I worked Apollo comms from late 67 until 71 in Hawaii and on Eniwetok Atoll. As I recall prior to Apollo there were astronauts deployed to all the ground stations who were sort of local CAPCOMs. They talked back to the Cape and later Houston by land line, some by 4 wire land line. If there was any HF involved it would have been to places like the Seychelles via commercial links or to the tracking ships.
It was with the advent of the ARIA aircraft that we started using HF between them and shore stations, and using them, shore stations and ships to connect the astronauts back to the single Houston CAPCOM. The ARIA filled in the over-the-ocean gaps between the shore stations. We built an elaborate system of multiple HF links to assure good comm through as many as 8 aircraft during the first few orbits and at recovery. One of the innovations we worked out was cross patching the AGC from a tone in one sideband of an HF receiver to the other channel to suppress the white noise when no one was talking. That let us do very effective double HF hops, plus S band. For example from Hawaii to Eniwetok on HF, Eniwetok to the ARIA on HF, S band via the dish in the nose of the ARIA to the Apollo capsule - with no more white noise than a phone line. There are some very good web sites about how all that worked. One is
http://honeysucklecreek.net/other_stations/ARIA/index.html There are also some great stories on flyaria.com
The most challenging part of the HF piece of this was that the launches almost all occurred as dawn was happening over the Pacific, and that was where they fired the engine to leave earth orbit (TLI) so we had to have ARIA comms to them for those first orbits. Imagine the challenge of establishing full duplex quite HF comms with 4 aircraft taking off before dawn from a couple of Pacific islands, then leap frogging frequencies up the bands until the Apollo capsule came over a couple of times in late morning. This was pretty much the height of the cycle so we might go from 5 MHz to 22 MHz freqs in a couple of hours with perhaps 5 or 6 frequency changes. It was actually much more complicated than I'm describing here with 5 ground stations around the Pacific and as many as 30 HF frequencies in use at once. All wonderful fun for us hams in the program, building these complex HF networks in changing conditions under great pressure not to mess up. And great fun using 10KW to 40KW transmitters and huge fields of Rhombics, giant rotatable log periodics, vertical logs, 400' tall discones and pretty much every other HF antenna you can think of.
Jim
On 1/9/2017 1:24 PM, Robert Bruninga wrote:
After seeing the great movie “hidden figures” last night, I had lots of questions from my faded memory of the time (it was the same year I got my ham license and was 14 years old). This Wiki page has a lot… but the questions lingering in my mind were:
https://en.wikipedia.org/wiki/Project_Mercury
Was his mission planned at 3 orbits? (I thought it was more andthen cut to three).
If #1, then they must have had to have recovery ships at adifferent spot for every potential orbit since he could not maneuver anything other than when to fire the retros. If it was 7 cut to three, then I guess they only needed two ship areas…
What frequency was CAPCOM? Was it the 108 MHz? I think thetracking stations all relayed the voice via HF?
Also related to #1, if something happened to the pilot, I assumeground control could fire the retros. _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb