[Milsurplus] Question ( RBS; submarine )

[Ray Fantini]

I am still not buying it, the Afghanis in there mud huts believe that the Americans can hear their conversations with drones five miles above them. QRP operations in the Ham bands are a wonderful thing but my experience of running low power CW and AM left me with the idea that life is too short for QRP, lots of time spent calling other stations or CQ with little response. If all the stars and planets are in perfect alignment sometimes they get lucky and have a short exchange and call that a QSO, but that’s just me.
I would have thought German surface raiders in there short period of time in operation relied on things like patrolling know shipping lanes and approaches and visual sighting of smoke way before they would use something as sketchy as receiver LO detection. And as to the noise floor remember that we are talking about a ship that also had many electrically powered motors and other potential noise sources.
No, if no one here can’t sight a document I am sticking with LO radiation being an issue in using multipole receivers in the same location and the idea of long range LO direction finding a myth.

Ray F/KA3EKH
From: Nick England [mailto:navy.radio at gmail.com]
Sent: Thursday, August 25, 2016 12:31 PM
To: Ray Fantini <RAFANTINI at salisbury.edu>
Cc: Military Surplus List <milsurplus at mailman.qth.net>
Subject: Re: [Milsurplus] Question ( RBS; submarine )

"It has been reported", .... but I don't know where -

From http://www.tubedevices.net/Lorenz.php
"It has been reported that a German raider during WWII indeed managed to locate merchant ships sailing on their own, not in convoy, by direction finding on the signal radiated by their receivers. Presumably, these ships had rather old-fashioned equipment, perhaps with an oscillating detector directly coupled to the antenna."
Certainly NRL and USN training documents say that the purpose of shielding and RF and stages was to prevent LO radiation that could be tracked by enemy ships. The NRL history states this rationale for the RAA, RAK, RAL, etc. designs, well before it could have been invented as a "cover story" for Ultra, etc. So it seems there was certainly the belief that it was possible.
I'm not so hot to dismiss this as myth or misdirection - The middle of the Atlantic in 1942 must have been pretty damn quiet RF-wise. (Unimaginably quiet compared to my house.)  And an oscillator connected to a nice long wire high above a steel ship in a salt water ocean is not to be sneezed at.

Current QRP efforts have shown 500+ mile reception on 80m with a 40 microwatt transmitter.
Here's some 100mw 500kc results - http://www.w4dex.com/medfer.htm

Nick England K4NYW
www.navy-radio.com<http://www.navy-radio.com>

On Thu, Aug 25, 2016 at 10:31 AM, Ray Fantini <RAFANTINI at salisbury.edu<mailto:RAFANTINI at salisbury.edu>> wrote:
Can anyone anywhere document just one example of active LO direction finding in use by any Navy in WW2? , I am not talking about DF operations in fixing locations of submarines or surface craft by receiving low to medium powered CW or AM transmissions, or the practice of receiving radar emissions to identify frequencies and pulse rates but the alleged practice of attempting to receive the LO of a receiver at any distance beyond a hundred feet.

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