MOSFET Needed...

[John Larkin]

On Sat, 11 Mar 2023 16:45:50 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On a sunny day (Sat, 11 Mar 2023 08:23:45 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
kcap0i9kf0tuc35hnlirtoobkqj6u19fgu@4ax.com>:

We do have an all-facility EMI test system:

https://www.dropbox.com/s/tmcpmvqp714c82o/Roof_West.JPG?raw=1

?
All I see is a roof with some boxes?
Or are you referring to that antenna tower?

Yes. Sutro Tower. I suspect that the bowl of Castro Valley focusses
the RF into our building. I have been meaning to use the field to
light up some LEDs.

I remember a discussion about that here some time ago.
I have a similar source of RF power here, the radar station just a few km from here.
https://panteltje.nl/pub/radar_2kHz_spectrum_burst.gif
it works at about 1.35 GHz but sweeps over a wide band.
Signal is VERY strong and interferes with satellite reception on some channels
as the 1.35 GHz is in the middle of the signal from the LNB down converter.

 

[Jan Panteltje]

On a sunny day (Sat, 11 Mar 2023 10:08:57 -0800) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<aegp0i55pmr0sggm9udi28i91b2pa9gao3@4ax.com>:

On Sat, 11 Mar 2023 16:45:50 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 08:23:45 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
kcap0i9kf0tuc35hnlirtoobkqj6u19fgu@4ax.com>:

We do have an all-facility EMI test system:

https://www.dropbox.com/s/tmcpmvqp714c82o/Roof_West.JPG?raw=1

?
All I see is a roof with some boxes?
Or are you referring to that antenna tower?

Yes. Sutro Tower. I suspect that the bowl of Castro Valley focusses
the RF into our building. I have been meaning to use the field to
light up some LEDs.

Yes, nice idea
Now I think about the radar making a flashing LED,
It is a rotating thing, every few seconds the beam hits here and some SAT channels get affected.

So a microwave antenna with high voltage output, and/or diode followed by a low voltage up-converter,
like this from a thermocouple:
https://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

Or maybe better for this purpose?
BAT diode voltage multiplier chain:
https://panteltje.nl/pub/bat15-99.gif

Or dish antenna? Bit big...


For lower frequencies just a few meters of wire may work (wavelength related).
So light your house with power from that tower
Was reading once about a guy who took power from the overhead powerlines by running a long
wire in parallel under it..
He was sued for stealing power IIRC.
Pretty cool idea though, if you have the land.

I remember a discussion about that here some time ago.
I have a similar source of RF power here, the radar station just a few km from here.
https://panteltje.nl/pub/radar_2kHz_spectrum_burst.gif
it works at about 1.35 GHz but sweeps over a wide band.
Signal is VERY strong and interferes with satellite reception on some channels
as the 1.35 GHz is in the middle of the signal from the LNB down converter.

 

[John Larkin]

On Sun, 12 Mar 2023 06:24:06 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On a sunny day (Sat, 11 Mar 2023 10:08:57 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
aegp0i55pmr0sggm9udi28i91b2pa9gao3@4ax.com>:

On Sat, 11 Mar 2023 16:45:50 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 08:23:45 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
kcap0i9kf0tuc35hnlirtoobkqj6u19fgu@4ax.com>:

We do have an all-facility EMI test system:

https://www.dropbox.com/s/tmcpmvqp714c82o/Roof_West.JPG?raw=1

?
All I see is a roof with some boxes?
Or are you referring to that antenna tower?

Yes. Sutro Tower. I suspect that the bowl of Castro Valley focusses
the RF into our building. I have been meaning to use the field to
light up some LEDs.

Yes, nice idea
Now I think about the radar making a flashing LED,
It is a rotating thing, every few seconds the beam hits here and some SAT channels get affected.

So a microwave antenna with high voltage output, and/or diode followed by a low voltage up-converter,
like this from a thermocouple:
https://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

Or maybe better for this purpose?
BAT diode voltage multiplier chain:
https://panteltje.nl/pub/bat15-99.gif

Or dish antenna? Bit big...


For lower frequencies just a few meters of wire may work (wavelength related).
So light your house with power from that tower

These people might. I\'ve been told that all sorts of things go wrong
on that street.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

The speakers on my ratty old Fiesta would buzz when I drove there,
with the radio turned off.

Was reading once about a guy who took power from the overhead powerlines by running a long
wire in parallel under it..
He was sued for stealing power IIRC.
Pretty cool idea though, if you have the land.

