Making a Spark-Gap Transmitter

00:16:22
https://www.youtube.com/watch?v=SnKKj2bonAI

Summary

TLDRThis video explores the creation and functioning of an arc transmitter, a concept based on early wireless RF (radio frequency) technology. The host attempts to recreate an early type of RF transmitter named after Nikola Tesla, using a Taser to produce electrical arcs. These arcs serve the purpose of generating high-frequency electromagnetic waves. The project involves designing a circuit using inductors, capacitors, and spark gaps to resonate at a specific frequency, thus mimicking a primitive form of wireless communication. Additionally, the host discusses how these concepts were initially used to carry information rather than power and offers insights into measuring inductance and resonance frequencies more accurately. The video is intertwined with an ExpressVPN sponsorship, emphasizing online privacy and security. It aims to educate viewers about basic electronics concepts and potentially inspire homemade experiments with wireless technology.

Takeaways

  • ⚡Arc transmitters were an early form of RF communication technology.
  • 🔌Using a Taser, high-voltage arcs are generated to transmit signals.
  • 📡Wireless technology stemmed from concepts similar to power transmission.
  • 🔄Capacitors and inductors resonate to tune frequency in circuits.
  • 📏Inductance measurements can determine resonance frequency.
  • 📈Enhanced signal transmission requires precise component alignment.
  • 🐍Inductor windings need spacing to prevent arcing due to high voltage.
  • 📡Antennas are essential for extending transmission range over distance.
  • 🛡️ExpressVPN can secure your online activities and protect privacy.
  • 🔋Loading the circuit affects voltage levels and transmission strength.

Timeline

  • 00:00:00 - 00:05:00

    The speaker aims to create an arc transmitter, considered the first RF radio wireless transmitter. Using a previously made Taser to generate necessary arcs, they explore circuit design challenges, examining problems like relay welding and high-voltage arcing. A Tesla coil circuit is discussed, focusing on resonance and high-voltage generation. Innovations to simplify Tesla's design led to early radio technology by replacing complex parts with a simple antenna to transmit electromagnetic waves. The presenter considers using their taser circuit to generate high voltage for this purpose. ExpressVPN is briefly promoted.

  • 00:05:00 - 00:10:00

    The speaker prepares to create a high-voltage capacitor using a Leyden jar for the transmitter, but encounters issues with a rotted screw, fixing it with a fresh one. To resonate at 1 MHz, they calculate needing a 19 micro henry inductor and design one using a 16 mm PVC pipe. However, they only manage 15 turns, resulting in about 7.8 micro henries, less than desired. They attempt to measure inductance accurately, discussing impedance and resonance frequency measurement techniques, and estimate an actual inductance of about 9.5 micro henries, leading to a resonance around 1.4 MHz.

  • 00:10:00 - 00:16:22

    They assemble the transmitter by connecting a capacitor and inductor, observing arc behavior. Despite some challenges, the system achieves a resonance at 1.4 MHz, suitable for radio frequency transmission. A receiver circuit, consisting of an inductor and capacitor, is constructed, but it initially displays weak performance. Connecting to an antenna and grounding, the receiver shows improved results, picking up radio signals. The discussion highlights the importance of strong filters and amplifiers for signal clarity. Final remarks reflect on the historical use of radio waves and data encryption by companies, tying back to ExpressVPN promoting online privacy.

Mind Map

Video Q&A

  • What is an arc transmitter?

    An arc transmitter is a type of radio transmitter that uses electrical arcs to create radio waves that can be transmitted wirelessly.

  • How is the arc created in the video?

    The arc is created using a modified Taser circuit that generates high-voltage power to produce the necessary arcs between electrodes.

  • Why is Nikola Tesla mentioned in the video?

    Nikola Tesla is mentioned because the concept of the arc-driven Tesla coil circuit, used for generating high-voltage, is based on his designs and ideas.

  • What role does a capacitor play in this circuit?

    In the circuit, the capacitor stores electrical energy and releases it to create a stronger arc when used in conjunction with an inductor.

  • How is the resonance frequency calculated?

    The resonance frequency is calculated using the inductance and capacitance in the circuit, creating a frequency where the reactive effects of the circuit components balance each other.

