[Milsurplus] Question ( RBS; submarine )

[Kenneth G. Gordon]

I am in total agreement with you, Ray.

Ken W7EKB

On 25 Aug 2016 at 21:21, Ray Fantini wrote:

> 
>     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
>      
>     On Thu, Aug 25, 2016 at 10:31 AM, Ray Fantini <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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