OTF/OWF
'Optimum Traffic Frequency/Optimum Working Frequency' - the best
(HF) frequency for reliable communication over a particular distance,
for the time of day/ night. Usually at the band below the MUF.Pan Pan
The voice 'Urgency Signal' - derived from the French expression 'en
panne' - meaning 'breakdown' or 'serious malfunction' (may refer to a
vessel or a person).
Pilot Station
Radio installation in a Pilot service office.
Port Operations
Radio traffic concerned with the safe movement of ships within port or
harbour limits (see also YTS).Prudonce
Used, during distress working, by the controlling station, to allow
'restricted working' (French word meaning 'be prudent' or 'be careful').
PTS tone
In the Inmarsat-A telephone service; you get a PTS (Proceed to send)
tone when connected to a CES, when the CES is ready to receive your
required telephone number.
Public Correspondence
Paid-for radio services (e.g. 'link calls' - telephone calls between people
onboard seagoing vessels and their office/home).
R3E
Single sideband voice, reduced carrier (used when a receiving station is
having difficulty tuning into aJ3E signal)
RCC
Rescue Coordination Centre - a shore office responsible for controlling
maritime and/or aeronautical Search & Rescue operations. When the
centre is purely for Maritime operations, it is known as a Maritime Rescue
Coordination Centre (MRCC).
RF
Radio Frequency - electromagnetic waves operating at radio frequency;
and a stage in a radio transmitter/receiver.
RF Gain
Radio Frequency Gain - a control for adjusting the sensitivity of a radio receiver.
214 THE NAUTICAL INSTITUTE