MYTH or FICTION
o...@uakron.edu
transmitters? Ie more then a meter from the source.
Please cite examples that you have observed or calculations you have
done/seen.
Steve
mike
Stick a 2.4GHz horn antenna on the input of your spectrum analyzer.
Turn the attenuation to zero.
Put a similar horn on the magnetron of your microwave oven.
Put them a meter apart and pointed at each other.
Flip the switch.
Report back.
Joerg
I wasn't there myself but have seen the aftermath and believe the guys
who dunnit: BIG pulsed radar on rooftop, guys testing their stuff at
other end of roof. Big pulsed radar was turned back on when guys were
off the roof, big dish starts to turn again ... *PHUT* ... no more
semiconductin' left in the input amp. Don't remember the distance but it
was several meters.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
RFI-EMI-GUY
I recall hearing of an orbiting communications satellite having its
output power amplifier destroyed during commissioning tests due to
excessive up link power.
--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"�
"Use only Genuine Interocitor Parts" Tom Servo ;-P
Robert Baer
at 5 feet, then receiver front-end burnout is certainly possible and
probably has happened many times.
Robert Baer
PeterD
wrote:
>o...@uakron.edu wrote:
>> Myth or Fiction, far field burnout of receiver front ends by microwave
>> transmitters? Ie more then a meter from the source.
>>
>> Please cite examples that you have observed or calculations you have
>> done/seen.
>>
>
>I wasn't there myself but have seen the aftermath and believe the guys
>who dunnit: BIG pulsed radar on rooftop, guys testing their stuff at
>other end of roof. Big pulsed radar was turned back on when guys were
>off the roof, big dish starts to turn again ... *PHUT* ... no more
>semiconductin' left in the input amp. Don't remember the distance but it
>was several meters.
I've had HIGH power radar affect electronics (not just front ends) at
distances of over a thousand meters. Not destroy anything, but cause
unintended/improper operation.
There is no way that at one meter these would not have totally fried
anything in the window...
(We're talking NORAD radar sets.)
mpm
Why not consider the front end to be an antenna and apply the Friis
equation?
Link: http://en.wikipedia.org/wiki/Friis_transmission_equation
That should tell you if it's possible, and if so, under what
conditions.
-mpm
Jan Panteltje
o...@uakron.edu wrote in
<dd13650f-d6d0-4166...@l30g2000yqb.googlegroups.com>:
There was one amateur radio operator who enjoyed burning converters
by pointing his beam at them, 1 kW I think.
They got to him IIRC.
Those old RF transistors were very sensitive.
Do not remember the frequency.
Was in the sixties?
Jim Thompson
Back in the days of 10GHz CW police speed radar, I had a friend that,
anytime he spotted a police radar in operation, he would walk up to
the car with his nice shiny aluminum clipboard and blow the mixer
diode, then ask the cop for "directions" ;-)
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Joerg
I knew a guy for whom it was very unfortunate. It basically fried his
eyes and he was gradually becoming blind. And that was over a long
distance as well.
VWWall
He was one of the greatest leaders able to get the best work from those
he supervised. He'd plant a thought in your mind and you'd leave his
office thinking it was one of the best things you'd ever conceived.
He had 25 patents himself, but was probably responsible for many more
issued to those he inspired.
I was once head of the radar department at a large electronics
corporation. We shared the roof with a radar rest range and a "dark
tunnel" used by the infra-red department. The head of IR was worried
about the proximity to an active radar. I once took a NE-2 neon bulb
with its leads cut and bent to act an an antenna into the dark IR range
with him. The bulb flashed every time the radar "scanned" it from a few
feet away. It took me a lot of time to convince him that there was no
health danger!
--
Virg Wall, P.E.
T
The-Enve...@My-Web-Site.com/Snicker says...
>
> On Fri, 08 Jan 2010 00:47:40 -0800, Robert Baer
> <rober...@localnet.com> wrote:
>
> >mike wrote:
> >> o...@uakron.edu wrote:
> >>> Myth or Fiction, far field burnout of receiver front ends by microwave
> >>> transmitters? Ie more then a meter from the source.
> >>>
> >>> Please cite examples that you have observed or calculations you have
> >>> done/seen.
> >>>
> >>>
> >>> Steve
> >> Oughta be easy enough to test.
> >> Stick a 2.4GHz horn antenna on the input of your spectrum analyzer.
> >> Turn the attenuation to zero.
> >> Put a similar horn on the magnetron of your microwave oven.
> >> Put them a meter apart and pointed at each other.
> >> Flip the switch.
> >> Report back.
> >FFFfffrapppP!
>
> Back in the days of 10GHz CW police speed radar, I had a friend that,
> anytime he spotted a police radar in operation, he would walk up to
> the car with his nice shiny aluminum clipboard and blow the mixer
> diode, then ask the cop for "directions" ;-)
>
> ...Jim Thompson
I love it. A nice low tech solution to a high tech problem.
Phil Allison
"mike"<spa...@go.com>
>> Myth or Fiction, far field burnout of receiver front ends by microwave
>> transmitters? Ie more then a meter from the source.
** Since when is 1 metre the " far field" ???? ?
You fucking TROLLING IDIOT !!
Go drop DEAD.
... Phil
o...@uakron.edu
target?
