APCO Help for DPS

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LarryN

South Texas DB Admin
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The following was sent to the DB for a submission. Would one of you guys that use digital scanners please help this guy out:

I have a major problem and need help for Texas DPS, P-25 channels. I have 2 Uniden BCD996T scanners, a BCD396T, and a Pro-96 and Pro-2096, all of which are APCO-25 capable. I have NO problems decoding or scanning ANY other APCO-25 systems around Texas, other than Texas DPS. I've even tried downloading ALL the APCO-25 sites for Texas DPS at once through RadioReference and also manually. Nothing! Through RadioReference, (compared to manually entering them), they will at least stop on a active channel, but I only get a carrier-type "buzzing" signal, with no decoding of voice. The Pro's won't even stop on a active channel, when loaded through RadioReference. I can monitor them, (sometimes), by stopping the scan mode, and going to the "Hold" mode, and monitoring a desired channel.

Please let me know if I'm doing something wrong, or does Texas DPS have something new that's built into their system whereby I/we are unable to monitor them? Is anyone else in Texas having this problem with DPS? Thanks for ANY help, or information anyone can give me.
 

hoser147

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Dec 17, 2005
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Grand Lake St. Marys Ohio
From the DB on DPS Most regions have converted to Conventional (non-trunked) Project-25 / APCO-25 digital mode with some exceptions. Region V appears to have just started their migration. Please see the Statewide Radio maps under the "Files" tab above. Sounds like for now most are Conventional channels that may be why when you hold on a channel you are getting the traffic..............Hoser
 

nd5y

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Wichita Falls, TX
I only have a BCD396T so I don't know about the 996 but I assume it iworks the same way.
Here is what to have to do to receive any conventional P25 system

1. Make sure you program the channels in a CONVENTIONAL (NOT TRUNKED) system.

2. Set CTCSS/DCS to OFF or else it will NOT decode P25.

3. Try changing the modulation to FM instead of AUTO or NFM.
I can't tell any difference but some people claim to get better decoding with FM.

4. A lot of the DPS channels are only 7.5 kHz away from eachother.
Make sure you are on the right frequency for your area. Scanners have very poor selectivity.
If for example your local station is on 155.4675 and the scanner stops on 155.4600
it probably won't decode and you might have to lock that channel out.
 
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Russell

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The Pro 96s have the co-channel problem real bad. If you're monitoring 155.46 and the the transmitter is on 155.4675 the radio will just buzz, but if you manually put it on the proper freq it will decode just fine. Unfortunately, the Pro96 will open up on the adjacent channel in scan mode. Program the channel FM only, CTCSS must off -if CTCSS/DCS is set (even in tone search) the radio will not decode P25.

Russell
 

hiegtx

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Dallas, TX
I only have a BCD396T so I don't know about the 996 but I assume it iworks the same way.
Here is what to have to do to receive any conventional P25 system

1. Make sure you program the channels in a CONVENTIONAL (NOT TRUNKED) system.

2. Set CTCSS/DCS to OFF or else it will NOT decode P25.

3. Try changing the modulation to FM instead of AUTO or NFM.
I can't tell any difference but some people claim to get better decoding with FM.

4. A lot of the DPS channels are only 7.5 kHz away from each other.
Make sure you are on the right frequency for your area. Scanners have very poor selectivity.
If for example your local station is on 155.4675 and the scanner stops on 155.4600
it probably won't decode and you might have to lock that channel out.
The BCD396T & BCD996T are very similar in programming.

Besides Tom's note to make sure that you have the CTCSS/CODE setting at OFF (or NONE), on the 996, you can select "Digital" as the Audio mode, & the scanner will ignore analog transmissions.
 

mike_webb59

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Jul 18, 2005
Messages
201
Location
New Braunfels, TX
TX DPS was --okay-- on the Pro96

My 796 does a better job, but it's base station so I don't travel with it.

The 396T just went through some firmware problems. I had to manually adjust for TX DPS to get it to work. Please review the 396T firmware yahoo group for all the details.

HTH, Mik
 
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