Re: Now that's an odd failure mode...
On 1/30/2015 16:23, Larry Sheldon wrote:
On 1/30/2015 16:13, Larry Sheldon wrote:
On 1/30/2015 07:36, Valdis Kletnieks wrote:
Lauren Weinstein shared a pointer to this video of one of the stranger failure modes I've ever seen.....
It is actually an execrable add for something--runs forever, finally followed by a very old video of repairs to a microwave site occasioned by a woodpecker (or woodpeckers--not squirrels, in any case) using the enclosure to store acorns.
I might have still had a valid radio license when I first saw that.
Here is the clip (still maligning squirrels) without the ad:
The questions that have always intrigued me about the clip: Who made the hole and how long did it take (assumption is "woodpeckers made it" but I have no idea how long it took to make the hole).) HOW did they make it--seems like it would have been like making a hole in a bass drum with a finger (lot of bounce, not much cut)? How long did it take to put that many in, and how many worked on the project? Why didn't some alarm or path measurement disclose the deterioration before the cavity was packed so full? Were the acorns cooked? -- The unique Characteristics of System Administrators: The fact that they are infallible; and, The fact that they learn from their mistakes. Quis custodiet ipsos custodes
In this case the cover is a thin, but ridged peice of plastic. It is possible that the link stayed up until it rained and the acorns absorbed water coming in through the hole. On Jan 30, 2015 4:33 PM, "Larry Sheldon" <larrysheldon@cox.net> wrote:
On 1/30/2015 16:23, Larry Sheldon wrote:
On 1/30/2015 16:13, Larry Sheldon wrote:
On 1/30/2015 07:36, Valdis Kletnieks wrote:
Lauren Weinstein shared a pointer to this video of one of the stranger failure modes I've ever seen.....
It is actually an execrable add for something--runs forever, finally followed by a very old video of repairs to a microwave site occasioned by a woodpecker (or woodpeckers--not squirrels, in any case) using the enclosure to store acorns.
I might have still had a valid radio license when I first saw that.
Here is the clip (still maligning squirrels) without the ad:
The questions that have always intrigued me about the clip:
Who made the hole and how long did it take (assumption is "woodpeckers made it" but I have no idea how long it took to make the hole).)
HOW did they make it--seems like it would have been like making a hole in a bass drum with a finger (lot of bounce, not much cut)?
How long did it take to put that many in, and how many worked on the project?
Why didn't some alarm or path measurement disclose the deterioration before the cavity was packed so full?
Were the acorns cooked? -- The unique Characteristics of System Administrators:
The fact that they are infallible; and,
The fact that they learn from their mistakes.
Quis custodiet ipsos custodes
On Fri, Jan 30, 2015 at 10:31 PM, Larry Sheldon <larrysheldon@cox.net> wrote: .....
HOW did they make it....
Maybe the woodpecker had a little help... Obligatory Friday xkcd ref: http://xkcd.com/614/
This one time, at band camp, a guy had pigeons get into his pop and sit on the warm ciscos til they gummed up the fans with coredumps til failure was achieved. But that might just be a Dalph rumour. /kc On Fri, Jan 30, 2015 at 11:12:56PM +0000, Gary Buhrmaster said:
On Fri, Jan 30, 2015 at 10:31 PM, Larry Sheldon <larrysheldon@cox.net> wrote: .....
HOW did they make it....
Maybe the woodpecker had a little help... Obligatory Friday xkcd ref: http://xkcd.com/614/
-- Ken Chase - math@sizone.org Toronto
On 1/30/15 14:31, Larry Sheldon wrote:
The questions that have always intrigued me about the clip:
Who made the hole and how long did it take (assumption is "woodpeckers made it" but I have no idea how long it took to make the hole).)
Most likely the woodpeckers, maybe helped by natural deterioration of the radome material or a defect in manufacture or installation or both.
HOW did they make it--seems like it would have been like making a hole in a bass drum with a finger (lot of bounce, not much cut)?
They pecked it. They can go pretty deeply into trees, and at the edge of the cover there wouldn't be much bounce.
How long did it take to put that many in, and how many worked on the project?
Unknown, but probably a long time, that's a lot of acorns!
Why didn't some alarm or path measurement disclose the deterioration before the cavity was packed so full?
