Ray,

From Nick's CEMB database, looks like the preselectors were installed for shipboard RAS to reduce oscillator radiation and improve sensitivity. See attached. It also could provide an interface from coax to hard-line, but still deciphering how that was done. The CN-49121 antenna cables are still on the bulkhead but a standard CME-50063 does not have a coax connection. Perhaps it was yard modified with a coax connector to the preselector. 


On Mon, Oct 16, 2023, 14:15 Ray Fantini <RAFANTINI@salisbury.edu> wrote:

The pre selectors are interesting, maybe they were used to try to eliminate the image issue of a low IF or maybe they just did the transition between the coax or what ever they used back then to the open wire feed on the RAS?

More pictures of RAS receiver in use during WW2, Albro Lake Receiving site outside of Nova Scotia, Ships entering Halifax Control obtained permission from  CFH on 425 Kc for CW or 1470 Kc for AM from Albro Lake, the receiving site and the transmitters were located at Newport Corner, Nova Scotia. They apparently had a CW link to Whitehall, England that relied on Marconi diversity receivers.

Don’t know any details about the transmitters at Newport Corner but apparently they were able to be  heard and read from Murmansk to the Falklands and half way around the world.

Web page at:

 

http://jproc.ca/rrp/albro_lake.html

 

About now everyone should be getting tired of me spouting off about the RAS.

 

Ray F/KA3EKH

 

From: Konrad Werzner <usstexasradio@gmail.com>
Sent: Sunday, October 15, 2023 3:22 PM
To: Ray Fantini <RAFANTINI@salisbury.edu>
Cc: David Stinson <arc5@ix.netcom.com>; MMRCG@groups.io; Nick England <navy.radio@gmail.com>; milsurplus@mailman <milsurplus@mailman.qth.net>
Subject: Re: [Milsurplus] [MMRCG] Refurbed (?) U.S. Navy RAS Receiver

 

 

 

Ray,

 

Battleship Texas appears to have used the RAS (-2 version specifically) for a good amount of WWII service career. Here's a couple radio inventories documenting their installation. At one time there were 4 in service but later reduced to 3 with the 4th one kept in radio spares. Each had a CME-50063 (RME DB-20) preselector.

 

3 type RAS-2 were in Radio I until one was later replaced by an RBK receiver: https://www.navy-radio.com/ships/bb35/DSCN0826.jpg (A -5 is on the left and -2 on the right. Both are recent acquisitions. -5 was reconfigured by a ham that had it floor mounted...)

 

1 type RAS-2 in Radio II (Main Transmitter room) located next to an RAA receiver(fairly obsoleted already): https://www.navy-radio.com/ships/bb35/DSCN0802.jpg (A TBS is stored there temporarily but you can see the CME-50063 preselector cabinet)

 

There's also 4 pin sockets on the bulkhead that route to emergency batteries to run these receivers: https://www.navy-radio.com/ships/bb35/DSCN0826.jpg