Common Mode Choke Question-Inverted L

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N1LOU, Dec 12, 2019.

ad: L-HROutlet
ad: l-rl
ad: abrind-2
ad: Left-3
ad: Left-2
ad: Subscribe
ad: L-MFJ
  1. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    He already said he plans to put a rod at the entrance but hasn’t yet because it’s very difficult to install. So that piece of the solution isn’t available now.
  2. AI3V

    AI3V Ham Member QRZ Page

    No, you did not.

  3. KK5JY

    KK5JY Ham Member QRZ Page

    If you don't like the answer you got, maybe you should just explain the answer you want. :rolleyes:
  4. AI3V

    AI3V Ham Member QRZ Page


    Do not overlook that the interference is being radiated by your antenna -after all, that's what antennas do- and is being received by the various wires in and into your shack.

    Repositing wires
    Coiling up extra long wires
    Uncoiling coiled up wires!
    Adding "chokes"
    Bypass capacitors
    LC filters on power wires
    Replacing unshielded wires with shielded ones
    Replacing wired connections with wireless ones
    Using fiber optic connections

    All these things can be the cause of, or the solution to, rfi.

    It really is a case of experimenting untill you hit a solution.

    Also, don't be supprised if a "solution" eliminates rfi on one frequency only to have it pop up on another.

  5. N1LOU

    N1LOU XML Subscriber QRZ Page

    Well, so far everything is working fine. I managed to get all my software installed and talking to the radio (Win4Yaesu, Omnirig, FLDigi, Log4OM) and made a few QSOs on a number of bands (18-160 tonight). I didn't notice any issues with RFI messing with CAT control. Tomorrow I will install the SDRPlay RSP1a and see if I can get the pan adapter running.
    N0TZU likes this.
  6. N0TZU

    N0TZU Platinum Subscriber Platinum Subscriber QRZ Page

    Excellent! Is that with the second choke at the tuner?

    (BTW, before thunderstorm season starts you really must get a ground rod installed at the coax entrance to the house, and connect it with the house electric service rod. It's required by code, besides helping with common mode noise problems.)
  7. N1LOU

    N1LOU XML Subscriber QRZ Page

    No, only one choke and it is at the entrance to the shack.

    I know, but thanks for the reminder. Hopefully we don't get any thundersnow this winter. And yes there is such a thing. :)
    N0TZU likes this.
  8. W5NNX

    W5NNX Ham Member QRZ Page

    a bit late, so use the 915 at the coax side close to the shack, and one at the feed of the antenna (or only one required for coax to antenna)?
  9. KI5FJ

    KI5FJ Ham Member QRZ Page

    Remember the farther away the shack is from the antenna, the less RF radiated into the shack.
    My 130 Ft Inverted-L is about 50 Ft from the shack. When operating 300 Watts on 20-Meters,
    the field strength meter indicates a very strong signal. All my CMCs and grounding will NOT
    stop this radiation. Be safe and update your RF Safety analysis. 73 Joe O, K I 5 F J, NNNN

Share This Page