  • What is the purpose of the inductor?

    The inductor is used to resonate with the capacitor at a specific frequency to create efficient transmission of energy through the circuit.

  • Why is ExpressVPN mentioned?

    ExpressVPN is mentioned as a sponsor of the video, highlighting its usefulness in securing internet communications and bypassing geographic restrictions.

  • What experiment is demonstrated using antennas?

    The experiment demonstrates transmitting RF signals via an antenna across a room, illustrating the potential for long-distance wireless communication.

  • What did the speaker use to measure inductance?

    The speaker used a frequency response analysis on an oscilloscope to measure the inductance in their circuit.

  • Why was the circuit adjusted for resonance at 1.4 megahertz?

    The circuit was adjusted to resonate at 1.4 megahertz to match the desired frequency for optimal performance.

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  • 00:00:00
    hi I want to try and make an arc
  • 00:00:02
    transmitter I think it's the first-ever
  • 00:00:05
    RF radio wireless transmitter ever
  • 00:00:07
    invented you know back when Tesla was
  • 00:00:10
    busy wasting his time trying to transmit
  • 00:00:12
    power wirelessly around the world other
  • 00:00:15
    people figured out they could use the
  • 00:00:16
    same technology to transmit information
  • 00:00:18
    which is literally the same thing as
  • 00:00:21
    transmitting power around the world just
  • 00:00:23
    that it wasn't enough to power anything
  • 00:00:24
    but was just enough to transmit the
  • 00:00:26
    information there see I made the Taser a
  • 00:00:30
    while back and I'm gonna use it to
  • 00:00:32
    create the arcs I need and there it is
  • 00:00:34
    let's see if it works after all these
  • 00:00:36
    years what what happened there is to be
  • 00:00:47
    two nails in there and the gap was
  • 00:00:48
    shorter if I put a piece of wire there
  • 00:00:51
    to make the gap shorter it starts going
  • 00:00:56
    yes there it is
  • 00:00:58
    now it works died again what's going on
  • 00:01:06
    there haha see this is the circuit I
  • 00:01:16
    designed for my taser which I explained
  • 00:01:18
    in my website electro boom come if you
  • 00:01:20
    are interested I have a relay here that
  • 00:01:23
    switches back and forth and when it's on
  • 00:01:25
    this side it charges the primary of the
  • 00:01:27
    transformer but when it disconnects
  • 00:01:30
    there is high-voltage energy here that
  • 00:01:32
    arcs between the contacts and they heat
  • 00:01:35
    up and eventually get welded and
  • 00:01:37
    permanently shorted and when I flick the
  • 00:01:40
    relay they disconnect and start working
  • 00:01:42
    again hopefully I won't have to deal
  • 00:01:44
    with that problem now now I have some
  • 00:01:46
    general knowledge and how this
  • 00:01:47
    transmitter should work and this might
  • 00:01:50
    or might not be good enough for my
  • 00:01:51
    transmitter let's give it a try this is
  • 00:01:54
    a typical arc driven Tesla coil circuit
  • 00:01:56
    designed by Nikola Tesla what it does is
  • 00:01:59
    that using an initial transformer it
  • 00:02:01
    amplifies some AC voltage to ten twenty
  • 00:02:04
    or thirty kilovolts this is a spark gap
  • 00:02:07
    and at the peak of the AC voltage when
  • 00:02:09
    the voltage across these two points is
  • 00:02:11
    maximum and our
  • 00:02:12
    is created between them and you know an
  • 00:02:15
    arc has a very low resistance so this
  • 00:02:17
    thing is like a switch that closes at
  • 00:02:19
    high voltage now when the switch closes
  • 00:02:21
    the high voltage energy of the capacitor
  • 00:02:23
    pours into the primary inductor of the
  • 00:02:26
    Tesla coil and they resonate and
  • 00:02:28
    oscillate at a certain frequency which
  • 00:02:30
    matches the resonant frequency of the
  • 00:02:32
    secondary of Tesla coil the huge winding
  • 00:02:35
    turn ratio of the Tesla coil combined to
  • 00:02:38
    the resonance frequency can create
  • 00:02:40
    millions of volts at the output now if
  • 00:02:43
    you're smart enough but not too smart
  • 00:02:44
    yet you might ask when this switch is
  • 00:02:47
