No announcement yet.

best antenna

  • Filter
  • Time
  • Show
Clear All
new posts

  • Originally posted by raptor22 View Post

    Do I need a filter?
    Here is my data capture record
    Screenshot 2021-09-17 195508.png
    Yes you do need a filter. Heavy mobile phone signal present in GSM850 band.

    Optional: You may conduct this scan also. It covers full band of DVB-T (24 Mhz to 1800 Mhz)

    ​​​​​​In thread "Do I Need a Filter":
    DVB-T plugged into Windows Computer - Using GUI Spektrum.exe
    Last edited by abcd567; 2021-09-18, 01:13.


    • Originally posted by abcd567 View Post
      Same wire data as above, simulated in software MMANA-GAL, gives Gain = 7.35 dBi, & very high SWR = 133 !!!!!!

      Which software to trust????

      Wire dia = 3mm
      Gap between stub wires =6 mm (center-to-center distance between stub wires = 1.5 mm + 6 mm + 1.5 mm = 9 mm)
      Optimum cable tap position = 45 mm from open end (or 69 mm -45 mm = 24 mm from shorted end)


      I used 3.5mm diameter copper wire with 6mm spacing, built the Franklin antenna according to your size, and tested it with a 50ohm feeder. The resonance point is 1080MHz, and the SWR is as high as 3 at 1090.

      Can you tell me where there might be a problem?


      • hello gentleman...
        i would like to show you my results of my development because of antennas. Years ago I started this development because of the unreliable ADS-B data during flying sharp u-turns, curves.
        The ads-b signal is generally vertical polarized. During flying curves the antenna is not vertical. Rod antennas and all other antennas on the market have all a vertical polarization.
        To avoid that problem I developed a new antenna which is very tiny, has a perfect pattern, can be used as sector antenna and no more filter is needed.
        attached I have a video which I made 2 days before ...the result was perfect and follows all simulated parameter ....

        Have fun


        Sorry I have made comments in german....but you will understand :-/


        • 20220403_180505.jpg

          Does anyone have an idea how I can shorten this antenna for 1090 MHz? Bought this antenna through Amazon a few years ago for some bucks, but it has performed / performs TERRIBLY....

          I don't know how to count the coils in the total length of the antenna (λ/4=6.88 cm or λ/2=13.75 cm). I've already read/searched a bit about coiled antennas/whips here in the forum, but didn't found a solution.

          I am grateful for any suggestion!
          Attached Files


          • No need to cut the whip.
            Unscrew the whip and use a thin copper wire like one of 6 wires from a scrap network cable, or a thin steel tie wire like the one in first two photos below.

            Optimized Whip Steel Tie Wire.jpg

            Optimized Whip Steel Tie Wire-Dimensions.jpg

            Dimensions of Optimized Whip.png

            Use one of the many wires in a Scrap network cable


            Last edited by abcd567; 2022-04-04, 04:03.