Post
by Mike Alpha » Mon Jul 24, 2023 9:02 pm
The defining difference between a hidden host system and a LSM simulcast system is the overlapping of frequencies and the proximity of each site to the other sites. With hidden host systems, the "slave" sites are isolated, usually indoors or in tunnels, so no chance of overlap will occur.
For example, Horsley Park has a hidden host site on 500MHz linking many other sites, such as Bass Hill Plaza, Liverpool Westfields and Penrith Wesfields all on the same frequencies internally, so they would never overlap and hence, not cause inteference to each other.
True LSM Simulcast systems using CQPSK have multiple sites that are all on the same frequency but also within reception distances of each other. If the GPS synchronisation and the other magical technology Citabria mentioned wasn't in play (the audio is held till synch on all sites happens...bloody amazing!) the radios would not work as the same frequency is received from multiple nearby sites. I've read that in the USA, multiple LSM sites are known as one site.
So get ready as more LSM sites go online for frustrating reception issues on our mere C4FM scanners.
Mike