    closed we still have this inductor
  • 00:02:49
    parallel to that circuit how come it
  • 00:02:50
    doesn't affect the resonance frequency
  • 00:02:52
    the reason is that this inductance is
  • 00:02:55
    much larger than that one and at the
  • 00:02:57
    resonance frequency which is much larger
  • 00:02:59
    than the input frequency this guy is
  • 00:03:01
    like an open circuit
  • 00:03:03
    now while Nikola Tesla was kicking
  • 00:03:05
    himself with this circuit other people
  • 00:03:06
    figured out that we don't need this
  • 00:03:08
    secondary part we can just add an
  • 00:03:11
    antenna here and this circuit was strong
  • 00:03:15
    enough to create electromagnetic waves
  • 00:03:17
    and radio frequencies that could be
  • 00:03:19
    picked up by a receiver on the other
  • 00:03:21
    side or at least that's what I think and
  • 00:03:23
    I'm thinking maybe I'm thinking maybe I
  • 00:03:26
    can use my taser circuit instead of this
  • 00:03:28
    transformer to create high voltage here
  • 00:03:31
    so the idea here is to transmit radio
  • 00:03:33
    frequencies to be picked up by another
  • 00:03:35
    circuit which is essentially another
  • 00:03:37
    inductor and capacitor with the
  • 00:03:39
    resonance frequency that matches the
  • 00:03:41
    transmitter and the voltage built up
  • 00:03:43
    here would be large enough to be
  • 00:03:44
    detected by another circuit so I guess
  • 00:03:46
    anyone with a proper inductor and
  • 00:03:48
    capacitor could read your information
  • 00:03:50
    yes we are talking about all times
  • 00:03:52
    nobody knew how to do it unlike now that
  • 00:03:54
    I'm telling you how to do it that's why
  • 00:03:56
    we need expressvpn the sponsor of this
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    video expressvpn is a simple and
  • 00:04:01
    powerful app that runs on pretty much
  • 00:04:03
    any platform turns on with the click of
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    a button and secures or network
  • 00:04:07
    communications especially on public
  • 00:04:09
    networks data protection hiding your
  • 00:04:12
    location content on location just visit
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    expressvpn comm / electro boom to get
  • 00:04:17
    three months free service and learn
  • 00:04:19
    anyway looking at this it's very much
  • 00:04:22
    the same as the original Tesla coil with
  • 00:04:24
    the primary resonating with the
  • 00:04:26
    secondary and creating a voltage there
  • 00:04:28
    except that in the Tesla coil these two
  • 00:04:30
    are much closer and the output voltage
  • 00:04:32
    is much higher and as you move this
  • 00:04:34
    further the voltage goes lower and lower
  • 00:04:36
    that's why Nikola Tesla's work was
  • 00:04:38
    essential in wireless communication
  • 00:04:40
    there are different configurations of
  • 00:04:42
    the same circuit that do the same thing
  • 00:04:44
    but for now I'll go with this one and
  • 00:04:45
    see what happens I'll have to make my
  • 00:04:47
    components and my capacitors have to be
  • 00:04:49
    very high voltage and my receiver though
  • 00:04:52
    the voltage is much lower so I can use
  • 00:04:53
    regular components so for my capacitor
  • 00:04:56
    I'm thinking to use my Leyden jar I made
  • 00:04:59
    a while back should clean it up a little
  • 00:05:02
    bit but it should be able to handle tens
  • 00:05:03
    of kilo volts smell oh jeez it's all
  • 00:05:11
    rotted in there oh why did I forget to
  • 00:05:14
    remove the water from there my screw
  • 00:05:19
    they're turning to powder look at this
  • 00:05:25
    there we go
  • 00:05:27
    a fresh screw and wire and with fresh
  • 00:05:30
    salt water so we are ready to go I don't
  • 00:05:33
    need the ball on the top and if it's
  • 00:05:35
    like last time the capacitance should be
  • 00:05:37
    around yeah 1.3 nano farad
  • 00:05:40
    okay so my capacitor is in good shape
  • 00:05:41
    now I need to make an inductor I'm
  • 00:05:43
    thinking to make it resonate at 1
  • 00:05:46
    megahertz and for that I have to do it
  • 00:05:52
    on paper there you go I need around 19
  • 00:05:58
    micro Henry of inductance now to make my
