Journal of Ann Devereaux

Date: Thurs, Jan 16 1997
From: Ann Devereaux, Palmer Station

(Ann is on the NASA ACTS Satellite team)

Ann Deveraux's second Journal told of lugging all the satellite TV gear up the hill to T5. On Jan 16, it was time to put it to its first semi-public test!


After days now of long hours of preparation and test, today is the day of the first dress rehearsal. Oh, it is not going to be nationwide or anything; in fact, only a handful of people will see it back in the States. Our first live television audience will consist only of the production and technical crews at Mississippi State University (MSU) and one school classroom in Mississippi. On the other hand, it is our FIRST LIVE AUDIENCE and we are not ready!

The last few days of satellite testing have been inconclusive. We sometimes see perfect picture, but it never lasts as long as we'd like. What to do? If you were to see an error in a live-via-satellite TV broadcast, whether it be a miscolored block in the picture, a momentary blank picture, or distorted sound, it can be caused by any number out of an innumerable list of things that can go wrong. The electronic signal multiplexer here at Palmer, which combines the live video and multiple telephone signals into one data stream, might not be communicating correctly with its counterpart at JPL, which takes apart these individual channels and allows them to be sent to different destinations at the MSU TV Center. There are satellite modems to do the actual communications across the satellite link (much like two computer modems talking across a network). These modems might not be composing or decoding the data correctly for transmit and receive. Connected to the modems on both sides of the link are radio frequency converter boxes, which change the modem's 70 MHz signal (close the 88 MHz on the bottom of your FM radio dial) to the final 19 or 29 GHz which is sent to or received by the satellite. These converters have sensitive electronics inside, which can suffer frequency drifts or add in too much noise. In addition, the satellite antenna itself may be mispointed, may vibrate in the wind, may suffer reflections off of the surrounding ice fields, et cetera. Trouble is, by the time you see errors on the TV screen, it is difficult to tell where in the line of equipment the original problem occurred. The trick is to narrow down where the problem is actually located, before even you figure out how to solve it.

Elephant seals on Humble Island, Adelie penguins in rear.

Comes the time of the test broadcast, though, and we have to force ourselves (and especially our boss!) to stop fiddling with things and just cross our fingers. At the same time the satellite link debugging is going on, there is a mad rush of activity around the building as people are connecting camera and video playback hookups, setting up phone lines, and trying to establish communications with Humble Island, where the remote live video is originating. We have a rough outline of the show, but no one is quite sure what we are really supposed to be doing and when. After hurriedly reading the outline minutes before the show, it turns out that they will be filming a few segments at our building, T5! Horrified, we race around to put together the equipment set up, to the point of shoving a pair of headphones out the door to our local host, a National Science Foundation representative here on station, in full view of the camera. This sort of last-minute catch is very valuable, however, because this is the way we learn what needs to be done AHEAD of time for the real broadcasts.

Our satellite link sends back video and audio from Antarctica to MSU, where it will be interspersed on-the-fly with live views of the MSU host scientist and a Mississippi schoolroom to create the overall program.

As this is being put together and broadcast, MSU sends a feed of the program back over the satellite link here to Antarctica, so we can monitor not only the local filming going on here but also the finished product as it is shown in the States. After the preceding hours of craziness, things are surprisingly quiet as everyone gathers around the monitor to see how it turns out. As we knew would happen, there are errors in the program video that we see and sometimes the picture even blacks out entirely; every time this happens Dan and I cringe, because we know it is our satellite link which is still flakey. I imagine I can feel accusing eyes boring into my back. Just a test, sure, but we wanted to be perfect, anyway.

Conclusion? The test broadcast is a big success. Though it was stressful to go through it, it was also very exciting, maybe even addicting!

-- Dear Mom, I might be getting the TV bug. Please send more warm clothes and forward my magazines here to Antarctica.--

Love, Annie

					Ann Devereaux

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