[Milsurplus] Mercury Comms

Sun Sep 10 23:40:56 EDT 2006

Just had this reflector reject the first attempt because the reflector
doesn't accept attachments. OK..the image referred to in the last 
paragraph can be found at the following URL

http://www.moorefelines.com/mercury/comm_interconnect.gif

David I. Emery wrote:

>kOn Sun, Sep 10, 2006 at 04:53:35PM -0400, jjhaggerty01 at excite.com wrote:
>  
>
>> > What communications systems were carried on the flights?
>>(designators, etc., communications training of the "Mercury Seven"?)
>>    
>>
>
>	(snip for brevity
>	
>	It should also be noted that much of the global NASA tracking
>network for Mercury and Gemini was linked together either via primary HF
>circuits or backup HF for undersea cable circuits.   Many of these
>circuits were ISB HF SSB mux transmissions with RTTY on one sideband and
>a voice circuit on the other.   
>
Very common in that era.. The mux would use an AN/UCC-8 multiplexer.. I
was very familiar with the ISB system
spent many a  happy hour kicking and beating the whole shebang back into
operation at NAVCOMMSTA Argentia, NFLD
(NWP) where I was stationed from 1967-1969.  I was 15 at the time of the
Mercury program, and like you, did hear some on the HF band, but being
located near Philly, even at 250MSL, didn't get a whole lot, even with
two circularly polarized antennas on my parent's house roof, and being a
twin, was rather high, maybe 50' at the highest point. I did however,
manage to get some of the copy.. The basic comm scheme of the ISB with
MUX 24 channel tonepack on the USB and voice on LSB was pretty standard
issue in the '60's

> Communications satellite based
>international circuits only came in about the time of the early Apollo
>flights, so much of the tracking network overseas used HF to link back
>to the US and many of these circuits were very strong in the US, so one
>could overhear lots of traffic associated with the flights.   A lot of
>reports of signals "between 4 and 8 mhz" were no doubt reception of
>ground based circuits as part of the tracking network or recovery ship
>communications.
>
>	As for communications training, the original 7 astronauts were
>military pilots and trained in use of communications systems of the era,
>probably including some CW though there was no actual CW gear on board
>the spacecraft AFAIK.
>  
>
The "CW" gear was extremely primitive, and involved a simple pushbutton
on the COMM audio panel which keyed the telemetry sidetone on and off.
As far as I know, this was never actually used on a Mercury flight.  The
official NASA press release of the
"Friendship 7" flight of John Glenn ( 20 FEB 62)  states that under
"Miscellanous Traning" that the astronauts did recieve "Morse Code
Practice" but doesn't state any specific requirement.

>Gemini used only the UHF AM, and I think may have later had some
>higher frequency than UHF telemetry.  No HF.
>
>	The spacecraft used a fixed call sign like "Freedom 7", and the
>various ground stations used call signs like "Cape" or "Tannarive". For
>the Mercury program the primary communicators, at least for the overseas
>ground stations, were located at the ground stations and not remoted
>from Houston as was the case later on.  So the astronauts actually
>talked to various local folks as they made passes over the world wide
>network of ground stations - they weren't talking to one person in
>Houston designated as cap com as they have been ever since.
>
>	And all the spacecraft of that era carried C band (5.9 ghz)
>radar transponders for tracking purposes.
>
>	Apollo introduced S band (2.2 ghz) communications with the UHF
>AM only serving as backup.
>
>	Ground equipment for the Mercury links was a GRC-27 (the ground
>version of the ARC-27).   I am not sure what was used for the HF.  
>Someone might know...
>
>  
>
I can't state for sure what gear was used for the A/G HF links, but I
would surmise that the Landbased
HF links would probably have used AN/FRT-50 Transmitters and either
R-390 Recievers with CV-591/URR SSB converters, or
R-1051 recievers.  Shipboard recievers would have been the same ( for
the Atlantic ship and the Indian Ocean ship) with the exception of the
Transmitters which would have been the AN/URC-32 standard Navy
shipboard unit of the times.

>>Was any HAM activities involved in flights during these two programs 1960's?
>>    
>>
>
>	Not that I remember.
>__
>   Dave Emery N1PRE,  die at dieconsulting.com  DIE Consulting, Weston, Mass 02493
>"An empty zombie mind with a forlorn barely readable weatherbeaten
>'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
>celebration of what could have been, but wasn't and is not to be now either."
>
>  
>
I hope this helps some, For your gratification, I have attached a .gif
of the interconnection of the audio of the Mercury spacecraft.
If this doesn't get thru. I will post same on my website tomorrow..
73 de
Greg "GW" Moore WA3IVX/ NNN0BVN

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