I\'m thinking that a resonated loop antenna might make enough voltage
to light an LED; a good LED is visible at a few uA. Maybe have the LED
capacitance be part of the resonance, or rectify with a low-barrier
Schottky. Some LEDs are fast and have low capacitance, some aren\'t.

I remember a discussion about that here some time ago.
I have a similar source of RF power here, the radar station just a few km from here.
https://panteltje.nl/pub/radar_2kHz_spectrum_burst.gif
it works at about 1.35 GHz but sweeps over a wide band.
Signal is VERY strong and interferes with satellite reception on some channels
as the 1.35 GHz is in the middle of the signal from the LNB down converter.

 

[Jan Panteltje]

On a sunny day (Sun, 12 Mar 2023 08:39:08 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<b1sr0ih1h89avbdndvannrbcvjta3nd5ot@4ax.com>:

On Sun, 12 Mar 2023 06:24:06 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 10:08:57 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
aegp0i55pmr0sggm9udi28i91b2pa9gao3@4ax.com>:

On Sat, 11 Mar 2023 16:45:50 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 08:23:45 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
kcap0i9kf0tuc35hnlirtoobkqj6u19fgu@4ax.com>:

We do have an all-facility EMI test system:

https://www.dropbox.com/s/tmcpmvqp714c82o/Roof_West.JPG?raw=1

?
All I see is a roof with some boxes?
Or are you referring to that antenna tower?

Yes. Sutro Tower. I suspect that the bowl of Castro Valley focusses
the RF into our building. I have been meaning to use the field to
light up some LEDs.

Yes, nice idea
Now I think about the radar making a flashing LED,
It is a rotating thing, every few seconds the beam hits here and some SAT channels get affected.

So a microwave antenna with high voltage output, and/or diode followed by a low voltage up-converter,
like this from a thermocouple:
https://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

Or maybe better for this purpose?
BAT diode voltage multiplier chain:
https://panteltje.nl/pub/bat15-99.gif

Or dish antenna? Bit big...


For lower frequencies just a few meters of wire may work (wavelength related).
So light your house with power from that tower

These people might. I\'ve been told that all sorts of things go wrong
on that street.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Very typical houses, likly related to the slope of the hill

The speakers on my ratty old Fiesta would buzz when I drove there,
with the radio turned off.


Was reading once about a guy who took power from the overhead powerlines by running a long
wire in parallel under it..
He was sued for stealing power IIRC.
Pretty cool idea though, if you have the land.



I\'m thinking that a resonated loop antenna might make enough voltage
to light an LED; a good LED is visible at a few uA. Maybe have the LED
capacitance be part of the resonance, or rectify with a low-barrier
Schottky. Some LEDs are fast and have low capacitance, some aren\'t.

Yes, e LED parallel to a tuned LC might work....
Using an Extra diode would drop some voltage..
------------------
| |Cv |k |a
L =/= LED1 LED2
| | |a |k
------------------
tuning
cap

In my school days I build a 250 W linear, anttenna wire in the garden from the house towards a tree.
A neon bulb would light when anywhere near that antenna when transmitting!
About 7 MHz.. shortwave ham band
No license back then, got almost caught..
Almost ;-)

 

[Ricky]

On Sunday, March 12, 2023 at 11:39:23 AM UTC-4, John Larkin wrote:

On Sun, 12 Mar 2023 06:24:06 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 10:08:57 -0800) it happened John Larkin
jla...@highlandSNIPMEtechnology.com> wrote in
aegp0i55pmr0sggm9...@4ax.com>:

On Sat, 11 Mar 2023 16:45:50 GMT, Jan Panteltje <al...@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 08:23:45 -0800) it happened John Larkin
jla...@highlandSNIPMEtechnology.com> wrote in
kcap0i9kf0tuc35hn...@4ax.com>:

We do have an all-facility EMI test system:

https://www.dropbox.com/s/tmcpmvqp714c82o/Roof_West.JPG?raw=1

?
All I see is a roof with some boxes?
Or are you referring to that antenna tower?

Yes. Sutro Tower. I suspect that the bowl of Castro Valley focusses
the RF into our building. I have been meaning to use the field to
light up some LEDs.

Yes, nice idea
Now I think about the radar making a flashing LED,
It is a rotating thing, every few seconds the beam hits here and some SAT channels get affected.

So a microwave antenna with high voltage output, and/or diode followed by a low voltage up-converter,
like this from a thermocouple:
https://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

Or maybe better for this purpose?
BAT diode voltage multiplier chain:
https://panteltje.nl/pub/bat15-99.gif

Or dish antenna? Bit big...


