Can 396T reject distant analog on P25 conv channel?

[davef3138]

I've got a 396T in service for a Radio Reference feed in Renville County, MN. Local law enforcement there uses a VHF P25 conventional system.

Since the 396T doesn't have the ability to set a conventional channel as "analog" or "digital" (as my 396XT does), is there a way to reject unwanted analog transmissions? Can I just set that channel for a random PL or DCS code, or will that also block the P25 transmissions?

The radio is 45 miles away so I can't easily experiment with it, I'll have to walk someone else through making the programming change.

-Dave

 

[krokus]

Wirelessly posted (BlackBerry8530/5.0.0.973 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/105)

If different CTCSS and/or DCS used, then it is easy. Since P25 systems use NAC, that could be useful, if the Uniden has that option.

Another option might be to enable the attenuator on that frequency.

 

[DJ88]

If you program a CTCSS (PL) or DCS tone on that channel it will block the digital..

 

[willdanl]

If the analog transmission that you want to block has a specific CTCSS or DCS in use, then you can use the SET LOCKOUT function in the Set CTCSS/DCS menu for that frequency. The scanner will not stop when it detects that tone, but the desired P25 transmission should not be affected. The limitation is that you can only select one tone to lockout - if there are multiple analog signals with multiple CTCSS or DCS on your frequency, this won't help you.

 

[davef3138]

Krokus: The 396T doesn't support NAC (as the 396XT does).

DJ88: That's what I was afraid of...

willdanl: The interference seems to come mainly from a specific user. I'll try to determine which tone they're using and have my colleague set it in the lockout. It will help, but probably not eliminate what we're hearing.

 

[n4yek]

As DJ88 stated, if you program CTCSS or DCS on that freq, the scanner will not decode the P25 signal on that freq. It's just the way the 396T is designed, I too wish you could set the channel like the XT model for digital only.

 

[N8IAA]

willdanl: The interference seems to come mainly from a specific user. I'll try to determine which tone they're using and have my colleague set it in the lockout. It will help, but probably not eliminate what we're hearing.

That will not work. You will still hear the analog transmission along with the P-25. The only way to block the unwanted signal is to use the NAC.
HTH,
Larry

 

[davef3138]

I'm going to try an alternate repeater site frequency instead. The law repeaters are all linked full time and each site uses a different output frequency. The site local to the scanner feed is on 154.785, which seems to be really common. One of the distant sites is using one of the recent narrowband frequencies (151.2575) which hopefully is quieter. I'll give that one a whirl...