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Low Frequency Antennas

We have the high performance low frequency antenna that you've been looking for!

Specializing in antennas for reception applications below 530 KHz:

  • Antennas for Long Wave, and Navigation Beacon band: 150 KHz - 530 KHz.
  • Antennas for LF low frequency band: 30 KHz - 300 KHz.
  • Antennas for VLF very low frequency band: 3 KHz - 30 KHz.
  • Antennas for ULF ultra low frequency band: 300 Hz - 3 KHz.
  • Antennas for SLF super low frequency band: 30 Hz - 300 Hz.
  • Antennas for ELF extreme low frequency band: 0.3 Hz - 30 Hz.
  • ELF Antennas for detecting earthquakes, ground vibrations, and infrasonic sound waves.
  • Antennas for lightning detection.
  • SCROLL DOWN to see different antenna types for individual radio frequency bands below on this page.
    RADIO ANTENNAS

    Antennas for reception in the frequency range of 0.1 Hz to 5 MHz


    Very Low Frequency Antenna

    ANTM1. This 6.5 inch long antenna can be tuned from 3 KHz to 39 KHz with an external capacitor value of 0.1 uF to 370 pF. @ 370 pF tunes to @ 39 KHz. 0.1 uF tunes to @ 3 KHz.

    Weather proof sealed. 6 inch wire leads. Great for series resonant use in small transmitters or receivers. 1 watt max.

    $ 30.00 + s/h.


    Low Frequency Antenna WWVB 60 KHz.

    ANTM2. This 6.5 inch long antenna can be tuned from 30 KHz to 90 KHz with an external capacitor value of 100 pF to 3000 pF. @ 370 pF tunes to 60 KHz. Great for series resonant use in small receivers.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    Longwave Antenna

    ANTM3. This 6.5 inch long antenna can be tuned from 150 KHz to 300 KHz with an external capacitor value of 100 pF to 384 pF. @ 370 pF tunes to 150 KHz. Great for series resonant use in small transmitters or receivers. 1 watt max.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    AM Radio Band Antenna

    ANTM4. This 6.5 inch long antenna can be tuned from 530 KHz to 1700 KHz with an external capacitor value of 10 pF to 384 pF. @ 384 pF tunes to 520 KHz. Great for series resonant use in small transmitters or receivers. 1 watt max.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    Marine Band Shortwave Antenna

    ANTM5. This 6.5 inch long antenna can be tuned from 2.0 MHz to 3.0 MHz with an external capacitor value of 10 pF to 384 pF. @ 370 pF tunes to 2 MHz. Great for series resonant use in small transmitters or receivers. 1 watt max.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    HAM Shortwave Antenna

    ANTM6. This 6.5 inch long antenna can be tuned from 3.5 MHz to 4.0 MHz with an external capacitor value of 10 pF to 384 pF. @ 370 pF tunes to 3.5 MHz. Great for series resonant use in small transmitters or receivers. 1 watt max.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    WWV 2.5 MHz Shortwave Antenna

    ANTM7. This 6.5 inch long antenna can be tuned from 2.4 MHz to 3.0 MHz with an external capacitor value of 100 pF to 384 pF. @ 370 pF tunes to 2.5 MHz. Great for series resonant use in WWV 2.5 MHz receivers.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    WWV 5 MHz Shortwave Antenna

    ANTM8. This 6.5 inch long antenna can be tuned from 4.9 MHz to 5.5 MHz with an external capacitor value of 100 pF to 384 pF. @ 370 pF tunes to 5 MHz. Great for series resonant use in WWV 5 MHz receivers.

    Weather proof sealed. 6 inch wire leads.

    $ 30.00 + s/h.


    RFID Antenna 134.2 KHz.

    These 7 inch long antennas are factory pre-tuned. Series resonant. 6 inch wire leads. Weather proof sealed. Great for low power transmitters (1 watt or less), and single frequency receivers.

    $ 30.00 each + s/h.
    Part number: 7SR-134.2 KHz.


    WWVB Clock Antenna. 60.0 KHz.

    These 7 inch long antennas are factory pre-tuned. Series resonant. 6 inch wire leads. Weather proof sealed. For single frequency 60 KHz receivers.

    $ 30.00 each + s/h.
    Part number: 7SR-60.0 KHz.

    Data Sheet pdf


    VLF Lightning Detection Antennas.
    6.5 KHz, 8.2 KHz, 10.0 KHz, 12.8 KHz, and 40.0 KHz.

    These 7 inch long antennas can be used to detect lightning flashes up to 300 miles away. Series resonant. Factory pre-tuned. 6 inch wire leads. Weather proof sealed.

    The higher frequencies will give slightly more range than the lower ones. Lightning emissions have a slight peak frequency centered around 10 KHz.

    $ 30.00 each + s/h.
    Part number: 7SR-4.7 KHz. Best detection range at night.
    Part number: 7SR-6.5 KHz. Day and night. Increased detection range at night.
    Part number: 7SR-8.2 KHz. Day and night.
    Part number: 7SR-10.0 KHz. Day and night. Peak frequency for cloud-to-ground lightning radio static emissions.
    Part number: 7SR-12.8 KHz. Day and night.
    Part number: 7SR-40.0 KHz. Day and night. Increased detection range at night.

    Data Sheet pdf


    LF Lightning Detection Antenna. 350 KHz.

