Chip with simple program for Toy

[Ken Fowler]

On 17-Apr-2008, Ecnerwal <LawrenceSMITH@SOuthernVERmont.NyET> wrote:

I have to pass a VGA display cable through a wall. To get the
connector through I'd have to drill a hole 1inch in diameter.

Big whoop - get a hole saw/core drill and have at it. Better yet, drill
2 inches and cover the next set of connections you'll think of later all
in one hole.

I like your suggestion better than mine and it's typically what I would do.

Ken Fowler, KO6NO

 

[pipedown]

So you think buying a connector and soldering all those pins is easier and
cheaper than backfilling the oversized hole with drywall mud, sanding and
painting. I don't and I have no trouble soldering.

Following the hole saw idea, save the plug of wall you drill out, carve a
notch to fit the cable then fit the plug back into the hole with a little
glue or drywall mud to smooth out the edge. A little paint and you are
done.

Another solution is to do it all behind the base molding. No paint, a quart
should cost only a bit more than a proper connector with a shroud and can be
used other places.





"Brotherwarren" <twarren@kesgrave.suffolk.sch.uk> wrote in message
news:261d06fa-a259-4162-90d1-778e8b79ea3a@p25g2000hsf.googlegroups.com...

Hi folks:

Is it possible to solder 15-pin D-Suub connector onto a cable?

I have to pass a VGA display cable through a wall. To get the
connector through I'd have to drill a hole 1inch in diameter.

Instead what I'd like to do is pass a narrow cable through, then
solder the connector on once it reaches the other side.

Is this advisable/possible?

I thinbk I've found the cable and connector I need to use here:-

http://www.maplin.co.uk/Module.aspx?ModuleNo=1310&Criteria=15%20D%20Sub&C=GKW&U=Auto_2003513&T=15%20D%20Sub&gclid=CI_ExM2_4pICFQSU1Aodm1xb-Q

and here:-
http://www.maplin.co.uk/module.aspx?ModuleNo=230&doy=17m4


Am I able to do this?

thanks for any and all suggestions!

Tony

 

[Paul E. Schoen]

"John Fields" <jfields@austininstruments.com> wrote in message
news:1fle04h5fv18h0t2b9lss868nrc1n4ko06@4ax.com...

On Wed, 16 Apr 2008 18:20:53 -0400, "Paul E. Schoen"
pstech@smart.net> wrote:


LTSpice has a voltage controlled switch component, but it only works for
DC
in one direction.

---
That's not true. It's fully bidirectional.
---

And you must set some of the parameters for it to work.

---
Yeah, but it's easy.

Go to:

http://ltspice.linear.com/software/scad3.pdf

and look on page 164.

I see what I did wrong. I had Vser set to 0.6 as in the example, and that
made it conduct only in one direction. I was using it to analyze switching
transients on AC relays. The corrected circuit follows.

Thanks,

Paul

==========================================================================

Version 4
SHEET 1 880 680
WIRE 64 -16 -112 -16
WIRE 16 16 -208 16
WIRE 64 16 64 -16
WIRE -16 64 -48 64
WIRE 0 64 -16 64
WIRE 128 64 80 64
WIRE 256 64 128 64
WIRE 256 112 256 64
WIRE -208 128 -208 16
WIRE -48 144 -48 64
WIRE 128 144 128 128
WIRE 128 160 128 144
WIRE -208 240 -208 208
WIRE -112 240 -112 -16
WIRE -112 240 -208 240
WIRE -48 256 -48 224
WIRE 128 256 128 240
WIRE 128 256 -48 256
WIRE 256 256 256 192
WIRE 256 256 128 256
WIRE -48 288 -48 256
FLAG -48 288 0
FLAG -16 64 Vin
FLAG 128 144 Vres
FLAG -208 240 0
FLAG 256 64 Vrly
SYMBOL res 112 144 R0
SYMATTR InstName R1
SYMATTR Value 270
SYMBOL cap 112 64 R0
SYMATTR InstName C1
SYMATTR Value 0.47ľ
SYMBOL voltage -48 128 R0
WINDOW 3 103 175 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 22 174 Left 0
SYMATTR Value SINE(0 360 60 0 0 0 150)
SYMATTR SpiceLine Rser=1
SYMATTR InstName V1
SYMBOL sw 96 64 R90
WINDOW 3 -36 -113 VRight 0
WINDOW 0 24 92 VRight 0
SYMATTR Value MySwitch
SYMATTR InstName S1
SYMBOL ind 240 96 R0
SYMATTR InstName L1
SYMATTR Value 5
SYMATTR SpiceLine Rser=50 Rpar=1Meg
SYMBOL voltage -208 112 R0
WINDOW 3 -219 162 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value PWL(0 0 .1041667 0 .104167 5 .5041667 5 .504167 0 1.00 0
1.001 5 1.50 5 1.501 0 2 0)
SYMATTR InstName V2
TEXT -88 496 Left 0 !.tran 2 startup
TEXT -392 344 Left 0 !.model MySwitch SW(Ron=.1 Roff=100Meg Vt=2 Vh=-.5
Lser=10n Vser=0)

