RADIO RECEIVERS

frequency, consult with the duty radiomen for the best available antenna to use to receive the desired broadcast. Aboard CVs, LHAs and LHDs, several shipboard antennas may be dedicated for use by the weather office. When dedicated antennas are present, one or more AN/SRA-12 antenna patch panels will be located within the Met Office (fig. 1-21). On the AN/SRA-12, the top row of jacks may contain plug connections to either antennas or receiver sets. In figure l-21, two antennas are available: INT ANT-2 and a LONG WIRE; and four radio receivers: R-2368 No.5, No.6, No.7, and No.8. The lower portion of the panel contains an antenna-input patch (on the far- left side), and four patches for each of the seven filtered frequency ranges varying from 32 MHz down to 14 kHz. ANT-2 has been selected as the input antenna and connected to the input jack. R-2368 No.5 has been patched to the filtered antenna output in the 32 MHz to 14 MHz range. NOTE: When patching, you must always insert the end of the antenna patch cord into the receiver first, and then into the lowest usable filtered frequency patch. When unpatching, remove the receiver jack first, and then the filtered frequency patch. Patch or unpatch from the top down. More than one receiver may be connected to the same antenna. For instance, receiver No.6 may be connected by use of an additional patch cord to another jack on the filtered 32 MHz to 14 MHz output or to another frequency range. RADIO RECEIVERS There are two basic types of radio receivers found in shipboard meteorological offices: the R-1051/URR receiver and the newer R-2368/URR. The R- 2368/URR is currently being installed in all new construction ships, and is being retrofitted to older ships to replace both the R-1051/URR medium- and high- frequency receivers and AN/WRR-3 low-frequency receivers. R-1051/URR Receiver The R-1051/URR receiver (fig. 1-22) receives CW, AM, USB, LSB, and ISB signals, plus frequency-shift keying (FSK) signals in the 2-MHz to 30-MHz range. Frequency settings are dialed into the windows on the front panel. This receiver is a very reliable receiver and is very easy to operate. Operator instructions and very simple operator maintenance procedures are contained in the operator’s manual for the R-1051(B), (C), or (D)/URR Receiver. Figure 1-21.—AN/SRA-12 antenna filter and receiver antenna patch panel. 1-38