End-Fed Half-Wave antennas, Grounding & RF Chokes

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by NI2M, Jan 8, 2020.

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  1. NI2M

    NI2M Ham Member QRZ Page

    Mike,

    The fact that I was able to make 88 contacts, 26 zones and 77 countries on 40 meters during the CQWW CW contest in November from a small antenna restricted city lot is "good enough" proof for me that my loop works OK. ;)
     
  2. WA7ARK

    WA7ARK Ham Member QRZ Page

    A typical 67ft long EFHW wire bent into your proposed configuration is not a bad 40m antenna. ni2m.png
    Swr2450 is 1.1. Best gain is broadside and away from the transformer:

    ni2mp.png

    This thing will beat your loop by about 2 S-Units.
     
    G5TM likes this.
  3. NI2M

    NI2M Ham Member QRZ Page

    Mike,

    I sure appreciate you providing this information! Not sure if I can deploy the end-fed as originally planned if it is too "obvious." Will see. The same antenna running 13-16 feet AGL with the 1st 20 feet going straight towards the back-fence and then taking a 90 degree to the right for the remaining length of the wire is another way that I could deploy it. However, I am not sure how poorly that would perform and I guess there is no way of knowing any of this unless the wire is up in the air.

    Best!

    Juha
     
    G5TM likes this.
  4. G5TM

    G5TM Premium Subscriber QRZ Page

    This is v similar to how I have deployed mine in the past - inverted L with the wire sloping down from a max height of 29 feet down to a height of about 10 feet. Very underrrated and mis-understood antennas.
     
  5. NI2M

    NI2M Ham Member QRZ Page

    Hi Tim,
    Did you ever compare that "inverted L" end-fed with the "100 foot (30 metre long) doublet fed with 450-ohm ladderline" that you are talking about on your qrz.com page? Would be curious to learn what the difference was.
    Best!
    Juha
     
    G5TM likes this.
  6. 2E0VSS

    2E0VSS Ham Member QRZ Page

    DL2KQ 4 Band LW


    Google translate.

    He is one serious Cookie.

    73
     
  7. G5TM

    G5TM Premium Subscriber QRZ Page

    Hi Juha

    The EFHW was superior for DX on 40 as it was up higher and much better on the higher HF bands. The doublet beat the end fed for close range contacts on 40 and gave me 80m .. good for up to 1,000 km. The noise floor on the end fed for 40m was an s point higher than the doublet.

    73
     
  8. NI2M

    NI2M Ham Member QRZ Page

    Appreciate it Tim!

    By the way, I enjoyed watching you make those contacts when mobile, using the Ham stick.

    Cheers!
    Juha
     
    G5TM likes this.
  9. NI2M

    NI2M Ham Member QRZ Page

    Mike,

    Under "4.", you bring up "breaking the coax." Now, what is the "science" behind having that tail or stub between the transformer a CM coax choke?

    Best!
    Juha
     
  10. NI2M

    NI2M Ham Member QRZ Page

    Scratch that, I am reading about your experiments on 160 meters and see that you had tried different lengths for the "stub" and landed on what you wrote here. Was just curious what theory might be.

    Juha
     

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