BEATING THE SUNSPOTS

Evening Post, Volume CXIV, Issue 18, 21 July 1932, Page 19

BEATING THE SUNSPOTS

G.P.O. WIRELESS SUCCESS

1 Tie opening of the Post. Office's beam wireless telephony service to Canada within the next few weeks will be a triumph for ■ the methods which have been throughout adopted-by the.'-Onr gineers of the. Departmontj ,says the "Morning Post."

Arrangements^ .£o.r ..the Jndia and Egypt service^ are-also'well .advanced, and it is., expected ;that.these will be opened in" the au,tumn..:: . ".. ....

: The;;i}riticisms;:of;Ppßt ; .Ofaco:.]jiothqds of: '&onstruetiqn were ;f reely made two years ago: have been proved By events to.: "be groundless; '■ While many; 9ther :wwelesS' "conoetis- have suffered serious inconvenience/from^the approach bfnths wprßt,,perioap£..the sunspot cycle, tbe.:P.oßt,Dffice.s.emces;have been little tSeow^, :,\ : .,,,-., wy : ;j::. .;;. , . . . Sunsppts aff ectthe electrically-charged layers 'of th'e^pper atmosphere, which; reflect ■TOreless-.way^.s round the earth, and astpady in?reaSje.-is at present tat-, ing placeto vtnWiengths of short waves which cafe-jiejsuccessfttHy used. . " I - The Bosrofflee.plani since.adopted iy' Lthe ; ,Radio Corporation of, America ana itKe Spanish-SouthVi&anerican service, was 'to::bhil4 short ae'riais/which-could be I comparatively cheaply replaced, and to i employ5 a'large number- ofi. alternative wave-lengths in ;orde# to. meet the' do-' Imaij^s for telejlioiie'servico without delays". ' .'•-■ "■■" ■ '•' ■'••■ ' ■' ":

i It is pointed out that the arguments for such low aerials .which.were put forward' in. the House oi Commons in 1930 by Mr; Lees-Smith, the then.PostmasterGeneralj have been entirely, substantiated. Quoting from an expert report, .Mn:iLees-Smith said:—. -:, - -~ .- I "there .appears to/be-no reason for supposing that an. efcective aerial array .would >need masts of over 180 feet in height/and there is no doubt that the cost of masts increases very rapidly when they,are over 200 feet in height. ' '' The Marconi Company were pioneers in beam development and the Marconi beam stations already erected are handicapped somewhat by this fact. The Post Offico system of aerial arrays be■ing carried';on lower masts could, threefore, probably bo made more effective than the Marconi array;'at a lbwor capi-: tal cost." ■■.;«' .; . •• ■

f - WAVE-LENGTHS-TO ORDER, i Beference was(als6 made in. the report to the gr.eater ease,-with which' a variety of wavelengths could be used to meet changing conditions- at :diSereiit hours, of the day. It is this adaptability which has saved the situation .now that the eleven-year sunspot isycle has (become a serious factor; in commercial transmission, ' .-..' i "The American aervitje is now being satisfactorily operated,??.stated an offi-cial-of the Post Office,.".on the four wave-lengths which we; already have: A3 conditions bocomo bad it will probably be necessary to add a fifth and higher wave-length, but. this, can be done at relatively small expense.''