Hi John, Thanks very much, for the detailed comments on PSKmail for this type of application. That is the probably the closest I've seen to approaching "push message" capability.
Here's some follow-up questions: How does the mobile operator determine which PSKmail base and frequency to check in to at any particular moment? Is it manually selected by the operator, i.e., does the mobile operator need to keep manually checking if they remain "linked-to-base" on an ongoing basis? Does the op need to keep finding another base to be linked-to-base" with, so that the notification messages get routed properly? What is the fall-back position for the system for notification, in the case that none of the bases show a link-to-base condition when the target mobile op hasn't checked in for a while? Is there a time-out or "not-linked" indication to the network or mobile op? I'm very interested in the network server side of how this can work smoothly. I think that it is the key to getting the best notification system. It would make sense to join as many ham networks as possible to this, to enable a message to be routed to the target operator by any method they are using. A mutual cooperation between ham networks could be forged, and this could make it a reality. If one dials a telephone number, it isn't necessary to know which telephone provider company that the called party is using. We need to carry this type of universal networking into the ham radio realm. The "email address" provides universal portability and networking opportunities for hams. Hams could adopt specific email addresses that are used for emcomm purposes, and use email forwarding. This simple feature could be leveraged to provide powerful networking for hams. At least for the HFN system, the high probability of linking on HF has already been achieved through the power of a network of geographically distributed HF base stations running simultaneously on all bands. It has often been pointed out that HF base-to-mobile can be statistically undependable for 24/7 point-to-point communications with a base station, due to the changing ionospheric propagation and channel conditions. However, the statistical probability for successful communications with a mobile goes way up when dynamic linking with any base in a geographically distributed HF network is added. A single ham band may not be open at any given instant between 2 specific stations. In fact, there might not be any HF band open between those 2 specific stations :) But, it is very rare that all HF bands are closed to everywhere. That points to the need to develop a wider, more flexible, network outlook for HF Emcomm systems; one that is not concentrated so much on NVIS or specific regular propagation patterns. The solar flare that happened during the Katrina disaster response certainly taught us how fragile traditional Net-Control-centric state nets can be that rely on 75 meters only. Bonnie VR2/KQ6XA > John (VK2ETA) wrote: > Bonnie, > The way Pskmail addresses the push messages is by using two concepts: > 1. A notion of Linked-to-a-base status and > 2. a centrally accessible (over the internet) > database so that servers can be coordinated and > avoid duplication). > > More details: The clients (mobile units) have to > "check in" by sending a "link to base". From there on, > the server will push any new APRS messages > (without ack) to the client. Of course other message > sources could be pushed as well.
