The radio master switches marked “RADIO MASTER 1” and “2”, with marked positions “OFF” and “ON”, are located on the overhead switch panel (Figure 1-2-9). The No.1 radio bus is powered from the essential bus through the RADIO MASTER 1 switch and provides power for the following:

a. AN/ARC-511 VHF/AM.
b. AN/ARC-164(V) UHF.
c. AN/APX-77A IFF.
d. AN/AIC-14 ICS.
e. AN/ARN-504(V) TACAN.
f. SEC/KY-58 Secure Voice.
g. VOR/ILS.

The No.2 radio bus is powered from the primary bus through the RADIO MASTER 2 switch and provides power for the following:

a. AN/R-1047 A/A OTPI.
b. AN/ARN-59 LF/ADF.
c. AN/ARA-25 ADF.
d. AN/ASN-123C TACNAV.
e. AN/ARC-505(V) HF.
f. AN/APN-513(V) Doppler.
g. The UHF antenna.

The No.3 radio bus does not incorporate a switch and is energized automatically from the primary bus. In the CH124A, it provides power to the following:

a. AN/ARC-513 VHF/FM.
b. AN/ARR-52A Sonobuoy Receiver.
c. AN/APN-171(V) Radar Altimeter.
d. AN/AQS-502 Sonar Power.
e. AN/AQS-502 Sonar Guillotine.

In the CH124B, the No.3 radio bus provides power to the following:

a. AN/ARC-513 VHF/FM.
b. KY-75 Secure Voice.
c. AN/APN-171(V) Radar Altimeter.

The LF/ADF, ICS, VHF/AM and UHF are operated on DC power only. All other radio equipment requires AC and DC power for operation.