[Milsurplus] Question ( RBS; submarine )

[Peter Gottlieb]

I suppose one could hook a spectrum analyzer to the antenna connection of such 
receivers to quantify the real levels we're talking about.


On 8/26/2016 5:42 PM, Bill Cromwell wrote:
> Hi Nick,
>
> There isn't any doubt the fears were real. Whether or not they were well 
> founded or how well founded is the mystery, My limited experience along with 
> lack of hard citations tells me that df'ing receiver oscillators (at microwatt 
> or even picowatt levels) is most unlikely. I have not had access to all the 
> regens that have been built and used and it is possible some of them on the 
> worst of days may have been a beacon for a submarine to find a target. The 
> engineers seeing the 'possibility' worked to reduce the risk. That is what I 
> think you are saying and I agree. Maybe I will try to better evaluate the bits 
> and pieces that comprise the possible threat. I think that means I will be 
> building some regens and that will be fine with me. I have reports that regen 
> detectors (tubes) draw low microamps for plate current and the plate voltage 
> is also quite low. I will try to measure that and try to get some kind of 
> handle on power output. I don't know if I can measure power that low!
>
> Yes, I have been to your web site. Awsome.
>
> 73,
>
> Bill  KU8H
>
>
>
> On 08/26/2016 01:52 PM, Nick England wrote:
>> Hi ray - I appreciate the compliments and your confidence in my web site :-)
>> But DF is far from my area of interest or expertise and my
>> www.navy-radio.com/rcvrs/d-df.htm <http://www.navy-radio.com/rcvrs/d-df.htm> 
>> page is just a catch-all place for info I happen to come across.
>>
>> For anyone  seriously interested in the topic, check out "Abstracts of the 
>> Available Literature on Radio Direction Finding 1899-1965" at
>> http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=AD0800110
>> which has entries for 5,224 articles to keep you entertained....
>>
>> My point was that NRL etc. were indeed concerned about the possibility of LO 
>> detection. When they designed the RAA, RAK, etc. in the 1930's they were 
>> worrying about what a very clever adversary *might* be able to do in the next 
>> 20 years. Predicting future technology is difficult and assuming the worst 
>> case sometimes makes good sense.
>>
>> From Gebhard's NRL history -
>> "... which included the Models RAA, 10 to 1000 kHz (1936), RAK, 15 to 600 kHz 
>> (1939), RAL, 300 to 23,000 kHz (1939), and RBA, 15 to 600 kHz (1941). These 
>> receivers were NRL concepts. They included the NRL multiplexing technique and 
>> the shielding needed to prevent radiation of local-oscillator energy which 
>> could cause detection by an enemy through interception."
>>
>> I'm just pushing back against what sometimes seems to be a narrative that 
>> this was all just a foolish concern and panicked over-reaction by ignorant 
>> engineers. It wasn't. Just because you are paranoid doesn't mean they aren't 
>> out to get you.
>>
>> You can't judge what might have happened, by what did happen - without Enigma 
>> decrypts, jeep carriers, centimetric radar, etc. maybe more effort would have 
>> been put into super-sensitive DF. I certainly don't know.
>>
>> Cheers,
>> Nick England K4NYW
>> www.navy-radio.com <http://www.navy-radio.com>
>>
>> On Fri, Aug 26, 2016 at 12:04 PM, Ray Fantini <RAFANTINI at salisbury.edu 
>> <mailto:RAFANTINI at salisbury.edu>> wrote:
>>
>>     The base of my argument is your web site.  I am not an expert on
>>     history or procurement but simply look at the listings,
>>     publications and items on line and seeing what’s listed on your
>>     web site (http://www.virhistory.com/navy/rcvrs/d-df.htm
>>     <http://www.virhistory.com/navy/rcvrs/d-df.htm> ). What I
>>     consider to be the premier web page for US Navy communications and
>>     looking at the DAK, DAQ and the shore base DAB don’t see anything
>>     up to that challenge.
>>
>>     If it existed I would think it would be evident in some
>>     publication and on your web site.
>>
>>     Ray F/KA3EKH
>>
>>
>>
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