Spark Plug Antenna: setup and first try

Discussion in 'Amateur Radio News' started by K9KMV, Oct 9, 2021.

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  1. K9KMV

    K9KMV Ham Member QRZ Page

    Here I am trying out the Spark Plug Antenna.

    Trying out my new Spark Plug Antenna. It's another EFHW.
    VE7JBT, 2E0CIT, KA0USE and 6 others like this.
  2. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    A better experiment might be to try a comparison of using just the wire as the antenna versus having the Balun (or is it just a base loading coil?) attached. I can’t imagine the Balun is making all that much difference… Seems to me it’s more of just a way to attach your antenna wire to the radio. An A/B video of with and without Balun might be more revealing

    Just a thought - nice video

    W7SJP, KC3LBR, KO4CES and 1 other person like this.
  3. KD2OKK

    KD2OKK Ham Member QRZ Page

    That is a neat form factor for a bnc mounted 1:49/1:64 autotransformer used with an EFHW. For POTS/SOTA use, this is really nice as it's compact and tidy. It's great to see the experimentation and the market for this part of the hobby is alive and well.

    K8PGJ, KA0USE, KN4CFT and 3 others like this.
  4. K9KMV

    K9KMV Ham Member QRZ Page

    The end fed half wave has a very high impedance at the feedpoint, so the 49:1 un-un on this 'spark plug' transforms the impedance of the wire from about 2500 ohms to about 50 ohms that the radio is looking for.

    Thanks for watching.
    WD8JTR, K0YO, KA0USE and 2 others like this.
  5. N2UHC

    N2UHC Ham Member QRZ Page

    That's not an antenna, that's a balun. Not that wire is hard to come by, but if they're going to call it an antenna they should at least supply the wire with it. It is a pretty neat design, though, and I wouldn't mind trying it out.
    N6SPP and KO4CES like this.
  6. KF5FEI

    KF5FEI Ham Member QRZ Page

    Here is one of a similar form factor, courtesy of N5JLD:

    K0PIR, N7KO, KN4SMR and 3 others like this.
  7. K9KMV

    K9KMV Ham Member QRZ Page

    It is also available as a full kit with wire and winder. They weren't available when I bought mine.
    AJ6KZ, KA0USE, W7UUU and 1 other person like this.
  8. N2UHC

    N2UHC Ham Member QRZ Page

    I like the idea of using a kite string holder to wind an antenna on.
    KA0USE, KD2OKK and K9KMV like this.
  9. W1YW

    W1YW Ham Member QRZ Page

    K9KMV said it correctly. It is a transformer that takes the high impedance of the voltage max and takes it to about 50 ohms. You still may need to further choke the coax .

    This particular transformer won't do well with high power, but that is so noted.

    End feeding dipoles, for example, is a fairly modern approach brought on by lower loss materials and the availability of ferrite for chokes. The downside is the high voltages can make things burn up with overheating or even wet conditions. BUT this is rare...
  10. HB9EPC

    HB9EPC Ham Member QRZ Page

    bien vu , bien dis... je vais essayer les bougies de ma regarder si YL va aimer... Hi
    K7KBN and KC7JNJ like this.

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