[GreenKeys] R-808 military receiver with built in TTY converter

[Bruce Gentry]

I have a GRC-14, and can attest to the weight of the power suppy! The 
transmitter uses a phase lock loop frequency control that stabilizes a 
manually tuned VFO. Instead of dividing the VFO sample by N and 
developing the error signal, it uses crystal oscillators that are mixed 
to produce the desired frequency, and then compares it to the VFO and 
makes corrections. This makes it very easy to modulate the VFO for FSK, 
but also is the supposed downfall of the transmitter. The VFO is 
sensitive to vibration, so  FSK can be scrubbled up even though the 
stabilizer circuit is keeping the average right on frequency. One good 
thing about the transmitter is that it covers 10 meters whereas the 
T-195 does not.  There is also a fair amount of empty space inside the 
cabinet, the modules are not of especially compact design, versus the 
T-195 where everything is shaped and fitted very tightly. It's a 
monster, but quite interesting .

      Bruce Gentry, KA2IVY


On 10/8/15 10:25 PM, Scott Johnson wrote:
>
> The GRC-14 possesses what might be the closest thing to t Rube 
> Goldberg electrical contraption if there ever was one:
>
> It uses an extremely LARGE dynamotor to supply the HV for the 
> transmitter, nothing really odd about that, but it will also run from 
> mains power.  To do that, there is a brute force 28VDC supply that 
> turns this magnificent dynamotor.  Hence, the 300#+ power supply.  The 
> GRC-14 seems to be a bit newer, and uses a clever frequency synthesis 
>  system in the transmitter, and the R-808 is a nice receiver, but the 
> mass of the system (with two R-808 receivers), is about twice that of 
> the GRC-19.  It also takes up about 75% more volume.  No wonder there 
> aren’t too many around.
>
> Scott W7SVJ
>
> *From:*greenkeys-bounces at mailman.qth.net 
> [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf Of *WA5CAB at cs.com
> *Sent:* Thursday, October 08, 2015 9:49 AM
> *To:* greenkeys at mailman.qth.net
> *Subject:* Re: [GreenKeys] R-808 military receiver with built in TTY 
> converter
>
> AN/GRC-14 was a USN/USMC competitor to AN/GRC-19 or more correctly to 
> AN/VRC-29 and AN/GRC-46.  Similar generic specs. Differences are that 
> FSK capability was built into the transmitter and receivers. there 
> were two receivers in the sets. and theyt weigh far more.  AFAIK, the 
> only manual done was the 2" thick (in two volumes) NAVSHIPS 92911(A) 
> on the AN/MRC-55 (AN/GRC-14 plus M38A1 with built-in auxiliary 
> generator).
>
> The R-808 receivers are electrically and functionally similar to the 
> R-392 (no HV) except that the FSK converters are built in.  They are a 
> little heavier but not too heavy for one person to move around.  They 
> are reported to work about as well as the R-392 but have analog 
> dials.  The receiver is a hybrid (mix of tubes and transistors).  The 
> first 115 sets (according to the manual - as there are two receivers 
> per radio set it should have been the first 114 or 116???) had audio 
> discriminator type FSK converters.  The balance had IF converters.
>
> Due probably to the weight, very few complete AN/GRC-14 and AFAIK no 
> AN/MRC-55 sets have survived.  But a fair number of receivers have.  
> About a dozen years ago, I extracted all of the R-808 information from 
> the AN/MRC-55 manuals and called the resulting manual NAVSHIPS 
> 92911(A) (R-808).   Reprints available for $30.60 plus shipping.  
> Heavy covers, 196 pages, 14 foldouts, screwpost bound.
>
> Robert Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
> In a message dated 10/08/2015 09:57:31 AM Central Daylight Time, 
> zarco at sonic.net <mailto:zarco at sonic.net> writes:
>
> Picked up one of these recently and have not been able to find out much.
> Has anyone used one? From the same era as the R-392. 2 to 32 MC.
> Google for pics.
> Steve W6SSP
>
>
>
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