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Re: Voltage required for proper radio operation

Bill N4XEO wrote:

I agree Wayne, but the bottom line is that the specs say 13.8 volts. This
is what they are saying is needed. Maybe the regulators are being pushed to
the max where they need the higher voltage just to make the 9.6 volts or

Wayne replies:

My FT-847 manual states that the input voltage requirement is 13.8V, +/-
10%.  Therefore, the radio should be nominally functional down to <12.5V.

If you have problems operating a FT-847 at "13.0V", I strongly suspect that
your FT-847 isn't really getting 13.0 volts when transmitting, due to

1. excessive cable resistance (DC cable too long, too small, or bad
2. Poor load regulation in your power supply

You can mask both of these deficiencies by running the power supply at a
higher voltage.

Wayne Estes W9AE
Mundelein, IL, USA

p.s.  My TSI downconverter (with internal 12V regulator disabled) seems
quite stable when powered via the FT-847, with the FT-847 powered by a 13.0V
lawn tractor battery.

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