For lower frequencies just a few meters of wire may work (wavelength related).
So light your house with power from that tower
These people might. I\'ve been told that all sorts of things go wrong
on that street.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

The speakers on my ratty old Fiesta would buzz when I drove there,
with the radio turned off.
Was reading once about a guy who took power from the overhead powerlines by running a long
wire in parallel under it..
He was sued for stealing power IIRC.
Pretty cool idea though, if you have the land.


I\'m thinking that a resonated loop antenna might make enough voltage
to light an LED; a good LED is visible at a few uA. Maybe have the LED
capacitance be part of the resonance, or rectify with a low-barrier
Schottky. Some LEDs are fast and have low capacitance, some aren\'t.

I\'ve done the math for a 60 kHz loop, 50 ft diameter. Nowhere near enough power. It\'s not enough to ask for voltage. Without power you just drag down the Q of the antenna. I suppose if you are talking about being \"visible\" in a dark room staring directly at the LED, you might be able to get enough power, but nothing useful.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

[Phil Hobbs]

On 2023-03-12 12:50, Jan Panteltje wrote:

On a sunny day (Sun, 12 Mar 2023 08:39:08 -0700) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
b1sr0ih1h89avbdndvannrbcvjta3nd5ot@4ax.com>:

On Sun, 12 Mar 2023 06:24:06 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 10:08:57 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
aegp0i55pmr0sggm9udi28i91b2pa9gao3@4ax.com>:

On Sat, 11 Mar 2023 16:45:50 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sat, 11 Mar 2023 08:23:45 -0800) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
kcap0i9kf0tuc35hnlirtoobkqj6u19fgu@4ax.com>:

We do have an all-facility EMI test system:

https://www.dropbox.com/s/tmcpmvqp714c82o/Roof_West.JPG?raw=1

?
All I see is a roof with some boxes?
Or are you referring to that antenna tower?

Yes. Sutro Tower. I suspect that the bowl of Castro Valley focusses
the RF into our building. I have been meaning to use the field to
light up some LEDs.

Yes, nice idea
Now I think about the radar making a flashing LED,
It is a rotating thing, every few seconds the beam hits here and some SAT channels get affected.

So a microwave antenna with high voltage output, and/or diode followed by a low voltage up-converter,
like this from a thermocouple:
https://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

Or maybe better for this purpose?
BAT diode voltage multiplier chain:
https://panteltje.nl/pub/bat15-99.gif

Or dish antenna? Bit big...


For lower frequencies just a few meters of wire may work (wavelength related).
So light your house with power from that tower

These people might. I\'ve been told that all sorts of things go wrong
on that street.

https://www.dropbox.com/s/4fzsmipz0rar4ke/Panoramic_Drive.jpg?raw=1

Very typical houses, likly related to the slope of the hill


The speakers on my ratty old Fiesta would buzz when I drove there,
with the radio turned off.


Was reading once about a guy who took power from the overhead powerlines by running a long
wire in parallel under it..
He was sued for stealing power IIRC.
Pretty cool idea though, if you have the land.



I\'m thinking that a resonated loop antenna might make enough voltage
to light an LED; a good LED is visible at a few uA. Maybe have the LED
capacitance be part of the resonance, or rectify with a low-barrier
Schottky. Some LEDs are fast and have low capacitance, some aren\'t.

Yes, e LED parallel to a tuned LC might work....
Using an Extra diode would drop some voltage..
------------------
| |Cv |k |a
L =/= LED1 LED2
| | |a |k
------------------
tuning
cap

In my school days I build a 250 W linear, anttenna wire in the garden from the house towards a tree.
A neon bulb would light when anywhere near that antenna when transmitting!
About 7 MHz.. shortwave ham band
No license back then, got almost caught..
Almost ;-)

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Mike Monett VE3BTI]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell




--
MRM

 

[Phil Hobbs]

On 2023-03-12 16:34, Mike Monett VE3BTI wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

A Joule Thief will start up and run from less than 100 mV. It does need
magnetics, e.g.

<https://rustybolt.info/wordpress/?p=10944>

(First search result for \"joule thief jfet\".)

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Mike Monett VE3BTI]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

A Joule Thief will start up and run from less than 100 mV. It does need
magnetics, e.g.

https://rustybolt.info/wordpress/?p=10944

(First search result for \"joule thief jfet\".)

Cheers

Phil Hobbs

Wow! I gotta build one. What is the core? Is it critical, or just about
anything will do?

The jfet is more difficult. How about a chopper?