    These 7 inch long antennas can be used to detect lightning flashes up to 50 miles away. Severe thunderstorms emit continuous radio static at this frequency due to in-cloud and cloud-to-cloud lightning flashes. Series resonant. Factory pre-tuned to 350 KHz. 6 inch wire leads. Weather proof sealed.

    $ 30.00 each + s/h.
    Part number: 7SR-350 KHz.

    Data Sheet pdf


    LOWFER Antennas.
    160 KHz - 190 KHz.

    These 7 inch long antennas can be used in the part 15 low frequency band of 160 KHz to 190 KHz for reception.

    Series resonant.

    $ 30.00 each + s/h.
    Part number: 7SR-160 KHz.
    Part number: 7SR-161 KHz.
    Part number: 7SR-165 KHz.
    Part number: 7SR-170 KHz.
    Part number: 7SR-175 KHz.
    Part number: 7SR-180 KHz.
    Part number: 7SR-185 KHz.
    Part number: 7SR-189 KHz.
    Part number: 7SR-190 KHz.


    Seismograph ELF Antenna.
    1 Hz - 1 KHz.

    This antenna is very sensitive and is the part you need for your seismograph. This antenna will detect large earthquakes over 1000 miles away. Perfect for your use in your DIY seismograph. We like this antenna the best because it is small and very sensitive.

    These 6.5 inch long by 1.125 inch diameter antennas are for use in seismographs. You can build a seismograph to detect earthquakes. Its easy: See Bucket Seismograph 3.

    The antenna has a response of 1 Hz to 1 KHz.

    Weather-proof.

    Part number: 8SR-1H-1K. $ 50.00 each + s/h.
    Data Sheet


    10 inch and 22 inch long antennas for ELF through Longwave

    tuned directional antenna

    These small portable antennas tune different radio bands as shown in the table below. Powerful reception in a compact water-proof size.

    Features super high impedance output for special receviers, but also allows tuned matching of any standard radio's antenna input jack from 50 ohms up to 500 ohms.

    C10T and C22T, part numbered antennas tune the indicated range with our 384 pF capacitor (available separately).

    AF part numbered antennas tune with a fixed value capacitor and/or are for wideband reception and operate at ultra low frequencies below 2 KHz.

    Designed for use in peaking received signals, random wire antenna matching, lightning detectors, specialized radio receivers, test equipmement, experimental research equipment, seismographs, etc.

    Narrow band reception when tuned.

    Additional magnetic coupling into and out of the antenna (a few turns you may add around the outer case if your application requires) is provided via the PVC plastic case which provides high electrostatic isolation to reduce electrical noise. Just a few turns of wire (about 2 - 3 turns) around the case will match a 50 ohm receiver's impedance value to the high value of the antenna. Antennas have a very high impedance when tuned, greater than 30,000 ohms, and narrow band width, for high sensitivity.

    The antenna is a great direct match for JFET or FET or vacuum tube inputs that have very high impedance.

    Or match any receiver's input impedance between 50 ohms to 500 ohms by wrapping a few (2 to 9) turns signal coupling loop around the antenna's PVC case. Most common receivers have inputs of 50, 75, or 300 ohms.

    You can peak the impedance match for best signal strength even if you are not sure of your receiver's input impedance value.

    Antenna can also be used as a tuned narrow band filter element especially below 100 KHz, by passing a low level magnetic coupled signal through the tuned antenna: input at one end and output at the other. Band width gets narrower at lower frequencies.

  • Greatly boost your reception with these narrow band directional antennas.
  • In most cases just tune the antenna and place it near your radio's built-in bar-core antenna for a great boost in reception.
  • For most longwave radios: no need to open the radio or connect wires. The antenna creates a powerful magnetic field coupling to your radio's built-in antenna.
  • These fully sealed antennas feature binding post connections for connection of tuning capacitor/output.
  • Just connect a tuning capacitor across the connector and (for 50 ohm match if needed) wrap a few turns of wire around the outer case for coupling to 50 ohm receiver antenna input.
  • Will easily match 50 ohms or 75 ohms for feeding standard coaxial cable or transistor input of home-brew receivers. Will feed long lengths of cable.
  • Also allows high impedance tuned output (+30000 ohms). Excellent direct match for low noise FET, MOSFET, JFET, or tube pre-amps.
  • When used with a longwave radio or AM radio, just lay the tuned portable antenna near the radio for greatly increased reception.
  • THESE MAGNETIC FIELD SENSING ANTENNAS DO NOT NEED TO BE MOUNTED HIGH UP TO WORK! WORKS INDOORS!
  • Directional "figure 8" sense pattern. Two deep null points on ends to cut interfering stations on the same channel.
  • Antenna can be used with random wires as the electric field signal pick up, or use it alone for direct pick up of the magnetic field radio signal.
  • Antenna can be permanently tuned to one channel (your favorite station) via an external capacitor.
  • Antenna can be permanently tuned to your favorite station and then mounted remotely for best reception.
  • Fully water-proof.
  • Tough plastic case.
  • Not for transmitting use.

  • C10T part numbered antennas are 12 inches long and 2 and 5/8ths inches diameter. Features a 10 inch long ferrite rod antenna.

  • AF22T part numbered antennas are 24 inches long and 2 and 5/8ths inches diameter. Features a 22 inch long ferrite rod antenna.

