Weather Rx decode

[TDR-94]

When setting up a P7100 VHF radio for Receiving and Decoding 162 MHz Weather Alerts,which default sequence is supposed to be used if the tone is in box B? Is the default still supposed to be set to A?

Is the radio supposed to be able to scan other conventional channels in the same system while waiting for the Alert tone to unmute the radio? When I turn scan ON the radio immediately unmutes the weather channel.

 

[kb4cvn]

When NWS started with the ALERT functions, they simply copied Moto's "supergroup" call sequence of a LONG (8-second) "B" tone.

In the T-99 Tone Decode table, uncheck the Harris (or Ericsson, M/A-Com, Tyco, etc.) box.
Enter 1050.0 Hz in to the box for B.
Then go to your conventional frequency set, and check the T99 decode box on the channels you want this to work on.
(In all of my radios, I have a separate Weather only system, where I have all seven of the weather channels listed, then I duplicate the seven with the alert decode enabled and call them "ALERT-1" though "ALERT-7". Works for me....




I found the draft copy (in MS-Word) of the TSM I wrote in 2002 on how to do this. It exceed the size limit on files to attach so I converted it to a PDF and attached it to this posting. It will get you going.


IMPORTANT:
The biggest thing people forget to do when incorporating this decode function is not programming a T99 button onto the radio's keypad to enable/disable the tone decoder function. It will not work without it.

 

[TDR-94]

It's set-up exactly as described and T99 enable is mapped to a keypad key.I thought maybe the default sequence setting "A" was incorrect,but it's not.It's a bummer that you can't scan other channels and still receive an alert.

 

[kb4cvn]

It's set-up exactly as described and T99 enable is mapped to a keypad key.I thought maybe the default sequence setting "A" was incorrect,but it's not.It's a bummer that you can't scan other channels and still receive an alert.

The reason you can scan and decode at the same time is the circuit used to decode CTCSS is also utilized to decode the paging tone.

At the time when it was developed, it was thought that a user (Volunteer Firefighter, etc.) who used the tone decode function would NOT be scanning, wanted the radio muted to all traffic except the tone when activated.