J111 Series N-Channel 35 V 20 mA Through Hole JFET Chopper Transistor - TO-
92-3

https://octopart.com/search?q=J111-D26Z&currency=USD&specs=0

- not as sharp cutoff tho

https://octopart.com/search?q=2sk170&currency=USD&specs=0

--
MRM

 

[Jan Panteltje]

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spamme@not.com> wrote in <XnsAFC5A8A94531Didtokenpost@88.198.57.247>:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

In the case of John Larkin\'s radio tower we need to know the frequency.
In this circuit you can get a lot of voltage gain like this:

\\ / antenna
|
| tunable core
| ---------------
| || | | |
| || ( |a |k
) || ( LED1 LED2
| || ( |k |a
| | | |
|--------------------
|
///
GND

Basically the normal antique antenna circuit,
Slide in a ferroxcube rod and you can tune it with that if it is AM medium wave, no antenna needed.


LEDs also work great on higher frequencies, I had a LED on my GPA 27 MHz CB antenna output once
and it would light up when the neighbor across the street transmitted,
Or something like this:
http://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG

 

[John Larkin]

On Mon, 13 Mar 2023 06:12:48 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spamme@not.com> wrote in <XnsAFC5A8A94531Didtokenpost@88.198.57.247>:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

In the case of John Larkin\'s radio tower we need to know the frequency.
In this circuit you can get a lot of voltage gain like this:

\\ / antenna
|
| tunable core
| ---------------
| || | | |
| || ( |a |k
) || ( LED1 LED2
| || ( |k |a
| | | |
|--------------------
|
///
GND

Yes. With RF from an antenna, impedance matching is easy. But a
schottky diode or two might still help.

Given my case, 22 megawatts spread over about 4 decades of frequency,
it would be academically fun to use a lot of spectrum to power my LED.

I recall a project in Popular Electronics magazine where they
rectified a bunch of the AM spectrum to power a 1-transistor amplifier
to gain up one of the stations and drive a loudspeaker. Cute.

Basically the normal antique antenna circuit,
Slide in a ferroxcube rod and you can tune it with that if it is AM medium wave, no antenna needed.


LEDs also work great on higher frequencies, I had a LED on my GPA 27 MHz CB antenna output once
and it would light up when the neighbor across the street transmitted,
Or something like this:
http://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG

I tested one LED that would make light as fast as I could drive and
measure it, about 2 ns in my case. I think some other LEDs are slow
and have high capacitance.

 

[Jan Panteltje]

On a sunny day (Mon, 13 Mar 2023 08:11:32 -0700) it happened John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote in
<3reu0i959g26722rhbrp97baaqvingl0r4@4ax.com>:

On Mon, 13 Mar 2023 06:12:48 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spamme@not.com> wrote in <XnsAFC5A8A94531Didtokenpost@88.198.57.247>:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

In the case of John Larkin\'s radio tower we need to know the frequency.
In this circuit you can get a lot of voltage gain like this:

\\ / antenna
|
| tunable core
| ---------------
| || | | |
| || ( |a |k
) || ( LED1 LED2
| || ( |k |a
| | | |
|--------------------
|
///
GND


Yes. With RF from an antenna, impedance matching is easy. But a
schottky diode or two might still help.

Given my case, 22 megawatts spread over about 4 decades of frequency,
it would be academically fun to use a lot of spectrum to power my LED.

Well, that is almost always a hit for some length of wire

Did you ever try a LED on a 1/2 wave antenna? this is the type of CB antenna I used:
https://moonrakeronline.com/eu/venom-gpa-1-2-wave-base-antenna
The bandwidth is really small, only about 2 MHz, you can fine tune SWR with the length...
It is 50 Ohms out, has a matching transformer inside:
https://pe4bas.blogspot.com/2014/12/whats-inside-old-gpa-27-12.html
You can make your own for any other frequency (length).
Need to know the frequency very precisely.

The loop antenna has even smaller bandwidth:
https://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG
https://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_dunno_IMG_4537.JPG

Must have been > 1.5V pp for the LED to glow brightly....
I asked my neighbor how many watts he was putting out, but he kept that a secret
there is a legal limit on the amount of watts you can use here for CB transmission.

Else just a RF inductor to ground with LED in parallel, any length of wire (depending on frequency)?

I recall a project in Popular Electronics magazine where they
rectified a bunch of the AM spectrum to power a 1-transistor amplifier
to gain up one of the stations and drive a loudspeaker. Cute.


