[Boatanchors] RCA Marine Receivers

Sat May 28 23:10:34 EDT 2022

     If I wrote AR 8511 is was a mistype. It is an AR-8516.
     I have been going over the handbooks for both this and the 
CRM-R6A. There are some significant differences but the specs of 
both are the same. The AR 8516 states it has two IF frequencies 
455 and 45, used for different filters. The lower bands are 
single conversion using the 455Khz IF but the higher bands are 
double or triple conversion using a tunable IF which has two 
bands from 1Mhz to 4 mhz. The CRM R6A states it has two fixed 
IF's at 825Khz and 455 Khz and the same arrangement for the 
higher bands using a two band tunable IF. I find the circuit 
descriptions a bit confusing and am studying them over. The 45Khz 
IF is evidently a narrow band LC filter for CW. Both receivers 
have a 3Khz mechanical filter and I think there is a 400Hz 
accessory mechanical filter for the R6A.  Again, both instruction 
books are on BAMA.
    Both receivers were designed as general purpose 
communications receivers but the AR-8516 was intended mainly for 
shipboard installation with a DC mains supply.
    I don't think I've ever seen either in the flesh.
    I was curious about the comparison of these receivers with 
the MacKay and Marconi equivalents.

On 5/28/2022 8:49 AM, Al Klase wrote:
> Gang,
> 
> I don't know if this reflector supports pix and attachments. 
> AR-8511 manual attached.
> If not, I can show the moderator how to fix that.
> 
> Regards,
> Al
> ARK Sig Block Al Klase - N3FRQ
> Jersey City, NJ
> http://www.skywaves.ar88.net/
> On 5/28/2022 11:30 AM, Al Klase wrote:
>> Richard,
>>
>> I do have a Radiomarine AR-8511 that was designed primarily for 
>> crew entertainment.  Runs on 115 VCD, and has six 35L6 tubes in 
>> push-pull-parallel to get the required audio output for 
>> multiple speakers from low B+.
>> Read about it on page 22 here: 
>> https://worldradiohistory.com/Archive-Radio-Age/Radio-Age-1945-July.pdf 
>>
>>
>> Al
>>
>> ARK Sig Block Al Klase - N3FRQ
>> Jersey City, NJ
>> http://www.skywaves.ar88.net/
>> On 5/28/2022 1:37 AM, Richard Knoppow wrote:
>>> 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.
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL