"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com...
Hi all

If I change the tank circuit components (reduce the capacitance and
inductance) and change the transistors to appropriate VHF ones, will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelto,


I have tried to read and understand the posts in this thread the best I
can. Can someone tell me; Is there a problem for the aircraft industry, or
me, if I sit at the end of Regan National airport outside DC and use this,

http://tinyurl.com/3ayskq

Thanks.

Wayne

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com...
Hi all

If I change the tank circuit components (reduce the capacitance and
inductance) and change the transistors to appropriate VHF ones, will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelto,


I have tried to read and understand the posts in this thread the best I
can. Can someone tell me; Is there a problem for the aircraft industry, or
me, if I sit at the end of Regan National airport outside DC and use this,

http://tinyurl.com/3ayskq

Thanks.

Wayne

On 4/19/08 5:28 PM, in article
C6wOj.2082$pS4.1634@newssvr13.news.prodigy.net, "Joerg"
notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 11:25 AM, in article lI5Oj.4682$iK6.2220@nlpi069.nbdc.sbc.com,
"Joerg" <notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 8:16 AM, in article fuae44$6tg$1@dns3.cae.ca, "Claude"
claudec@cae.com> wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:cJMNj.6968$GE1.6102@nlpi061.nbdc.sbc.com...
Michael Black wrote:
On Wed, 16 Apr 2008, Bob Eld wrote:

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com.
..
Hi all

If I change the tank circuit components (reduce the capacitance and
inductance) and change the transistors to appropriate VHF ones, will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelton.
Not likely. I doubt you'd ever get that circuit to work at VHF
frequencies
no matter what you did with the resonant circuit portion. There are
many
problems including wrong impedances for the various parasitic
capacitances.

Secondly air traffic stuff is FM I believe.

Military may use FM, I don't know, but airplane related communication is
unique in that it does use actual AM.

A project that saw publication a number of times in the old days took
advantage of that, a "crystal radio" that tuned VHF. It was nothing
more than a tuned circuit and a diode detector feeding an earphone, not
sensitive but useful near airports and since it didn't radiate anything,
even useable (though maybe not legally) on an actual airplane.

The description of the circuit says it's a regen receiver, and those
were never popular at VHF, I'm assuming instability came into play.
You did see superregen receivers there. Either type will radiate, and
that's not a good thing in the aircraft band.

Yes, and then you'd quickly have visitors coming with vehicles bearing
government license plates. A regen-receiver is most definitely not a good
idea in the aircraft band.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Quite correct, it is most likely jail time where you will have hours and
hours of fun designing electronics such as movement alarms
that will detect the proximity of "fellow inmates" . Just swearing on an
ATC
frequency will net you a $2,500 fine in Canada, I can't even imagine what
they would do to you if you jammed one of their frequencies.

Claude
Montreal


One of you naysayers should estimate the amount of radiated energy from a
typical regen receiver.

Also, what is the distance from the intended regen location to the airport,
and what would you imagine the comparative strengths would be of the regen
signal and air traffic signals at air traffic receivers?

The regen receiver radiated signal would be lost in the noise.

The other party to air traffic communication are aircraft. Those happen
to roam about quite a bit :-)

Seriously, disregarding the airstrip that's almost next to the office
here we are also roughly in the flight path for Mather Field. Altitude
above our building maybe 1500ft, give or take. If Fedex, DHL and other
pilots would report some weird shhhhht noise everytime they pass a
certain spot, guess what would happen?
I doubt that at 1500 feet the signal from a regen receiver would break the
squelch.

From a regen that misbehaves it certainly can.

Yes, just about anything and everything that misbehaves can can cause a
problem. When I lived in Ketchikan, AK, I received one of those
salmon-colored FCC QSL cards from a listening station at Point Reyes, CA due
to a misbehaving multiplier in my HT9. Got a 579 on my second harmonic.

