You operate HF with THAT???

Discussion in 'On the Road' started by N3EG, Dec 29, 2020.

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  1. N3EG

    N3EG Ham Member QRZ Page

    Years ago, I modified NMO coils for HF operation. I started with a stacked Maxrad coil arrangement and wound telephone wire externally to make a coil for 75 meters along with a base capacitor, and used it to check into nets. Yes, it's only good for about 30 kHz without a tuner - so I have a MFJ autotuner under the seat. Eventually I had NMO antennas for almost all the HF bands 75-10 meters with 4 foot whips, and they all are good for real communications. The main reason for this is I drive vans with no room for a long antenna and bumper mount. Now I have an Elecraft KX2 for mobile/portable use, and I'm winding even smaller coils inside old CB coils along with base capacitors for the work van. I actually got the 75 meter coil to fit inside a single Maxrad housing. I start with 180pF across the base for 10 meters, 360 pF for 20, and keep increasing as I go down. Internal coils are close wound, and around 11 MHz the single winding maxes out and I have to start overlapping a second layer of windings. Somewhere around 3 MHz would involve a third winding if I ever get that far and decide to do a 160 meter antenna!

    Has anyone else tried this?
  2. N3EG

    N3EG Ham Member QRZ Page

    Nobody is responding to this, so I had to do something. I'm winding a 9 inch NMO coil for...160 meters! Close wound, outside of the coil form which is 3 stacked empty NMO CB coil shells 1 3/8" diameter. Whip is another 4 footer. Should be putting it on the nanoVNA on Monday.
  3. W2SGM

    W2SGM Ham Member QRZ Page

    This sounds interesting, would you be willing to share some photos?
    KC5AKB and WA5QEC like this.

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