underground dog fence

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KE0YRP, Dec 13, 2019.

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  1. KE0YRP

    KE0YRP XML Subscriber QRZ Page

    Does anyone have experience installing antennas near an underground dog fence? Mine runs close to the sides of the house and around the front, and along the physical fence in the backyard. Of course it puts out RF.

    I contacted DogWatch (guys who installed it) and he told me it operates at 8KHz. I figure that's probably a good thing since it's not in the ham bands. I'm pretty sure it's low power since it just needs to work within a few feet of my dog's collar.

    I bought a MFJ 40m EFHW and am planning on running it under the eves of my house. The problem is with the counterpoise... I don't see any way to get it away from the DogWatch wire.

    My plan is to use a sdrplay attached to the wire to see what noise I get while it's being installed, but I just wonder what to expect.

    I don't have a lot of options b/c I live in a HOA where antennas are banned. I really think this is my best shot for getting on HF.

    I just got my tech license yesterday, so there's a lot to take in with this stuff. I'm going to start studying for general so i can really use the icom 7300 I bought. I'll probably take the test next month.

    Red line is the DogWatch fence. Green is my planned location for the EFHW

    Jason Jenkins

  2. AK5B

    AK5B Ham Member QRZ Page

    Of course it puts out RF....
    ...it operates at 8KHz.

    8 KHz is still in the audio range; no RFI involved at all down there. Are you sure that's the right frequency? (even for dogs that run underground)
  3. KE0YRP

    KE0YRP XML Subscriber QRZ Page

    Yes, i double checked with him. it's 8KHz
  4. KF5LJW

    KF5LJW Ham Member QRZ Page

    OP might NOT be sure, but I am because they operate at 7 to 10 Khz. Most of the Dog Collars and fences allow you to select frequencies (7 to 10 Khz) to avoid RFI issues. Cable Locating, Power Line Carriers, and dog fences all can use 7 to 10 Khz radio waves. You can pick them up with a lot of SDR radios that cover LF range.

    Submarines use even much lower ELF RF of 3 to 30 Hz below the hearing range. Propagation is to all oceans and seas worldwide. All it takes is really poor conductive soil.

    OP it is a non issue.
    Last edited: Dec 14, 2019
  5. AK5B

    AK5B Ham Member QRZ Page

    Well, that's a bit odd since most any tweeter will reproduce that in any audio system (human hearing runs from around 16 Hz (deep, bone shaking bass) up to 20KHz (the highest highs like brushed cymbals produce)). If dogs can hear that (and I would imagine they could easily)---then why is it underground?

    Anyway, if it really is 8 KHz you have zero to worry about. House borne RFI is a much more serious concern where antennas are concerned.
  6. KF5LJW

    KF5LJW Ham Member QRZ Page

    There is no audible, it is EMF
    Last edited: Dec 14, 2019
  7. AK5B

    AK5B Ham Member QRZ Page

    I researched dog hearing audio frequencies and apparently they can hear sound from about 40Hz up to 40 KHz. Perhaps that is why the old RCA Victor recordings had a dog listening to an early phonograph as a branding logo :D---better hearing than us humans.

    Anything beyond 20KHz is considered ultrasonic and is also the generally accepted point where RF begins, too. Perhaps your dog fence operates at 18 KHz instead of 8? It might very well operate at 8KHz as your installer claims but that is still not RF...
  8. KL7AJ

    KL7AJ Ham Member QRZ Page

    I'm a bit leery of those underground dogs.
    W1TRY, KI4ZUQ, ND6M and 2 others like this.
  9. AK5B

    AK5B Ham Member QRZ Page

    I'm just the opposite; ever since I almost had a chunk of my left arm bitten by a lunging Doberman I am much more leery of dogs above ground (DAG as opposed to DUG). Fortunately that Doberman only got a mouthful of my long-sleeved shirt before the owner was able to reel him back in...
    KI4ZUQ likes this.
  10. KE0YRP

    KE0YRP XML Subscriber QRZ Page

    So I'm confused. will the "fence" cause interference on the EFHW?

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