Major disaster comms options

[smittie]

The questions I would pose are

1. Who does a person want communications with

In the first hour after the event, first local family and friends.
In hour two through four, remote family and friends.
On day 2+ of the event, remote resources that might be able to provide or coordinate resources, services and information.

2. What do they want to communicate along with what do they expect out of the communications.

In the first hour, status and location.
In the second and third hour, points of possible rendezvous, modes of travel and actual rendezvous, coordinate immediate needs and resources (warmth, shelter, water, food).
Day 2+, situation, status and needs; coordination of logistics and services.

3. How long do they expect the disaster related communications to last

As long as necessary.

 

[smittie]

I'm kind of wondering why we are so focused on EMP, since the idea of the discussion is communications options in a major disaster.

The EMP discussion was comically entertaining for a minute or so.

 

[MUTNAV]

In the first hour after the event, first local family and friends.
In hour two through four, remote family and friends.
On day 2+ of the event, remote resources that might be able to provide or coordinate resources, services and information.



In the first hour, status and location.
In the second and third hour, points of possible rendezvous, modes of travel and actual rendezvous, coordinate immediate needs and resources (warmth, shelter, water, food).
Day 2+, situation, status and needs; coordination of logistics and services.



As long as necessary.

I like it, systematic and mirroring my thoughts on the subject a lot. There still remains the ideas of equipment that is appropriate (which is up to each individual and family of course).

Thanks for the thoughtful reply.

Joel

 

[MUTNAV]

The EMP discussion was comically entertaining for a minute or so.

for more entertainment, here is a collection of slightly more factual things than are usually presented here in casual discussion.

It's actually a library devoted to EMP.

EMP Reports - EMP Library for Protection & Education

Our EMP Shield Library has been created to assist the Department of Homeland Security (DHS) in its #1 Strategic EMP Goal referenced in their OCT 2018 publication which can be found in our EMP library of references.

www.empshield.com

Thanks
Joel

 

[Boombox]

EMP is a fascinating subject because of its nature, and because it could conceivably be used by a rogue nation to bring down the US. Of course, the US would respond in kind. And then be a low status nation for a couple decades.

We are so dependent on our electrical grid that anything that could threaten it nationwide is an important thing to consider, even for hams and radio folks. But EMP is like any other major terror attack. It's a maverick event. One you hope simply won't happen. No one I knew thought 9/11 would happen when we were going about our lives on 9/10.

In my section of the US earthquakes, tsunamis, and volcanoes are a more pressing SHTF emergency concern. Even at that, most people really don't prepare for those happening.

 

[Boombox]

right, so, if the ionosphere is saturated and/or there are millions of tons of dust in the atmosphere, could I still get reception on SW and long dx AM?

I haven't read enough on EMP's effects, short term or long term, on the ionosphere to determine that answer.

But I think Starfish Prime, which was shot off in the lower reaches of the ionosphere, affected the ionosphere for a few hours at least. Dust wouldn't probably affect radio transmissions, or propagation on the HF and MF. But if you're talking nuke war, there wouldn't be much radio to hear.

The 'Futurescience' website you linked earlier probably has info that would help in determining what, if any, long term affects a nuke blast would have on the ionosphere.

 

[Boombox]

^^^^^ And when I mentioned that Starfish Prime "affected the ionosphere", I think that was locally, or in that particular region of the Pacific, definitely not worldwide.

 

[wenzeslaus]

the ionosphere is saturated over North America. you are in North America. would you be able to hear a SW broadcast from overseas? would you be able to hear AM broadcasts at night from hundreds of miles away like you usually do?

 

[MUTNAV]

EMP is a fascinating subject because of its nature, and because it could conceivably be used by a rogue nation to bring down the US. Of course, the US would respond in kind. And then be a low status nation for a couple decades.

We are so dependent on our electrical grid that anything that could threaten it nationwide is an important thing to consider, even for hams and radio folks. But EMP is like any other major terror attack. It's a maverick event. One you hope simply won't happen. No one I knew thought 9/11 would happen when we were going about our lives on 9/10.