Basically the normal antique antenna circuit,
Slide in a ferroxcube rod and you can tune it with that if it is AM medium wave, no antenna needed.


LEDs also work great on higher frequencies, I had a LED on my GPA 27 MHz CB antenna output once
and it would light up when the neighbor across the street transmitted,
Or something like this:
http://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG

I tested one LED that would make light as fast as I could drive and
measure it, about 2 ns in my case. I think some other LEDs are slow
and have high capacitance.

27 MHz was a cheap LED from local shop I think.
I now have a nice assortment of different colors and 2 sizes from ebay, something like this:
https://www.ebay.com/itm/385132659452
200 for $8.96


So, now I am posting this from the Raspberry Pi4 8 GB with a new compiled NewsFleX usenet reader I wrote.
(else I used the laptop).
Cut and paste is a bit easier that way, else I have to ssh to the other thing all the time.
Tried that Pi4 thing yet?
Now also have Apache webserver running on it (to test website things before I upload i).

I see I need to install ispell spellchecker on this Pi4 now.... just did (apt-get install ispell), but no go:
Can\'t open /usr/lib/ispell/english.hash

So sorry for any typos

 

[Phil Hobbs]

On 2023-03-13 11:11, John Larkin wrote:

On Mon, 13 Mar 2023 06:12:48 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spamme@not.com> wrote in <XnsAFC5A8A94531Didtokenpost@88.198.57.247>:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

In the case of John Larkin\'s radio tower we need to know the frequency.
In this circuit you can get a lot of voltage gain like this:

\\ / antenna
|
| tunable core
| ---------------
| || | | |
| || ( |a |k
) || ( LED1 LED2
| || ( |k |a
| | | |
|--------------------
|
///
GND


Yes. With RF from an antenna, impedance matching is easy. But a
schottky diode or two might still help.

Given my case, 22 megawatts spread over about 4 decades of frequency,
it would be academically fun to use a lot of spectrum to power my LED.

I recall a project in Popular Electronics magazine where they
rectified a bunch of the AM spectrum to power a 1-transistor amplifier
to gain up one of the stations and drive a loudspeaker. Cute.


Basically the normal antique antenna circuit,
Slide in a ferroxcube rod and you can tune it with that if it is AM medium wave, no antenna needed.


LEDs also work great on higher frequencies, I had a LED on my GPA 27 MHz CB antenna output once
and it would light up when the neighbor across the street transmitted,
Or something like this:
http://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG

I tested one LED that would make light as fast as I could drive and
measure it, about 2 ns in my case. I think some other LEDs are slow
and have high capacitance.

That\'s potentially pretty useful, if it\'s not super expensive. What
part was it?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John Larkin]

On Mon, 13 Mar 2023 17:15:41 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

On a sunny day (Mon, 13 Mar 2023 08:11:32 -0700) it happened John Larkin
jlarkin@highlandSNIPMEtechnology.com> wrote in
3reu0i959g26722rhbrp97baaqvingl0r4@4ax.com>:

On Mon, 13 Mar 2023 06:12:48 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spamme@not.com> wrote in <XnsAFC5A8A94531Didtokenpost@88.198.57.247>:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

In the case of John Larkin\'s radio tower we need to know the frequency.
In this circuit you can get a lot of voltage gain like this:

\\ / antenna
|
| tunable core
| ---------------
| || | | |
| || ( |a |k
) || ( LED1 LED2
| || ( |k |a
| | | |
|--------------------
|
///
GND


Yes. With RF from an antenna, impedance matching is easy. But a
schottky diode or two might still help.

Given my case, 22 megawatts spread over about 4 decades of frequency,
it would be academically fun to use a lot of spectrum to power my LED.

Well, that is almost always a hit for some length of wire

Did you ever try a LED on a 1/2 wave antenna? this is the type of CB antenna I used:
https://moonrakeronline.com/eu/venom-gpa-1-2-wave-base-antenna
The bandwidth is really small, only about 2 MHz, you can fine tune SWR with the length...
It is 50 Ohms out, has a matching transformer inside:
https://pe4bas.blogspot.com/2014/12/whats-inside-old-gpa-27-12.html
You can make your own for any other frequency (length).
Need to know the frequency very precisely.

The loop antenna has even smaller bandwidth:
https://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG
https://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_dunno_IMG_4537.JPG

Must have been > 1.5V pp for the LED to glow brightly....
I asked my neighbor how many watts he was putting out, but he kept that a secret
there is a legal limit on the amount of watts you can use here for CB transmission.

Else just a RF inductor to ground with LED in parallel, any length of wire (depending on frequency)?



