[Hackrf-dev] Script

[Ian W]

Hello Michal

I take your point that there exist various devices for jamming and
'electronic warfare' as you describe it. In fact there are some truly
horrific devices, some of them generating huge amounts of pulsed power in
to highly directive antenna arrays. Shutting off drones in some cases could
even be considered socially useful if it weren't for the obvious fact that
they fall from the sky, potentially damaging persons in the way.

For sure, encourage people to find out about WiFi and how to cause
interference to it, if you must; but I suspect that any useful technique to
cover more than a short distance will require either a lot of power or a
highly directional gain antenna, or both. At the frequencies of interest
you are advised to take precautions as some people have discovered, a few
notable experiments resulting in the loss of eyesight and damage to limbs.
Well, of course, that's not your problem as you are only sketching a very
rough plan about how to start such things.

I also see that you wish to detach the legalities of radio spectrum use
from the pursuit of engineering knowledge. Good luck with that! In my view,
they are interdependent, but the argument is perhaps to complex to examine
here.

Whilst I agree that 'Life-saving appliances should not rely on WiFi or any
other radio signal transmission', unfortunately for that argument there are
a number that do. Airport Radar facilities use radio signals. Air-to ground
radio communications also use it. Ambulance and Police services use it.
Yes, it's possible to cause interference to all of those things.

Consider the upload of cardiac records from my friends' heart monitor, to
the hospital which he attends, sent via WiFI over the internet. Is this a
"highly irresponsible" use of WiFi according to your definition? I would be
quite annoyed if some idiot was generating noise using a zener diode and a
PLL/VCO, put through some dubious filter and fed into an RF amplifier, no
doubt sourced via EBay, with exceptionally poor harmonic suppression and
possible instability.

"That concept can be easily scaled for any band You like. Best of all, You
leave the band noise generation to the analog circuits saving Your cpu
power ;)" Oh, very good. An astute observation. Yes, the engineering has
completely ignored the possible consequences. Engineering, free of moral
problems. Yes, indeed.

All I can say is that I hope you don't ever have to deal with unwanted
deliberate interference to WiFi. Or to your use of radio frequencies.

regards,

Ian

On Mon, Jul 11, 2016 at 5:27 PM, Michał Byrecki <
michal.byrecki at techniline.com> wrote:

> Howdy,
> To be more specific (and off-topic a bit), we have to separate the
> know-how engineering ideas apart of the law.
>
> 1. Jammers exit and they are used in many occasions - like securing the
> VIP locations, There are ECM systems for electronic warfare. There are
> systems under development for shutting off the drones.
>
> 2. Life saving appliances should not rely on WiFi or any other radio
> signal transmission. That kind of devices I would consider highly
> irresponsible, as parsing the radio spectrum may not always result with a
> valid information (check out excellent material from Travis Goodspeed &
> Sergey Bratus: https://www.youtube.com/watch?v=Ffss-p2JfKw).
>
> I took a shot to share a part of my electronic knowledge with the author.
> If he is not willing to go into _technical_ details due to a lack of
> knowledge, I am out :)
>
> Brgds,
> Mike SP5BYK
>
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