How does GRE handle lockouts ?

[Sownman]

I have a multisite TSYS as well as two individual TSYS that share 152 TGRP'S, for a total of 456 TGRP. I also like to have a wildcard TGRP for each bringing the total TGRP's up to 459. Many of these TGRP are water and power and sanitation and MDT and things I don't care to hear, so I deleted them from programming. However the wildcard, doing it's job still picks up these missing TGRP ID's. So, I put them all back and marked the unwanted ones as locked out so the wildcard would not keep presenting them to me.

I'm curious and yes I know it's not a great deal of time either way but does a PSR-500 look at a locked out group during a scan then move on even if it's got signal or does it not check for activity on locked out TGRP's thereby saving time ? Assuming a scan rate of 50 per second having 50 of my 152 TGRP's locked out of three TSYS would add 3 seconds to each scan if the unit scans but does not present results vs. not scanning at all. Of course I understand I could also delete the TGRP's and the wildcard but I'd miss any newly added TGRP that way.

If nobody here knows and GRE really does read this forum, would they care to comment ?


Steve

 

[mikey60]

I have a multisite TSYS as well as two individual TSYS that share 152 TGRP'S, for a total of 456 TGRP. I also like to have a wildcard TGRP for each bringing the total TGRP's up to 459. Many of these TGRP are water and power and sanitation and MDT and things I don't care to hear, so I deleted them from programming. However the wildcard, doing it's job still picks up these missing TGRP ID's. So, I put them all back and marked the unwanted ones as locked out so the wildcard would not keep presenting them to me.

I'm curious and yes I know it's not a great deal of time either way but does a PSR-500 look at a locked out group during a scan then move on even if it's got signal or does it not check for activity on locked out TGRP's thereby saving time ? Assuming a scan rate of 50 per second having 50 of my 152 TGRP's locked out of three TSYS would add 3 seconds to each scan if the unit scans but does not present results vs. not scanning at all. Of course I understand I could also delete the TGRP's and the wildcard but I'd miss any newly added TGRP that way.

If nobody here knows and GRE really does read this forum, would they care to comment ?


Steve

My understanding is that all talkgroups associated with a TSYS object are loaded into the scan list, with the ones that are locked out having a lockout flag attached. The lookup for the talkgroups is very quick, so when it sees one of these talkgroups it only uses a very small amount of time to determine how to handle that talkgroup.

In short, it adds very little time to have them in the scanlist and locked out.

Mike

 

[doug408]

I agree with Mike. A key consideration here is that talkgroups aren't scanned the same way that conventional frequencies are. Scanning 150 conventional frequencies would be much slower. Your "3 seconds to scan 150+ talkgroups at 50 channels per second" assumption is therefore not valid.

As I understand it, what really happens is closer to scanning all talkgroups of a given control channel in parallel, rather than serially, with a (very quick) check when activity is discovered in order to see if an actively transmitting talkgroup is selected, locked out, etc. by the scanner user.

Think of someone sorting mail, with 150 numbered mailboxes. When a letter comes in, they don't ask, "Is it for box 1? No. Is it for box 2? No. Is it for box 3? Yes." They look at the letter, see it's for box 3, and stuff it in box 3 without checking boxes 1 and 2 (and 4-150). Things are probably a bit more complicated for the scanner, because talkgroups aren't necessarily sequentially numbered, and there may be limitations on available memory, but there are simple firmware programming techniques that can make the lookups nearly as fast despite that.