[Boatanchors] RCA Marine Receivers

[Richard Knoppow]

    RCA made two late marine receivers, the CRM R6A and a 
shipboard (DC) version, the AR 8516. These are nearly identical 
but use different tubes so that the AR-8516 can have series 
heaters on a 110V DC mains supply. It has two more tubes in its 
tube count, haven't figured out which ones yet. I have neither of 
these receivers but am curious about them. One big question is 
the specs. The image rejection for both receivers is the same and 
not very good. At 30Mhz its listed as 30db. That would be 
acceptable for a single conversion receiver with a single RF 
stage and 455Khz IF but not for a double RF stage even if single 
conversion and this is a double conversion receiver. In 
comparison the RCA AR-88 is speced (and performs) with an image 
rejection of 200 at 30Mhz, which translates to 46db. This is very 
good for a single conversion receiver but how could a deluxe 
receiver of twenty years later be so much worse. So, the question 
occurs to me is the spec for the R6C really that bad. I have none 
to test and am not likely to ever get one so I wonder if anyone 
has experience with them and has ever tested the image rejection. 
A bit of a puzzle.
-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL