Application Note 002

FF-800 NOAA WX alert receiver connection and configuration


IN THIS AP-NOTE:

NOAA WX radio auto-alert connection

This section discusses the connection of a NOAA wx receiver to an FF-800 in such a way that allows NOAA wx alerts can be broadcast over the repeater.

This discussion assumes the following:

The receiver connection uses a DPDT relay (12 volt coil), and a 1N4001 diode (for reverse spike protection on the relay coil). If there is an un-used port available on your system, the relay can be omitted and the NOAA receiver audio can be directly connected to the FF-800 (also, be sure to ground the COS input for the same port to "false" the COS active).

Be sure that the NOAA receiver is connected to a port that is configured as a remote base (this prevents a possible time-out situation that might occur if the receiver is connected to a "main" or "link" port).

The following schematic shows how to connect the relay and the receiver:


                    nc
 RCV COS >----------o\       rlyA 1/2 DPDT relay
(active low)          \
                       \o------------> port D COS (active low)


     GND >----------o



                    nc
 RCV audio >----------o\     rlyB 1/2 DPDT relay
                        \
                         \o------------> port D audio


NOAA audio >----------o


                       relay coil (12V)

			|| (-------o--------- +12V
			|| (       |
			|| (       -
			|| (       ^ 1N4001 diode
			|| (       |
			|| (_______o_________ OUT#7




NOAA alert trigger (logic signal) >-------------------> CMD trigger #1
                                                     (P3-6 on the FF-800)

The GND connection on the "no" contact of rlyA is to "false" a true COS when the NOAA receiver is connected. If the remote base is configured for active "high" COS, then this "GND" connection should be changed to +12V to false an active "high" COS.

After the connection is made, the FF-800 must be configured to act upon the alert signal that can be derived from a NOAA radio receiver (the derivation of this alert signal is left up to the user). It must be a logic signal that is at or below 0.8V (no alert) and at or above 4.2V (alert received) for proper operation.

Configuring the NOAA alert feature

The first step in configuring the new receiver connection requires that you enter the following macros:
100				unlock security
"O K"
139
"O K"
01590				start macro entry process
"M R O Enter"
001				speech = off
"M E"
0159607				abort this macro if port D = rx
"M E"
11570				out 7 = ground (to turn on relay)
"M E"
1351				port D = rx
"M E"
01598281			set user flag #1
"M E"
001				speech on
"M E"
004202				lock main tx(s) on for 2 min (can be longer)
"M E"
001				speech off again
"M E"
11571				out 7 = float (turn off relay)
"M E"
1353				port D = off
"M E"
0159271				save to bank 7, number 1
"Complete"
		{ next macro }
01590
"M R O Enter"
001				speech = off
"M E"
01598280			clear user flag #1
"M E"
1491				try to do 1st macro (here it is bank#7, slot#1)
"M E"
001				speech = off
"M E"
0159628				abort if user flag #1 = true (ie., abort if
				1st macro worked)
"M E"
11570				out 7 = ground (to turn on relay)
"M E"
001				speech on
"M E"
004202				lock main tx(s) on for 2 min (can be longer)
"M E"
001				speech off again
"M E"
11571				out 7 = float (turn off relay)
"M E"
0159272				save to bank 7, number 2
"Complete"
Of course, the set-up is not complete as yet. Macro #72 must be assigned to the active edge of the NOAA trigger line. Here, I assume that this line goes from ground to high (or high-Z) when a NOAA alert is broadcast:
100
"O K"
004751172			set input#1 rising edge for macro #72
"C M D T Seven Two"
If the logic output goes low (instead of high) when an alert sounds, set macro #72 for the FALLING edge of input #1 (leave the rising edge OFF):
004751072			set input#1 falling edge for macro #72
"C M D T Seven Two"
These macros illustrate the use of Macro Flags to control the outcome of a macro. Here, macro #71 checks to see if port D = rx and if this is true, the macro aborts. If macro #71 continues, it must set port D for receive mode before it performs its other operations. When the macro is complete, the port is turned off to restore it to its original state. Macro #71 also sets one of the user flags which indicates that it executed -- this information is passed back to macro #72.

When macro #72 is executed, it first clears user flag #1 and then it executes macro #71. After macro #71 is finished, it returns to macro #72 where execution continues. Then, #72 checks the user flag to see if the first macro executed. If so, #72 aborts and the macro sequence is complete. If not, the remainder of the macro is executed. This part of #72 is similar to the last part of #71 except that the status of port D is not changed (since it is already in recieve or transmit).

While the alert is in progress, it can be canceled by entering any DTMF digit from any active receiver. NOTE: if you use a different port (other than port D) for connecting a NOAA receiver, you should use the TR PRIORITY command to set the NOAA port for the LOWEST priority (see section 4.1 of the FF-800 manual). This will allow the alert to occur without interfering with the basic operation of the repeater.

I case you haven't deduced why this macro scheme is so involved, it is done so to allow the NOAA wx alert without altering the status of port D. If port D is active (ie., RX or TX) when the alert comes in, it will still be active after the alert is complete. Conversely, if port D is inactive (ie., OFF) when the alert comes in, it will be returned to the OFF state after the alert is complete.

The user should note that the structure of this macro configuration is NOT the only way to go. There are endless variations that can be designed to fit your particular desires. This only serves as an example of one particular method of connecting the NOAA wx alert. Of course, this example can also be adapted to other applications (such as fire alarms, over temperature alarms, etc...) that use a logic input to trigger an action by the FF-800.

As noted before, this document does not discuss the derivation of the alert logic signal. As information on various receivers comes available I will post another application note. If you implement this feature, or have knowledge of how to get a logic signal from a particular receiver(s), please let me know so that I can publish the information here.

Firmware bugs found

Now the receiver is ready to go... however, there are some bugs in rev 2.11 that I discovered while checking these steps. One of the bugs is minor (from a functionality standpoint) and has to do with the macro speech mute cmd (001). The other bug is fatal (to the NOAA alert that is) and won't allow you to properly set the trigger input macro -- without this, the feature won't fly.

If you have V2.11 or earlier, you may download the new firmware from the FTP page. If you need to order EPROMs, (pre-programmed) you may e-mail Joe, ke0ff, to place an order.

The macro speech supress toggle command

The Speech Supress Toggle command is used inside a macro to supress un-wanted or un-needed command responses. This allows the user to streamline their macros to speak only those responses that are meaningful (if any response at all).

Using the supress toggle command in a single macro is relatively straightforward. Every ocurrance of the "001" (default control prefix) toggles the speech enable status. However, when using nested macros (ie., a macro that has another macro command inside) the speech supress option becomes a bit more complicated. In this case, the speech supress status is reset when entering or leaving the nested macro(s). Thus, the nested macro enters and leaves with speech on (regardless of what the first macro has done).

This makes life easier for the macro programmer because you don't have to chase down the status of the speech enable through a complicated network of macros. The advent of the macro abort commands also complicates the speech enable scheme because they allow a macro to terminate early. with two or more possible exit points, it can become very difficult to predict what the speech enable status is when a macro is finished.

It should be noted that the speech supress toggle command is for appearences, and its use, mis-use, or lack thereof will not affect the execution of any macro (except for the amount of execution time).