinated band is set as Rx only we will > not transmit on that band. The effect of the last check is that a > transmit slot is lost and the overall number of transmits per two hours > will fall short of the expected Tx ratio. If only a few bands are > enabled for hopping and some of them are flagged as Rx only then the > overall effect on the Tx ratio could be dramatic. I believe this is > acceptable given the other constraints and given that it is better to > receive with the herd than Tx somewhere else just to maintain the Tx ratio. > > The other scenario is when the coordinated band is not enabled, in this > case WSJT-X builds a list of all the bands that are enabled as a > candidate list for a random selection. This allows other bands outside > of the coordinated 10 bands to be included in band hopping as the > operator feels fit. In the case where the next period is scheduled as a > transmit period, only the bands enabled and not flagged as Rx only are > considered for a random choice so this will not reduce the overall > transmit ratio. > > The above description is of r5564. Is this agreeable to everyone, > particularly the lowering of the expected Tx ratio if coordinated bands > are marked as Rx only? > > 73 > Bill > G4WJS. > > ------------------------------------------------------------------------------ > _______________________________________________ > wsjt-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/wsjt-devel ------------------------------------------------------------------------------ _______________________________________________ wsjt-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/wsjt-devel