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com...
Hi all

If I change the tank circuit components (reduce the capacitance and
inductance) and change the transistors to appropriate VHF ones, will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelto,


I have tried to read and understand the posts in this thread the best I
can. Can someone tell me; Is there a problem for the aircraft industry, or
me, if I sit at the end of Regan National airport outside DC and use this,

http://tinyurl.com/3ayskq

Don Bowey wrote:
On 4/19/08 5:28 PM, in article
C6wOj.2082$pS4.1634@newssvr13.news.prodigy.net, "Joerg"
notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 11:25 AM, in article
lI5Oj.4682$iK6.2220@nlpi069.nbdc.sbc.com,
"Joerg" <notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 8:16 AM, in article fuae44$6tg$1@dns3.cae.ca, "Claude"
claudec@cae.com> wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:cJMNj.6968$GE1.6102@nlpi061.nbdc.sbc.com...
Michael Black wrote:
On Wed, 16 Apr 2008, Bob Eld wrote:

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com.
..
Hi all

If I change the tank circuit components (reduce the capacitance
and
inductance) and change the transistors to appropriate VHF ones,
will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelton.
Not likely. I doubt you'd ever get that circuit to work at VHF
frequencies
no matter what you did with the resonant circuit portion. There
are
many
problems including wrong impedances for the various parasitic
capacitances.

Secondly air traffic stuff is FM I believe.

Military may use FM, I don't know, but airplane related
communication is
unique in that it does use actual AM.

A project that saw publication a number of times in the old days
took
advantage of that, a "crystal radio" that tuned VHF. It was
nothing
more than a tuned circuit and a diode detector feeding an
earphone, not
sensitive but useful near airports and since it didn't radiate
anything,
even useable (though maybe not legally) on an actual airplane.

The description of the circuit says it's a regen receiver, and
those
were never popular at VHF, I'm assuming instability came into
play.
You did see superregen receivers there. Either type will radiate,
and
that's not a good thing in the aircraft band.

Yes, and then you'd quickly have visitors coming with vehicles
bearing
government license plates. A regen-receiver is most definitely not
a good
idea in the aircraft band.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Quite correct, it is most likely jail time where you will have hours
and
hours of fun designing electronics such as movement alarms
that will detect the proximity of "fellow inmates" . Just swearing
on an
ATC
frequency will net you a $2,500 fine in Canada, I can't even imagine
what
they would do to you if you jammed one of their frequencies.

Claude
Montreal


One of you naysayers should estimate the amount of radiated energy
from a
typical regen receiver.

Also, what is the distance from the intended regen location to the
airport,
and what would you imagine the comparative strengths would be of the
regen
signal and air traffic signals at air traffic receivers?

The regen receiver radiated signal would be lost in the noise.

The other party to air traffic communication are aircraft. Those
happen
to roam about quite a bit :-)

Seriously, disregarding the airstrip that's almost next to the office
here we are also roughly in the flight path for Mather Field. Altitude
above our building maybe 1500ft, give or take. If Fedex, DHL and other
pilots would report some weird shhhhht noise everytime they pass a
certain spot, guess what would happen?
I doubt that at 1500 feet the signal from a regen receiver would break
the
squelch.

From a regen that misbehaves it certainly can.

Yes, just about anything and everything that misbehaves can can cause a
problem. When I lived in Ketchikan, AK, I received one of those
salmon-colored FCC QSL cards from a listening station at Point Reyes, CA
due
to a misbehaving multiplier in my HT9. Got a 579 on my second harmonic.


That one would be worth placing it in a frame :-)

Problem with homebuilt regens is that unless they have a preamp they can
easily emit lots of RF power if something goes wrong, straight out the
antenna. "Dang, why doesn't it receive anything?" ... "Hey, Joe, uncle
Leroy said the ballgame just started." ... "Ok, coming." ... Meantime the
regen is forgotten and happily keeps humming until after the overtime.
Back when I was a kid people built their own RC electronics because the
stuff from companies such as Robbe was financially out of range for most
of us. More than once have I seen someone flick that switch on the boat,
followed by other boats instantly going out of control.

--
Regards, Joerg

"Archimedes" <shelton.dc...@gmail.com> wrote in message

news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com...

Hi all

If I change the tank circuit components (reduce the capacitance and
inductance) and change the transistors to appropriate VHF ones, will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelto,

I have tried to read and understand the posts in this thread the best I
can. Can someone tell me; Is there a problem for the aircraft industry, or
me, if I sit at the end of Regan National airport outside DC and use this,

http://tinyurl.com/3ayskq

Thanks.

Wayne

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:xINOj.2155$pS4.1361@newssvr13.news.prodigy.net...
Don Bowey wrote:
On 4/19/08 5:28 PM, in article
C6wOj.2082$pS4.1634@newssvr13.news.prodigy.net, "Joerg"
notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 11:25 AM, in article
lI5Oj.4682$iK6.2220@nlpi069.nbdc.sbc.com,
"Joerg" <notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 8:16 AM, in article fuae44$6tg$1@dns3.cae.ca, "Claude"
claudec@cae.com> wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:cJMNj.6968$GE1.6102@nlpi061.nbdc.sbc.com...
Michael Black wrote:
On Wed, 16 Apr 2008, Bob Eld wrote:

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com.
..
Hi all

If I change the tank circuit components (reduce the capacitance
and
inductance) and change the transistors to appropriate VHF ones,
will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelton.
Not likely. I doubt you'd ever get that circuit to work at VHF
frequencies
no matter what you did with the resonant circuit portion. There
are
many
problems including wrong impedances for the various parasitic
capacitances.

Secondly air traffic stuff is FM I believe.

Military may use FM, I don't know, but airplane related
communication is
unique in that it does use actual AM.

A project that saw publication a number of times in the old days
took
advantage of that, a "crystal radio" that tuned VHF. It was
nothing
more than a tuned circuit and a diode detector feeding an
earphone, not
sensitive but useful near airports and since it didn't radiate
anything,
even useable (though maybe not legally) on an actual airplane.

The description of the circuit says it's a regen receiver, and
those
were never popular at VHF, I'm assuming instability came into
play.
You did see superregen receivers there. Either type will radiate,
and
that's not a good thing in the aircraft band.

Yes, and then you'd quickly have visitors coming with vehicles
bearing
government license plates. A regen-receiver is most definitely not
a good
idea in the aircraft band.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Quite correct, it is most likely jail time where you will have hours
and
hours of fun designing electronics such as movement alarms
that will detect the proximity of "fellow inmates" . Just swearing
on an
ATC
frequency will net you a $2,500 fine in Canada, I can't even imagine
what
they would do to you if you jammed one of their frequencies.

Claude
Montreal


One of you naysayers should estimate the amount of radiated energy
from a
typical regen receiver.

Also, what is the distance from the intended regen location to the
airport,
and what would you imagine the comparative strengths would be of the
regen
signal and air traffic signals at air traffic receivers?

The regen receiver radiated signal would be lost in the noise.

The other party to air traffic communication are aircraft. Those
happen
to roam about quite a bit :-)

Seriously, disregarding the airstrip that's almost next to the office
here we are also roughly in the flight path for Mather Field. Altitude
above our building maybe 1500ft, give or take. If Fedex, DHL and other
pilots would report some weird shhhhht noise everytime they pass a
certain spot, guess what would happen?
I doubt that at 1500 feet the signal from a regen receiver would break
the
squelch.

From a regen that misbehaves it certainly can.
Yes, just about anything and everything that misbehaves can can cause a
problem. When I lived in Ketchikan, AK, I received one of those
salmon-colored FCC QSL cards from a listening station at Point Reyes, CA
due
to a misbehaving multiplier in my HT9. Got a 579 on my second harmonic.

That one would be worth placing it in a frame :-)

Problem with homebuilt regens is that unless they have a preamp they can
easily emit lots of RF power if something goes wrong, straight out the
antenna. "Dang, why doesn't it receive anything?" ... "Hey, Joe, uncle
Leroy said the ballgame just started." ... "Ok, coming." ... Meantime the
regen is forgotten and happily keeps humming until after the overtime.
Back when I was a kid people built their own RC electronics because the
stuff from companies such as Robbe was financially out of range for most
of us. More than once have I seen someone flick that switch on the boat,
followed by other boats instantly going out of control.

