APRS FUNDAMENTALS LEFT OUT OF MANY CLIENTS 16 Jan 2008 ----------------------------------------------------------------- WB4APR You will notice that almost all of my complaining over these years rarely has to do with displays, but instead is the lack of any care for the the optimal -transmission- of data keeping in mind the limitations of the network and human nature which can not be relied on for real-time settings in each changing situation. Too many clones simply focused on the maps, and just figured transmit at afixed rate and they were done. Extremely simple, but not at-all what APRS transmission was all about as a SYSTEM and a network. Many of the following parts of the TRANSMIT algorithms were left out of many clones making APRS hard to use in real time: - High initial rate (8 seconds) for any new data - Continuous decay (doubling of time to next pkt) - 10m final rate if path is direct or one hop - 30m final rate if path is 2 or more hops - Decay applies to GPS input too (parked cars) - Decay also applies to OBJECTS, WX and own station - Smart (redundant and delayed) acks for messages - embedded reply-acks to greatly improve message throughput - proportional pathing (lower rate for higher hops) - Message delivery time out -and- RETRY-ON HEARD - ALOHA circle automatically computed & displayed - Aloha circle determines max hop count - Warnings against improper settings - Transmitting PHG data so we can SEE the RF network - Transmitting the user-activity bit if present Well, I guess I also complain about displays too..., I may as well list the DISPLAY processes that were left out of many clones: - the 8 or so Symbol color attributes - Moving or dead reckoned versus fixed. - message or non message capable (trackers vs users) - Fresh, stale or Old versus new - Objects versus stations - own objects versus other station's objects - Special, priority and emergency stations - Display of stations activity bits (user present) - Vicinity plotting for packets without position info - Position ambiguity for things with less precision - A consistent and easy to see map RANGE scale - Display of PHG data for network visualization - Display of the stations individual ALOHA circle Oh well, I run on... Bob, WB4APR