[Milsurplus] SCR-269 & SCR-273 differences

[Sean Barton]

Dave,

The SCR-273 uses a manually rotated loop antenna.  The I-75 indicator has spline connectors to connect it through an MC-204 crank to the loop antenna to rotate the loop and indicate bearing.  The I-65 indicator consists of a center-zero needle that indicates left-right course.  I have been gathering components for the SCR-263 system for a number of years which is the 24V version of the SCR-273 (with some minor differences).

Sean
KB0OVD

> Date: Fri, 12 Apr 2013 09:02:54 +1000
> From: davprin1 at optusnet.com.au
> To: milsurplus at mailman.qth.net
> Subject: [Milsurplus] SCR-269 & SCR-273 differences
> 
> G'day all,
> 
> I have a query about the differences between components of 
> these two Radio Compass systems. SCR-269-* was used in 
> aircraft with 12 or 24V electrics whereas the SCR-273-* 
> appears to be (more or less) the equivalent for use in 
> aircraft with only 12V electrics. The component of each 
> system are as set out below - other components not mentioned 
> such as cords and tuning cable/fittings are common to each 
> system.
> 
> The receivers do have different frequency ranges.
> 
> My question is, why the different indicator units? I thought 
> it might be just different illumination bulb voltages but 
> the SCR-269 can be used on both 12 and 24v anyway. 
> Functionally, can I use the 269 indicators on the 273?
> 
> I would like to build up functioning systems for both 
> SCR-269 and SCR-273. I do have all the components for the 
> 269 and I have the receiver for the 273
> 
> I would be interested to hear from anyone who has spare 
> components for the SCR-273 system particularly the control 
> box BC-414. The two control boxes look identical except for 
> the tuning ranges.
> 
> 
> SCR-269 (12/24 volt)
> Frequency ranges Band 1 - 200 to 410kc, Band 2 - 410 to 
> 850kc, Band 3 - 850 to 1750kc.
> 
> BC-433* receiver
> BC-434* control box
> LP-21* loop antenna
> BK-22* relay
> I-82* indicator Navigators
> I-81* indicator Pilots
> PL-112 connector
> 
> 
> SCR-273 (12 volt)
> Frequency ranges Band 1 - 150 to 325kc, Band 2 - 325 to 
> 695kc, Band 3 - 695 to 1500kc.
> 
> BC-413* receiver
> BC-414* control box
> LP-19* loop antenna
> BK-21* relay
> I-75* indicator Navigators
> I-65* indicator Pilots
> PL-117 connector
> 
> Cheers
> Dave
> VK4KDP
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