At present, aside from those few hounds who have got themselves out of synch and the odd message between hounds, most of the waterfall is empty when the fox transmits way over on the left. That’s potentially a lot of bandwidth/capacity unused.
However, wouldn’t spreading the fox’s transmitter power over a wider bandwidth with one wider signal result in reduced signal strength and no decodes under marginal conditions, the same issue as with the current multi-signal transmissions? How about, instead, varying the power between multiple fox signals e.g. with 3 Tx sigs, the power per signal would be P, 0.75P and 0.5P (or whatever). The Fox Tx logic could ensure that repeated messages to the same station (due to nonreception of previous messages) are sent at higher power. If there are no repeated messages to send in a given slot, any RR73 messages in the Tx queue could go to a higher power Tx to increase the chances of QSOs in progress being successfully completed. 73 Gary ZL2iFB From: Bill Somerville <[email protected]> Sent: 12 June 2019 03:28 To: [email protected] Subject: Re: [wsjt-devel] Fox power level On 11/06/2019 16:06, Black Michael via wsjt-devel wrote: S9A has been hard to work...seems what is happening is they will call "CQ" and then answer two slots and the power drops and won't see them again. Or I'll see two decodes from them and they disappear again...all very likely due to the power drop from multiple slots. I've seen them a few times when they transmitted one slot in their QSOs...but never saw them do two slots....which I'm sure they're doing. Perhaps somebody else has some logs to show their activity to be sure. There has to be some logic we can put in there. For example. #1 After callling CQ restrict > 1 slot for a while or use incoming signal reports to determine if # of slots can be increased at that point -- so somehting like -12 or better before slots can be increased during that QSO. #2 Maybe do the same for each slot level. What's happening is a lot of ops aren't seeing the RR73's. So they keep calling over and over again...even though they've been logged. Just throwing some idea out there to start a discussion of a better way to manage the power level from the Fox's. de Mike W9MDB Mike, look at it from the Fox operators point of view, they know how many QSOs they are logging and if increasing the number of slots increases the rate then that is the best thing to do. Weaker stations will have trouble but when the propagation improves for them or the rate drops and they reduce slots then they should get a chance. It is up to the Fox operator to manage the pile up and other things in their control like the aerial direction etc.. The optimum solution would probably be an asymmetric mode where multiple QSOs can be held using a single MFSK message. Perhaps 3 times as much information for the Fox with messages like: K1ABC -10; W9MDB -05; G4WJS RR73; K1JT -06; K9AN RR73; DE P5RAREDX Just sending the Fox call once per period would give a considerable information density advantage over the current multi-channel Fox transmissions. So one MFSK signal for the Fox utilizing 3/4 of the time and many standard FT8 signals for the Hounds. Another approach could be to use a wider bandwidth and symbol rate for the Fox staying with symmetric 15s FT8 T/R periods. The latter could be particularly attractive when using GFSK modulation to reduce the sidebands and optimize the Fox waveform inside a typical SSB bandwidth, although narrow band digital mode band planning would probably limit to 200Hz or less and the commensurable signalling rate. Even a 200 Hz width FT8 Fox mode variant could allow several QSOs simultaneously with Fox messages in the style above. 73 Bill G4WJS.
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