pa0r

The 'connect' sequence of PSKmail is rather long. It looks like 00cPA0R:1024 PI4TUE:24 4EDF1. When link conditions are bad, or the server has qrm on the channel sometimes it is impossible to know if the server is active at all. Of course you can wait for an hour to catch a beacon transmission, but that is impractical for the mobile station who just wants to do a quick APRS update. The beacon transmissions are meant for the server sysops to see if the system is alive. (and to gather propagation info of course).

To overcome this practical problem I have written a 'ping' service. The link layer sequence is '00uPA0R:7 ABCD' , short enough to penetrate most qrm. If this is not working, the link will be unuseable anyway...

The 'u' in the header is an indication that this is a datagram service, not unlike the packet 'UI' sequence. This saves a lot of time on the channel. The client has been changed to include this. A ping is started with ctrl-p, and the server will answer with a similar packet with its call inserted. An adjustable delay at the server will allow more than 1 server to answer to a ping, so you can see very quickly which server has the bes chance of being useable.The ping service will be included in version 0.1.6. More to come...