[ARC5] Navigational Beacons

[Michael A. Bittner]

The "elaborate procedure of  flying back and forth over the station to determine the right departing beam" you refer to was called a Fade Ninety. It allowed you to find your way onto a beam if you found yourself in a solid A .- or N -. zone.  Somewhere I still have a little plastic card that describes and diagrams the procedure.  If the 4-course, A/N ranges were still operational today, all you would need to fly on the Federal Airways System would be a cheapo transistor radio that covers the LF band.  The airways that were formed by interconnecting beams were called Red or Green airways if they ran north or south, and Blue or Yellow airways if they ran east or West.  Or, was it the other way 'round?  I've forgotten.

I'd still like to know what loop, if any, was ever used with the R-23 and R-24 ARC-5s.  Mike Hanz suggests that ARC made a prototype that never got into service but is probably the basis of the AT-382/ARC used with the ARC Type 12 receivers.

So far, no one has mentioned the 75 MHz Z-markers that were beamed straight up in the middle of the cone-of-silence when you flew over the range station.
Mike W6MAB


----- Original Message ----- 
  From: gordon white 
  To: Robert Eleazer 
  Cc: arc5 at mailman.qth.net 
  Sent: Saturday, April 30, 2011 6:36 AM
  Subject: Re: [ARC5] Navigational Beacons


        As someone who flew the A-N ranges in light aircraft after WW II - 
  they were a challenge. If you flew right on the "beam" you got a solid 
  audio tone (no BFO required). If you deviated to one side you got a 
  Morse "A" or to the other side a Morse "N" signal.

       This was known as being "on the beam," which became a slang term, 
  maybe still in use today? The procedure was shown in several pre-war movies.

       Approaching the station of course the audio became louder (I think 
  the AVC was either turned off or non-existent in the receivers).  There 
  was a "cone of silence" right over the station. Assuming the departing 
  beam was straight ahead, it picked up after you flew over the 
  transmitter, with the "A" and "N" sides reversed. Many stations had the 
  departing beam at an angle to the approaching beam (there were four 
  beams in the Adcock system, thus the name "four-course range." )  You 
  had to be sharp to pick up the correct "departing" beam.

       And if you were even slightly disoriented, discovering exactly 
  which beam you were on, was a bit difficult. Your magnetic compass was 
  probably not "swung" well enough to be completely accurate. There was an 
  elaborate procedure of flying back and forth over the station to 
  determine the right departing beam. Not being IFR qualified, I got in 
  the clear "on top" once and had quite a time assuring myself I was not 
  heading out to sea from an Adcock range in New Jersey.

    - Gordon White
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