User's Manual

FT-512 Trailblazer Installation and User Manual version 1.09 13
When the power is connected and turned on you should see the LED D1
(heartbeat) flashing at a rate of 1 per second.
2.4.2 Power Supply Feed Cable
Most users can simplify the powering of the radio by using several of the unused
voice/data pairs in a standard 6 pair buriable telephone feed cable. Don’t forget
to allow for additional current if add-on card options are selected.
The standard 6 pair buriable telephone feed cable is a 22 AWG size copper. This
means that both legs will have 3.2 ohms of resistance per 100 feet. Ohms law
can be used to calculate the voltage drop in the feed cable. For example, using
200 feet of 22 AWG, and doubling up on a pair would cause an effect of 3.2
ohms of resistance. If you were providing 13.8 volts than you would have a
current demand of ~150 ma x 3.2 ohms = or 0.5 volt drop. To calculate the
power loss you square the current and multiply by the resistance i.e., 0.150 x
0.150 x 3.2 = 70 mWatts. Good design will keep the power losses below 10% off
the consumption.
Cable Size Ohms/100 feet per Ohm if feeding 13.8, if feeding 24,
A.W.G. mm. both legs both legs
distance with 5%
voltage loss 2pr.
distance with 5%
voltage loss 2pr.
14 1.63 0.516 194 1783 6202
16 1.29 0.818 122 1125 3912
18 1.09 1.302 77 707 2458
19 0.91 1.642 61 560 1949
22 0.64 3.3 30 279 970
24 0.51 5.24 19 176 611
26 0.41 8.32 12 111 385
Table 4: Feed Cable Sizing and Distance - FT-512 alone
The above table shows the distance at which you have a 5% maximum
recommended voltage drop using 2 pairs of wires paralleled together.
2.4.3 Connecting the optional CWT Battery Backed-up Supply
The FT-512 Trailblazer operates on a DC voltage of 12-48V. Commonly, AC line
voltage is readily available. In these cases, the model 640-3600 Power
Converter is available as an option for powering and providing an 8 hour backup
in case power is lost.
Accepting any international AC voltage (90-264 VAC, 50-60 Hz), this Power
Converter provides an output voltage of 13.8V with 14 Watts of power available.
This power is sufficient to supply power to one FT-512 Trailblazer device and