Is your P25 system conventional or trunked? Is is Phase I or Phase II. Is it simulcast?
If it's Phase I trunked simulcast, you might try the following settings. They helped quite a bit on my local system. They seemed to have a cumulative positive effect, I can't say any one change by itself made much difference:
Upgraded the firmware to latest version (1.11.20)
AGC set to OFF (system setting)
Lock out all but your one best site.
For the site, set the Digital Threshold Mode to Manual, and set Digital Threshold Level to 5
Attenuator left OFF (site setting)
Delete ALL the site frequencies except the control channel and alternate cc (Sentinel downloads ALL the RR site frequencies)
Squelch set at 2
Lastly, I set the System Hold time to 3 sec., but go higher if your only monitoring one system.
See post #15 in this thread regarding the System Hold Time:
http://forums.radioreference.com/fl...m/232146-new-p25-system-help.html#post1694341
Also post #5 here showing it relates to the x36 models as well:
http://forums.radioreference.com/uniden-tavern/291925-some-intresting-notes-scanner.html#post2196782
After these changes the 536 is still clipping or missing a tx occasionally, but it's more like 3-4% of tx's now. So it's back in the error range of its conventional P25 performance.
Probably the most effective thing you can do to help with simulcast though is to purchase a yagi antenna.
Hope that helps.
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