I monitor a system that has about 150 sites which none are simulcast. The manner in which I scan is with ID search, so looking for any talk group. The issue I am having is that at most instances the scanner is scanning between these 150 sites and rarely pauses on the active sites. So more time appears to be scanning sites, than spending waiting for call grants from a control channel. If I use the scanner while stationary in an area I know, then I hold to the specific site for that area. However these sites cover relatively small areas, and while driving I would lose reception with the held site. I understand that Uniden provides GPS as an upgrade and can solve this, however perhaps there’s a better way specifically for these large trunked systems where GPS isn’t necessarily needed. GPS can come in more useful if I was traveling between conventional systems, or connecting to new trunked systems. But once in a trunked system, and only monitoring the trunked system perhaps there’s a better way to find the best site.
In the original post I mentioned the need to discover sites within the system, and while that would be nice too, it isn’t necessarily relevant, especially for most people.
Often with the Uniden SDS100, for any given area I can only pick up one site with the stock antenna. A bit more with a roof mounted antenna for that band. But probably max of 3 sites. So even though it was described in this thread the interest of prioritizing sites to the held talkgroup, it won’t necessarily be possible anyways, because not all sites are within range, so not all talkgroups can be received.
An APX, with non affiliate scan, does pose the issue you described, especially because the non subscriber user can’t directly choose a site to lock onto, or affiliate with the current site to receive a particular talk group.
The APX radio utilizes multiple methods to determine when to switch sites, and which sites to switch to. It is my understanding that on boot the radio will scan through the programmed frequencies to find the best site. Once locked on the radio decodes the adjacent site data which contains the channels and status for nearby sites. Then depending on the programming of the radio, if the radio goes below a certain RSSI values with the site, it will attempt to switch to a better one. But unless programmed otherwise it will only look through the list of adjacent sites it decoded earlier. It will then lock onto one of them, I am assuming the one with the best RSSI. In addition certain talkgroups can be programmed to have preferences on which sites they are allowed on, or preferred on.
It was also mentioned in this thread that Uniden cannot use the method of reading adjacent site data because it's patented. However I was told that it is a part of the P25 Standard, and is not exclusive to one brand of radio or system.
What I want, is the ability to actually continuously receive voice channels, rather than scan between all the 150 sites and occasionally stop for a second on the 1 to 3 sites that are in range. In addition I don't want to have to manually scroll through all the sites and hold to whichever one I think is best for the location I am currently at. I think it's better to automatically lock onto the best currently received site. Or at least only scan between the sites that have acceptable reception. While less frequently finding new sites, and switching between them only when necessary.
I understand that for most people this may not be the case, and some might want to scan all the sites all the time. However I would much rather have the scanner act more like a radio would with these trunked radio systems or even any multi site system. So the system can actually be followed no matter where I am within the coverage area, by locking onto the best sites automatically.
