[ARC5] VHF, HF, and LF ARC-5s in one installation

[Mike Morrow]

I wrote:

> That would be a "ferry" configuration which allows the R-23 to  
> provide reception of civil aviation tower frequencies (the standard
> one was 278 kHz), and transmission on the standard civil aviation
> aircraft transmission frequency of  3105 kHz.

Roy wrote:

>That first frequency in the radio beacon band, isn't it?  I do  
>remember just a few air bases that could transmit voice on their NDB  
>frequency (I was in Navy flight training in 1966/67), but I expect  
>things had changed a LOT since the time you are talking about.
>
>The situation you report is the early 1940's, right?  ah yes, I see  
>you mention "in operation by 1944".

Yes, the old system of ground station transmitting in the LF/MF
beacon band and receiving on 3105 (and sometimes on 6210) kHz
pre-dates WWII.  After WWII, there many civil aviation radio sets
commercially available that included a tunable beacon band (and
often broadcast band) receiver, plus a crystal-controlled transmitter
on 3105 kHz).  One of my favorites is the GE AS-1B, but there were
many others, made by Harvey-Wells, Motorola, RCA, Bendix, just to
name a few (some found today on ebay pretty cheap).

That gave way in the late 1940s to early 1950s to substituting a
VHF AM transmitter, but still using the LF/MF receiver.  In the early
1950s, both the receiver and transmitter became VHF-AM.  Most
of the directional (Adcock) LF/MF beacons were gone by the late
1950s, leaving only those NDBs such as are still in operation today in
the LF/MF band.  Navigation was by then VHF Omni-Range (VOR).

By the very early 1960s, every thing was VHF-AM comms, VOR navigation,
and maybe an ADF receiver for those NBDs and BC stations.

It's hard to believe today how important the LF/MF beacon and tower
band once was, and how simple the equipment was for navigating
and communicating across the country.  At one time, if an aircraft
carried nothing else electronic, it carried a simple dry-battery-powered
200 to 500 kHz AM receiver (both pre- and post-WWII).  Such receivers
often ran about $30 then (post-WWII, so about $300 today).

Mike / KK5F