Doesn't necessarily work after an earthquake. Roads, bridges, and so on are
"unavailable" after an earthquake. You might not be able to get to a site,
and/or the damage is so extensive, you need equipment that can't get to the
site.
We've had earthquakes with significant horizontal displacement, and the
microwave links have remained functional. Sometimes we've seen minor SNR
dropoff, but not in most cases.
I would make the argument that each can be a backup for the other. If a
link is really important, having multiple paths (microwave AND fiber) is
probably a better argument.
--
bp
part15sbs{at}gmail{dot}com
On Mon, Feb 25, 2019 at 8:31 AM <ch...@wbmfg.com> wrote:
> I know I can throw a temp chunk of fiber on the ground and have things up
> and running in an hour or two.
>
> -----Original Message-----
> From: Robert
> Sent: Monday, February 25, 2019 9:23 AM
> To: af@af.afmug.com
> Subject: Re: [AFMUG] Earthquake Fiber vs Microwave
>
> I would think that depends hugely upon the geography of the fiber run.
> Fault zones in california can shift 9-12 feet in very tight shear in a
> big one. Look at some of the pictures from the last quake in AK and
> you can see 15-18 foot displacements in x y and z. Would be tough to
> have confidence that your fiber would not get sheared in those
> conditions. Might be tough to have a microwave link survive that as
> well but if the tower isn't 100 feet tall and is anchored in bedrock
> might not have as much trouble. I don't know of any towers that went
> down in the Loma Prieta quake, the last large one I experienced. But
> there might be some people on this list that have more data on that.
>
> On 2/25/19 8:10 AM, ch...@wbmfg.com wrote:
> > Trying to make the case that underground fiber will survive an
> earthquake
> > better than mountain top microwave for public safety uses.
> >
> > -----Original Message----- From: Seth Mattinen
> > Sent: Monday, February 25, 2019 9:07 AM
> > To: af@af.afmug.com
> > Subject: Re: [AFMUG] Earthquake Fiber vs Microwave
> >
> > On 2/25/19 7:07 AM, ch...@wbmfg.com wrote:
> >> Anyone have some stories, perhaps from Alaska on earthquake
> survivability
> >> of fiber and microwave?
> >> I have to go to a meeting with some lawmakers later in the week to make
> >> the case that fiber has some slack, fiber can be fixed quickly. Towers
> >> can tilt or tumble. Antennas can get misaligned. And sometimes it is
> >> impossible to get to a snowy peak for a weak during a storm.
> >> Fiber is scalable. Microwave can be jammed and intercepted. Etc etc.
> >> Trying to be truthful and not gaslight anyone.
> >
> >
> > Just make sure your fiber doesn't run in conduit attached to any Cypress
> > Street Viaduct like structures.
> >
>
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