[Milsurplus] Command Set Receiver Coffee-Grinder

[Mike Morrow]

Clete wrote:

>The "directional beacon" is really a four-course LF
>Radio Range.  The map is full of points where the leg
>of one intersects the leg of another. 

You'd need to be flying *along* a radial to your airfield with your receiver tuned to that beacon most of the time, while frequently tuning that receiver to the beacon with the intersecting radial to catch the transition from A to solid tone to N (or vice versa) as you fly *across* that radial.  Doesn't leave too much time to precisely catch that intersecting radial.  You'd also need the intersecting radial to cross your flight path radial fairly close to the airfield for the fix to be all that useful on an approach.

Is that practical by a pilot in control of an aircraft, near final approach?  I'm asking because the old A-N directional LF/MF beacons were long gone at least a decade before I ever did any flying.  It would seem to me that under VFR rules, flying along a radial would get you within visual range of the airfield.  Under IFR, better nav equipment than just a simple beacon receiver should have been available.

>Also, some aircraft had a fixed loop, hence the "wing tip null".

That little bit of directivity to the aircraft receiver simplifies things.  But there'd still be a lot of back and forth tuning between beacons.  The tuning of command sets started this discussion, and they didn't have even that fixed loop.

If time-critical back and forth tuning between two beacons had been frequently required, it would seem that the manufacturers of all those light aircraft radios (BCN/BC band receiver, 3105 kc transmitter) of that era would have implemented a pushbutton frequency select mechanism as found in car BCB radios.

If all you ol' airdales tell me that this "crossed A-N beacon radials" technique was practical and often used for landing approaches, I'll believe you (though I would still doubt it as the reason for coffee-grinder tuning controls on the command sets).

73,
Mike / KK5F