[Milsurplus] LO DF ing

[Boeing377]

In my years of commercial fishing I used DFs a a lot for NAV (200-400KHz) , for finding gillnet buoys to avoid entanglements (1.8-2.1 MHz), and finding other boats who were in hotspots (2-3 MHz). For those who haven't actually used RDFs there is an idea that you can get a good bearing on any signal you can hear. In practice that's not usually the case. It takes a strong signal to get a sharp reliable null. Weak signals give really broad to almost useless nulls. For fun I tuned around for LO sigs from AM marine band xcvrs and never was able to even hear any at any appreciable distance from another boat much less shoot a bearing on them. I'm sure the designs were a lot less leaky than WW2 radios however,


I spoke extensively with a man who commanded a US Navy DF station in Brazil, They got good bearings on high speed CW reports from Nazi subs off the Brazilian coast. He said most of the time the subs transmitted at night and were long submerged by the time any plane or boat could get to their general area. He said that during his 3 years at the station, only two U Boat sinkings were attributed to DF catches.
I asked him about DFing on receiver radiation and he said they never did it.  



AF6IM
www.parachutemobile.com
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