Date   

Re: GMRS and FRS Channels

Lou Giliberto (KD7HCW)
 

My understanding meshes with Bob's except one point:

"Baofeng class radios"

GMRS radios still need to be type accepted, and AFAIK Baofengs don't meet type 95.

Here's the legal nonsense:

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-95/subpart-E

Sent with ProtonMail Secure Email.

------- Original Message -------
On Monday, February 28th, 2022 at 2:36 PM, Bob (KI7RMO) <rmot47@...> wrote:

My simplistic understanding is the following.

  1. If you buy a radio that is designed for the FRS/GMRS 22 channels, are limited to 2W on channels 1-7 and 16-22 and 0.5W on channels 8-15, and have a fixed antenna, you don’t need a license. I believe the FCC made this ruling in 2017. These radios are your standard Motorola, Midland, Uniden, etc. walkie-talkies.
  2. If you buy a radio that has higher power on any of those channels, or if the antenna is changeable, you need the GMRS license and a call sign. That cost $70 when I bought one some time ago. These are the Baofeng class radios and/or GRMS radios that can be programmed to transmit on frequencies outside the amateur radio bands and at higher power than 2W.
  3. We are all aware of the rules for amateur radio, so nothing on that.

Bottom line, I bought a pair of Motorola walkie-talkies and I use those whenever I don’t use a call sign. If I use a Baofeng, I use a call sign which is on a post-it note in my wallet (I rarely do this).

Hope this helps and is reasonably correct.

Bob

From: snovarc@snovarc.groups.io <snovarc@snovarc.groups.io> On Behalf Of Rowland
Sent: Monday, February 28, 2022 12:37 PM
To: snovarc@snovarc.groups.io
Subject: [SnoVARC] GMRS and FRS Channels

Can someone explain to me what the new FCC guidelines/rules are as they apply to FRS/GMRS radios and channels. From what I understood in the past there were certain channels that were assigned to FRS and others assigned to GMRS (license required). Reading on google now it looks like all the 22 channels are approved for both FRS and GMRS but with power limitations accordingly. Some clarification on this would be nice.

Thanks,

Rowland



Re: GMRS and FRS Channels

Bob (KI7RMO)
 

My simplistic understanding is the following.

  1. If you buy a radio that is designed for the FRS/GMRS 22 channels, are limited to 2W on channels 1-7 and 16-22 and 0.5W on channels 8-15, and have a fixed antenna, you don’t need a license.  I believe the FCC made this ruling in 2017.  These radios are your standard Motorola, Midland, Uniden, etc. walkie-talkies.
  2. If you buy a radio that has higher power on any of those channels, or if the antenna is changeable, you need the GMRS license and a call sign.  That cost $70 when I bought one some time ago.  These are the Baofeng class radios and/or GRMS radios that can be programmed to transmit on frequencies outside the amateur radio bands and at higher power than 2W.
  3. We are all aware of the rules for amateur radio, so nothing on that.

 

Bottom line, I bought a pair of Motorola walkie-talkies and I use those whenever I don’t use a call sign.  If I use a Baofeng, I use a call sign which is on a post-it note in my wallet (I rarely do this).

 

Hope this helps and is reasonably correct.

 

Bob

 

From: snovarc@snovarc.groups.io <snovarc@snovarc.groups.io> On Behalf Of Rowland
Sent: Monday, February 28, 2022 12:37 PM
To: snovarc@snovarc.groups.io
Subject: [SnoVARC] GMRS and FRS Channels

 

Can someone explain to me what the new FCC guidelines/rules are as they apply to FRS/GMRS radios and channels.  From what I understood in the past there were certain channels that were assigned to FRS and others assigned to GMRS (license required). Reading on google now it looks like all the  22 channels are approved for both FRS and GMRS but with power limitations accordingly. Some clarification on this would be nice.

 

 

Thanks,

 

Rowland

 


GMRS and FRS Channels

Rowland
 

Can someone explain to me what the new FCC guidelines/rules are as they apply to FRS/GMRS radios and channels.  From what I understood in the past there were certain channels that were assigned to FRS and others assigned to GMRS (license required). Reading on google now it looks like all the  22 channels are approved for both FRS and GMRS but with power limitations accordingly. Some clarification on this would be nice.


Thanks,

Rowland


Re: DX Contact

 

Cool, too bad I'm at work.
Yesterday got new station in Chile 100 in the afternoon. 