In my section of the US earthquakes, tsunamis, and volcanoes are a more pressing SHTF emergency concern. Even at that, most people really don't prepare for those happening.

as far as responding, one of the big fears is that if the launch is from a shipping container off of the California or east coast, and doesn't go high enough to affect more than part of a coast, attribution may be a problem.

Thanks
Joel

 

[rescuecomm]

Isn't there a minimum altitude for a warhead to generate a large EMP? If detonated in the atmosphere, the gamma ray photons are immediately absorbed? So the EMP would be weak?

 

[MUTNAV]

Isn't there a minimum altitude for a warhead to generate a large EMP? If detonated in the atmosphere, the gamma ray photons are immediately absorbed? So the EMP would be weak?

They generate EMP at any altitude, even a surface burst does, although with a surface burst the radius isn't supposed to be much more than the blast, so that isn't a factor.


This is from
"Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack, [Place of publication not identified], 2017"


1. The first, a “prompt” EMP field, also referred to as E1, is created by gamma ray
interaction with stratospheric air molecules. It peaks at tens of kilovolts per meter in a
few nanoseconds, and lasts for a few hundred nanoseconds. E1’s broad-band power
spectrum (frequency content in the 10s to 100s of megahertz) enables it to couple to
electrical and electronic systems in general, regardless of the length of their
penetrating cables and antenna lines. Induced currents range into the 1000s of
amperes. Exposed systems may be upset or permanently damaged.

2. The second component of the EMP field, referred to as E2, is produced by delayed
gamma rays and neutron-induced currents, lasts from microseconds to milliseconds,
and has a magnitude in the hundreds of volts per meter. Its spectral characteristics
are similar to those of naturally occurring lightning.

3. The third component, late-time EMP, also referred to as magnetohydrodynamic (MHD)
EMP or E3, is caused by the distortion of the earth’s magnetic field lines due to the
expanding nuclear fireball and rising of heated and ionized layers of the ionosphere.
The change of the magnetic field at the earth’s surface induces currents of 100s-
1000s of amperes in long conducting lines (a few kilometers or greater) that damage
components of the electric power grid itself as well as connected systems. Long-line
communication systems are also affected, including copper as well as fiber-optic lines
with repeaters. Transoceanic cables are a prime example of the latter.


Also... the height information for radio antenna line of site doesn't work for figuring line of sight for high altitude nuke bursts....

for example, if a theoretical antenna were as high as the moon, the range would be larger than the earths diameter, but since the earth is roughly spherical, the max range is 1/2 of the earths surface.

If you have excel, here is an example of the formula for figuring range vs height....

I don't know if I properly implemented the formula in excel, so if the world ends and you were depending on this, sorry....

The EMP library that I referenced earlier has a lot of very good info, the report on the threat from N. Korea is very interesting, including non-nuclear devices to disrupt air traffic that had damaged automobiles in south korea...




Thanks
Joel

 

[FFPM571]

This whole conversation is going exactly the way I thought it would

 

[MUTNAV]

This whole conversation is going exactly the way I thought it would

Me too... Lots of information being exchanged that is really useful, getting different peoples ideas on how best o prepare, communications wise, for various levels of contingencies. It went great

Thanks for starting it Krokus. Maybe Communications in SHTF and ITEOTWAWKI should be a forum !!

Thanks
Joel

 

[wenzeslaus]

where it said EMP peaks at tens of kV/m, that info is obsolete. modern (classified) nukes are rumored to be 100-200 kV/m and same for Russia, China, NK and maybe Iran too. it's not hard to do. just use less shielding and you get less bang, more gamma, therefore more EMP. so any of the results of testing (damage) you look at are obsolete. newer ones are up to 4x more powerful.

it's ironic that the govt does a study to save our asses from a threat, using obsolete data to defend against it, when the current capabilities that require stronger defense are known but not used because they're classified.