  • 00:06:00
    inductor I need a big cylinder to wind
  • 00:06:04
    the wires around let's assume for now
  • 00:06:07
    I'm going to use this PVC pipe with a
  • 00:06:09
    diameter of 16 millimeters now I want to
  • 00:06:13
    make an air core inductor like this with
  • 00:06:17
    windings separated by some distance
  • 00:06:19
    because the voltage across the
  • 00:06:21
    inductance I have is like tens of kilo
  • 00:06:23
    volts so it could arc between the
  • 00:06:25
    windings if there are too close I'm
  • 00:06:28
    going to use this calculator because
  • 00:06:29
    their model seems to match what I'm
  • 00:06:32
    trying to do
  • 00:06:32
    and if I put my parameters in 30 turns
  • 00:06:35
    and half a centimeter spacing between
  • 00:06:37
    the wires my inductor will end up being
  • 00:06:39
    around 18 micro henries which is close
  • 00:06:42
    enough damnit I only have enough water
  • 00:06:57
    for 15 turns hopefully that's enough
  • 00:06:59
    otherwise I'll have to add according to
  • 00:07:01
    the calculator with 15 turns I should
  • 00:07:04
    get around 7.8 micro henries that would
  • 00:07:07
    significantly raise my resonance
  • 00:07:09
    frequency let's measure the actual value
  • 00:07:12
    let's see how much is the inductance
  • 00:07:17
    zero after all this I think this is not
  • 00:07:20
    accurate for the small inductance I have
  • 00:07:23
    to do it another way
  • 00:07:24
    I measured inductor like this I put a
  • 00:07:26
    hundred on series resistor with the
  • 00:07:28
    inductor provide a sine wave input and
  • 00:07:31
    measure the output now if I plot the
  • 00:07:33
    output on a logarithmic scale versus
  • 00:07:36
    frequency at low frequency the inductor
  • 00:07:38
    is like a short circuit so the output is
  • 00:07:41
    low and as the frequency rises the
  • 00:07:43
    impedance Rises and so the output
  • 00:07:45
    voltage until at some point the inductor
  • 00:07:48
    is like an open circuit and the line
  • 00:07:50
    goes flat now at a certain frequency the
  • 00:07:53
    output to input difference is three
  • 00:07:55
    decibels or the output voltage to input
  • 00:07:57
    ratio is around 0.7 if we measure that
  • 00:08:01
    frequency using this equation we can
  • 00:08:03
    calculate the inductance here you know
  • 00:08:05
    is the input sine-wave
  • 00:08:06
    and green is the output voltage across
  • 00:08:08
    the inductor and if I sweep the
  • 00:08:11
    frequency higher you see that the green
  • 00:08:14
    voltage across the output rises - and
  • 00:08:17
    when it reaches around 70 percent of the
  • 00:08:20
    input voltage that's where your 3 DB
  • 00:08:23
    frequency is but fortunately for me my
  • 00:08:25
    scope has this frequency response
  • 00:08:27
    analysis function that will plot these
  • 00:08:29
    graphs for me automatically and here the
  • 00:08:31
    blue curve is my amplitude change and I
  • 00:08:34
    can see that around here is my 3 DB drop
  • 00:08:38
    and it is at 1.68 megahertz and that
  • 00:08:43
    means my inductor is around nine and a
  • 00:08:46
    half micro henries see in the ballpark
  • 00:08:49
    and if I use these numbers to calculate
  • 00:08:51
    my resonance frequency it's around 1.4
  • 00:08:54
    mega Hertz
  • 00:08:55
    I guess it's okay let's actually measure
  • 00:08:58
    it when I have a LC circuit like this
  • 00:09:00
    and measure the output at low frequency
  • 00:09:03
    the inductor is like a short circuit and
  • 00:09:05
    the output is low at high frequency the
  • 00:09:07
    capacitor is like a short circuit and
  • 00:09:09
    the output is low so when I raise the
  • 00:09:12
    frequency the output goes up and then
  • 00:09:15
    goes down again and this spot which is
  • 00:09:19
    my resonance frequency is where the
  • 00:09:22
    impedance of these two is infinite and
  • 00:09:24
    the output is equal to input all my
  • 00:09:26
    wires here probably will add some
  • 00:09:28
    inductance to the system and drop the
  • 00:09:30
    frequency a little bit but yeah here we
  • 00:09:35
    are we have a terrible looking peak and
  • 00:09:37
    the amplitude starts rising at higher
  • 00:09:40
    frequency again and the peak frequency
  • 00:09:43
