The Platoon sailed from Brooklyn Port on the USAT Uruguay on 1 March 1942. They arrived in Melbourne on 10 April 1942. They set up camp at Camp Pell where they trained in intercept and direction finding operations until 6 June 1942. On 19 May 1942, the Platoon was redesignated and became the First Operating Platoon, 126th Signal Radio Intelligence Company.

The Platoon moved to Mount Macedon in Victoria on 6 June 1942. The Platoon established independent operations, performed its own house-keeping and cooking chores. Intercept facilities, consisting of three positions, were operated in the van of a 1 1/2 ton truck. One direction finder, 206-C, was placed in operation on top of Mount Macedon at a location about 3/4 mile from their camp.

On 1 July 1942, T/Sgt. Messer of the 823rd Signal Service Company was attached to the Platoon for temporary duty to instruct the Platoon's intercept operators in ROMAJI and Japanese KANA telegraph code.

On 10 July 1942, the Platoon moved to Townsville in north Queensland by motor convoy. They arrived in Townsville on 2 August 1942. 1st Lt. Menear reported to Captain Brown, the GHQ radio intelligence officer. Captain Brown assigned two GHQ Officers, Lt. Phelan and W/O Card to work with the 126 SRIC. The Platoon was assigned to monitor Allied Air Reconnaissance frequencies, copying clear and coded messages during the attacks on Guadalcanal and reporting by TTY to GHQ.

The Platoon's 206-C direction finders were set up to work with No. 1 Wireless Unit, RAAF which was also located in the Townsville area. The DF's were located at Townsville, Cairns, Charters Towers, and Cloncurry. They communicated back to Townsville by wire. Their mission was to work with No. 1 Wireless Unit, RAAF to secure bearings on enemy aircraft. This work however was not that successful due to:-

• the long lines of communications,

• the DF's were not suited for long range work and 

• the rapid action required to obtain bearings on short aircraft transmissions

• the DF operators were not trained to read Japanese code

The DF Operators were unable to readily distinguish between the various transmissions they intercepted.

The Platoon moved to Brisbane by train on 15 November 1942. M/Sgt Nurss had travelled to Brisbane earlier to arrange for the establishment of a radio station and antenna equipment. He reported directly to Captain Brown and GHQ, SWPA during this time. The Platoon arrived in Brisbane on 18 November 1942 where they set up a new operational site at Northgate on the north side of Brisbane. They began to intercept Japanese Army and Diplomatic radio traffic. Captain Brown and Lt. Phelan and W/O Card directed the operation of the Platoon from this point in time.

All their intercept traffic was handed over to Central Bureau, GHQ for analysis. It was necessary to train more men as intercept operators.. All men, regardless of their present assignments with the Platoon were trained. The best became intercept operators. No direction finding work occurred during this period at Northgate.

The rainy season in Brisbane led to the radio station site at Northgate being flooded. The Platoon moved to Stafford in Brisbane on 10 January 1943. They established an independent camp at Stafford and a temporary radio station which was housed in two tents. The radio station utilised very simple antenna equipment.

Work started on a new GHQ radio station not far from their tents. The radio station building was constructed by Australian workmen. Grounded V-antennas were installed to cover directionally the arc from northwest through northeast of Brisbane. Fifteen antennas weer set up for this purpose, arranged in groups of three, each group covering the same direction with spacing for diversity use if necessary. The new radio station was operational by the beginning of March 1943.

In April 1943, the First Operating Platoon, 126 SRIC, was merged with the rest of the 126th Signal Radio Intelligence Intelligence Company which had arrived in Brisbane on 25 March 1943. The 126 SRIC had its origins at Camp Crowder, Missouri, where it was activated on 14 August 1942 with a strength of 5 officers and 85 enlisted men. 2nd Lt. Joe L. Thurston was the first Commanding Officer. The other officers were:-

2nd. Lt. Swomley
2nd Lt. Dibos
2nd Lt. Wilson
2nd Lt. Hadd

The Table of Organisation at that time showed that the 126 SRIC included a group known as the First Operating Platoon which had already been activated. Its whereabouts were apparently unknown. 

The October 1943 Brisbane Military telephone Directory shows a Captain W.B. Menear working in the Wire Section of the Signal Office, GHQ, SWPA in Room 65 of the Old Courier Building, in Brisbane.

The May 1944 Brisbane Military telephone Directory shows a Major H. W. Brown of the 126 RI Co. at Stafford who was in charge of Direction Finding and attached to the Signal Office, GHQ, SWPA.