[Milsurplus] Command Set Receiver Coffee-Grinder

[Mike Morrow]

Breck wrote:

>>>The "coffee-grinder" tuning was necessary during the enroute navigation 
>>>and approach phase where two or three different Low Freq Nav Aids were 
>>>utilized

>Mike says:

>That decribes more accurately the use of an RDF/ADF connected to a loop.

Breck wrote:

>Nope.
>The paragraph above  describes a very--very--  busy pilot  trying to get an 
>off shore fix or shooting a two beacon approach. If you want to know why the 
>little  coffee-grinder handle is on the sets then  the above  is the 
>explanation.  The task of changing frequencies and getting a proper 
>identification was often tedious, time consuming, and sometimes lethal. 

Using only a **loopless** BC-453 type beacon receiver, how could more than one LF/MF directional beacon be utilized on approach?  (There's not much documentation of the command set navigation receivers being used with a loop, even though the RAV and AN/ARC-5 navigation receivers have that capability.)

Navigation toward or away from a directional LF/MF beacon could only be done on one of its four radials, spaced approximately but certainly not always 90 degrees apart.  Off-radial the pilot heard either an A or N or both at varying volume, while on-radial they merged at nearly equal volume to make a solid tone.

I know of no way that two such A-N directional beacons could have been utilized on an approach, and it was only these *directional* beacons that a *non-directional* receiver like a command set (or BC-1206 or any other such beacon receivers) could be used for navigating from beacon to beacon.

To use two beacons for a fix, the aircraft receiver would have to be able to determine the bearing to the beacons, treating at least one of them as a NDB.  Only a loop-equiped receiver allows that, i.e., a direction finder, hence RDF or ADF, even one having coffee-grinder tuning, and in the case of an RDF, likely a coffee-grinder loop oreintation control too.

But not a non-directional command set receiver.

Mike / KK5F