[UK-CONTEST] Open Line

[Ray Hills]

All the BBC wartime HF stations used four-wire open line (two conductors 
about 3 inches apart strapped for each leg).  The Zo was 320 ohms. 
Transmitter power was usually 100kW. This continued right up until 1964 when 
the introduction of 250 kW transmitters dictated something that could carry 
the current and was not prone to flashover and corona caused by insects at 
that power level.  After trying an open wire balanced feeder made up of two 
"sausage" conductors each of six wires on about a 1 inch p.c.d. (an 
expensive failure), the change was made to a balanced screened line formed 
of two copper tubes about 1 inch dia.within a continuous rectangular 
aluminium box section screen.  Still in use as far as I know.  Don't 
recommend that for AR use on cost grounds !!

I thought we had buried the old "my frequency" issue?  Provided MIR went 
away straight afterwards so that Ray FON could resume, that seems not 
unreasonable.  What would not be reasonable, polite or good operating would 
be if MIR then stole the frequency for himself.  We really don't want to go 
back to the days when stations started warming a frequency as much as 
half-an-hour before the contest, do we?  Trouble is that those of us of 
great years get confused between sprint and non-sprint !!!

Ray  G3HRH