Re: [TSCM-L] {2741} Re: {2737} Electromagnetic Radiation....

From: btskhi <b..._at_charter.net>
Date: Tue, 1 Jul 2008 17:48:23 -0500

If you don't kow the transmitted power you can calculate it from a
measurement of flux density at you location.

Now I might guess that you would not have a field strength meter to measure
this. So I'll give you that quick method.

Build or buy a filter that passes the band you are concerned with.
Capacitors, inductors, crystals...there are a lot of ways of doing it.
James (our fearless leader) probably has a design to use. You want this as
a band pass filter.

The cage or screen has to have holes in it with dimensions less than 1/4
wave length to the shortest frequency, (3khz). The smaller the better.
solid wall is even better.

Attach a ground to the cage. Atleast one for each cage panel including the
floor.

Attach the pass filter to an O scope or preferably a spec analyzer and tune
in that band.

If the transmitter in that band is transmitting all the time, then you can
use that as a source. If not , then you have to have another generator to
transmit a somewhat equal power.

Now move around the cage attaching the other end of the filter to the walls
of the cage. When you see that freq on the scope, then attach another
ground strap in that location.

When you have "painted" the entire inside of the cage, then you can attach
an antenna to the filter and walk around the inside. Everything should be
flat.

The other way is to do a full design ahead of time, but that requires more
work and I would have to charge you for it.


James Greenwold
Bureau Of Technical Services
P.O. Box 191
Chippewa Falls, WI 54729


----- Original Message -----
From: "madscientist rc_mc_vktm" <madscie..._at_gmail.com>
To: "TSCM-L Professionals List" <TSCM-..._at_googlegroups.com>
Sent: Monday, June 30, 2008 8:39 PM
Subject: [TSCM-L] {2741} Re: {2737} Electromagnetic Radiation....


>
> Thanks for replying,
> Well I thought there was just one protection for
> the entire Electromagnetic Spectrum, guess not how gullible of me.
>
> In the Frequency's ranging from:
> 300 kHz---3 kHz.
> Over-the-Horizon distance of about 1/4 mile.
>
> Can you counter that energy?
> Can it be deflected?
>
> On Jun 28, 11:36 am, "btskhi" <b..._at_charter.net> wrote:
>> I don't know of anything that can if the cage is grounded properly, what
>> are
>> you finding that penetrates?
>>
>> In another life I worked on EMP defenses. And the screen room we used
>> didn't pass anything.
>>
>> The grounding system has to be able to capture and transfer the power
>> that
>> is being transmitted. If that is not set up properly, the shield can act
>> like an inefficient antenna and retransmit into the cage.
>>
>> What are you specifically trying to block? How much power is being
>> transmitted? How far away? What frequency?
>>
>> These are the question that need to be answered before a design can be
>> specified.
>>
>> James Greenwold
>> Bureau Of Technical Services
>> P.O. Box 191
>> Chippewa Falls, WI 54729
>>
>> ----- Original Message -----
>> From: "madscientist rc_mc_vktm" <madsci..._at_gmail.com>
>> To: "TSCM-L Professionals List" <TSCM-..._at_googlegroups.com>
>> Sent: Thursday, June 26, 2008 2:27 PM
>> Subject: [TSCM-L] {2737} Electromagnetic Radiation....
>>
>> > Is there any protection against electromagnetic weapons and radio
>> > frequency devices?
>>
>> > What can counter electromagnetism frequencies that go through just
>> > about anything even Faraday cages?
>
> >
>
Received on Sat Mar 02 2024 - 00:57:16 CST