 

[Ecnerwal]

Hi, I've done a couple microcontroller projects, but otherwise I'm
pretty new to electronics.  I recently bought an antique typewriter
that I'd like to automate for fun.  My idea is that I could mount
solenoids under each key(which are essentially levers that push up on
some rods) and pull down with the same force that it would take press
key.  I haven't measured how much force is necessary yet, and the
stroke is probably about an inch.

Should be easy enough to fit - just remember that you can use longer and
shorter rods to connect the solenoids to the keys, so all 45 don't need
to be in the same vertical plane - then you should have plenty of room.
You might consider pushing at the far end - depending on the layout,
that may provide better spacing, as those are often arranged in a radial
pattern, so things would fan out.

You may have an interface problem for manual use, however - I think the
solenoid space is going to eat up the knee room for sitting at the thing.

It's definitely in the crazed project zone, given the relative ease of
getting the same result out of an electronic typewriter, if the
typewritten (and automatically typewritten) aspect was more important
than the antique manual (but not manual) typewriter. So long as you
recognize that going in, crazed projects are OK. Enjoy yourself. I'd
seriously consider starting with a Selectric(tm), but it would be a very
different end result.

The automated hands would be a very interesting and artistic approach.

--
Cats, coffee, chocolate...vices to live by

 

[Bob Eld]

"Bob Monsen" <rcmonsen@gmail.com> wrote in message
news:gcQNj.8663$V14.5876@nlpi070.nbdc.sbc.com...

"Bob Eld" <nsmontassoc@yahoo.com> wrote in message
news:dIANj.5301$GO4.2306@newssvr19.news.prodigy.net...

chesemonkyloma@gmail.com> wrote in message

news:786a05af-57b3-44b8-80f8-e408f04cdeb7@m44g2000hsc.googlegroups.com...
My sister would like to use a light on the end of a string, and I was
wondering how that could be made. I was thinking of putting a bright
LED, and resistor, and some hook-up wire in a clear, plastic ball or
even in some Saran Wrap with a battery to power the circuit. This may
be completely implausible, I don't know.

When I was in College one of the guys in the dorm hung a bare 60 watt
incandescent light bulb, 120Volts, from the concrete ceiling of his room
on
a piece of string. The bulb would just hang there lit, fully bright, but
looking at it you couldn't figure out how it was powered. It was a great
conversation piece and kept a lot of people guessing. A bare bulb just
hanging there on a sting without a socket or apparent wires burning
away,
it
was great.

What he had done is twisted some very thin magnet wire, like 36 Ga. into
the
string and soldered the ends to the bulb base where the string was tied.
The
wires went up the string then across the concrete ceiling hidden in the
natural cracks and roughness of the painted concrete. The string was
taped
to the ceiling. You could not see the wires without climbing up and
very
closely inspecting the situation. The wires came down one wall to a wall
plug where other stuff was plugged in concealing the termination.

I wouldn't recommend this as it could be a fire hazard but it sure would
be
a hell of a lot more impressive than an LED. It takes a clever artistic
person to weave and conceal the thin wires. If not carefully done it
would
be a dead giveaway if wires can be seen. If you try it be sure to never
leave this kind of thing plugged in unattended.




Is it safe?

