BCD996XT P25 Settings

[bmc257]

Why does it seem to be closely guarded information that no one seems to know what P25 settings to use for the ARMER system specifically in north Hennepin county. I have a scanner antenna on the roof of the house, I can visually see the Sharif's radio tower from the roof of my house and I still get errors on the audio.
What am I doing wrong? My currant settings are P25 Mode 08 P25 Level 50. I've tried several combinations of the 2 with no luck as of yet.

Any ideas?

Thanks

 

[mmtstc]

The problem, as i understand it, is that although you have great visual reference on a tower in the simulcast system, there are like 9 other towers sending the same data at your radio and your radio cannot make sense and you get a kind of echo error. The hardware is much more advanced in the professional radios, so they donthave trouble getting crossed signals.

I have always used default settings and never really had too much issue. I've never played with it but perhaps you might get some improvement using the attenuator.

Its really odd that although you think you should have amazing reception, it sucks. I live in Anoka and only get mediocre coverage on the Anoka county system, but can still get about 45% decode on the Minneapolis 1-009 system. Makes no sense.

 

[bat_wings_2000]

What site are you trying to listen to ?. Zone 2, Site 1 (Henn East) is what I would suspect.
If you can verify that and also fill us in on what city you are in that might help the diagnoses.
You might have to go to a directional antenna pointed at the strongest sub-site.

TI

 

[bmc257]

I live in Maple Grove, and I'm trying to tune the HC north main 90002 only. Strange that I get the fire main much better than the north main. I am also using a home brew biquad cut for 850Mhz antenna pointed at the Sharif's office just off of Jefferson Hwy & 83rd Ave N in Brooklyn Park (not far from my QTH). I have also used my omni that I have on the roof of my house and the antenna that comes with the scanner and they all get the same results. The biquad, I think works the best. I looked at the scanner settings and I couldn't find and attenuator setting, I did find a AGC (automatic gain control) settings, but I'm not sure how that would play a role in my problem.

 

[ofd8001]

I was in Minneapolis a couple of weeks ago. I set my mode at 10 and level at 50 and heard the system reasonably well.

The attenuator can be set by going Menu>Program System>Edit Site>Set Attenuator. It's about the sixth line down. The attenuator is site specific, in other words - you are not attenuating a system, rather you are attenuating sites.

 

[bat_wings_2000]

A biquad design has a pretty broad radiation pattern, probably more than 60 degrees at 850 MHz. You might still be getting to much signal from other sites that are farther away.
You might have to try a long yagi, 12-14 elements to get that reduced.
Also if the ant is not outside in the clear it will be getting muti-path reflections from nearby objects which can
further complicate things.
Remember in this situation the challenge is not to get more signal (you have plenty I'm sure) but to reduce signals from other sites below a level that they cause problems. Also, sometimes pointing at the nearest site isn't the answer, you might be able to point at a further away site and get a cleaner signal, depending on a lot of factors.

 

[bmc257]

Well I tried turning on the attenuator and it cut the signal from full bars to two bars and I only got bits and pieces of conversations, so I turned it back off. I put the settings back to stock 3/50 and now I get most of the conversations. Its weird tho, I hear dispatch but not the responding car most of the time, on scan or held on the north main.

Thanks for the great input fokes, it helps allot to troubleshooting this issue.
I greatly appreciate it!

 

[JT-112]

Hate to be blunt, but really there's not much you can do here, short of buying commercial gear.

Both GRE and Uniden scanners basically blow at decoding simulcast P25.

Oh sure, you'll find some happy listeners here and there (reception is of course, location-dependent), but frankly the performance is terrible.

 

[KC0CSE]

The Paper Clip Antenna

this is what works for me on the P25 system in KC...I use the same paper clip antenna on my PRO 197....it de-codes the signal great!!! I use my 800meg when mobile....but in house...the "clip" works!! I will take some other pic's and add them soon...put a loop in the paper clip...only 2inches high..it cut's down on the over load and de-codes great...

 

[KC0CSE]

PRO 197 Paper clip antenna

the "CLIP" antenna...on the PRO 197 I live very close to the towers...I have to cut down the over load of the simmulcast P25 system...this is my way of doing so....I hope this helps some of you...let me know send me a PM or post....even though this is not the radio you are talking about it should or maybe will work for your unit...antenna jacks are the same..

