• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

BCD436HP system/site frequencies question

Status
Not open for further replies.
Joined
Nov 17, 2016
Messages
397
Location
Lafayette, LA
#1
I have been contemplatng buying a Uniden BCD436HP and I have been reading an online manual to familiarize myself with it. In the manual it says that Motorola Systems are limited to 28 frequencies per site or system. I can understand 28 per site but is 28 per SYSTEM correct? If I want to monitor the Louisiana statewide 700 MHz system which sometimes rotates control channel frequencies at several sites then I have a problem if I want to enter all the active control channel frequencies and alternates for each site in the system. Or can I enter several frequencies per site and have a lot more than 28 for the entires system? The 28 frequency limit is not a problem if you are sitting at home monitoring but if you get on the road and want to enter many sites there will be more than 28 frequencies. Will the scanner allow more than 28 frequencies per system?
 
Joined
Nov 17, 2016
Messages
397
Location
Lafayette, LA
#3
Awesome! Thank you. While reading the manual I was planning out in my head how I was going to program the scanner. If I can have a lot more than 28 freqs per system then that is a good thing. I like being able to program all control channels in a large area into the scanner and let it seemlessly switch from one to the other as I drive.
 

ofd8001

Member
Premium Subscriber
Joined
Feb 6, 2004
Messages
6,102
Location
Louisville, KY
#5
There has been a shift in how Uniden addresses this. There isn't a limit on the number of talkgroups. Rather if you create a Favorites List (something that contains Systems, Departments (Groups) and Channels), the maximum file size for the Favorites List cannot exceed 1MB.

As a point of reference, I have programmed a statewide trunked system in a Favorites List. There are 280 sites, 154 Departments (Groups) and 6,400 talkgroups. It also has about 2,000 Unit ID numbers. The size of the file for that Favorites List is 652 KB. So that limit is pretty generous.

Also numerous Favorites Lists can be loaded into the scanner - as many as you can fit on a 32 GB card. I've got about 30 Favorites Lists that I have on an SD card (probably a lot more than the typical user) and it takes about 10 seconds for the load/boot process.

A fair amount of users, me included, upgrade to a larger SD card instead of using the supplied 4GB card.
 

W8RMH

Member
Premium Subscriber
Joined
Jan 4, 2009
Messages
7,805
Location
Grove City, Ohio (A Bearcat not a Buckeye)
#6
The actual trunked systems themselves can only have a maximum of 28 frequencies per site. If you download Sentinel now and look in the database for your area you will see all the sites and their frequencies. A large statewide system already has all the sites loaded. You can scan them by using location control via a zip code or GPS and only receive the sites which are within range.

You can append anything you want from the DB into favorite lists and edit them anyway you choose. You can even set up this programming while you are waiting for your scanner to arrive.
 
Last edited:
Joined
Nov 17, 2016
Messages
397
Location
Lafayette, LA
#7
Here is a quick question for monitoring very large systems. I remember when the BCD396XT came out Upman said that it was limited to 500 talkgroups per system for the following reason:

A control channel transmits packets of data containing the id of active talkgroups and what frequency those active talkgroups are assigned to. The scanner takes each packet of information and checks the list of talkgroups you have entered to find if that talkgroup is listed and if so it tunes the frequency, opens squelch, and displays your alpha tag. All of this takes up processor time. If you have a very large list of talkgroups programmed in then it may take the processor longer than the amount of time between the control channel's data packets to look up the talkgroup in your list of programmed talkgroups. If this happens then the scanner will begin missing some of the control channel's active talkgroups announcements. So as a result they limited each system to 500 programmed talkgroups.

The main system I will be monitoring is the Louisiana statewide 700 mhz system which has many thousands of talkgroups. My question is will the large number of talkgroups overwhelm the scanner's processor for the reason stated above or does it possibly have a much faster processor than the BCD396XT? If this would be an issue I guess I could break up the state into regions corresponding to the state police troop areas and assign only those departments within that troop area to that area's favorites list. That would significantly reduce the number of talkgroup lookups the scanner has to do while monitoring the control channel.
 

bee

Member
Premium Subscriber
Joined
Jan 5, 2003
Messages
1,049
Location
Belmont, Ms.
#10
When setting up a favorites list with the 436, should only the control cannels be entered--

or should the control channels and alternate channels be entered?

This is for the "Mississippi Wireless Integrated Network".

MSWIN
 

rwier

Member
Premium Subscriber
Joined
Nov 6, 2006
Messages
1,904
Location
Phoenix, AZ
#11
When setting up a favorites list with the 436, should only the control cannels be entered--

or should the control channels and alternate channels be entered?

This is for the "Mississippi Wireless Integrated Network".

MSWIN
If the scanner allows it, I enter only the control channels and alternates (as determined by the RRDB or by program option, if available).
 