I recall a project in Popular Electronics magazine where they
rectified a bunch of the AM spectrum to power a 1-transistor amplifier
to gain up one of the stations and drive a loudspeaker. Cute.


Basically the normal antique antenna circuit,
Slide in a ferroxcube rod and you can tune it with that if it is AM medium wave, no antenna needed.


LEDs also work great on higher frequencies, I had a LED on my GPA 27 MHz CB antenna output once
and it would light up when the neighbor across the street transmitted,
Or something like this:
http://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG

I tested one LED that would make light as fast as I could drive and
measure it, about 2 ns in my case. I think some other LEDs are slow
and have high capacitance.

27 MHz was a cheap LED from local shop I think.
I now have a nice assortment of different colors and 2 sizes from ebay, something like this:
https://www.ebay.com/itm/385132659452
200 for $8.96


So, now I am posting this from the Raspberry Pi4 8 GB with a new compiled NewsFleX usenet reader I wrote.
(else I used the laptop).
Cut and paste is a bit easier that way, else I have to ssh to the other thing all the time.
Tried that Pi4 thing yet?

I fired it up and got the home screen. That\'s all so far. I\'d hire
some programmers to do the real work. I prefer architecture and
hardware design lately.

I ordered a Pi 400, the keyboard with a Pi inside. That could be our
development system. I\'m thinking of doing a PCB that would plug into
it and have a ribbon cable that runs to our product boards, for debug
access and power supply monitoring and such.

We could have a dozen such dev systems, they would be so cheap.

I\'m still at the architecture stage of a new product line and it\'s
worth thinking for a while to get things right.

Now also have Apache webserver running on it (to test website things before I upload i).

I see I need to install ispell spellchecker on this Pi4 now.... just did (apt-get install ispell), but no go:
Can\'t open /usr/lib/ispell/english.hash

So sorry for any typos

No need to be prissy about typing and spelling, as long as people can
understand your intent.

 

[Mike Monett VE3BTI]

Mike Monett VE3BTI <spamme@not.com> wrote:

(First search result for \"joule thief jfet\".)

Cheers

Phil Hobbs

Wow! I gotta build one. What is the core? Is it critical, or just about
anything will do?

The jfet is more difficult. How about a chopper?

1. explore different configurations to find the lowest starting voltage

Oscillator with super low supply voltage
http://www.dicks-website.eu/fetosc/enindex.htm

2. typical low voltage JT do not deliver any power

Low voltage Joule thief - exotic transistors?
https://www.eevblog.com/forum/projects/low-voltage-joule-thief-exotic-
transistors/

2A. The LTC3108, available in either a 3 mm × 4 mm × 0.75 mm 12-pin DFN or
16-pin SSOP package, solves the energy harvesting problem for ultra-low
input voltage applications. It provides a compact, simple, highly
integrated monolithic power management solution for operation from input
voltages as low as 20 mV. This unique capability enables it to power
wireless sensors from a thermoelectric generator (TEG), harvesting energy
from temperature differentials (?T) as small as 1°C. Using a small (6 mm ×
6 mm), off-the-shelf step-up transformer and a handful of low cost
capacitors, it provides the regulated output voltages necessary for
powering today’s wireless sensor electronics.

3. this ic harvests energy from thermoelectric generators

Ultra-Low Voltage Energy Harvester Uses Thermoelectric Generator for
Battery-Free Wireless Sensors

https://www.digikey.com/en/articles/ultra-low-voltage-energy-harvester-
uses-thermoelectric-generator-for-battery-free-wireless-sensors

https://octopart.com/search?q=LTC3108&currency=USD&specs=0



--
MRM

 

[Phil Hobbs]

On 2023-03-13 14:26, Mike Monett VE3BTI wrote:

Mike Monett VE3BTI <spamme@not.com> wrote:

(First search result for \"joule thief jfet\".)

Cheers

Phil Hobbs

Wow! I gotta build one. What is the core? Is it critical, or just about
anything will do?

The jfet is more difficult. How about a chopper?

1. explore different configurations to find the lowest starting voltage

Oscillator with super low supply voltage
http://www.dicks-website.eu/fetosc/enindex.htm

2. typical low voltage JT do not deliver any power

Low voltage Joule thief - exotic transistors?
https://www.eevblog.com/forum/projects/low-voltage-joule-thief-exotic-
transistors/

2A. The LTC3108, available in either a 3 mm × 4 mm × 0.75 mm 12-pin DFN or
16-pin SSOP package, solves the energy harvesting problem for ultra-low
input voltage applications. It provides a compact, simple, highly
integrated monolithic power management solution for operation from input
voltages as low as 20 mV. This unique capability enables it to power
wireless sensors from a thermoelectric generator (TEG), harvesting energy
from temperature differentials (?T) as small as 1°C. Using a small (6 mm ×
6 mm), off-the-shelf step-up transformer and a handful of low cost
capacitors, it provides the regulated output voltages necessary for
powering today’s wireless sensor electronics.