I'm sure it did, over a period of months or years the signal strength would gradually go down as the dish filled up. No immediately obvious cause, this would be a real puzzler. There's typically a pretty good fade margin built in to such links, so it would be a very slowly decreasing RSSI coupled with likely a hockey-stick graph increase in BER as the dish got fuller. Depending on the RF frequency, could get worse with rain as the fade margin decreased. It may have been discovered accidentally if a tech happened to observe a bird while troubleshooting. Filling half the dish would be only a 3dB decrease, but once the acorns started to cover the feedhorn it probably got worse in a relative hurry. I have no idea of the dielectric properties of an acorn, it would probably vary depending on the moisture content and the RF wavelength relative to the size of the acorn. ;-)
Were the acorns cooked?
Probably not. RF output likely a watt or two, spread out over a large area and several tens of thousands of acorns. -- -- Jay Hennigan - CCIE #7880 - Network Engineering - jay@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV
At OARNet, the leading cause of aerial fiber outages was squirrels, followed closely by weather, distantly by angry farmers and once in Akron, random gunfire... At OSU, the leading cause of fiber outages is squirrels, followed distantly by fire. Somewhere I have a great picture of a squirrel gnawing on a fiber that's illuminated with a red visible laser. Don't squirrels go back to their stash? Could a squirrel get through that hole, or were those just a lost stash? On Fri, Jan 30, 2015 at 6:20 PM, Jay Hennigan <jay@west.net> wrote:
On 1/30/15 14:31, Larry Sheldon wrote:
The questions that have always intrigued me about the clip:
Who made the hole and how long did it take (assumption is "woodpeckers made it" but I have no idea how long it took to make the hole).)
Most likely the woodpeckers, maybe helped by natural deterioration of the radome material or a defect in manufacture or installation or both.
HOW did they make it--seems like it would have been like making a hole in a bass drum with a finger (lot of bounce, not much cut)?
They pecked it. They can go pretty deeply into trees, and at the edge of the cover there wouldn't be much bounce.
How long did it take to put that many in, and how many worked on the project?
Unknown, but probably a long time, that's a lot of acorns!
Why didn't some alarm or path measurement disclose the deterioration before the cavity was packed so full?
I'm sure it did, over a period of months or years the signal strength would gradually go down as the dish filled up. No immediately obvious cause, this would be a real puzzler. There's typically a pretty good fade margin built in to such links, so it would be a very slowly decreasing RSSI coupled with likely a hockey-stick graph increase in BER as the dish got fuller. Depending on the RF frequency, could get worse with rain as the fade margin decreased. It may have been discovered accidentally if a tech happened to observe a bird while troubleshooting.
Filling half the dish would be only a 3dB decrease, but once the acorns started to cover the feedhorn it probably got worse in a relative hurry. I have no idea of the dielectric properties of an acorn, it would probably vary depending on the moisture content and the RF wavelength relative to the size of the acorn. ;-)
Were the acorns cooked?
Probably not. RF output likely a watt or two, spread out over a large area and several tens of thousands of acorns.
-- -- Jay Hennigan - CCIE #7880 - Network Engineering - jay@impulse.net Impulse Internet Service - http://www.impulse.net/ Your local telephone and internet company - 805 884-6323 - WB6RDV
Once upon a time, Chris Hartley <hartleyc@gmail.com> said:
At OARNet, the leading cause of aerial fiber outages was squirrels, followed closely by weather, distantly by angry farmers and once in Akron, random gunfire... At OSU, the leading cause of fiber outages is squirrels, followed distantly by fire.
What about the random moron trying to steal copper wire from the pole (and getting glass instead)?
Don't squirrels go back to their stash? Could a squirrel get through that hole, or were those just a lost stash?
Eh, if the number of small oak trees I find sprouting in my flower beds is any indication, the squirrels' brains are smaller than the acorns and they forget where they left them. -- Chris Adams <cma@cmadams.net>
On 1/30/15 9:37 PM, Chris Adams wrote:
Don't squirrels go back to their stash? Could a squirrel get through that hole, or were those just a lost stash?
Eh, if the number of small oak trees I find sprouting in my flower beds is any indication, the squirrels' brains are smaller than the acorns and they forget where they left them.
The oak tree has successfully resisted domestication for the last 20,000 years because it doesn't need us, the thing with the squirrel has worked out pretty well.
participants (8)
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Chris Adams -
Chris Hartley -
Gary Buhrmaster -
Jay Hennigan -
joel jaeggli -
Ken Chase -
Larry Sheldon -
Philip Dorr