996xt onondaga county p25 receive issues

[bobcatpat]

I have my 996xt programed with the onondaga county p25 digital system. It seems to work awesome in close proximity to county towers. However, it seems that if i am more than approx 5-10 miles from a tower I'm not receiving any transmission. The signal strength meter is flashing 5 bars signal strength, but nothing will come through. Occasionaly a transmission will break through but it is garbled.

I updated to the 1.04 firmware which did not seem to help. Also I am using stock antenna. I wonder if I just need a better antenna?

Anyone have any good advice?

 

[RF-Burns]

i have a 396xt with a stock antenna and it works fine almost every where is the county. I would say something is wrong with the radio. A friend of mine had the same problem with his radio working on the Monroe County Digital system and it turned out to be the radio not the antenna.

 

[bobcatpat]

i have a 396xt with a stock antenna and it works fine almost every where is the county. I would say something is wrong with the radio. A friend of mine had the same problem with his radio working on the Monroe County Digital system and it turned out to be the radio not the antenna.

Do you think it could be a setting on the radio? As I said, the signal indicator shows 5 bars but no voice coming through except occasional garble. Move closer to a tower, maybe within 5-10 miles of, and it works awesome. Very loud and clear.

 

[bobcatpat]

Also I should mention I have no problem at all receiving analog signals. This 996xt receives very well.

 

[KE7FEH]

Hello

I'm originally from CNY DeWitt area and using the 996XT out in Tempe Arizona for the P25 out here. I have the same problems with my 996XT and PRS600..

What really helped me was this antenna for the 996XT

Crane SCA GAINER Antenna, Diamond RH771 Antenna

and for the PSR600

Center-Loaded Telescoping Whip Antenna - RadioShack.com

Good luck and enjoy the hobby...

 

[bobcatpat]

I'm originally from CNY DeWitt area and using the 996XT out in Tempe Arizona for the P25 out here. I have the same problems with my 996XT and PRS600..

What really helped me was this antenna for the 996XT

Crane SCA GAINER Antenna, Diamond RH771 Antenna

and for the PSR600

Center-Loaded Telescoping Whip Antenna - RadioShack.com

Good luck and enjoy the hobby...

Thanks for reply. will the radio shack antenna do anything for my 996xt?

 

[w2csx]

I know the Onondaga county p25 digital system is UHF system, so I would try to find a UHF antenna tuned around the 460mhz range.

 

[studgeman]

The problem with 996xt is the same problem that every digital scanner will have in Tompkins or Onondaga and soon to be Madison, Oswego and Cayuga counties. Those systems are a CQPSK Linear Simulcast system. When you move into overlap zones, scanners have a hard time with diferentiating the individual symbols. Sometimes its OK sometimes it is not, thats why you see variations in singal strength. mobile/portable scanning will always be tough on these systems, but for a base, shop around for a direction (yagi) antnnna and point it at the closest tower, the more gain the better, you may also want to consider a corner reflector.

 

[KE7FEH]

Hello

Yes, the Radioshack Antenna should work on any rig. You will have to purchase a female to male angled BNC from Radioshack as well $4.99 added. The gentleman is correct with the simulcast issue. I work at the police department and I'm just under the P25 controller that provides this section of town. The signal is awesome. However at home I'm 3 miles from one tower and 10 miles (line of site) from the main sites on Southmountain. I received every other transmission if I'm lucky. Good luck wih whatever works for you..

 

[SCPD]

I would get a yagi antenna. Antenex Y4506 or YS4506 would be good choices.

Economy 2-Way Distributors Inc. |  Low Cost Silver Series Yagi's
Economy 2-Way Distributors Inc. | Directional Yagi Antennas

Economy two way is a good place to order from....

Also use high quality coax cable... Something like LMR-400.

Coax Cable assemblies |RF 50 OHM| RFID Cables | Custom coax assemblies

Cable experts is a great place to order cable. Be sure to order the correct ends!

Point the yagi at the closest tower site and you should be able to hear the new Onondaga System fairly well.


Hope this helps!

 

[KA1RBI]

The problem with 996xt is the same problem that every digital scanner will have in Tompkins or Onondaga and soon to be Madison, Oswego and Cayuga counties. Those systems are a CQPSK Linear Simulcast system. When you move into overlap zones, scanners have a hard time with diferentiating the individual symbols. Sometimes its OK sometimes it is not, thats why you see variations in singal strength. mobile/portable scanning will always be tough on these systems, but for a base, shop around for a direction (yagi) antnnna and point it at the closest tower, the more gain the better, you may also want to consider a corner reflector.

The root cause of the problem seems to be that by the time the signal has been processed by the receiver's FM detector stage, it's already too late; the damage has irrevocably been done. When/if scanner mfgr's roll out a proper solution (such as tapping the IF prior to the FM detector) scanner users are going to be *blown away* by the improvement. For folks too impatient to wait:
LSM Gallery
A 455 KHz IF Downconverter for Digital Radio Reception

73 de KA1RBI

 

[studgeman]

the actual problem is the FM in a CQPSK in a simulcast or multicast envornment can't detect the phase shifting properly. A real commercial radio doesnt have an FM detector at all, and after the mixer circuit, it is a DSP chip. All the detection is done in a DSP with an I/Q detection. If GRE or Uniden go to this method, is shouldnt cost much more than we are paying now. (I compare to some other commercial digital radio using DVSI vododers)