  • C22T part numbered antennas are 24 inches long and 2 and 5/8ths inches diameter. Features a 22 inch long ferrite rod antenna.

    Some antennas have data sheets in table below. Click part number for PDF file.

    Antennas have +/- 15% tolerance for all frequency, impedance, weight, and resistance values given in PDF data sheets or listed below. Specifications subject to change and improvement without notice

    Part # Radio Band / ApplicationLow Freq
    @ 370 pF
    Hi Freq
    @ 130 pF
    __Price
    Long Wave Radio Antennas
    C10T-460K-670K-BC Beacons / Marine band / Low end AM Band 460 KHz670 KHz $ 140.00
    C10T-350K-530K-BC Aeronautical Navigation Beacons / utility 350 KHz530 KHz $ 140.00
    C10T-280K-420K-BC Aeronautical Navigation Beacons 280 KHz420 KHz $ 140.00
    C10T-240K-360K-BC Long Wave / Aeronautical Navigation Beacons 240 KHz360 KHz $ 140.00
    C10T-200K-310K-BCLong Wave / Aeronautical Navigation Beacons 200 KHz310 KHz $ 140.00
    C10T-180K-280K-BC Long Wave / Aeronautical Navigation Beacons 180 KHz280 KHz $ 140.00
    C10T-150K-230K-BC Long Wave / Aeronautical Navigation Beacons 150 KHz230 KHz $ 140.00
    Low Frequency Antennas
    C10T-130K-190K-BC Low Frequency ( industrial, utility) 130 KHz190 KHz $ 150.00
    C10T-100K-150K-BC Low Frequency ( industrial, utility) 100 KHz150 KHz $ 150.00
    C10T-90K-130K-BC Low Frequency ( beacons, utility) 90 KHz130 KHz $ 150.00
    C10T-70K-100K-BC Low Frequency ( Utility ) 70 KHz100 KHz $ 150.00
    C10T-59K-85K-BC Low Frequency ( WWVB time 60 KHz )59 KHz85 KHz $ 150.00
    C10T-50K-72K-BC Low Frequency ( beacons )50 KHz72 KHz $ 150.00
    C10T-43K-60K-BC Low Frequency ( beacons ) 43 KHz60 KHz $ 155.00
    C10T-38K-56K-BCLow Frequency 38 KHz56 KHz $ 155.00
    C10T-30K-46K-BC Low Frequency 30 KHz46 KHz $ 155.00
    Very Low Frequency Antennas
    C10T-26K-39K-BC Very Low Frequency ( beacons ) 26 KHz39 KHz $ 155.00
    C10T-23K-33K-BC Very Low Frequency ( beacons ) 23 KHz33 KHz $ 155.00
    C10T-20K-29K-BC Very Low Frequency ( beacons ) 20 KHz29 KHz $ 155.00
    C10T-17K-26K-BC Very Low Frequency ( beacons ) 17 KHz26 KHz $ 155.00
    C10T-16K-24K-BC Very Low Frequency ( beacons ) 16 KHz24 KHz $ 155.00
    C10T-15K-21K-BC Very Low Frequency ( beacons ) 15 KHz21 KHz $ 155.00
    C10T-14K-20K-BC Very Low Frequency 14 KHz20 KHz $ 155.00
    C10T-13K-19K-BC Very Low Frequency 13 KHz19 KHz $ 155.00
    C10T-12K-18K-BC Very Low Frequency 12 KHz18 KHz $ 155.00
    C10T-11K-17K-BC Very Low Frequency 11 KHz17 KHz $ 160.00
    C10T-10K-16K-BC Very Low Frequency ( Lightning Detection 'A' Band: 10 KHz - 15 KHz ) 10 KHz16 KHz $ 160.00
    C10T-9K-13K-BC Very Low Frequency ( 'A' band, 'B' band )9 KHz13 KHz $ 165.00
    C10T-8K-12K-BC Very Low Frequency ( 'A' band, 'B' band )8 KHz12 KHz $ 165.00
    C10T-7K-10K-BC Very Low Frequency ( Lightning Detection 'B' Band: 7 KHz - 10 KHz ) 7 KHz10 KHz $ 165.00
    C10T-6K-9K-BC Very Low Frequency ( 'B' band, 'C' band ) 6 KHz9 KHz $ 165.00
    C10T-5.5K-8.5K-BC Very Low Frequency ( 'B' band, 'C' band ) 5.5 KHz8.5 KHz $ 165.00
    C10T-5K-7K-BC Very Low Frequency ( Lightning Detection 'C' Band: 5 KHz - 7 KHz ) 5 KHz7 KHz $ 165.00
    C10T-3K-5K-BCVery Low Frequency ( Lightning Detection 'D' Band: 3 KHz - 5 KHz ) Whistlers3 KHz 5 KHz $ 175.00
    C22T-3K-6K-BCVLF. Whistlers, tweeks, lightning 3 KHz6 KHz $ 225.00
    Ultra Low Frequency Antennas
    C10T-2K-3K-BCUltra Low Frequency ( Lightning Detection 'E' Band: 2 KHz - 3 KHz ) Whistlers 2 KHz 3 KHz $ 210.00
    C10T-1K-2K-BCUltra Low Frequency ( Lightning Detection 'F' Band: 1 KHz - 2 KHz ) Whistlers1 KHz 2 KHz $ 225.00
    AF10T-0.5K-1.5K-BCUltra Low Frequency. Tweeks, Dawn Chorus, Whistlers, Lightning, Electron Hiss0.5 KHz *1.5 KHz *$ 235.00
    AF22T-300H-3K-BCUltra Low Frequency. Geologic Research Applications. 300 Hz * 3 KHz *$ 275.00
    Super Low Frequency Antennas
    AF10T-30H-300H-BCSuper Low Frequency (natural radio waves) geology, audio, bass30 Hz *300 Hz *$ 245.00
    AF22T-30H-300H-BCSuper Low Frequency. Geologic Research, Remote Sensing. 30 Hz 300 Hz $ 299.00
    Extreme Low Frequency Antennas
    for use in earthquake detection.
    ELF antennas are useful for research applications in seismology, geophysics, infrasonic microphones.
    AF4T-0.1H-40H-BC-EBSeismograph Antenna, Infrasonic Microphone Pickup Coil. The AF4T0.1H-40H is the very basic unit you need for your experimental seismograph. 0.1 Hz 40 Hz $ 125.00
    Extreme Low Frequency Antennas
    for use in earthquake detection.
    ELF antennas are useful for research applications in seismology, geophysics, infrasonic microphones.
    AF6T-0.1H-1K-BC-EBSeismograph Antenna for earthquake and geomagnetic storm detection 0.1 Hz 1000 Hz $ 175.00
    AF10T-0.1H-30H-BC-EBSeismograph Antenna for earthquake and geomagnetic storm detection 0.1 Hz 500 Hz $ 260.00
    Extreme Low Frequency Antennas
    for use in EM wave reception
    ELF antennas are useful for research applications in seismology, geophysics, infrasonic microphones, remote sensing, geomagnetic storm sensing.
    AF10T-0.1H-30H-BCGeophysical remote sensing, geomagnetic storms, slow lightning, seismograph 0.1 Hz 500 Hz $ 255.00
    AF22T-0.3H-30H-BCELF. Sensitive long antenna for pipeline inspection guage PIG detection. 0.3 Hz 30 Hz $ 375.00
    AF22T-0.2H-20H-BCELF. Geomagnetic Research Applications, Seismomagnetic Research 0.2 Hz 20 Hz $ 475.00

