[time-nuts] More pictures of the mystery Collins Ru

[Robert Atkinson]

Hi Tim,
Three possible reasons for needing a Rb standard,
1/ Coherent detection with a local clock
2/ Hyperbolic navigation (local reference improves the fix and holdover)
3/ Secure communications.

Robert G8RPI




________________________________
 From: Tim Shoppa <tshoppa at gmail.com>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
Sent: Sunday, 28 July 2013, 15:25
Subject: Re: [time-nuts] More pictures of the mystery Collins Ru
 

Googling a little bit, I find several references to a Collins rubidium
package AFS-81 for airborne survivable VLF communications in the 60's
(predating this unit by maybe two decades). Still trying to wrap my head
around why that would need rubidium unless it was an airborne WWVB
replacement or something.

Googling also turned up the modern Rockwell-Collins 617A-1 VLF amp which
seems to be a dinky solid state unit that is rated at a third of a
megawatt. Still having a hard time wrapping my mind around that! Maybe I'm
off by 2 or 3 orders of magnitude or the picture is just the control head,
the real amplifier is the size of a building. A third of a megawatt must be
the size of the fixed transmitters used for VLF submarine communications.

Tim N3QE


On Sun, Jul 28, 2013 at 9:40 AM, Pete Lancashire <pete at petelancashire.com>wrote:

> maybe I should read things more often .. yikes I need a vacation
>
>
> On Sun, Jul 28, 2013 at 7:01 AM, George Dubovsky <n4ua.va at gmail.com>
> wrote:
>
> > Well, the outside label does claim it was made by GENRAD... ;-)
> >
> > 73,
> >
> > geo - n4ua
> >
> >
> > On Sat, Jul 27, 2013 at 9:24 PM, Pete Lancashire <
> pete at petelancashire.com
> > >wrote:
> >
> > >
> > >
> >
> https://plus.google.com/u/0/photos/111617808980322733757/albums/5890266601277045697
> > >
> > > The board with the edge connector was inside the same bag the
> > > connector was in, the bag was taped to the unit.
> > >
> > > I pulled the ends off first, but was immediately stopped with foam, it
> is
> > > glued in place.
> > > Then when I finally got the lid with all the screws off, all there is,
> is
> > > one board covered in potting compound.
> > >
> > > The compound breaks away pretty easily. One can see where a couple
> parts
> > > were
> > > replaced and there soft RTV was used. There are two precision resistors
> > in
> > > that area.
> > >
> > > The biggest surprise is the General Radio logo on the board !
> > >
> > > goo.gl/1XGG2F
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