Sponsored, Licensed, Owned & Maintained by
N7ULY & WB7TUJ
Coverage from most of the East Valley!
Very poor coverage between Power Rd & Signal Butte from McDowell South.
The radio is a 110 watt
continuous duty GE Mastr II station.
The only modification to the station is the addition of an identifier and battery back-up telemetry.
Tx power out of the dux is 75 watts into a DB-222E antenna which has a gain of 6db to the West.
This radio encodes 162.2Hz, so you can decode this tone if your radio has this capability.
The time out timer is on
the receiver. Thus you don't have to let the transmitter's 5 second hang time
But you will time it out if you talk into it for 3 minutes without unkeying your mic for 1/2 second.
There is no courtesy tone or any other "bee-doops" and there never will be.
The system does have back up battery power.
You will hear a continuous low level *1200Hz tone when the radio is running on back up power.
Please keep use to a minimum of necessary traffic when you hear this tone to conserve battery power.
There are other radios that use this same back up battery.
This repeater is available to any
group or organization that is involved with
to use for nets, drills, events and actual emergencies.
At all other times this
is an OPEN system.
For more information on the Usery Pass Antenna Site, including
coordinates & coverage area:
Other open repeaters owned & or maintained by WB7TUJ & N7ULY
*Power / Power Supply Failure Telemetry:
Let me start with the power supply. 146.660 and 4 other radios are powered by an Astron RM-60 that is set at 14.4 VDC and backed up with 400 amp hours of batteries that are floated by a separate 15 amp power supply set at 13.6 VDC.
Both the battery system and the RM-60 are isolated from each other using two Schottky diodes.
The diode from the battery is normally reverse biased by the Astron.
The diode from the Astron blocks battery DC from the Astron's pass transistors, preventing damage to them when the Astron is powered off.
And provides *control for the relay coil described below.
I set the voltage from the Astron at 14.4 to insure this, as well as to compensate for the .6 volt drop across the diode.
Thus under normal conditions my equipment will see about 13.8VDC.
I ran a wire from the output of the Astron *(before the diode) to drive the coil of a small spdt relay.
I use a Comm Spec tone burst board, set to produce a continuous tone and power it from the 10V supply in the GE Mastr II.
It continuously runs. I take the audio output lead and connect it to the center of the relay.
Then I run a wire from the switch contact that closes when the relay coil is de-energized to the local mic pin on the Mastr II's backplane.
I set the tone freq to about 1200Hz and the deviation to about 400Hz. And that's it.
Thus, whenever the Astron power supply fails, no matter what the reason, the relay closes and whenever the repeater's transmitter is on the air, the tone is heard.
About 400Hz deviation, voice audio going through the repeater is not hindered, as you can barely hear the tone with voice on there. And on the hang-time, it's perfectly readable.
On another repeater I do the same thing, except I power the relay coil from a wall-wart that's plugged into 120VAC.
Thus, by kerchunking & listening to the 5 second hang time on the 2 repeaters, I can tell if I have a power outage or a power supply failure.
If I have a power supply failure, the battery system & float charger can run the system forever, unless the radios were transmitting so long that the battery ran down because the 15 amp float charger couldn't keep up. This would most likely never happen though, as it's so unlikely that the radios would ever see that much duty.
Keep in mind that each Mastr II draws about 25 amps when transmitting. And the load on my system with nothing transmitting is 7 amps.
You can do the same thing, for other telemetry; oil pressure on a generator, high building temp, etc, etc, etc.
I prefer to do these things with mechanical relays rather than some home made solid state switch, as it really Keeps It Simple Stupid and it is virtually Fail Safe!
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