 

[FFPM571]

Me too... Lots of information being exchanged that is really useful, getting different peoples ideas on how best o prepare, communications wise, for various levels of contingencies. It went great

Thanks for starting it Krokus. Maybe Communications in SHTF and ITEOTWAWKI should be a forum !!

Thanks
Joel

It is actually laughable ..

 

[MUTNAV]

where it said EMP peaks at tens of kV/m, that info is obsolete. modern (classified) nukes are rumored to be 100-200 kV/m and same for Russia, China, NK and maybe Iran too. it's not hard to do. just use less shielding and you get less bang, more gamma, therefore more EMP. so any of the results of testing (damage) you look at are obsolete. newer ones are up to 4x more powerful.

it's ironic that the govt does a study to save our asses from a threat, using obsolete data to defend against it, when the current capabilities that require stronger defense are known but not used because they're classified.

Your correct...

Although I agree infrastructure should be protected to the current threat level, it's WAY above my pay-grade.


The Korean threat report references up to 100Kv, it's from 2021 (the new one), so it's plausible for higher ones also (page 1 from the report, on "key judgements"), I especially liked how they pointed out that some test "failures" were actually successful, and pointed out various delivery modes.

Thanks
Joel

 

[wenzeslaus]

vacuum tubes are resistant to EMP but I heard other components in the radio aren't. the transformer? I forgot. yall would know more about what else might get damaged and I don't have a tube radio.

 

[MUTNAV]

I would just want someone to do tests of these things.
i can tell there are a lot of barriers to testing (like neighbors that want there stuff to work) so it would have to be professionals.


In reality, there is more to disaster comms than EMP,

I think comms. during a disaster was covered nicely, the small, inexpensive satellite things seem great, GMRS and CB seem like good possibilities for very local communications if you can get family / friends to have them. MW radios along with networking friends/family/neighbors and a family communications plan could make a huge difference during a disaster.

Flexibility and whats between the ears may be the most important though, In QATAR I had to help (I'm not radio) solder a connector onto an NVIS antenna, the other guy (responsable for it) had no idea, literally the night of Khobar towers being bombed (they were our "distant end"). HF NVIS wasn't terribly useful , but would have been useful if things went more south.

Thanks
Joel

 

[Boombox]

the ionosphere is saturated over North America. you are in North America. would you be able to hear a SW broadcast from overseas? would you be able to hear AM broadcasts at night from hundreds of miles away like you usually do?

When you hear a SW station from across the ocean, the section of the ionosphere that reflects/refracts those signals might be hundreds, if not more than a thousand miles away from you, and those sections of the ionosphere might not be affected by the EMP.

My guess is that you would be able to hear SW and MW stations from hundreds of miles away after an EMP attack, in theory, at least -- but this depends on the condition of the electrical grid in the regions where the stations are. Most stations in the US, after a major EMP attack, would be off the air, as there would be no power.

FEMA has some 'hardened' AM stations in each state apparently, with diesel generators, and you may hear them. That, of course, also depends on personnel.

But really, no one can say what would be heard after a major EMP attack, because it hasn't happened before. Not on the scale we're talking about. So all that anyone here can do is guess. And, of course, if there were a major EMP attack your radios might not operate.

Cyber (and other) attacks to the electrical grid are probably much more likely than EMP. That's just my guess.

 

[Boombox]

It is actually laughable ..

Not really. It's just information. People can do what they want with it.

I remember in the 1970s a terror attack that was the magnitude of 9/11 was considered laughable by a lot of folks. I remember books that came out, fiction books that had similar level terror attacks and those books were considered to be so way out there that no one would consider the possibility of the financial center of the US's largest city being hollowed out.

It was considered to be in the realm of conspiracy/wacko/paranoia territory. But 9/11 happened.

I'm not saying EMP is going to happen. Hopefully, it never does. I think the fact that the US would respond in kind to any country that carried out such an attack keeps us safe from that sort of thing ever happening. But disasters do happen from time to time. When the 9 pointer hits the NW US, it will be similar locally to what EMP discussed here would be nationally.