Ken W7ECK 

On Feb 28, 2022, at 12:20 PM, Ralph Lease <ralph.lease@...> wrote:


Just made a 59 contact in Spain with EA3JE at 14.242.000 Mhz USB with 100 watts at 20:10 UTC. Signal is holding up well from Spain.

Cheers,
Ralph
KC7QXD


DX Contact

Ralph Lease
 

Just made a 59 contact in Spain with EA3JE at 14.242.000 Mhz USB with 100 watts at 20:10 UTC. Signal is holding up well from Spain.

Cheers,
Ralph
KC7QXD


Re: Farraday cage time for equipment?

Rowland
 

This is the same film they showed us when I was training to work on Minuteman Missiles in 1970.

I find it interesting they were allowed to enter the blast area within 24 hours.  Would be interesting how many workers suffered from radiation poisoning later on in life.


Thanks,

Rowland



On Sat, Feb 26, 2022 at 7:54 PM Ken Kosters <kenkosters@...> wrote:

Ugh, help if I added the link.

 

https://www.youtube.com/watch?v=thPfjOt5WEo

 

Ken

 

 

 

From: snovarc@snovarc.groups.io [mailto:snovarc@snovarc.groups.io] On Behalf Of Ken Kosters via groups.io
Sent: Saturday, February 26, 2022 7:51 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Farraday cage time for equipment?

 

I find it interesting in this old video that the radio, gas and grid equipment managed to survive. Perhaps some real testing is needed on the effects of EMP on de-energized equipment would be of use.

 

Ken W7ECK

 

From: snovarc@snovarc.groups.io [mailto:snovarc@snovarc.groups.io] On Behalf Of Jackson Beard
Sent: Friday, February 25, 2022 7:33 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Farraday cage time for equipment?

 

Regarding a microwave - it's a Faraday cage on 5 sides and a Faraday shield on the magnetron side.

 

On Fri, Feb 25, 2022, 19:20 Jackson Beard via groups.io <macleanofduart=gmail.com@groups.io> wrote:

At USAF critical defense installations we literally used mesh cages. Think about how electrical or radio energy moves in a conductor.

 

A solid cage is only more effective against a broader frequency range.

 

On Fri, Feb 25, 2022, 18:56 Paul Zoba <pezoba@...> wrote:

I’m thinking Yaesu 857 in an ammo box and put that in a gun safe. That should work as long as I can open the safe in the event of an EMP.


On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:



A Faraday cage does not need to be an absolute enclosure.

 

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:

What about the gap thru which the magnetron injects microwave radiation into the cavity? 

 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

 

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:



Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.

 

 

Thanks,

 

Rowland

 

 

 

On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:

Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

 

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

 

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)

 

 

Sent with ProtonMail Secure Email.

 

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:

Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 

 


Re: Farraday cage time for equipment?

 

Ugh, help if I added the link.

 

https://www.youtube.com/watch?v=thPfjOt5WEo

 

Ken

 

 

 

From: snovarc@snovarc.groups.io [mailto:snovarc@snovarc.groups.io] On Behalf Of Ken Kosters via groups.io
Sent: Saturday, February 26, 2022 7:51 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Farraday cage time for equipment?

 

I find it interesting in this old video that the radio, gas and grid equipment managed to survive. Perhaps some real testing is needed on the effects of EMP on de-energized equipment would be of use.

 

Ken W7ECK

 

From: snovarc@snovarc.groups.io [mailto:snovarc@snovarc.groups.io] On Behalf Of Jackson Beard
Sent: Friday, February 25, 2022 7:33 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Farraday cage time for equipment?

 

Regarding a microwave - it's a Faraday cage on 5 sides and a Faraday shield on the magnetron side.

 

On Fri, Feb 25, 2022, 19:20 Jackson Beard via groups.io <macleanofduart=gmail.com@groups.io> wrote:

At USAF critical defense installations we literally used mesh cages. Think about how electrical or radio energy moves in a conductor.

 

A solid cage is only more effective against a broader frequency range.

 

On Fri, Feb 25, 2022, 18:56 Paul Zoba <pezoba@...> wrote:

I’m thinking Yaesu 857 in an ammo box and put that in a gun safe. That should work as long as I can open the safe in the event of an EMP.