36 ga wire has 418 ohms/1000 ft. Your friend's display probably used 6
feet
of wire. That is about 2.5 ohms. A 60W bulb uses 500mA at 120VAC, so your
friend was dissipating about 5/8 of a watt in the wire. Enough to get it
toasty, but probably not enough to start a fire. However, it exceeds the
maximum current allowed by the American wire gauge guys by 1400%...!

http://www.powerstream.com/Wire_Size.htm

When the bulb first turns on, it'll be alot more power, but only for a
second or so. Just don't hold the wire when you turn it on or you'll get
burned.

Regards,
Bob Monsen

I don't know if it was 36 Ga. or not, it might have been 34. In any case, a
watt or two, even 5 watts dissipated in a few feet of wire won't get the
wire hot. There is too much air all around that length wire for any
appreciable temperature rise. Is it safe? Hell no! I don't think I'd be
showing it to any electrical code inspectors or UL types. It's a dorm room
or party trick, not to be left unattended. It is probably no more dangerous
than a candle, however.

 

[Claude]

"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

 

[Phil Allison]

"Bob Monsen"

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.



....... Phil

 

[Phil Allison]

"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
ne - 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

 

[Phil Allison]

"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
ne - 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

 

[John G]

"????" <engg_msc@yahoo.com> wrote in message
news:9de68324-e4ae-492d-9fe7-74915f72439d@s50g2000hsb.googlegroups.com...

how can i use visual basic for serial network using 89c52 and rs232
using 9 bit protocol

It is Light Years beyond your comprehension.

John G.

 

[Nigel Heather]

Not necessarily. The hFE will vary for each transistor depending on IC
(Collector Current). So for the same transistor the hFE will vary depending
on what collector current you drive through it. So the range of hFE they
give is probably not so much an indictation of manufacturing tolerance (this
transistor is better than that one) but more an indication that ant
transistor will vary depending on how you drive it.

Of course there are manufacturing tolerances aswell so the range is a
combination of the two.

The tester probably uses a low IC which will lead to a high hFE. If in your
application you drive IC to say 1A you would probably find the hFE for your
transistor would drop down low.

Cheers,

Nigel


"ArameFarpado" <a-farpado.spam@netcabo.pt> wrote in message
news:fucasb$cru$1@news.datemas.de...

Hi all...

a transistor "BD435" is giving me 440 in hFE test on the multimeter, when
the tecnical data i've found tell me min=40 max=475...

does this mean the transistor is really in good shape?
can it be busted and still give a good hFE test result on the multimeter?

thanks
ArameFarpado

 

[christofire]

"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

 

[christofire]

"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

 

[Charles]

Leaky transistor or bad instrument or both.

 

[Phil Allison]

"ArameFarpado"

a transistor "BD435" is giving me 440 in hFE test on the multimeter, when
the tecnical data i've found tell me min=40 max=475...

** You have it connected wrong or it is a dud.


...... Phil

 

[Phil Allison]

"ArameFarpado"

i've just made a strange descovery:
if i leave the base pin not connected, the hFE result is the same.

** You have it connected wrong or it is a dud.

so i guess this hFE test is not for checking if the transistor is fine or
busted.

** You have it connected wrong or it is a dud.

Connect a good device correctly and the Hfe reading wil be in the order of
50 - 150.



........ Phil

 

[christofire]

"Wayne" <NOwaynerr@SPAMcomcast.net> wrote in message
news:l6udnTgHSKeUD5bVnZ2dnUVZ_tGonZ2d@comcast.com...

"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

The discussion was about regenerative receivers, which can radiate through
their antenna at the tuned frequency. The Ramsey kit is a superhet which
might radiate a lot less, and possibly in a different band (e.g. if it uses
an IF like 10.7 MHz).

Nowadays, if you were to park anywhere near the runway at a major British
airport you'd probably be visited by the police. If you were then found to
be operating dodgy home made electronics, any amount of explanation on your
part would probably not prevent your arrest. Perhaps it's the same in the
US.

Chris

 

[christofire]

"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.

Chris

 

[christofire]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:BiROj.21064$%41.11949@nlpi064.nbdc.sbc.com...

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

Chris

 

[christofire]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:BiROj.21064$%41.11949@nlpi064.nbdc.sbc.com...

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

Chris