RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog

Go Back   The Forums > Commercial, Professional Radio and Personal Radio > Harris / MA/COM / GE / Ericsson Forum

Harris / MA/COM / GE / Ericsson Forum - For general discussion of MA/COM EDACS and ProVoice systems, including equipment.

LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 06-05-2017, 3:40 PM
Join Date: Mar 2014
Posts: 372
Default Conventional Scan Options

Why does conventional scanning work so much differently than trunk group scanning on these (P7100 P5100 P7200) radios? It's almost useless to use the priority scan,being that it cuts into the current channel activity, checking for the priority, to the point of it making the current channel unintelligible.

Does the radio not scan the current channel that the radio is parked on if "Always Scan Selected Channel" isn't selected? Does the radio pick-up any traffic on the selected channel if that feature is off? I seem to be getting mixed results.

Last edited by TDR-94; 06-05-2017 at 3:54 PM..
Reply With Quote
Sponsored links
  #2 (permalink)  
Old 06-05-2017, 7:24 PM
DisasterGuy's Avatar
Join Date: Aug 2013
Location: Maryland Shore
Posts: 1,123

Trunked system scanning isn't actually scanning. The radio is getting low speed data on the working channel to perform priority revert. In conventional the radio is needing to leave the frequency to check the priority frequency.

Sent from my SM-G900V using Tapatalk
Reply With Quote
  #3 (permalink)  
Old 06-05-2017, 10:31 PM
kb4cvn's Avatar
  Amateur Radio Operator
Amateur Radio
Join Date: Mar 2004
Location: Nowhere near a paved road, away from the maddening world.
Posts: 829

The ability to NOT scan the selected channel is usually used for TWO-FREQUENCY SIMPLEX systems. (IE: base is on one frequency, the mobiles/portables are on a different frequency, where the users in the field cannot hear each other intentionally. Users in California are all too aware of this system!)

The reason for this is the radio needs to be scanning one or more receive frequencies for traffic, but only transits on a single frequency. You see in some older public safety systems and in Taxicab and Wrecker dispatch comms.

For most cases, you must have ALWAYS SCAN SELECTED CHANNEL checked.

Why you seen the audio "hole" when scanning conventional with PRIORITY is the radio must physically change channels to sample the priority channel for a signal. There are minimum time requirements to be able to do this. A plain analog channel without any CG or DCG is the fastest at about 30 milliseconds. And in a CG or DCG, then there is some additional overhead time required to validate the CG/DCG if present to see if it is valid. If it is a digital voice mode channel, even more time !!! I starts to add up quickly. This is simple time constraints which must be met to perform the required functions.

P1 is the worst. I samples every second. P2 is a bit easier to listen to, as it only samples the designated priority channel half as often.

If it can be avoided, I NEVER recommend P1 scanning on conventional for this reason.
Reply With Quote
  #4 (permalink)  
Old 06-06-2017, 9:03 AM
Join Date: Mar 2014
Posts: 372

It makes more sense to me now why it must work that way.Conventional P1 is certainly the worst!
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -5. The time now is 8:13 PM.

Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
All information here is Copyright 2012 by LLC and Lindsay C. Blanton III.Ad Management by RedTyger
Copyright 2015 by LLC Privacy Policy  |  Terms and Conditions