Talk:A Message from Earth

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Attenuation

Given that the strength of transmissions even from powerful defence radars falls below the strength of the inter-stellar background within a light year of leaving the solar system, what strength will the transmission be by the time it reaches Gliese? I can't just use the inverse square rule as it is a focused beam —Preceding unsigned comment added by 81.101.252.188 (talk) 11:24, 24 April 2009 (UTC)[reply]

defense radar is wide-angle, typically 1.5 degrees, compared to a 70m dish, which is probably around 8 arc minutes @1GHz. attenuation of a focused beam depends on the solid angle covered by the transmitter, which is determined by the beam width, which depends on the instrument and the frequency. -- 99.233.186.4 (talk) 17:59, 25 October 2009 (UTC)[reply]

It is focused, but sure not 100% coherent, so it does have attenuation. The question is to know then at waht distance does it fade into background noise, or the background solar spectrum.

Besides that, what was the power of the beam? What was the encoding scheme? What was the modulation scheme? (polarization, Amplitude, Frecuency) which values? How many times was it repeated? Were also decoding instructions sent?

Like it is now, doesn´t seem to be much more than a marketing product, not a wikipedia article.

contradictory reports

the following australian news report appears to contradict information in the article, can the facts please be verified? http://www.theaustralian.news.com.au/story/0,25197,25994209-12377,00.html?FORM=ZZNR5 -- 99.233.186.4 (talk) 17:29, 25 October 2009 (UTC)[reply]

okay, i guess these were two separate events. this message had a bit rate of 4600 bps; and transmitted power of 302 GW, sent by the Canberra Deep Space Communications Complex's DSS-43 70 m dish -- 99.233.186.4 (talk) 18:19, 25 October 2009 (UTC)[reply]
both used a 70m dish; beam width is narrower for higher frequencies; at the low end is ~8 arc minutes[1], which implies the beam will be 3000 AU diameter by the time it gets there. This corresponds to 256 dB attenuation, ignoring scattering and glare. So, it is similar to EME. -- 99.233.186.4 (talk) 13:47, 26 October 2009 (UTC)[reply]

Format of message contents

I wonder what format they put the "message" into? It is quite obvious that if text messages are encoded using ASCII, that it is unlikely to be decipherable by some distant civilization who are not likely to use the same representational scheme as us. If images are encoded as black and white bitmaps, they at least would have some chance of being decodable, but I wonder how they will separate the apparent grouping of content from the one stream of bits, since they are not likely to use the same types of compression as we do on Earth!

Number of Occurrences

Is it worthwhile to have sent one message? What if they miss it? Would it not be better to send the same message, multiple times at frequent intervals for eternity if we wish to give an opportunity to other intelligent beings to receive a communication from us?

Exactly I was thinking the same thing when I read this article. Didn't anyone think about this from the point of view of who we are sending it to? What if the message comes in when people are sleeping, or when whatever detection facility they have is in a bad position relative to the signal, or if they have a solar flare at that moment. What a wasted effort. Suso (talk) 19:38, 5 October 2010 (UTC)[reply]

What were the messages?

Is there a record of all the messages or at least the 500 that were selected? — Preceding unsigned comment added by 220.255.1.84 (talk) 10:25, 31 July 2011 (UTC)[reply]

This Message was described in a book published by Springer "SETI -- Past, Present, Future

See Chapter 21 "METI: Messaging to Extra-Terrestrial Intelligence" [2] METIfan (talk) 19:50, 22 September 2011 (UTC)[reply]

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