--
Regards, Joerg


Once upon a time, before Led Zep, I built a super-regenerative receiver that
used an acorn valve for the RF gain, a 958 if I remember correctly, a
Jackson air-spaced variable capacitor with a knob connected directly to its
1/4" shaft, and a small air-spaced coil wound from chunky silver-plated
copper wire. I connected it to the 144 MHz 'ground-plane' aerial I'd
installed on a pole at the end of the garden of our family house and found I
could tune-in to BBC television sound which, in those days, was AM (possibly
around 44 MHz in Band I).

I thought this was a great facility ... until I switched the telly on
downstairs and noticed the dreadful interference on the picture of BBC1. Of
course, it was my receiver that was causing it. Then I looked outside and
realised the distance between my ground-plane and our TV aerial was greater
than the distance between it and a load of aerials on other houses. Ooops!

I think I got away with that one, but I learned a bit of a lesson about
super-regen (or just regen) receivers that have the aerial connected
directly to the detector, not via an RF amp.

christofire wrote:
"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:xINOj.2155$pS4.1361@newssvr13.news.prodigy.net...
Don Bowey wrote:
On 4/19/08 5:28 PM, in article
C6wOj.2082$pS4.1634@newssvr13.news.prodigy.net, "Joerg"
notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 11:25 AM, in article
lI5Oj.4682$iK6.2220@nlpi069.nbdc.sbc.com,
"Joerg" <notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 8:16 AM, in article fuae44$6tg$1@dns3.cae.ca, "Claude"
claudec@cae.com> wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:cJMNj.6968$GE1.6102@nlpi061.nbdc.sbc.com...
Michael Black wrote:
On Wed, 16 Apr 2008, Bob Eld wrote:

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com.
..
Hi all

If I change the tank circuit components (reduce the
capacitance and
inductance) and change the transistors to appropriate VHF
ones, will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelton.
Not likely. I doubt you'd ever get that circuit to work at VHF
frequencies
no matter what you did with the resonant circuit portion. There
are
many
problems including wrong impedances for the various parasitic
capacitances.

Secondly air traffic stuff is FM I believe.

Military may use FM, I don't know, but airplane related
communication is
unique in that it does use actual AM.

A project that saw publication a number of times in the old days
took
advantage of that, a "crystal radio" that tuned VHF. It was
nothing
more than a tuned circuit and a diode detector feeding an
earphone, not
sensitive but useful near airports and since it didn't radiate
anything,
even useable (though maybe not legally) on an actual airplane.

The description of the circuit says it's a regen receiver, and
those
were never popular at VHF, I'm assuming instability came into
play.
You did see superregen receivers there. Either type will
radiate, and
that's not a good thing in the aircraft band.

Yes, and then you'd quickly have visitors coming with vehicles
bearing
government license plates. A regen-receiver is most definitely
not a good
idea in the aircraft band.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Quite correct, it is most likely jail time where you will have
hours and
hours of fun designing electronics such as movement alarms
that will detect the proximity of "fellow inmates" . Just swearing
on an
ATC
frequency will net you a $2,500 fine in Canada, I can't even
imagine what
they would do to you if you jammed one of their frequencies.

Claude
Montreal


One of you naysayers should estimate the amount of radiated energy
from a
typical regen receiver.

Also, what is the distance from the intended regen location to the
airport,
and what would you imagine the comparative strengths would be of
the regen
signal and air traffic signals at air traffic receivers?

The regen receiver radiated signal would be lost in the noise.

The other party to air traffic communication are aircraft. Those
happen
to roam about quite a bit :-)

Seriously, disregarding the airstrip that's almost next to the
office
here we are also roughly in the flight path for Mather Field.
Altitude
above our building maybe 1500ft, give or take. If Fedex, DHL and
other
pilots would report some weird shhhhht noise everytime they pass a
certain spot, guess what would happen?
I doubt that at 1500 feet the signal from a regen receiver would
break the
squelch.

From a regen that misbehaves it certainly can.
Yes, just about anything and everything that misbehaves can can cause a
problem. When I lived in Ketchikan, AK, I received one of those
salmon-colored FCC QSL cards from a listening station at Point Reyes,
CA due
to a misbehaving multiplier in my HT9. Got a 579 on my second
harmonic.