3. this ic harvests energy from thermoelectric generators

Ultra-Low Voltage Energy Harvester Uses Thermoelectric Generator for
Battery-Free Wireless Sensors

https://www.digikey.com/en/articles/ultra-low-voltage-energy-harvester-
uses-thermoelectric-generator-for-battery-free-wireless-sensors

https://octopart.com/search?q=LTC3108&currency=USD&specs=0

Some years ago I worked with a medium-sized defense contractor on a
proposal to use IR antennas to scavenge power from the temperature
difference between the inside and outside of a soldier\'s shirt.

The idea was to power a short-burst radio beacon that would keep working
until the temperature difference went away.

A bit macabre, but potentially lifesaving. The feasibility calculation
looked pretty promising--a pity it didn\'t get funded.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[whit3rd]

On Sunday, March 12, 2023 at 11:21:48 PM UTC-7, Jan Panteltje wrote:

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spa...@not.com> wrote in <XnsAFC5A8A945...@88.198.57.247>:

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell
Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

It\'s also possible nowadays to get a MOSFET instead of a JFET that
has a good zero-volt threshold, from ALD...

and they make prebuilt circuits for this DC/DC convert function, too
<https://www.aldinc.com/ald_ehlvbooster.php>

 

[John Larkin]

On Mon, 13 Mar 2023 13:48:46 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-03-13 11:11, John Larkin wrote:
On Mon, 13 Mar 2023 06:12:48 GMT, Jan Panteltje <alien@comet.invalid
wrote:

On a sunny day (Sun, 12 Mar 2023 20:34:46 -0000 (UTC)) it happened Mike Monett
VE3BTI <spamme@not.com> wrote in <XnsAFC5A8A94531Didtokenpost@88.198.57.247>:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

Or failing that, a regular low-barrier Schottky detector and a Joule
Thief to drive the LED.

Might be fun making a Joule Thief out of a depletion pHEMT.

Cheers

Phil Hobbs

Need about 1V at some current

Diodes Inc. ZXSC310E5

https://octopart.com/search?q=ZXSC310E5&currency=USD&specs=0

or

2 X 2N3904
https://www.edn.com/single-cell-lights-any-led/

or

BC550C, 2N2222, BYV1030

https://www.electronicdesign.com/technologies/leds/article/21802105/ledstri
ng-driver-operates-from-single-cell

Yes, but mine runs from a simple thermocouple :
http://panteltje.nl/pub/lighting_a_LED_with_a_candle_IMG_3604.GIF

JFET (you only need 1 for a LED).

In the case of John Larkin\'s radio tower we need to know the frequency.
In this circuit you can get a lot of voltage gain like this:

\\ / antenna
|
| tunable core
| ---------------
| || | | |
| || ( |a |k
) || ( LED1 LED2
| || ( |k |a
| | | |
|--------------------
|
///
GND


Yes. With RF from an antenna, impedance matching is easy. But a
schottky diode or two might still help.

Given my case, 22 megawatts spread over about 4 decades of frequency,
it would be academically fun to use a lot of spectrum to power my LED.

I recall a project in Popular Electronics magazine where they
rectified a bunch of the AM spectrum to power a 1-transistor amplifier
to gain up one of the stations and drive a loudspeaker. Cute.


Basically the normal antique antenna circuit,
Slide in a ferroxcube rod and you can tune it with that if it is AM medium wave, no antenna needed.


LEDs also work great on higher frequencies, I had a LED on my GPA 27 MHz CB antenna output once
and it would light up when the neighbor across the street transmitted,
Or something like this:
http://panteltje.nl/pub/testing_the_20_meter_inductive_loop_antenna_IMG_4536.JPG

I tested one LED that would make light as fast as I could drive and
measure it, about 2 ns in my case. I think some other LEDs are slow
and have high capacitance.

That\'s potentially pretty useful, if it\'s not super expensive. What
part was it?

Cheers

Phil Hobbs

Sorry, can\'t remember now.

 

[Carl]

On 3/13/23 14:26, Mike Monett VE3BTI wrote:

Mike Monett VE3BTI <spamme@not.com> wrote:

(First search result for \"joule thief jfet\".)