On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:



A Faraday cage does not need to be an absolute enclosure.

 

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:

What about the gap thru which the magnetron injects microwave radiation into the cavity? 

 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

 

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:



Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.

 

 

Thanks,

 

Rowland

 

 

 

On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:

Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

 

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

 

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)

 

 

Sent with ProtonMail Secure Email.

 

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:

Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 

 


Re: Farraday cage time for equipment?

 

I find it interesting in this old video that the radio, gas and grid equipment managed to survive. Perhaps some real testing is needed on the effects of EMP on de-energized equipment would be of use.

 

Ken W7ECK

 

From: snovarc@snovarc.groups.io [mailto:snovarc@snovarc.groups.io] On Behalf Of Jackson Beard
Sent: Friday, February 25, 2022 7:33 PM
To: snovarc@snovarc.groups.io
Subject: Re: [SnoVARC] Farraday cage time for equipment?

 

Regarding a microwave - it's a Faraday cage on 5 sides and a Faraday shield on the magnetron side.

 

On Fri, Feb 25, 2022, 19:20 Jackson Beard via groups.io <macleanofduart=gmail.com@groups.io> wrote:

At USAF critical defense installations we literally used mesh cages. Think about how electrical or radio energy moves in a conductor.

 

A solid cage is only more effective against a broader frequency range.

 

On Fri, Feb 25, 2022, 18:56 Paul Zoba <pezoba@...> wrote:

I’m thinking Yaesu 857 in an ammo box and put that in a gun safe. That should work as long as I can open the safe in the event of an EMP.


On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:



A Faraday cage does not need to be an absolute enclosure.

 

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:

What about the gap thru which the magnetron injects microwave radiation into the cavity? 

 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p



On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:



Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.

 

 

Thanks,

 

Rowland

 

 

 

On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:

Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

 

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

 

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)

 

 

Sent with ProtonMail Secure Email.

 

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:

Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 

 


Re: KBARA Link issues

 

Hi all,

Just an update as the hum from KBARA has been corrected so wanted to know what was found if this issue happens to the club node.

It seems after 7 or so years the 3 amp 5v power supply that was upgraded larger for the nodes failed and was causing the hum.

One for the notes for this type of problem.

Ken W7ECK


Re: Farraday cage time for equipment?

Jackson Beard
 

Regarding a microwave - it's a Faraday cage on 5 sides and a Faraday shield on the magnetron side.


On Fri, Feb 25, 2022, 19:20 Jackson Beard via groups.io <macleanofduart=gmail.com@groups.io> wrote:
At USAF critical defense installations we literally used mesh cages. Think about how electrical or radio energy moves in a conductor.

A solid cage is only more effective against a broader frequency range.

On Fri, Feb 25, 2022, 18:56 Paul Zoba <pezoba@...> wrote:
I’m thinking Yaesu 857 in an ammo box and put that in a gun safe. That should work as long as I can open the safe in the event of an EMP.


On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:


A Faraday cage does not need to be an absolute enclosure.

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:
What about the gap thru which the magnetron injects microwave radiation into the cavity? 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:


Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:
Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Jackson Beard
 

At USAF critical defense installations we literally used mesh cages. Think about how electrical or radio energy moves in a conductor.

A solid cage is only more effective against a broader frequency range.

On Fri, Feb 25, 2022, 18:56 Paul Zoba <pezoba@...> wrote:
I’m thinking Yaesu 857 in an ammo box and put that in a gun safe. That should work as long as I can open the safe in the event of an EMP.


On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:


A Faraday cage does not need to be an absolute enclosure.

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:
What about the gap thru which the magnetron injects microwave radiation into the cavity? 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:


Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:
Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Paul Butzi (W7PFB)
 

Yes, a faraday cage need not be an absolute enclosure.

But an aperture wide enough to admit microwaves will admit, well, microwaves and anything with shorter wavelength.

And a wire running from outside the cage thru the wall into the cage will pretty much just be an antenna outside connected to an antenna inside.

-p W7PFB
73, Don’t forget to smile and have fun!

On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:

A Faraday cage does not need to be an absolute enclosure.

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:
What about the gap thru which the magnetron injects microwave radiation into the cavity? 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:


Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:
Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 







Re: Farraday cage time for equipment?

Paul Zoba, W7PEZ
 

I’m thinking Yaesu 857 in an ammo box and put that in a gun safe. That should work as long as I can open the safe in the event of an EMP.


