Hi Tom,

I have most of the Kreusi system put together here, missing only the control box, which is fairly trivial.  I have the parts to make a facsimile for that.  It doesn't answer your question directly, because I don't think Geoffrey Kreusi made any differentiation in terms of what his DF system was capable of receiving.  A stable signal from a known position is...well, the same thing.

You can read more about that in the second part the web page at https://aafradio.org/flightdeck/1935/SCR-AE-183.html - along with some of the controversy at the Aircraft Radio Laboratory at Wright Field.  I do have quite a bit of paper on it, but nowhere can I find an specific mention of the specific history of NDBs - simply the ability to receive and provide a direction to them.   I'm happy to share any info I have in the files.

         73,
- Mike  KC4TOS

On 7/27/2023 2:02 PM, Tom Brent wrote:

Can anyone point me to information regarding when dedicated aeronautical non-directional beacons were established? An article in the February 1935 issue of Aero Digest by Fred Lutz talks about the Kruesi radio compass being

 

“available for the first time for the use of air transport lines, commercial operators and private pilots”

 

and further, that it had been adopted by the US Army Air Corps. However, it also states that it will work as long as there is a broadcasting station within the sets range and I’m interpreting this use of the term “broadcasting station” to mean a commercial radio station operating in the AM broadcast band. The Kruesi receiver tunes 150-1500 KHz.

 

The establishment of low frequency radio range systems (A-N radio ranges) is well documented online but it is the simple NDB that I’m curious about. I’ll continue along my course of looking through old aviation magazines but if anyone could steer me on the correct bearing to find this information it would be appreciated.