Steve
Vladimir Vassilevsky
o...@uakron.edu wrote:
> So how do convert the power level from Friis to a field level at the
> target?
Friis is irrelevant.
Compute the area over which the power is distributed (don't forget to
account for antenna gain. Then convert W/m^2 to V/m (free space
impeadance = 376 Ohm).
Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
o...@uakron.edu
Thats what I needed to know, thanks.. With a bit of egg on my face as
I was just trying to explain to my non techie boss what a horn
does....
Thanks, Steve
Archimedes' Lever
wrote:
>PeterD wrote:
>> On Thu, 07 Jan 2010 18:35:13 -0800, Joerg <inv...@invalid.invalid>
>> wrote:
>>
>>> o...@uakron.edu wrote:
>>>> Myth or Fiction, far field burnout of receiver front ends by microwave
>>>> transmitters? Ie more then a meter from the source.
>>>>
>>>> Please cite examples that you have observed or calculations you have
>>>> done/seen.
>>>>
>>> I wasn't there myself but have seen the aftermath and believe the guys
>>> who dunnit: BIG pulsed radar on rooftop, guys testing their stuff at
>>> other end of roof. Big pulsed radar was turned back on when guys were
>>> off the roof, big dish starts to turn again ... *PHUT* ... no more
>>> semiconductin' left in the input amp. Don't remember the distance but it
>>> was several meters.
>>
>> I've had HIGH power radar affect electronics (not just front ends) at
>> distances of over a thousand meters. Not destroy anything, but cause
>> unintended/improper operation.
>>
>> There is no way that at one meter these would not have totally fried
>> anything in the window...
>>
>> (We're talking NORAD radar sets.)
>
>
>I knew a guy for whom it was very unfortunate. It basically fried his
>eyes and he was gradually becoming blind. And that was over a long
>distance as well.
An old Navy demonstration practice on a ship to show sailors why one
should NOT walk in front of microwave dishes, was to put a grapefruit
onto the end of a broomstick and hold it out in front of the dish when it
gets turned on.
The grapefruit explodes.
The demonstration is over. Back to work. Watch where you are walking.
Archimedes' Lever
I wouldn't walk in front of an active RADAR emitter with or without
you.
o...@uakron.edu
Just Curious...
Steve
Jamie
Well, I once meant some one a few years ago, that got burned 90% of his
body working on a 2M watt navy radar unit, changing the bleeder
resistors. Some one turned it on. He woke up in a military hospital
where he stay for some time.
He had skin graphs done and still had to live with severe nerve damage
and you can imagine what his skin looked like.
Very smart and interesting navy radio tech. It was hard to talk to him
with his eyes and face twitching due to nerve damage!.
JosephKK
I think that is a microwave oven stunt.
Just the same i saw an SPG-51 with the illuminator on drop
a seagull out of the air at about 100 feet. Maybe 100 ms
time within the beam. Still a freak chance. Tracking radar
portion 50 kW and illuminator an additional 50 kW. Pumped
klystron outputs.
apda
<o...@uakron.edu> wrote in message
news:dd13650f-d6d0-4166...@l30g2000yqb.googlegroups.com...
Easy, this will burn out front ends 10 to 20 miles out or more;
http://www.fas.org/man/dod-101/sys/ship/weaps/an-slq-32.htm
Jon Slaughter
> On Fri, 08 Jan 2010 00:47:40 -0800, Robert Baer
> <rober...@localnet.com> wrote:
>
>> mike wrote:
>>> o...@uakron.edu wrote:
>>>> Myth or Fiction, far field burnout of receiver front ends by
>>>> microwave transmitters? Ie more then a meter from the source.
>>>>
>>>> Please cite examples that you have observed or calculations you
>>>> have done/seen.
>>>>
>>>>
>>>> Steve
>>> Oughta be easy enough to test.
>>> Stick a 2.4GHz horn antenna on the input of your spectrum analyzer.
>>> Turn the attenuation to zero.
>>> Put a similar horn on the magnetron of your microwave oven.
>>> Put them a meter apart and pointed at each other.
>>> Flip the switch.
>>> Report back.
>> FFFfffrapppP!
>
> Back in the days of 10GHz CW police speed radar, I had a friend that,
> anytime he spotted a police radar in operation, he would walk up to
> the car with his nice shiny aluminum clipboard and blow the mixer
> diode, then ask the cop for "directions" ;-)
>
Was this the same friend that was killed by a speeding driver?
mpm
And what do you propose to do regarding the aperture efficiency?
I would not (necessarily) assume that the field would be uniformly
absorbed by the "front end".
I agree that it's a trivial matter to calculate the equivalent
electric field density at the front end, but that field must still be
intercepted by something - to do any damage.
Friis is the classic equation for the transfer of power between two
antennas, and thus, if you treat the "front end" as an antenna, then
there you have it.
Perhaps we may disagree on whether it is appropriate to treat the
"front end" as an antenna, but that's sounds like a separate
discussion...
I don't want to get into a pissing contest over it.., but I do think
the question about the destructive capability of radiofrequency energy
must at least consider the transfer efficiency and/or the absorption
of the field.
In short, knowing the RF illumination at the front end does not tell
you how much power is being dissipated -- rather, how much power is
"available" to be dissipated.
Assuming of course, that we are in the far field, that the fields are
in quadrature, etc...