1090 MHZ for Radar Box

AGRANDIR Here is, how to make just a small 1090 MHZ antenna
That will allow it to provide a gain about 4.5 dB
for the receiver Radar Box (or SBS-1).



FRANKLIN antenna is an antenna colinéaire of the Extended Zepplin family
it feeds into phase two "Extended Zepplin", what gives four dipoles
with a theoretical gain of 4.5 dBd.

In practice its allows to build a small antenna (56 cm / 22 inch)
Easy to make and that will help to extend the reception area of your Radar Box.


Here the schema with the documents of the FRANKLIN antenna for the 1090 MHz frequency

133 mm / 66 mm / 7 mm
5.24 / 2.60 / 0.275

The ideal is to use a copper rod (easier to work) 4/5 mm (0.157/0.197 inch)in diameter with a length of 1 m.

  • Draw a template scale 1 on a large sheet of paper and taking into account the thickness of the stem (4/5mm).
  • Begin to bend the stem with a étaut (later the longest).
  • Getting the electrical terminal fixing at the center of the stem to bend before the other parties.
  • To bend the blow, the stem working on a piece of iron 4mm (0.157 inch) thick (see photo).
  • More bit by bit by checking in relation to gauge until the final form.



  • The connection between the antenna and receiver must be made with a high-quality coaxial cable like RG58 or with television parabolic antenna cable.

  • We can fix the link caoxial on the antenna points circles XX, or with small electrical terminal
  • , or (as in my version 6mm) with the heat shrink sleeve.
  • Without amplifier, not to exceed 6 m cable
  • For the receiver I chose an adapter BNC/SMA

  • This antenna is more efficient than the original model and brings "a few milles".
  • It's less just above it.
  • The 6mm is the limit on the size of the rod to be used.
  • Do not hesitate to try placement and position the more clear posssible.
  • Very well with an amplifier like KHUNE.

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