User's Manual

Viking™ VP600 Portable Radio Operating Manual 6-19
SmartNet / SmartZone / P25 Trunked Features
With the ZoneFail Site Lock feature enabled, the radio continues to roam normally when
the system zone controller is active. However, if the zone controller fails, this is detected
and the ZoneFail Site Lock mode is entered. The only site the radio is then allowed to
operate on is its home site. If its home site is not available, “Out-of-Rng” is displayed. A
zone controller failure is detected by determining that every site in the dynamic site list is
in Site Trunking. Currently, this condition must be detected for at least one minute for the
ZoneFail Site Lock mode to be selected.
The result of this operation is that all radios with the same programmed home site are
forced to the home site to communicate which ensures that they can continue to
communicate. If the home site is not available, the Out-of-Range condition tells the user to
attempt communication on another system or by some other means.
6.12.7 P25 Wide Area Scan
This feature is intended to enhance roaming performance, especially when system level
steering through radio or talkgroup permissions is used.
With this option enabled on a talkgroup, as the talkgroup affiliates with a site, that site is
saved if the radio is changed to a new talkgroup. When the radio moves back to the Wide
Area Scan talkgroup, it will attempt to affiliate on the saved site before looking for a new
site.
The Wide Area Scan can be programmed to minimize the problem just outlined. The Wide
Area Scan feature functions as follows:
1 Assume TG1 is selected. If it is the first time this talkgroup is selected, normal
searching for a control channel occurs according to the hunt methods previously
described.
2 When another talkgroup is selected, the active valid site for TG1 is stored in memory.
3 The next time TG1 is selected, the following procedure is performed before performing
the normal hunt methods previously described.
a The last valid site ID and its receive and transmit channel numbers are loaded from
memory.
b The dynamic site list is checked to see if any newer receive/transmit channel
information is available for the last site ID.
c The best receive/transmit information is used and the radio checks to see if this
control channel is available.
The result of the preceding operation is that the radio has a reasonable chance of finding a
valid site, usually on the first try. This greatly reduces access time, even on systems which
have highly restricted talkgroup based access.