That one would be worth placing it in a frame :-)

Problem with homebuilt regens is that unless they have a preamp they can
easily emit lots of RF power if something goes wrong, straight out the
antenna. "Dang, why doesn't it receive anything?" ... "Hey, Joe, uncle
Leroy said the ballgame just started." ... "Ok, coming." ... Meantime
the regen is forgotten and happily keeps humming until after the
overtime. Back when I was a kid people built their own RC electronics
because the stuff from companies such as Robbe was financially out of
range for most of us. More than once have I seen someone flick that
switch on the boat, followed by other boats instantly going out of
control.

--
Regards, Joerg


Once upon a time, before Led Zep, I built a super-regenerative receiver
that used an acorn valve for the RF gain, a 958 if I remember correctly,
a Jackson air-spaced variable capacitor with a knob connected directly to
its 1/4" shaft, and a small air-spaced coil wound from chunky
silver-plated copper wire. I connected it to the 144 MHz 'ground-plane'
aerial I'd installed on a pole at the end of the garden of our family
house and found I could tune-in to BBC television sound which, in those
days, was AM (possibly around 44 MHz in Band I).

I thought this was a great facility ... until I switched the telly on
downstairs and noticed the dreadful interference on the picture of BBC1.
Of course, it was my receiver that was causing it. Then I looked outside
and realised the distance between my ground-plane and our TV aerial was
greater than the distance between it and a load of aerials on other
houses. Ooops!

I think I got away with that one, but I learned a bit of a lesson about
super-regen (or just regen) receivers that have the aerial connected
directly to the detector, not via an RF amp.


At least you didn't get zinged. When I built my first receiver with
controlled feedback (to set the BW) the structure was such that the cap
for the feedback had to ride between two points on plate level. Meaning
250VDC or so. No problem I thought since the knob was bakelite and would
certainly isolate that. Fired it up, connected earth and antenna, reached
for the feedback and *OUCH*. I had forgotten the minor detail that the
bakelite knob did not have a recessed set screw.

--
Regards, Joerg

respect

respect

"Bob Monsen"
"Phil Allison"

One of the nice things about AM, and the reason they use it for
aviation, is that power wins. If two signals are colliding, the more
powerful one will always be heard.


** That is how FM behaves - ie the "capture effect".

AM does no such thing - " colliding " signals simply combine in the
receiver and are heard together.

Weak signals are heard in the background of strong ones.


Thanks for the clarification. However, I'm curious about this.


** Firstly - I am very impressed that you accepted my comments in the
spirit they were intended.

A rarity on usenet - my congrats.


An FM signal is really just a frequency shift on the carrier. As I
understand it, the transmitted signal is the carrier frequency shifted in
proportion to the amplitude of the sound that will get transmitted (for
mono).

So, given two transmitters on the same frequency, you end up with two
varying carriers. If your receiver is just receiving both signals, mixing
them down to a lower frequency, detecting the shift, and converting that
into an amplitude, the detector must be doing this locking on. Do you
know how it works? How does it lock on rather than just outputting a
mess?


** Capture effect is almost entirly due to the " limiting " that occurs
in the IF amplifier stages.

Unlike AM, the IF stages of an FM receiver are normally operated very
heavily into overload ( ie gross amplitude clipping ) so the weaker of two
( IF frequency FM signals ) is completely over-whelmed by the stronger
e - which them becomes the only signal present at the FM detector.

There is even a Wiki about it:

http://en.wikipedia.org/wiki/Capture_effect


This feature was seen as a BAD idea for aircraft radio comms - it being
preferable to have something more like a telephone party line, so the
weaker voice could still be heard and even if not read clearly, the pilot
or ground controller could ask for a repeat of the message.

This got screwed up once at Tenerife and two jumbo collided as a result.

http://en.wikipedia.org/wiki/Tenerife_disaster#Communication_misunderstandings




...... Phil

"Don Bowey" <dbowey@comcast.net> wrote in message
news:C42E653D.B6601%dbowey@comcast.net...
On 4/18/08 11:25 AM, in article lI5Oj.4682$iK6.2220@nlpi069.nbdc.sbc.com,
"Joerg" <notthisjoergsch@removethispacbell.net> wrote:

Don Bowey wrote:
On 4/18/08 8:16 AM, in article fuae44$6tg$1@dns3.cae.ca, "Claude"
claudec@cae.com> wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:cJMNj.6968$GE1.6102@nlpi061.nbdc.sbc.com...
Michael Black wrote:
On Wed, 16 Apr 2008, Bob Eld wrote:

"Archimedes" <shelton.dcruz@gmail.com> wrote in message
news:b3b30960-27bc-4d59-924f-4312caffe7c2@x41g2000hsb.googlegroups.com...
Hi all

If I change the tank circuit components (reduce the capacitance
and
inductance) and change the transistors to appropriate VHF ones,
will I
be able to pick up ATC (Air Traffic Conversations) using this
circuit ?

http://www.electronics-lab.com/projects/rf/006/index.html

Thanks
Shelton.
Not likely. I doubt you'd ever get that circuit to work at VHF
frequencies
no matter what you did with the resonant circuit portion. There are
many
problems including wrong impedances for the various parasitic
capacitances.

Secondly air traffic stuff is FM I believe.

Military may use FM, I don't know, but airplane related
communication is
unique in that it does use actual AM.

A project that saw publication a number of times in the old days
took
advantage of that, a "crystal radio" that tuned VHF. It was nothing
more than a tuned circuit and a diode detector feeding an earphone,
not
sensitive but useful near airports and since it didn't radiate
anything,
even useable (though maybe not legally) on an actual airplane.

The description of the circuit says it's a regen receiver, and those
were never popular at VHF, I'm assuming instability came into play.
You did see superregen receivers there. Either type will radiate,
and
that's not a good thing in the aircraft band.

Yes, and then you'd quickly have visitors coming with vehicles
bearing
government license plates. A regen-receiver is most definitely not a
good
idea in the aircraft band.

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Quite correct, it is most likely jail time where you will have hours
and
hours of fun designing electronics such as movement alarms
that will detect the proximity of "fellow inmates" . Just swearing on
an ATC
frequency will net you a $2,500 fine in Canada, I can't even imagine
what
they would do to you if you jammed one of their frequencies.

Claude
Montreal



One of you naysayers should estimate the amount of radiated energy from
a
typical regen receiver.

Also, what is the distance from the intended regen location to the
airport,
and what would you imagine the comparative strengths would be of the
regen
signal and air traffic signals at air traffic receivers?

The regen receiver radiated signal would be lost in the noise.


The other party to air traffic communication are aircraft. Those happen
to roam about quite a bit :-)

Seriously, disregarding the airstrip that's almost next to the office
here we are also roughly in the flight path for Mather Field. Altitude
above our building maybe 1500ft, give or take. If Fedex, DHL and other
pilots would report some weird shhhhht noise everytime they pass a
certain spot, guess what would happen?

I doubt that at 1500 feet the signal from a regen receiver would break
the
squelch.



If a malfunctioning DTT set-top box can radiate enough to set off a SARSAT
and call out air-sea rescue, I have little doubt what a regen receiver is
capable of if it goes anywhere near the relevant frequency, especially if
connected to an antenna cut for one of the aero bands. See
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/01/15/ufreeview.xml&sSheet=/portal/2006/01/15/ixportaltop.html

I wonder what they charge for vexatious call-outs!

Chris
Which probably explains why the new 406 EPIRB transmits to the satellite at

While I am here , anyone out there have plans for a functional cell phone
jammer that could jamm all 4 protocols to within 50 feet or so? I have seen
theoretical papers ( Google) but would like to know if any hobbyist has
ever built a successful one?

Claude wrote:

While I am here , anyone out there have plans for a functional cell phone
jammer that could jamm all 4 protocols to within 50 feet or so? I have
seen
theoretical papers ( Google) but would like to know if any hobbyist has
ever built a successful one?


If that is why you are here, go away.


--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

It's just for fun amongst friends, not to antagonize the general public!
Touchy touchy aren't we? I've done the spook the neighbour on the FM band
trick, it's time for the next fun packed spook.

Claude wrote:

It's just for fun amongst friends, not to antagonize the general public!
Touchy touchy aren't we? I've done the spook the neighbour on the FM band
trick, it's time for the next fun packed spook.


It is illegal in every country in the world, and your little 'prank'
could cost someone their life.


--
http://improve-usenet.org/index.html


Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm