P25 Settings

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ofd8001

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I'm still scratching my head on this topic. There are about 4 different P25 settings. P25 LP Filter, P25 Wait Time, P25 Adjustment Mode (I think that's what it is and it goes up to 15) and P25 Level (that goes from 0 to 200).

Can anyone explain to me what these are, or what is happening when these are tinkered with?
 

Baley

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You are NOT alone. I have been reading everything I can get my hands on and still cant figure it out. I have tried changing all the settings to see if I could get better decoding on my feed, but never notice ANY difference. I know I must be doing something wrong, but cant figure out what it is. Maybe someone will give us a "poster child" explanation that we can understand.
 

Danny6569

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P-25 settings

P25 LP Filter
This setting lets you set the scanner to apply a software filter that removes the 4kHz tone you can hear on some P25 systems. Note that turning on this setting increases the CPU load and could slightly degrade P25 decode performance on some systems.

P25 Waiting Time (BCD396XT and BCD996XT Only)
On channels that contain a mix of analog and digital signals (i.e., where the Audio Mode is set to All), it is possible to have false decode problems caused by digital noise at the beginning of transmissions. To prevent this, a user-configurable P25 wait time (from 0 to 1000 ms) has been added.

During the wait time, the scanner evaluates the received signal; if it detects P25 data, the scanner opens squelch immediately. If it does not detect any P25 data, the scanner opens squelch as soon as the wait time expires.

Note: Any analog transmissions on this channel will lose the first part of the transmission, up to the wait time you set here. Select the number of milliseconds (after the start of a transmission) the scanner should wait while checking for P25 data. Choose a number from 0 through 1000 ms in 100 ms increments. The scanner only applies the wait time setting to Conventional or Motorola (non P25) systems, and only when the channel's Audio Mode setting is All.

P-25 adjustment level settings If you press and hold the "hold" button and turn on the scanner the screen will flash colors and allow you to get into the P25 settings. Then press menu and go to settings and then go to P25 adjust level. You will notice it is set to 50 for the default auto setting. If you change it to 200 (press 200 enter) now the default level will always be 8 and if you change it to 100 the default will be set to 11. You can check this when scanning by pressing Func then volume, Func then volume to watch the threshold. Auto works well for me but setting it to 200 isn't bad because most of the digital systems level off around 8 using the auto setting anyway. If you find that the default setting works best just set it back to 50 by pressing 050 enter.
 

Danny6569

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P-25 settings

and i think the P-25 adjust mode is for how fast youre scanner scans the digital system, but i would not mess with all these settings, they are supposed to be automatic settings from uniden from what i hear, and you could really mess up youre scanner by messing with them, so if youre scanner is working fine without touching any of these settings, then i wouldnt bother trying any of them, the only one i went into is the P-25 adjustment level, and i set mine to 200 which is supposed to make the radio decode at 8, this is supposed to make the radio decode better thats all, but the default setting is 50.
 

n4yek

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new_to_scanners
Press and hold the 'HOLD' button while you power up the scanner. This will put the hidden menu items back into the scanner under the 'Settings' menu.

Adjust Mode 3
P25 Waiting time 400ms
P25 Adjust level 50 ( I have mine set at 85. The lower this setting is the faster it tries to correct the audio but this can cause the decode audio to sound a little fluttery. The higher the number, the slower it samples the signal but can give you better decode on some systems. )
Auto / Manual decode is user specified ( keep mine on manual & 8 but that is the best for systems I monitor)

One last thing, it isn't polite to ask about your scanner in someone else's thread. Always start your own.
Happy scanning :)
 
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iweberdudei

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Daniel,
thanks for such an generous and informative reply. I had a sidebar question in regard to P-25.

I just bought a New Bearcat Uniden scanner - The APCO25 BCD996XT digiatl scanner. Now the software I bought with it, the ARC-XT Basic, does allow one to adjust the mode from "conventional" to "P-25", among other modes.

OK, now the frequencies in question (Texas DPS Highway Patrol) are mixed. Some channels indicate P25 mode while others say FMN or FM according to Radio Reference dot com.

My vendor, Scanner Master, pre programmed a few DPS channels for me at their shop before mailing the scanner to me. So I could get the ball rolling and learn for myself by their examples.
They set all channels in a group as "conventional" mode. There are about 30 channels in each group. I am only interested in monitoring teh group with freq in my area. And out of that specific group (roughly 25- 30 channels- all DPS ) I can only hear traffic on TWO, out of the 30 channels.

I toyed around with the ARC-XT application and switched the mode from "conventional" to "P25".
OK, But when I did that, it changed the look of my application and I could no longer view my frequencies. It confused me. It was a whole different format under the P25 mode. So I switched it back to "conventional" where it was originally programmed until I inquire about this a little further.

My questions are :

If Radio Reference says s specific channel is a P25 mode, doyou think my scanner or other digital scanners auto detect the various typs of modes like you mentioned or do scanners HAVE to be set to P25 mode for P25 channels... I have at least two channels I am monitoring that say P25 in the book but am not listening to them in P25 (just conventional mode).

Do you have an insight on this? And also what does FM and FMN stand for? My guess is VHF or something (as in FM radio stations)....

Thanks for any help.

Jimmy M
Corpus Christi, Tx
 

Danny6569

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texas

Hey jim im pretty sure the 996 xt you have will auto detect the P-25 systems, whether you have it in conventional mode or the P-25 mode set up, i looked at the state of texas database and it looks like there is a lot of mixed vhf channels and a few but not too many uhf channels, it looks like most of the vhf channels are both digital and just conventional, and what i mean by that is the ones that have the nac codes next to them are digital only, and the other ones that have the pl code tones are just conventional only, the ones that are digital you might see the P-25 come up sometimes if they are a P-25 system, some systems are mixed, some use both analog channels and P-25 in the same system, by looking at the state of texas, the way you should start a new system in the 996 xt is too go into menu and then click on program system and then click on new system, and for youre state you should select the conventional setting, and then make a group. and then you can separate the digital channels from the conventional channels, the way to put the nac code in the scanner for a digital channel is to hold onto that channel and then push enter, and then go to where it says set audio type and then click on whatever the channel should be, if its digital only then you can either search for the nac code, or you can put it in manually, just turn the volume knob to put the numbers in, then use the right arrow thing the > to jump over to put the next number in then once youre done hit enter, or the same thing for a conventional channel select analog only and then put the ctcss code numbers in and then push enter, and you should see that the scanner will automatically detect P-25 systems, if they are a P-25 system so to answer youre ? about should the scanner be set to up to pick up P-25 the answer should be no, and to answer youre ? about what is fm or what i think you meant is nfm, the one should be frequency modulation, and the other one should stand for narrow frequency modulation hope this helps you out Daniel...
 
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rvictor

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If it is a conventional frequency, the scanner will determine whether it is digital or analog as long as you have the "Audio Type" setting for that channel set to "All". If you set it to "Analog Only" or "Digital Only", it will believe you and treat it as what you've said it is.

If the P25 transmissions are part of a trunked system, then they must be set up as a trunked system of the correct type. You can have a Motorola system that uses P25 voice and you can have a P25 system. The settings are different.

Dick
 

iweberdudei

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Thanks everyone for your replies....

I think my local police is on an EDACS system... I bought the scanner primarily for highway patrol, which I can get. But my local police (corpus christi) is on EDACS and it's my understanding that my particualr radio (that I dropped $500 on) can only do analog, and P25 digital. The EDACS is different. They are talk goups within talk groups or something....

Does anyone know of a scanner that will be friendly with EDACS?
 

tampatracker

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Your BCD996XT will handle EDACS systems just fine. Are you having problems receiving them, and if so what system in particular?
 

dracer777

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EDACS are programmed in the identical matter in which you would program a trunking system, at least to my knowledge.

You have control channels and talkgroups, don't learn more than you can handle. lol.

And yes, I use my 396xt to track P25 digital and an EDACS system. You will have no problem with EDACS.
 

Danny6569

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edacs systems

theres one difference between being able to pick up an edcas system though, because if they are using the pro voice on some of there channels, then you wont be able to hear them at all, its unmonitorable by any scanner.
 

iweberdudei

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Thanks to all who replied......Someone earlier sent me a link that is actually as HEX-DEC converter webstie. It will convert the HEX-DEC to a decimal (numeric) frequency. I have not tried it yet. I'm about to this evening. Thanks again....
 

W2SJW

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Just remember that the Corpus Christi talkgroups marked as 'D' in the mode column are ProVoice digital, and the 396 will not decode that type of digital...
 

iweberdudei

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DEC vs. HEXADECIMAL...what in the world?

YEs, very True Scott. ProVoice wont do...

But, Im looking at the talk groups and 90% are classified as "A". Analog.
But here is what it looks like.

DEC AFS Mode Alpha Tag Description Tag

273 02-021 A PATROL-1 "A Alpha Units

So I am wondering. How would I type that DEC number (273) and AFC (02-021) into a decimal frequency?

On the HEX DECIMAL CONVERTER it reads as follows:

Decimal 273 = 111 HEXADECIMAL... that is is still greek to me lol.....

Not sure what to do because there are a lot of channels I'd love to monitor on my Uniden APCO25 BCD996XT scanner. Robstown, TX PD is also formatted that way !

Any insight to that?
THANKS so much.
JIMMY
 

W2SJW

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You don't need any kind of converter at all. Your scanner will take the AFS ID layout just fine (and it should have been set for that from the factory).

AFS = 02-021

The only scanners I can ever remember that forced you to use decimal format for EDACS systems were the RS Pro-92 & it's matching mobile version...
 
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