    is around 1.4 megahertz see here's the
  • 00:09:46
    problem we have when we measure the
  • 00:09:48
    output voltage at this point and we have
  • 00:09:50
    alligator clips here that have some tiny
  • 00:09:53
    inductance associated with them at low
  • 00:09:56
    frequency this inductance is like a
  • 00:09:58
    short circuit and as the frequency Rises
  • 00:10:01
    the voltage Rises until we reach the
  • 00:10:03
    resonance frequency after which this
  • 00:10:06
    capacitor takes over and the voltage
  • 00:10:08
    drops again but above some frequency
  • 00:10:10
    these tiny inductors become much larger
  • 00:10:13
    impedance and isolate the capacitor from
  • 00:10:15
    the measurement point and the voltage
  • 00:10:18
    Rises again but if we measure as close
  • 00:10:20
    as possible to the capacitor to reduce
  • 00:10:22
    the line inductance then we will push
  • 00:10:26
    this voltage return thing to much higher
  • 00:10:29
    frequencies which doesn't affect what we
  • 00:10:31
    are trying to do just that our resonant
  • 00:10:34
    circuit will have a little bit of higher
  • 00:10:35
    inductance due to these wires let's try
  • 00:10:38
    the same thing with the Leyden jar what
  • 00:10:40
    do we do
  • 00:10:41
    there we go now my peak is around one
  • 00:10:43
    and a half megahertz and my high
  • 00:10:45
    frequency inductive crap happens at much
  • 00:10:47
    higher frequency if we run our wires a
  • 00:10:49
    straight compared to looping them a
  • 00:10:51
    couple of times it will make a
  • 00:10:52
    significant difference in
  • 00:10:54
    resonance frequency which we could use
  • 00:10:56
    let's put them together first off the
  • 00:10:58
    capacitor this is the art without the
  • 00:11:00
    capacitor and now here we have the arcs
  • 00:11:05
    with the capacitor connected see it
  • 00:11:08
    doesn't work anymore because I think the
  • 00:11:10
    capacitor is loading the output voltage
  • 00:11:13
    and reducing it so I have to bring the
  • 00:11:14
    contacts further close never rely on the
  • 00:11:23
    wire coating very high voltage easily
  • 00:11:26
    breaks through it here I made a
  • 00:11:28
    sophisticated spark gap here
  • 00:11:30
    that's adjustable too now this is with
  • 00:11:33
    the capacitor across the output arcs are
  • 00:11:37
    much stronger and without the capacitor
  • 00:11:42
    much weaker the reason is the capacitor
  • 00:11:44
    stores a much greater energy and release
  • 00:11:47
    it in a stronger and now I add my
  • 00:11:50
    inductor to the circuit - so now the arc
  • 00:11:53
    has to go through the inductor and arcs
  • 00:11:56
    are a little bit weaker now because the
  • 00:11:59
    inductor limits this spike of current
  • 00:12:01
    and resonates with the capacitor goody
  • 00:12:03
    now I have a loop on my probe and let's
  • 00:12:06
    see what will pick up on this scope look
  • 00:12:10
    at this beauty it's clearly resonating
  • 00:12:13
    at a frequency of around 1.4 megahertz
  • 00:12:16
    with a peak of 5 volts let's make a
  • 00:12:18
    receiver so here I made an inductor
  • 00:12:20
    that's around 14 micro henries parallel
  • 00:12:23
    with the 1 nano farad capacitor to give
  • 00:12:26
    me a resonance of around 1.4 megahertz
  • 00:12:28
    and this is what we get on the receiver
  • 00:12:31
    these voltages are above 40 volts is
  • 00:12:37
    smaller the power of resonance I should
  • 00:12:41
    be able to turn on some LEDs with this
  • 00:12:43
    here I put two parallel reverse LEDs
  • 00:12:45
    across the circuit and it's barely turn
  • 00:12:50
    on even very close to the inductor which
  • 00:12:52
    means that the received energy is very
  • 00:12:54
    small and as soon as we loaded the
  • 00:12:56
    voltage significantly drops which means
  • 00:12:58
    as long as we don't load the circuit it
  • 00:13:00
    should have high enough voltage to
  • 00:13:02
    detect so I'm gonna use this circuit I
  • 00:13:03
    made a while back that
  • 00:13:05
    takes AC voltages from the wire there we
  • 00:13:08
    go
  • 00:13:08
    and I'm running it off a 9-volt battery
  • 00:13:10
    so it's a little bit more sensitive and
  • 00:13:12
    if I press the switch it's turning on