    Antennas have +/- 15% tolerance for all frequency, impedance, weight, and resistance values given in PDF data sheets or listed below. Specifications subject to change and improvement without notice
    Some antennas have data sheets in above table. Click part number for PDF file.

    U.S.A. only. No Foreign Orders.

    For reception uses only.


    Other specialty Antennas below

    SUPER LOW FREQUENCY ANTENNA

    SLF antenna for 30 Hz to 300 Hz.

    tuned directional antenna
  • "AF22T" Antennas are 24 inches long and 2 and 5/8ths inches diameter. Features a 22 inch ferrite antenna.
  • Antennas in this range are useful for geologic research and specialized remote sensing applications.

    Research applications include: Seismology, Volcanology, Geophysics, Meteorology, Mineral Exploration,

    Part # Radio Band Low Freq Hi Freq __Price
    AF22T-30H-300H-BCSLF 30 Hz 300 Hz
    $ 299.00

    SEE ANTENNA DATA GRAPH HERE ( pdf file ).

    Antennas have +/- 15% tolerance for all frequency, impedance, and resistance values given in data sheets or table below. Specifications subject to change without notice

    U.S.A. only. No Foreign Orders.

    For experimental and research applications.

    "AF" prefix antennas are tunable over a wide range with an external fixed value capacitor.

    NOTE: These antennas have output impedances over 50,000 ohms at resonance peak.


    EXTREMELY LOW FREQUENCY ANTENNA

    ELF antennas for 0.2 Hz to 30 Hz.

    Our lowest frequency antennas.

    These ELF antennas can be used to do research in to the following areas:

    Seismology, Volcanology, Geophysics, Meteorology, Mineral Exploration, ELF Radio Astronomy, traffic counting, vehicle detection, and more.

    DETECTS MAGNETIC FIELDS!

    Detects down to 0.2 Hz. All will detect movement of Earth's magnetic field down to 0.01 Hz.

    Reach out and detect natural ELF wave events with these sensitive antennas.

    ELF antenna
  • "AF22T" Antennas are 24 inches long and 2 and 5/8ths inches diameter. Features a 22 inch ferrite antenna.
  • Part # Radio Band Output Impedance at DCLow Freq Hi Freq __Price
    AF22T-0.3H-30H-BCELF7800 ohms 0.3 Hz 30 Hz
    $ 375.00
    AF22T-0.2H-20H-BCELF12500 ohms 0.2 Hz 20 Hz
    $ 475.00

    SEE ANTENNA DATA GRAPH HERE ( pdf file ).

    Antennas have +/- 15% tolerance for all frequency, impedance, and resistance values given in data sheets or listed below. Specifications subject to change without notice

    U.S.A. only. No Foreign Orders.

    32XL,33XL

    You can't hear ELF waves (below 20 Hz) they are too low in frequency. You don't need an ELF receiver to use the antenna: Just connect antenna to a data recording oscilloscope or PC chart recorder having a good sensitive input. Use the DC-couple setting. Sensitivity should be 10 microvolts per division or better. A single transistor amplifier may be needed if the chart recorder or PC recorder's input is not sensitive.