PRO 106
PRO 197

 

[bmc257]

Now there's a antenna! I like to use my biquad pointed toward the tower, it seems to work, it works better than the stock antenna for some reason. A friend of mine who has actually my first Uniden digital scanner the BC 796D has no problems with digital packet loss, and he is using the stock antenna. He lives just a block away from my QTH. Some day I just might have to invest in a Motorola Astro Digital. I will have to give the lolly pop antenna a try, I will let ya know how it works.

 

[Raven95150]

I'd agree with what others have said, you may just be pulling in too much signal.

First, verify that you are listening to the Hennepin East site. Primary CC should be 852.3625. If you are on Hennepin East, you could try switching to Hennepin West and see if it comes in any better. Primary CC for Henn West is 852.6125.

Assuming you are on Hennepin East, if you can see the tower from your house then there's no reason you need a directional antenna up on the roof pointed at the tower. Maybe try pointing the antenna away from the tower and see what happens.

Honestly, I've never used anything but a handheld with a rubber duck antenna for ARMER and I don't seem to have many reception issues unless I am out of range of the site I'm trying to listen to.

I think I would simplify things here. Go to Radio Shack and get their 800mhz rubber duck and a 90 degree BNC adapter. Just put this right on the back of the scanner and see how it works out. This seems to be the most recommended antenna for handhelds and most everyone who uses one seems to say it works great. No reason it wouldn't work just as good mounted on the back of a 996. If it doesn't work out, you can always take it back.


Sent from my SPH-D710 using Tapatalk 2

 

[bmc257]

Yes I am on the East ARMER simulcast CC. And I don't have a directional antenna on the roof, I have a omini antenna on the roof. I use the biquad straight out the back of the scanner. I will give the west CC a try.

I'd agree with what others have said, you may just be pulling in too much signal.

First, verify that you are listening to the Hennepin East site. Primary CC should be 852.3625. If you are on Hennepin East, you could try switching to Hennepin West and see if it comes in any better. Primary CC for Henn West is 852.6125.

Assuming you are on Hennepin East, if you can see the tower from your house then there's no reason you need a directional antenna up on the roof pointed at the tower. Maybe try pointing the antenna away from the tower and see what happens.

Honestly, I've never used anything but a handheld with a rubber duck antenna for ARMER and I don't seem to have many reception issues unless I am out of range of the site I'm trying to listen to.

I think I would simplify things here. Go to Radio Shack and get their 800mhz rubber duck and a 90 degree BNC adapter. Just put this right on the back of the scanner and see how it works out. This seems to be the most recommended antenna for handhelds and most everyone who uses one seems to say it works great. No reason it wouldn't work just as good mounted on the back of a 996. If it doesn't work out, you can always take it back.


Sent from my SPH-D710 using Tapatalk 2

 

[Raven95150]

Yes I am on the East ARMER simulcast CC. And I don't have a directional antenna on the roof, I have a omini antenna on the roof. I use the biquad straight out the back of the scanner. I will give the west CC a try.

Oh, sorry I guess I misread what you had said before.



Sent from my SPH-D710 using Tapatalk 2

 

[kb0uxv]

Did you try the clip? that is a smart idea if you live close to a site, that lossy antenna should pick up the closest site, and not hear the other simulcast ones that are giving you multipath. Like others have said, its more about focusing on one site rather than having gain and reaching out.

 

[KC0CSE]

The clip again

"THE CLIP" made from a key chain..

 

[KD0NDO]

for me it has gotten to the point where it is not worth my time to turn my scanner on because it usually disappoints me

 

[bmc257]

Ok, I made a small loop antenna and the signal jumps around allot from 2 to 5 bars and now i get more digital garble. Thats the biquad i made sitting on top of the scanner.

 

[Ronaldski]

On all the P25 systems I have I always set the Motorola end code & Digital Motorola End code on.
Does it make a dramatic difference? Eh... helps.

 

[kb0uxv]

Maybe try a shorter "clip" antenna. The 1/4 wave length for 855 mhz is only 3.284 inches, that looks a little long to me...but since you are trying to only hear the closest site perhaps try something even shorter.

Unless the problem here is more to do with general CQPSK decoding rather than multipath? The Uniden and Radioshack scanners I have programmed for others seem to be worrking well on a simulcast, with stock antennas. Are there any firmware updates for that unit?