BRITISH TRANSMISSION EXPERIMENTS 



1<) 



After a few iiioiitlis of Dpei'aliuii of all Ki links il 

 was realized that the available effort would uot be 

 sufficient to cope adequately with tlie tasks of editing 

 and examining the signal records. Consequently a 

 rather drastic reduction of the centimeter wave pro- 

 gram was agreed to for a trial period of 6 months, 

 starting October 1, 1944. For this period the follow- 

 ing links were operated continuously (without beam 

 switching) : on S bandj A to C and D (57 miles) and 

 B to E (300 miles) ; on X band, A to C and B to D 

 (both 57 miles). (The possibility of a link from B 

 to D on S band with separate equipment was also 

 envisaged. ) 



It was agreed to postpone oiieration on G cm, InU 

 at least one 3V2-m link over each of the two path 

 lengths would be added; preliminary measurements 

 on this longer wavelength were already being made. 

 In addition, K-band equipment for at least the optical 

 57-mile path was to be installed at an early date. 



Figure 1 shows a general view of the equipment in 

 one of the stations (D). The X- and S-baud receivers 



are in llie center of llie [iii-lui-e, with the minors and 

 can\as-covered wijidows behind. The S-baiid signal 

 generator and monitoring equipment aie on the small 

 table Ijeside the S-liaiid receiver. The recorders are 

 mounted on a temjioraiy table (now leplaced by the 

 central control desk), extieme right. The empty bay, 

 extreme left, was designed to house the K-band equip- 

 ment. The meter-wave equipment was mounted in an 

 adjoining room. 



In addition to the radio measurements, some study 

 was made of the behavior of a light beam over the 

 57-mile path during the summer of 1944 in the hope 

 that this might provide useful information on the 

 refraction produced (nearly) by temperature gradient 

 alone. Measurable changes in elevation were some- 

 times observed by means of a theodolite, but the in- 

 cidence of adequate visibility was small, and little 

 quantitative information was obtained. 



A detailed study of the S-band signal records and 

 meteorological data obtained from February 1944 is 

 being made at the National Physical Laboratory, par- 



FiGURE 1. General view of the equipment in Aberdaron, North Wales. 