    Will sense movements of Earth's magnetic field down to 0.01 Hz.

    Antenna outputs a micro-voltage and current when ELF waves are detected. Will feed IC pre-amplifiers or transistor amplifiers.


    ELF-SLF-ULF ANTENNAS
    with suspension hook

    Antennas for 0.01 Hz to 2 KHz.

    THIS ANTENNA DETECTS MAGNETIC FIELDS!

    USE IT TO BUILD A SEISMOGRAPH. FEATURES SUSPENSION HOOK FOR EASY USE.

    Detects Extremely Low Frequency 0.01 Hz - 30 Hz, Super Low Frequency 30 Hz - 300 Hz, Ultra Low Frequency 300 Hz - 2 KHz.

    These small ELF antennas can be used to do research in the following areas:

  • Some ideas for your experimentation:

  • Detect earthquakes with an easy to build Seismograph. This antenna is designed to be used in a seismograph.

  • Detect infrasonic sound waves. Use this antenna in an infrasonic microphone design to detect slow inaudable sound waves and quick barometric pressure changes in the range of 0.01 Hz to 10 Hz. You'll use a balloon, a glass jar, and a magnet with this antenna to make a very sensitive infrasonic microphone.

  • Detect geomagnetic storms with the 10T antenna. Connect to a sensitive oscilloscope or PC chart recorder to allow recording slow ELF waveforms from geomagnetic storms down to 0.01 Hz. Detect any motion of Earth's magnetic field, or any motion of the antenna through Earth's magnetic field.

    Many more uses.

    Antennas have +/- 15% tolerance for all frequency, impedance, weight, and resistance values given in data sheets or listed below. Specifications subject to change without notice

    4T weighs @ 2.5 pounds. This is the basic antenna you need to detect earthquakes.

    4T antenna is @ 7 inches long and @ 2.6 inches diameter. Maximum working frequency is @ 2500 Hz. Top end frequency value may vary +/- 15 %.

    Includes eye-bolt loop for suspending the antenna over nearly any magnet to make a seismograph or ground vibration sensor. Nearly any ceramic or NdFeB magnet of 1/2 - 3/4 inch diameter with a power greater than 1000 gauss will work.

    6T weighs @ 3.2 pounds.

    6T antenna is @ 9 inches tall and @ 2.6 inches diameter. Maximum working frequency is @ 1000 Hz. Top end frequency value may vary +/- 15 %.

    Includes eye-bolt loop for suspending the antenna over nearly any magnet to make a seismograph or ground vibration sensor. Nearly any ceramic or NdFeB magnet of 1/2 - 3/4 inch diameter with a power greater than 1000 gauss will work.

    10T antenna weighs @ 5 pounds.

    10T antenna is @ 12 inches long and @ 2.6 inches diameter. Maximum working frequency is @ 500 Hz. Top end frequency value may vary +/- 15 %.

    Includes eye-bolt loop for suspending the antenna over nearly any magnet to make a seismograph or ground vibration sensor. Nearly any ceramic or NdFeB magnet of 1/2 - 3/4 inch diameter with a power greater than 1000 gauss will work.

    Antennas have +/- 15% tolerance for all frequency, impedance, weight, and resistance values given in data sheets or table below. Specifications subject to change without notice

    Part # Radio Band Output Impedance DCLow Freq Hi Freq __Price
    AF4T-0.1H-40H-BC-EBSeismograph Antenna, Infrasonic Microphone Pickup Coil. The AF4T0.1H-40H is the basic unit you need for your experimental seismograph. @ 1640 ohms 0.1 Hz @ 2500 Hz $ 125.00
    AF6T-0.1H-1K-BC-EBELF - ULF@ 2060 ohms 0.01 Hz@ 1000 Hz$ 175.00
    AF10T-0.1H-30H-BC-EBELF - ULF @ 3480 ohms 0.01 Hz @ 500 Hz $ 260.00

    VIEW EARTHQUAKES RECORDED WITH THE ANTENNAS

  • READ MORE ABOUT THESE ELF EARTHQUAKE DETECTION ANTENNAS HERE.

    Click part numbers in table above for tuning graph pdf documents.

    Part # AF10T-0.1H-30H-BC-EB is about 3 times more sensitive and has greater mass of 5 pounds. It is good up to 500 Hz on the high frequency side.

    Antennas have +/- 15% tolerance for all frequency, impedance, weight, and resistance values given in data sheets or table below. Specifications subject to change without notice

    U.S.A. only. No Foreign Orders.

    Antenna is water-proof, fully sealed.

    Binding post bannana terminal connections.
    33N


  • 2 transistor lightning detector circuit for detecting cloud-to-ground lightning strikes.
    AM / LW BAR CORE ANTENNA
    AM antenna rod core coil

    This AM / LW loopstick antenna is for tuning between 100 KHz - 1710 KHz.

    When used with our AM variable capacitor, above, this AM core will the full AM band and down to about 310 KHz. This tuning range is with the coil centered as in the photo.

    Size: 3.53 inches long by 0.31 inch diameter at widest dimension. 0.026 inch diameter at narrowest dimension (has two flat sides top and bottom so it won't roll away).

    Coil inductance value (centered on rod) is: 788 uH. Permeability value: @ 125 (designed primarily for AM broadcast band).

