RF Choke, Iron powder core vs Ferrite

Discussion in 'Homebrew and Kit Projects' started by SA7CNG, Aug 4, 2021.

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  1. G0TNU

    G0TNU Ham Member QRZ Page

    Sorry my input did not meet your high expectations.
  2. WA7ARK

    WA7ARK Ham Member QRZ Page

    Nothing to do with my expectations. A vertical Marconi is just very different (current driven) compared to a EFHW (voltage driven) antenna. The tendency to create CM current on the feeding coax, and how blocking that CM affects these two antenna types is night and day.
  3. G0TNU

    G0TNU Ham Member QRZ Page

    Your absolutely correct they are 2 very different antennas & perhaps i should not have suggested instead.
    I just quoted what i use.

    Marconi type antennas are not something i typically use, Mainly i use efhw or homebrew open wire doublets.

    The only thing i use remotely related to Marconi is Morse code.
  4. SA7CNG

    SA7CNG Ham Member QRZ Page

    I threw away the old design, it was clearly not a good idea to build a balun that way. Instead i wound a bit of RG58 coax 8 turns around an FT140-43, and used a BNC-wire adaptor to connect it to my vertical antenna. After i added the FT140-43 RF-Choke lowest SWR dropped from 1.4:1 to a bit below 1.1:1.

    Since i live in an apartment and only have a very small garden i havent been able to have full length radials in all directions, and the vertical antenna isnt completely free from obstructions.

    Next step will be to try to build some kind of roof/rain protector for the connections.


    Last edited: Aug 9, 2021
    KU3X likes this.
  5. SA7CNG

    SA7CNG Ham Member QRZ Page

    Also, thanx for the help from everyone!
    SWL37632 and KU3X like this.
  6. WB7TDG

    WB7TDG Ham Member QRZ Page

    take it from this old on the air 40+ years ham...
    I have tried various baluns, transmatches, etc...and have found to feed an antenna with balanced transmission line, nothing can beat the old link coupled transmatches for efficiency.
    they also are a band pass filter and will work very well without any sort of grounding.
    they will also reject common mode noise pretty darn good.

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