[Milsurplus] [ARC5] Mystery Black Box

Sat Apr 26 21:02:15 EDT 2014

Yes. But LORAN-C can have more SLAVES per MASTER than LORAN-A. Also,
LORAN-A has several operating frequencies, LORAN-C only one.

The box is an LO and one or two BPFs. And possibly an AGC.

-John

==================

> 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
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