I used aprs.fi to look at my track after driving home (up the M20 from the Channel Tunnel and round the M25). I was surprised to see that there were some serious problems with the paths. This was backed up when a Kent I-gate owner, M0RXW enquired on the aprsig email list to solve the problem. |he group came up with an interesting solution – it seems that Alan, G3RJI’s new bi-directional I-gate, MB7UUE, is translating local internet packets to RF. I have no problem with this (*if* it is limited to very local packets) but, Alan has a great location and a high gain antenna giving him a large RF footprint and therefore high channel occupancy. This meant that timing of packets was being disrupted as the I-gate had to wait for a free slot on the air to TX a packet queued from the internet. As we have reasonable I-gate density around the perimeter of London the overall effect was to cause my position to jump around on the map.
Time 1; M0BPQ-9 heard by M0RXW and gated to the internet at position X. Time 1: The channel at MB7UUE is busy so the position X received via the internet packet is stored until the freq is clear
Time 2: M0BPQ-9 Heard by M0RXW and at position Y and gated to the internet
Time 2: Channel clears at MB7UUE and the stored packets (including M0BPQ-9’s the out of date position X) are sent to RF
Time 3: The MB7UUE packets are gated back to the internet by M0RXW.
This is certainly not a criticism of Alan and his efforts to get more activity back onto RF (which I applaud), but an interesting example of the pitfalls faced by this system. I am happy to report that once Alan realised what was going on the resolved the problem quickly, so well done that man.