On Feb 25, 2022, at 6:49 PM, Jackson Beard <macleanofduart@...> wrote:


A Faraday cage does not need to be an absolute enclosure.

On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:
What about the gap thru which the magnetron injects microwave radiation into the cavity? 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:


Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:
Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Jackson Beard
 

A Faraday cage does not need to be an absolute enclosure.


On Fri, Feb 25, 2022, 18:38 Paul Butzi (W7PFB) via groups.io <w7pfb=butzi.net@groups.io> wrote:
What about the gap thru which the magnetron injects microwave radiation into the cavity? 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:


Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:
Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Paul Butzi (W7PFB)
 

What about the gap thru which the magnetron injects microwave radiation into the cavity? 

Either the magnetron is outside the shielded cage and there’s a window it injects thru, or the magnetron is inside the cage and there’s a power feed thru the wall of the cage. Either one defeats the cage in the event of an EMP. 

-p

On Feb 25, 2022, at 6:05 PM, Rowland <rowland.brasch@...> wrote:


Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:
Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Rowland
 

Read an article several years ago about using a non working microwave as it is completely shielded so microwaves cannot leak out during use. So the RF cage will shield equipment inside from bad things on the outside.


Thanks,

Rowland



On Fri, Feb 25, 2022 at 1:20 PM Lou Giliberto (KD7HCW) via groups.io <louis.giliberto=protonmail.com@groups.io> wrote:

Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Lou Giliberto (KD7HCW)
 

Here's the nerd answer:  https://physics.stackexchange.com/questions/230728/would-a-faraday-cage-protect-something-from-an-emp

Having used them for telcoms stuff, you really do need to make sure they are "completely sealed".  Any kind of wire running out from them (e.g., power) will cause signal and such to leak in.  

They also make "faraday bags" which are what they sound like - a bag you put an object into and it provides some measure of protection.  We used that and a metal garbage can with a ground strap when we wanted to test loss of signal stuff for telecoms.  Cell phone signals are designed to be very aggressive so that our phones work.  If the EMP burst is purposeful, it, too, will be aggressive. There are also "faraday tents" but they often leak like a sieve.

Step one is the EMP burst on the equipment.  Step two will be the EMP burst effects on your power source (e.g., the grid, generators, batteries) and anything along the antenna path that is susceptible (e.g., rotor, loop amplifier, etc.).

+1 for tube amps which are more resistant to the effects.  Sometimes the old ways are the best ways. I should build a spark gap transmitter ;-)


Sent with ProtonMail Secure Email.

------- Original Message -------
On Friday, February 25th, 2022 at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Paul Butzi (W7PFB)
 

For small items that won’t be used often (backup HT’s for instance) a good solution is to put them in a metal ammo can and then cover the gap between the lid and the container parts with aluminum tape.

you want space between the conductive container and the equipment, so line the ammo can with some sort of nonconductive padding.

Some people feel that enclosing the gear in an anti-static bag will do.  I suspect the conductivity of the plastic material is not high enough.  And again, you need some padding to keep the enclosing bag a small distance away from the protected gear.  But I am by no means an expert.

A metal footlocker would do nicely if you close the gap between lid and body with conductive tape.

You could always wrap the gear in some sort of non-conductive padding and then wrap that with several layers of aluminum foil.  That’s probably not ideal but…

It is probably ALWAYS faraday cage time.  We don’t get much warning with respect to either solar flares or EMP attacks.

-p W7PFB
73, Don’t forget to smile and have fun!

On Feb 25, 2022, at 7:12 AM, Robin WA7CPA <wa7cpa@...> wrote:

Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Aaron K
 


On Fri, Feb 25, 2022 at 7:12 AM Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 


Re: Farraday cage time for equipment?

Jackson Beard
 

It's very easy to accomplish,  providing you can disconnect the antenna. 

We had mesh cages in the military. 

On Fri, Feb 25, 2022, 07:12 Robin WA7CPA <wa7cpa@...> wrote:
Someone on 100 Watts and a Wire suggested it may be Farraday cage time. Only asking for suggestions on creating them.  Not trying to start a geopolitical discussion. Seems easier for the handhelds.  My biggest concern is HF equipment. Pointless to try? Metal roof overhead. Basement windows could be covered with what effective material? What about the concrete walls? Anyone delved into this theoretically? 

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