A little question.

Message boards : Number crunching : A little question.
Message board moderation

To post messages, you must log in.

AuthorMessage
bluestar

Send message
Joined: 5 Sep 12
Posts: 7031
Credit: 2,084,789
RAC: 3
Message 1581682 - Posted: 4 Oct 2014, 1:29:12 UTC
Last modified: 4 Oct 2014, 1:34:31 UTC

A question for you after watching a YouTube video here.

Seti@home is designed to be listening to different radio frequencies.

But in certain instances the term "channel" is being used.

Really, I should know right now, but in fact I do not.

Can someone please expain the difference or similarity between a channel and a certain frequency range. A single channel is only a small portion of the whole frequency area being listened to at around 1420 MHz (or 1.42 GHz).

https://www.youtube.com/watch?v=AW1aC-fVRwk

At about 43:26 and following in this video.

BTW: By coincidence only. In fact UFO videos was on my playlist yesterday evening.

Thanks!
ID: 1581682 · Report as offensive
Josef W. Segur
Volunteer developer
Volunteer tester

Send message
Joined: 30 Oct 99
Posts: 4504
Credit: 1,414,761
RAC: 0
United States
Message 1581686 - Posted: 4 Oct 2014, 2:06:13 UTC - in response to Message 1581682.  
Last modified: 4 Oct 2014, 2:06:41 UTC

It's an unrelated use of the "channel" term. The ALFA receiver system at Arecibo has seven feedhorns, each of those has two detectors at right angles, so there are 14 information streams. A splitter deals with the data recorded from one of those streams, and when the Server status page was coded, they decided to call them channels.

For AP tasks, the channel shows in the task name in the form Bx_Px indicating which of the seven feedhorn beams (0 thru 6) and which of the two polarities was the source. For MB tasks, the information is also in the name and is supposed to be a numerical value from 3 to 16, but since they switched to 64 bit builds a bogus additional value from the upper 32 bits has often been added. For WU 16fe08ac.4705.15205.438086664199.12.45 the 438086664199 is the field of interest. The current bogus added value is hex 6600000000 or decimal 438086664192, so that actually should be a 7. A quicker conversion is to just subtract 192 from the last 3 digits.

LoL, I suppose that's more than you wanted to know. ;-)
                                                                  Joe
ID: 1581686 · Report as offensive

Message boards : Number crunching : A little question.


 
©2024 University of California
 
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.