    The unit contains two coils. One coil (the green and red) are the smaller coil. The black and the white are the longer coil. The coils are isolated from eachother, but can be connected make one continuous coil having a tap. The above tuning results were tested only with the white and black wires used (the larger coil side).

    The red and green wires are isolated from larger section and can be used to couple an outdoor long-wire antenna.

    A very useful part!

    AM-LW BAR-1 is $ 6.95 + s/h.

    s/h extra.

    Sales to U.S.A. only.


    How to use the antennas and General Antenna Info

    These antennas will pick up without needing any external wire antenna or ground wire. They sense the magnetic field portion of the radio wave.

    C10 part numbered antennas will tune the indicated range with our 384 pF variable capacitor sold separately. Will go lower than specified if a 1000 pF variable is used.

    NOTE: AF10T-0.5H-1.5K-BC operates just below the ionospheric cutoff line of 1.7 KHz. Excellent for observing Tweeks (which occur only at night time) and other emissions with less effect of long distance lightning static.

    * NOTE: AF10 part numbered antennas will tune the indicated range with fixed value capacitor greater than 100 pF to 100 uF.

  • Earthquake Detection Antennas:

    Earthquakes are detectable in the frequency range of 0.1 Hz to 10 Hz, with the center range being betwen 0.3 Hz to 3 Hz, and the best reception band is 0.75 Hz to 1.5 Hz.

    The antennas with eyebolt hooks (EB suffix on part number) are designed to be suspended over a magnet. They will swing like a pendulum when an earthquake is detected. This mode of reception is very sensitive and will detect average quakes hundreds of miles away. Other antennas for the ELF frequency range can be buried underground (no magnet needed) and will shake with the earth during a local quake of 3.0 or higher, the antenna moves through the Earth's magnetic field allowing detection of actual ground movements and waveforms of an earthquake.

    Antenna size (AF4T) is 6 inches tall x 2.6 inches diameter. Weighs @ 1.5 pounds.

    Antenna size (AF6T) is 8 inches tall x 2.6 inches diameter. Weighs @ 3.2 pounds. Good weight and compact size with extra sensitivity.
    This antenna will also detect sudden changes in the Earth's magnetic field and can also be mounted down tight so as to shake with the earth during an earthquake. The movement of the antenna through the Earth's magnetic field results in a recorded copy of the exact earthquake waveform felt in your area on your equipment, without any moving parts to do it.
    Can be used experimentally as a geophone: This antenna may be useful in seismic echo location of gas, oil, and water.

    Antenna size (AF10T) is 12 inches tall x 2.6 inches diameter. Weighs @ 5 pounds for extreme sensitivity.
    This antenna will also detect sudden changes in the Earth's magnetic field and can also be mounted down tight so as to shake with the earth during an earthquake. The movement of the antenna through the Earth's magnetic field results in a recorded copy of the exact earthquake waveform felt in your area on your equipment, without any moving parts to do it.
    Can be used experimentally as a geophone: This antenna may be useful in seismic echo location of gas, oil, and water.

    The antennas with eyebolt hooks (EB suffix on part number) are designed to be suspended over a magnet. They will swing like a pendulum when an earthquake is detected. This mode of reception is very sensitive and will detect average quakes hundreds of miles away. The larger antennas AF6, AF10, for the ELF frequency range can also be buried underground (no magnet needed for this 2nd mode of operation) and will shake with the earth during a local quake of magnitude 3.0 or higher, the antenna moves through the Earth's natural magnetic field allowing detection of actual ground movements and waveforms of an earthquake.

    NOTE: AF4T-0.1H-2K-BC-EB and AF6T-0.1H-1K-BC-EB and AF10T-0.1H-30H-BC-EB have an eye bolt hook to allow it to be suspended by a rope over a magnet to make a seismic sensor for a seismograph. Very sensitive. Can also be used to sense infrasonic sound waves.

    * NOTE: The AF10T-0.1H-30H-BC-EB antenna is good up to @ 500 Hz. High end may vary +/- 200 Hz. AF4T-0.1H-2K-BC-EB is good to @ 2800 Hz. High end may vary +/- 400 Hz. See data charts in pdf file links above in table.

    Antennas have +/- 15% tolerance for all frequency, impedance, weight, and resistance values given in data sheets or table below. Specifications subject to change without notice

    More info on these Seismograph Antennas is found down lower on this page. Scroll down.

    Lightning Detection: Using the antennas for lightning detection and geophysical research.

    The antennas detect the magnetic field part of the radio wave for lightning detection so no other wire antenna is needed. The antennas are directional (bi-directional) so aim antenna for best reception.

  • Lightning Detection Antennas:

    Lightning Detection Band A is useful 24 hours a day. Global range possible. Lightning's power output is centered in this band allowing easy detection.

    Lightning Detection Band B is useful 24 hours a day. Extreme range possible. High lightning power in this band.

    Lightning Detection Band C is useful 24 hours a day. Long range possible. Range increases greatly at night.

    Lightning Detection Band D opens at night for very long range detections. Only short range in daytime.

    Lightning Detection Band E opens at night for very long range detections. Only short range in daytime. May have power line harmonic hum interference in this band.

    Lightning Detection Band F is useful only for detecting local cloud to ground strikes. May have power line hum noise in this band.

