Terminated End Fed antenna vs EFHW

Discussion in 'Videos and Podcasts' started by W9HJ, Jul 20, 2020.

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  1. W9HJ

    W9HJ QRZ Lifetime Member #294 Platinum Subscriber Life Member QRZ Page

    Here is a little comparison between my homemade Terminated End Fed antenna and a traditional EFHW antenna. The difference in receive signal is night and day different. Also, contrary to popular opinion, transmitting on it is good also. I've gotten over 22,000 km on it. Best of all, for pretty much anything from 630M to 6M ... no need for an antenna tuner as the SWR is pretty much below 2:1 most of the time (even on non-ham bands) and below 3:1 across the board.



    Here is the design (which can also be seen in my QRZ page.

    [​IMG]
     
    N4XRD likes this.
  2. WB5AGF

    WB5AGF Ham Member QRZ Page

    That would be long-path ... right ?

    - Paul, WB5AGF
     
  3. WR2E

    WR2E Ham Member QRZ Page

    How so? Better or worse? When you say "different" what exactly do you mean? Stronger sigs? Better s/n ratio? How are you measuring? Have an A/B switch between the two antennas?

    Measured where, and how? At the feedpoint with an analyzer?

    How much power ya reckon is heating up the resistor? Does it get warm?
    How much power are you running into the antenna?

    That's a fairly miraculous claim!
     
    KD6RF likes this.
  4. WR2E

    WR2E Ham Member QRZ Page

    If the half-way point is 24,900 miles, maybe not! ;)
     
  5. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Thus proving it is always possible to create a poorer performing antenna!

    1. It's always possible to obtain excellent broadband SWR by placing a resistive load in the circuit. Try putting 50 Ohm resistors on dipoles or yagis feed points! When you have broad level SWR, especially across multiple bands, that is a clue something is being fudged.

    2. Your ground rods serve no function.
     
    Last edited: Aug 12, 2020
  6. WN1MB

    WN1MB XML Subscriber QRZ Page

    If the 71 foot elevated "counterpoise" wire is grounded at four points as shown, my question is this: can it be accurately called a "counterpoise" at all? My knee jerk, unedumacated* thought is "no."

    * Being a lowly Advanced, I defer to the better informed Extras on this.
     
  7. W9HJ

    W9HJ QRZ Lifetime Member #294 Platinum Subscriber Life Member QRZ Page

    Better as in a much lower noise floor.

    Measured by my transceiver. You can hear the difference, and even see it in the meter in my attached video. I'm measuring in the shack with my RigExpert AA-55 Zoom.

    At most I only push out 200 watts out of my FTdx-101MP. The terminating resistor from Palomar Engineering is rated at 375 watts. I worked FT8 on it for an hour straight, then after my last contact ran out and touched the resistor and it was barely warm. I've done an 8 hour session of FT8 before and no issues.

    Yes, it is, but seeing and hearing is proof enough for me.
     
    WR2E likes this.
  8. W9HJ

    W9HJ QRZ Lifetime Member #294 Platinum Subscriber Life Member QRZ Page

    1. Yup, you can do it to other designs as well. Terminated antennas are nothing new. The design I use is based off a military grade antenna that has been used since the 1950.

    https://palomar-engineers.com/broad-band-terminated-dipoles

    2. The drawing is different than my actual installation. I only have 2 ground rods, one at the resistor end and one at the feed point. They do help.

    https://www.bwantennas.com/acs.html
     
    KA0HCP likes this.
  9. WN1MB

    WN1MB XML Subscriber QRZ Page

    How?
     
  10. W9HJ

    W9HJ QRZ Lifetime Member #294 Platinum Subscriber Life Member QRZ Page

    Depending on who you talk to, a radial is ground mounted. Some say that if you take it off the ground it is called a counterpoise, others call it an elevated radial. According to the ARRL Handbook (Straw 2003) defines counterpoise as "A wire or group of wires mounted close to ground, but insulated from ground, to form a low impedance, high-capacitance path to ground."
     
    WN1MB likes this.

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