  • 00:13:17
    and it's getting brighter
  • 00:13:19
    get closer go away of course I didn't
  • 00:13:27
    put an antenna on me so I should do that
  • 00:13:29
    in AM radio frequencies where I'm at it
  • 00:13:32
    greatly helps if we ground the
  • 00:13:34
    transmitter and receiver and have one of
  • 00:13:36
    those massive antennas you have probably
  • 00:13:38
    seen around the roads at least at the
  • 00:13:40
    transmitter the radio waves like a
  • 00:13:42
    mirror bounce of Earth and ionosphere
  • 00:13:45
    which is a charged layer in the
  • 00:13:47
    atmosphere and can travel long distances
  • 00:13:49
    I have an extension cord I'll connect to
  • 00:13:51
    my transmitter as the antenna and
  • 00:13:53
    another extension code as the receiver
  • 00:13:55
    antenna I guess I'll just connect it to
  • 00:13:57
    my ceiling delight the other side to air
  • 00:14:00
    through my scope ground well let's just
  • 00:14:03
    move it all the way back in this corner
  • 00:14:06
    and I'll use the outlet airs to connect
  • 00:14:09
    it to ground there you go no antenna
  • 00:14:12
    connected don't see anything now I'll
  • 00:14:18
    just hook my receiver antenna to this
  • 00:14:20
    corner here and here it is with the
  • 00:14:23
    antenna of course at the receiver the
  • 00:14:32
    signal will be very small over long
  • 00:14:35
    distances so you need a very sharp
  • 00:14:36
    filter to extract your signal from noise
  • 00:14:39
    and a very low noise amplifier to
  • 00:14:41
    increase the signal to a usable level
  • 00:14:44
    well it's always encouraging to know
  • 00:14:46
    your knowledge is not absolute this is
  • 00:14:49
    what they used a while back to send
  • 00:14:51
    Morse codes help me of course these
  • 00:14:56
    radio waves are always available for
  • 00:14:58
    everyone to pick up and read that's why
  • 00:15:00
    when there were sending Morse codes they
  • 00:15:02
    would use a special code to encrypt
  • 00:15:04
    their data so that nobody could
  • 00:15:06
    understand them same thing they do at
  • 00:15:08
    expressvpn even when you're at home
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    which you should be right now your ISP
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    can see all your internet
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    activity like the websites you visit for
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    how long and how much data is
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    transmitted and can sell this
  • 00:15:20
    information to advertisement companies
  • 00:15:22
    you turn on the expressvpn
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    app on your device and bam the
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    communication from your device to the
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    server of your choice is heavily
  • 00:15:29
    encrypted private and secure this is why
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    I use Express VPN the other reason is
  • 00:15:34
    that some companies websites or
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    governments block your access based on
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    your location and content you know who
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    you are so I use Express VPN to connect
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    to a different country and pull my data
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    from there the government doesn't know
  • 00:15:49
    why I connected to say Venezuela and
  • 00:15:51
    don't know what my encrypted data is and
  • 00:15:54
    the company thinks hey Venezuela is
  • 00:15:57
    whitelisted so I get what I need from
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    their specific typical Iranian
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    day-to-day life anyway my link gives you
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    three months of free service and then a
  • 00:16:06
    low monthly fee afterwards register and
  • 00:16:08
    enjoy your privacy security and access
  • 00:16:11
    and thank you for watching
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