    Lightning Detection 'A' band properties: The 'A' band at 10 KHz to 15 KHz allows global cloud to ground lightning strikes to be monitored. Propagation is strong day and night for easy very long distance reception. Signals at 10 - 15 KHz can at times circle the globe, coming back to the point of origin as an "echo". No man-made transmissions in this band in the USA. Constant crackling of global lightning static can be heard in this band.

    Lightning Detection 'B' band properties: The 'B' band at 7 KHz to 10 KHz allows global cloud to ground lightning strikes to be monitored. The range is greater toward the top end (10 KHz) of the band. Lower range toward the bottom. Slightly better range at night time. No man made signals in this band. Constant crackling of static can be heard in this band. No man made signals in this band.

    Lightning Detection 'C' band properties: The 'C' band at 5 KHz to 7 KHz allows hemispheric lightning ground strikes to be monitored. The range is greater at night time than daytime. Static crackling is constantly heard in this band, and it increases greatly at night time as the band opens due to dissipating ionospheric "D" layer for very long range reception. No man made signals in this band.

    Lightning Detection 'D' band properties: The 'D' band at 3 KHz to 5 KHz allows hemispheric lightning ground strikes to be monitored at only night time. Range is markedly shorter during the day time, less than 75 miles. Very long range after local midnight when ionosphere "D" layer is faded. The larger strikes are heard here. Natural radio wave emissions and Whistlers (an ionospheric dispersion effect, which causes a very distant lightning strike to sound like a sliding whistle tone instead of the usual static sound) are heard in this band. Whistlers are centered around 3 KHz, but also can be lower or higher in frequency. Geomagnetic storms can cause natural radio wave emissions in this band and in bands lower in frequency. No man made signals in this band.

    Lightning Detection 'E' band properties: The 'E' band at 2 KHz to 3 KHz allows long distance lightning ground strikes to be monitored at night time, especially after midnight. Range up to 300 miles night time. Only the larger strikes are detected here. Range is markedly shorter during the daytime, less than 50 miles. No man made signals in this band, except for power line hum harmonics.

    Lightning Detection 'F' band properties: The 'F' band at 1 KHz to 2 KHz allows local lightning ground strikes to be monitored as well as signals from geomagnetic storms. Range (for lightning detection) is markedly shorter during the day time, less than 30 miles. The band opens after midnight local time for range up to 300 miles (above 1.7 KHz) for the stronger cloud-to-ground strikes. Whistlers and geomagnetic storm noise (dawn chorus and hiss noise) is heard in the lower half of this band. The Earth - Ionosphere waveguide effect does not support electromagnetic waves of a frequency lower than approximately 1.7 KHz. Range of less than 30 miles will be obtained below this frequency. A sharp contrast (at night) can be heard in the static level at 2 KHz and the static level below 1.5 KHz due to this effect. No man made signals in this band except for powerline harmonic hum. Whistlers extend down to this band. Dawn chorus (a natural radio wave emission that occurs just after dawn, especially during geomagnetic storms) is heard in this band. Dawn chorus range is from 700 Hz to 1.4 KHz.

    Lightning Detection 'G' band properties: The 'G' band at 500 Hz to 1 KHz allows local lightning ground strikes to be monitored. Range is less than 30 miles. Whistlers extend down to this band, becoming drawn out and slow sounding. Dawn chorus extends down to 700 Hz and up to 1400 Hz this band. Hiss can be heard in this band. Propagation mode is solely through the ground, water, or along earth's magnetic field lines for non-lightning signals originating more than 30 miles away.

    Other Lightning Detection Bands:

    Other bands can be used for lightning detection. These bands may have broadcasts or communications and are not used exclusive for lightning detection. Rotate the antenna to completely null any station.

    38 KHz - 56 KHz This band allows good long range detection day or night. Better range at night. Time signal beacons and utility stations may be in this band. Powerful static from storms up to 300 miles away.

    59 KHz - 61 KHz This band allows good long range detection day or night. Much better range at night. Time signal beacons and utility stations may be in this band. WWVB at 60 KHz heard in this band, aim end of antenna toward this station (located in Colorado, USA), to null it out completely for reception. Powerful lightning static in this band from storms up to 300 miles away.

    90 KHz - 110 KHz This band allows good reception of lightning static, storms emit a very high amount of power in this range. The LORAN-C navigation system has been dismantled leaving this range generally clear. Other stations may exist in this range. Rotate antenna to null out completely. Range better at night than in day.

    Hearing Whistlers and Tweeks and other natural emissions.

    These antennas allow pick up of natural radio emissions. You can tune the antenna or use it broad band. Antennas can be coupled into your tape recorder or audio amplifier to allow direct reception of natural radio waves below 5 KHz.

    This pre-amplifier example design allows direct tuning of the antennas, pre-amp does not load down the antenna's extremely high output impedance when operated in tuned mode.

    VLF / LF (Tunable) FET Pre-amplifier using field-effect transistor MPF-102 (parts from Radio Shack).

    This pre-amplifier example design allows wideband reception.

    VLF Whistler Receiver using field-effect transistor MPF-102 (parts from Radio Shack).

    U.S.A. only. No Foreign Orders.

    Sales to USA only.

    EXAMPLE USE:

    These directional antennas detect the magnetic field part of the VLF or LF radio wave. This field is strongest near ground level so do not mount the antennas high in the air. Simply 5 feet above ground will do the trick. The antenna will also work indoors in most cases and can even work underground, especially the VLF and lower frequency antennas.