UPMan

Uniden Representative
Premium Subscriber
Joined
Apr 19, 2004
Messages
13,287
Location
Arlington, TX
#12
For MSWIN, only control channels are necessary, but there is no real downside to entering all the frequencies.
 

ofd8001

Member
Premium Subscriber
Joined
Feb 6, 2004
Messages
6,102
Location
Louisville, KY
#13
The main system I will be monitoring is the Louisiana statewide 700 mhz system which has many thousands of talkgroups. My question is will the large number of talkgroups overwhelm the scanner's processor for the reason stated above or does it possibly have a much faster processor than the BCD396XT? If this would be an issue I guess I could break up the state into regions corresponding to the state police troop areas and assign only those departments within that troop area to that area's favorites list. That would significantly reduce the number of talkgroup lookups the scanner has to do while monitoring the control channel.
Here's why there isn't the issue: Scanning trunked systems is much different than with conventional systems. With conventional, the scanner goes frequency by frequency to check for activity. With trunked, only active control channels are monitored. When transmissions occur, the scanner looks at the list of programmed talkgroups to see if the active transmission's talkgroup is present.

On programming control channels: I program only primary and alternate control channels if I'm up against a scanner memory limit issue, otherwise I program all frequencies including voice channels. Less risk of missing something because control channels get changed but the database does not.

I suspect this is why Uniden includes all frequencies with their downloads. Particularly since memory limit issues are very rare.
 
Joined
Jun 20, 2007
Messages
4,112
Location
Anne Arundel County, MD
#14
The explanation for the 500 limit has nothing to do with the initial post, re: 396xt. It takes no longer to scan 1 talkgroup or 1000 because you are not scanning talkgroups, just following the control channel. It takes no time at all to look up whether it is in your scanlist.

The 396xt, and entire XT line had the 500 limit because of memory considerations only. Back in those days, systems that big (500 total of frequencies, talkgroups) did not exist.

Later, they did a firmware upgrade to include unit id's also in that 500 items, which did exacerbate that limit, followed by bigger and bigger systems being created.

On the other hand, if your system of 700 or so talkgroups require you to scan a huge pile of different sites, then there can be reduced speed.

Mark
WS1095/536/436/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652
 

ofd8001

Member
Premium Subscriber
Joined
Feb 6, 2004
Messages
6,102
Location
Louisville, KY
#15
If you end up getting a 436 I suggest programing the whole state system in a Favorites List and set its Location Control to On.

The scanner will "select" only those sites that are within Range settings of your entered location turning off those that are not. Additionally the scanner "selects" only those Departments (which contain talkgroups) that are within Range just like with sites. So that means the worry about "how many talkgrops to look-up" is even less of a worry.
 
Joined
Nov 17, 2016
Messages
397
Location
Lafayette, LA
#16
Ahh, I see. So if I don't have location control on then does the scanner rotate through all sites trying to check a control channel for each instead of sitting on the first good control channel it finds? If so is there a setting that allows it to simply use the first control channel it finds instead of rotating through all sites without having to use location control? I am asking this for when I am driving. It would be nice to just let the scanner switch from one site to another only after it loses the control channel without any intervention from me.
 
Joined
Jun 20, 2007
Messages
4,112
Location
Anne Arundel County, MD
#17
It won't be based on losing the control channel, but by your location, the locations of the sites, their range settings, and the range setting of the scanner.

No intervention by you.

Mark
WS1095/536/436/996P2/HP1e/HP2e/996XT/325P2/396XT/PRO668/PSR800/PRO652
 
Joined
Nov 17, 2016
Messages
397
Location
Lafayette, LA
#18
No, what I mean is there a way to leave all the sites programmed with their respective control channels and NOT use location or GPS and set the scanner to park itself on the first good control channel it finds and not let go of that control channel to check other sites unless I move away from that tower and the control channel gets too weak to monitor?
 

phask

Member
Premium Subscriber
Joined
Dec 19, 2002
Messages
3,020
Location
KZZV - SE Ohio
#19
No - been told Whistler has something similar to that but Uniden will lock on, then when no xmission - scan.

It would also be extremely slow depending on how many sites it may receive.
For travel - can't beat location based scanning either GPS or a lot of zipcode entry.


No, what I mean is there a way to leave all the sites programmed with their respective control channels and NOT use location or GPS and set the scanner to park itself on the first good control channel it finds and not let go of that control channel to check other sites unless I move away from that tower and the control channel gets too weak to monitor?
 

ofd8001

Member
Premium Subscriber
Joined
Feb 6, 2004
Messages
6,102
Location
Louisville, KY
#20
So if I don't have location control on then does the scanner rotate through all sites trying to check a control channel for each instead of sitting on the first good control channel it finds?
Yes. If it "finds" an active control channel, it will dwell on it for a second or two to see if there is channel activity. It then moves on to the next site in range, repeating the process. If all sites are being scanned, it will check each frequency for control channel activity. I'll probably get beat up for this, but it is sort of like scanning inactive conventional frequencies - keeps going until it finds something but takes time in doing so.

If so is there a setting that allows it to simply use the first control channel it finds instead of rotating through all sites without having to use location control? I am asking this for when I am driving. It would be nice to just let the scanner switch from one site to another only after it loses the control channel without any intervention from me.
This scenario lends itself to connecting a GPS device to your scanner. The GPS device will report location information to the scanner. The scanner will then turn off and on those sites and departments within range. Otherwise you can leave Location Control Off and scan through all sites. It will work, but not efficiently and you can miss transmissions.
 
Status
Not open for further replies.
Top