In working out some additional battery power for portable operation I wanted to know the current consumption of some of the HF radios that I own. While I have a KX2 I didn’t include it as I’m not all that concerned about power consumption as it sips electrons.
Sometimes more than 10W may be necessary so taking a 100W radio for some portable operations is a nice option. I measured the current consumption in 5W increments for the following radios:
Yaesu FT-857D
Kenwood TS-590SG
Icom IC-7100
Kenwood TS-480SAT
While I would never use the TS-590SG for portable operation I included it just for comparison. The results are in the table below (current in Amps):
857 |
590 |
7100 |
480 |
|
---|---|---|---|---|
Power |
||||
5 | 3.77 | 6.43 | 5.66 | 5.08 |
10 | 4.93 | 7.47 | 6.77 | 6.34 |
15 | 5.42 | 8.23 | 7.46 | 7.08 |
20 | 6.02 | 9.02 | 8.07 | 7.88 |
25 | 6.62 | 9.77 | 8.67 | 8.67 |
30 | 7.18 | 10.09 | 9.35 | 9.22 |
35 | 7.76 | 10.51 | 9.93 | 9.85 |
40 | 8.34 | 11.18 | 10.53 | 10.40 |
45 | 8.90 | 11.81 | 11.19 | 11.02 |
50 | 9.47 | 12.50 | 11.80 | 11.64 |
55 | 9.75 | 12.90 | 12.21 | 12.13 |
60 | 10.08 | 13.23 | 12.58 | 12.63 |
65 | 10.49 | 13.61 | 12.94 | 13.12 |
70 | 10.82 | 13.94 | 13.40 | 13.62 |
75 | 11.17 | 14.30 | 13.79 | 14.03 |
80 | 11.58 | 14.67 | 14.16 | 14.26 |
85 | 11.93 | 14.99 | 14.53 | 14.36 |
90 | 12.27 | 15.32 | 14.92 | 14.37 |
95 | 12.70 | 15.59 | 15.31 | 14.45 |
100 | 13.07 | 15.75 | 15.72 | 14.49 |
Receive | 0.68 | 1.39 | 0.65 | 1.00 |

Current consumption vs. Power level
The measurements were made using a Samlex SEC-1223 power supply and a Powerwerx Inline Power Meter.

Powerwerx meter
Measurements were made in CW mode on 20m into a Drake DL1000 dummy load.

Drake DL1000
Current consumption was a bit higher on lower frequency bands. For instance, on 40m most of the measurements were anywhere from 300-500mA higher.