    You can tune the antenna simply by placing a variable or permanent-value capacitor across the binding post connectors. Examples for min-max values for this capacitor are shown above on this page with the antenna models.

    ELF and ULF and SLF antennas can also be tuned with a fixed-value capacitor. The ELF antennas are generally wideband antennas, however.

  • HOW TO USE WITH A RADIO THAT DOES NOT HAVE ANTENNA JACKS:

    Most portable longwave radios have a built-in bar-core antenna that will very easily pick up the strong magnetic field from this antenna.

    Simply place the (top) of the portable longwave radio near the antenna, and tune capacitor until the signal gets louder and stronger. Results should be -very- dramatic.

    Rotate radio and ANTENNA for best reception.

  • HOW TO USE WITH A RADIO THAT HAS ANTENNA INPUT VALUE BETWEEN 50 ohms to 150 ohms:

    This keeps the antenna isolated to prevent noise pickup:

    Wrap 4 turns of wire around the center of the antenna's outer plastic case. Connect these wires (with some coaxial cable or other antenna cable) to the radio's antenna and ground terminals. Adjust tuning capacitor across antenna's binding posts for strongest signal. Add or subtract wire turns on antenna's outer case until signal strength does not increase further when re-peaked each time after adding or subtracting one turn at a time. The point where signal strength does not increase further is the correct match point for your radio.

  • HOW TO USE THE ANTENNAS HAVING 100,000 OHMS OUTPUT:

    These antennas are usually for use below 1000 Hz.

    Connect antenna directly to equipment's high Z input jack. Equipment should have JFET or FET input, or an input impedance of about 1 meg ohm. Most oscilloscopes and some test equipment have this type of input.

    A tuning capacitor can be placed directly across the binding posts if applicable to tune the antenna to desired frequency.


    NEED MORE GAIN? OR DON'T HAVE A HIGH IMPEDANCE INPUT?

    High impedance preamplifier for use with antennas having 100,000 ohms output impedance.

    You can greatly boost signal gain by using a pre-amplifier if your equipment does not already have a high impedance input. "CF" is a capacitor that controls frequency. Typical values are shown above on this page. Q1 is 2N3904 NPN transistor. R1 is 470 K-ohms. R2 is 1000 - ohms. R3 is 10 K-ohms. C1 is 47 pF. C2 is 0.001 uF.

    Supply voltage can be from 3 volts to 12 volts, depending on how much gain you want. Works well at 6 to 12 volts.

    Other amplifiers or IC chips or an FET may be more suitable than this sample single transistor example. But, if building this example circuit for the first time, do not substitute the 2N3904.

    See below on this page for link to an FET pre-amplifier you can build.


    Most test equipment already contains a built-in preamplifier. Just connect antenna directly to equipment input.


    LIST OF Do-It-Yourself VLF RADIO PROJECTS:

    VLF and Longwave Receiver for High Impedance "C" Antennas.
    07-08-2011. This direct input tuned receiver works with our Model "C" antennas above on this page, in the range of 10 KHz to 530 KHz.

    Lightning Detector project 11.
    07-16-2011. Uses our Lightning Detection Antenna part # D6T-3KC-BC.

    ELF Extremely Low Frequency Receiver. project 12.
    07-19-2011. For use with any of our high impedance ELF antennas.

    Longwave and VLF Receiver with Signal VU Meter.


    Build an AM radio!

    VLF Receiver with Signal Strength Meter.

    Wideband ULF - VLF FET Pre-amplifier.

    VLF / LF (Tunable) FET Pre-amplifier

    ELF Magnetic Field Detector.

    VLF Whistler Receiver.


    Some users in the AM and LONGWAVE bands who like to use long wire antennas (that sense the radio wave's electric field) can also use the C10 antenna as a pre-selection tuned antenna.

    It is important to match your long wire antenna to the receiver to cut interference and maximize signal strength.

    Diagram above shows how to connect the antenna to your radio's 50 ohm antenna jack for matching a random wire antenna. You can also match a random wire to your AM radio's built-in bar core antenna by just laying the tuned antenna near the radio. Use our part # AMVC384 variable tuning capacitor to tune the indicated range.

    To match a 50 ohm input in the AM and longwave bands only 1 to 4 turns centered on the outer case will be needed.

    For matching VLF down to 3 KHz it is possible to get a 50 ohm match by winding more than 10 turns around the center of the outer case. A 50 ohm match gives a very narrow bandwidth at VLF. Most VLF receivers have a high input impedance value which the antenna will directly match across the binding posts.

    MATCHING TIPS: You have a correct antenna match (usually 50 or 75 ohms) to your receiver's input when adding 1 more turn does not greatly improve the reception strength (less than 0.5 dB increase in added signal strength). Remove that extra turn for the correct match point. You can also slide the turns over the case to find strongest signal strength point.

    For matching a ULF, SLF, or ELF receiver, connect C10T antenna directly into the receiver's high impedance input. If a 50 ohm match is needed at ELF, you may need to wind @ 200 turns around the case.

    For matching FET, JFET pre-amplifier's with high impedance: Connect tuned antenna directly across input terminals.

    For maching 50 ohm pre-amplifier: Use several turns around outer case with antenna tuned to desired channel.