Cheers

Phil Hobbs

Wow! I gotta build one. What is the core? Is it critical, or just about
anything will do?

The jfet is more difficult. How about a chopper?

1. explore different configurations to find the lowest starting voltage

Oscillator with super low supply voltage
http://www.dicks-website.eu/fetosc/enindex.htm

2. typical low voltage JT do not deliver any power

Low voltage Joule thief - exotic transistors?
https://www.eevblog.com/forum/projects/low-voltage-joule-thief-exotic-
transistors/

2A. The LTC3108, available in either a 3 mm × 4 mm × 0.75 mm 12-pin DFN or
16-pin SSOP package, solves the energy harvesting problem for ultra-low
input voltage applications. It provides a compact, simple, highly
integrated monolithic power management solution for operation from input
voltages as low as 20 mV. This unique capability enables it to power
wireless sensors from a thermoelectric generator (TEG), harvesting energy
from temperature differentials (?T) as small as 1°C. Using a small (6 mm ×
6 mm), off-the-shelf step-up transformer and a handful of low cost
capacitors, it provides the regulated output voltages necessary for
powering today’s wireless sensor electronics.

3. this ic harvests energy from thermoelectric generators

Ultra-Low Voltage Energy Harvester Uses Thermoelectric Generator for
Battery-Free Wireless Sensors

https://www.digikey.com/en/articles/ultra-low-voltage-energy-harvester-
uses-thermoelectric-generator-for-battery-free-wireless-sensors

https://octopart.com/search?q=LTC3108&currency=USD&specs=0

The voltage of a thermocouple junction is determined by the properties
of the two materials and the temperature difference, but what determines
how much current is available? Just wondering if it\'s the
cross-sectional area of the junction, and if so which is better for a
given amount of thermocouple material: lots of small junctions in
series to give higher voltage but very small current (standard
thermopile), or a small number of high-area junctions feeding a Joule
thief circuit?

--
Regards,
Carl

 

[John Larkin]

On Mon, 13 Mar 2023 18:19:30 -0400, Carl <carl.ijamesxx@yyverizon.net>
wrote:

On 3/13/23 14:26, Mike Monett VE3BTI wrote:
Mike Monett VE3BTI <spamme@not.com> wrote:

(First search result for \"joule thief jfet\".)

Cheers

Phil Hobbs

Wow! I gotta build one. What is the core? Is it critical, or just about
anything will do?

The jfet is more difficult. How about a chopper?

1. explore different configurations to find the lowest starting voltage

Oscillator with super low supply voltage
http://www.dicks-website.eu/fetosc/enindex.htm

2. typical low voltage JT do not deliver any power

Low voltage Joule thief - exotic transistors?
https://www.eevblog.com/forum/projects/low-voltage-joule-thief-exotic-
transistors/

2A. The LTC3108, available in either a 3 mm × 4 mm × 0.75 mm 12-pin DFN or
16-pin SSOP package, solves the energy harvesting problem for ultra-low
input voltage applications. It provides a compact, simple, highly
integrated monolithic power management solution for operation from input
voltages as low as 20 mV. This unique capability enables it to power
wireless sensors from a thermoelectric generator (TEG), harvesting energy
from temperature differentials (?T) as small as 1°C. Using a small (6 mm ×
6 mm), off-the-shelf step-up transformer and a handful of low cost
capacitors, it provides the regulated output voltages necessary for
powering today’s wireless sensor electronics.

3. this ic harvests energy from thermoelectric generators

Ultra-Low Voltage Energy Harvester Uses Thermoelectric Generator for
Battery-Free Wireless Sensors

https://www.digikey.com/en/articles/ultra-low-voltage-energy-harvester-
uses-thermoelectric-generator-for-battery-free-wireless-sensors

https://octopart.com/search?q=LTC3108&currency=USD&specs=0

The voltage of a thermocouple junction is determined by the properties
of the two materials and the temperature difference,

Not exactly, but close.

but what determines
>how much current is available?

The loop resistance. T/C wire tends to have a lot of resistance
compared to copper. Fatter and shorter wire allows more current but
conducts more heat so is harder to force a temperature difference
across.

Just wondering if it\'s the
cross-sectional area of the junction, and if so which is better for a
given amount of thermocouple material: lots of small junctions in
series to give higher voltage but very small current (standard
thermopile), or a small number of high-area junctions feeding a Joule
thief circuit?

Probably lots of little ones in series. That\'s easier to use.