Re: [ldm-users] Those with direct satellite feeds of NOAAport...

On Wed, 14 May 2008, Mike Schmidt wrote:

Hi Mike,

This is the post I was looking for...


For what it's worth, we hardly ever have a day free of Gap messages.
On the day you cited, May 11th for example, we have six Gaps;

May 11 11:01:58 burns dvbs_multicast[2328] ERROR: Gap in SBN last 5921901, this
May 11 12:10:48 burns dvbs_multicast[2327] ERROR: Gap in SBN last 19263061,
this 19263064
May 11 12:16:58 burns dvbs_multicast[2327] ERROR: Gap in SBN last 19278632,
this 19278634
May 11 14:56:20 burns dvbs_multicast[2330] ERROR: Gap in SBN last 5000158, this
May 11 20:13:33 burns dvbs_multicast[2330] ERROR: Gap in SBN last 5263333, this
May 11 22:56:57 burns dvbs_multicast[2327] ERROR: Gap in SBN last 21252753,
this 21252755

We feed directly from a 3.8m heated NWS installed and maintained
NOAAport dish installed for COMET.  Other than local terrestrial
interference, a truck driving in front of the dish (it's possible
with the installation here), or a solar eclipse, the data reception
should be about is good as it gets.

OK.  I had 40 that day, but we also had 45 MPH winds and heavy rain.
That certainly didn't help. I know that our struts vibrate in high wind slightly, and I suspect that might be a problem (we are ordering heavy-duty struts to replace the ones we have there now). But
outside of that...

We have found that the Gap messages we see are usually consistent
system-wide.  In other words, the majority of the Gaps we see here in
Boulder are the same ones that SSEC and LSU see.  Check your data for
May 11th and see if you have the above six Gaps in your logs.

Yes, I do.

Otherwise, you may have additional issues to find and resolve which
can include anything from temperature and moisture sensitivities in
the LNB and cabling, all the way down to overflowing buffers, too
many interrupts or a bad driver for the ethernet interface.

Here's a week's worth of our recent Gap history;

May 07          25
May 08          28
May 09          35
May 10          9
May 11          6
May 12          95
May 13          23

Hope that helps.


That's better! That's what I am typically seeing, or very close to it. With a 12' dish, a Norsat 3120 LNB and a Novra box, I should be smokin',
especially with a variable bit error rate one level better than standard.
I will try one more thing: my Novra box is 5" away from the computer; I'll try moving it off the computer stand and see if that helps any. I'm using quad-shielded RG-6, but you know how much computers spew RF... :-) Looks like I'm trying to make a problem where none exists. Thank you for the verification.

Gilbert Sebenste                                                     ********
(My opinions only!)                                                  ******
Staff Meteorologist, Northern Illinois University                      ****
E-mail: sebenste@xxxxxxxxxxxxxxxxxxxxx                                  ***
web:                                      **

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