Posted by Bruce WA1HGJ on December 13, 2025 at 16:02:38.

The link below takes you to a photo of a 1930s/1940s-era maritime radio direction finder (RDF) I recently saw on display at the Maine Maritime Museum in Bath, Maine: lwca.net/mbarchiv/pix/2025/image0(1).jpg Such RDFs were used to take bearings from coastal marine radiobeacons that operated from the 1920s to 1980s/1990s in the 285-325 kHz marine radiobeacon band. The RDF unit shown here appears to be a Bludworth Model DF-22C RDF according to a photo of a similar unit I found online: www.worthpoint.com/worthopedia/bludworth-marine-df-22c-radio-430061362 I could not ID a year of manufacture of this RDF, but comparison to a 1947 Bludworth RDF I saw 2 years ago at the Cape Ann Museum in Gloucester, MA (see Member News Spotlight, Sept-Oct 2023 LOWDOWN) suggests that the Maine Maritime Museum RDF is a somewhat earlier model, perhaps 1930s or pre-WW2. But for sure, sometime in the 1930s-1940s. Interesting to ponder that such RDFs, once ubiquitous on virtually all marine vessels large and small, were once the mainstay of marine radionavigation before more modern technologies such as LORAN-C and GPS were developed. 73, Bruce WA1HGJ P.S. Many thanks to John Davis for creating a link to the RDF photo on the LWCA server.

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