[ARC5] Mystery Black Box

Sat Apr 26 20:49:17 EDT 2014

Other than carrier frequencies, how are LORAN A and C "different animals"?.  I think both are pulse modulated hyperbolic systems. Couldn't up-converted LORAN C signals be displayed on the APN-4 and used for navigation with a suitable chart?
Mike-W6MAB
  ----- Original Message ----- 
  From: D C _Mac_ Macdonald 
  To: KE6PPF Jay Coward ; mmab at cox.net ; Military Surplus Mail List ; ARC-5 Mail List 
  Sent: Saturday, April 26, 2014 5:38 PM
  Subject: RE: [ARC5] Mystery Black Box

  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  