[ARC5] Mystery Black Box

Sat Apr 26 20:38:23 EDT 2014

As far as I know, LORAN-A and LORAN-C are totally different animals. 

I trained on APN-9 at USAF Navigator School back in 1961-1962.  As the VLF (~ 100 kHz) LORAN-C came in much later, LORAN-A went away gradually and the 1.8 - 2.0 MHz 160 Meter band was returned totally to amateur radio usage.  LORAN-C was so accurate that additional transmitting stations were added in the central part of the USA to boost navigation accuracy on the inland rivers and Great Lakes. LORAN-C was discontinued as GPS and Differential GPS became available. 

* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk hotmail com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
* * * * * * * * * * * 

> To: mmab at cox.net; ARC5 at mailman.QTH.net; Milsurplus at mailman.QTH.net
> Date: Sat, 26 Apr 2014 20:24:48 -0400
> Subject: Re: [ARC5] Mystery Black Box
> From: arc5 at mailman.qth.net
> 
> 
> The RF connectors may provide a clue. They have a bail retainer and that seems to be to be used on UK gear.(?)
>  Smarter people speak up!
>  Jay
>  
>  
> -----Original Message-----
> From: Michael A. Bittner <mmab at cox.net>
> To: ARC5 <ARC5 at mailman.QTH.net>; Milsurplus <Milsurplus at mailman.QTH.net>
> Sent: Sat, Apr 26, 2014 3:19 pm
> Subject: [ARC5] Mystery Black Box
> 
> 
> I found this mystery black box in mint condition, still in its herm. sealed 
> overseas packing at the TRW swap meet.  Does anyone have any further information 
> on it?  Tech. manual availability?  See photos here:
> 
> http://s1367.photobucket.com/user/kmmab/library/?sort=2&page=1
> 
> 
> 
> Description 
> 
> Name/Nomenclature:                Frequency Converter CV-27/UPN
> 
> Power:                                     115/80 Volts, 60/400 Hz, 1 Phase
> 
> Serial No.                                 A-327
> 
> Contract No.                            CAON-2000-DAY-DE-AR
> 
> Stock & Part No.                     1660-211 963 170 XD2 2C720-27
> 
> Name of Activity or Mfg.:         Dayton AFD
> 
> Date:                                        16 Dec 1955
> 
> Tech. Order Compliance Record: 00-20K-11
> 
>  
> 
> Front Panel Description (left to right):
> 
> Top Row: Antenna Connector, Spare Fuse, Receiver Connector.
> 
> Middle Row: 4-Pos. Antenna Match Switch, 3-Pos. Switch (HF/ L.F. Distant/L.F. 
> Local)
> 
> Bottom Row: Power Connector, Power Switch, Pilot Light, Fuse, 115V/80V Selector 
> Sw.
> 
>  
> 
> Size: 6-5/8" Wide x 6-1/8" High x 8-5/8" Deep (Not including shock mounts & 
> controls)
> 
>  
> 
> Tubes: 6SJ7, 6SA7, 6X5
> 
>  
> 
> Probable Function:
> 
> With middle 3-position switch in the L.F. Distant or L.F. Local positions, it 
> probably converts signals in some unknown low frequency range to some unknown 
> high frequency range for tuning on an HF receiver.  With the switch in the H.F. 
> position, it probably connects the two antenna connectors together for normal HF 
> reception on a connected HF receiver.
> 
> 
> 
> I found an instruction manual reference at: 
> 
> http://books.google.com/books/about/Handbook_of_Operating_Instructions_for_L.html?id=r3mmtgAACAAJ
> 
> http://www.jproc.ca/hyperbolic/loran_a.html
> 
> 
> 
> The manual doesn't seem to be available in print or on line, but the manual 
> title says "Loran Low Frequency Converter", so it has something to do with 
> LORAN.
> 
> My own experience is with LORAN A using the AN/APN-4 in the Martin PBM Mariner 
> flying boat.
> 
> A good description of LORAN A can be found at: http://www.jproc.ca/hyperbolic/loran_a.html
> 
> 
> 
> Questions:
> 
> So what did this black box do? Convert LORAN C to LORAN A?  Can't be because 
> LORAN C wasn't invented yet in 1955.
> 
> What LF range does it cover?
> 
> What HF range is its output?
> 
> How was is used, with what receiver(s), for what military purpose?
> 
> Anybody know?  Guesses welcome.
> 
>   
> 
> Mike - W6MAB  