JA4DRP's Home made AO-40/UO-14 Dish (1.4m) 

Appendix A is added(5/18/2003)


AO-40とUO-14用に3バンド(430MHz 1200MHz 2400MHz)のヘリカルフィードを使ったディッシュアンテナを作りました。

I have made my dish antenna for AO-40 and UO-14. It has Tri-Band (70cm 23cm 13cm) helix feed.


(1)設計方針  Design Policy

 (a) フィード部は、最初はヘリカル方式にするが、後でパッチアンテナも実験してみたい。その為にはF/Dを


        The helix feed is used at first, I want to use patch antenna later . For that purpose, F/D is 0.35.

 (b) 出来るだけ軽く、安価に作る。構造的には、反射面前面に8本の棒によるサポートを入れて強度を上げて


         It should be designed as lightly as possible and cheaply. The support with eight sticks is put on the in front of 

         reflector and It makes dish strong.


 (c) フィードは3バンド使えるものを作る。使用バンドは430/1200/2400とする。

       Feed unit has 3 bands capability. The frequency is 70cm/23cm/13cm.









The actual design was done by software called dish_C2.lzh of Mr. JA5GOJ/3. Sorry this soft ware is Japanese only. You can also use bcc-dishcalc.xls. (Excel software). The maximum diameter is 140cm. I  bought 1m length of aluminum pipe to use for ribs. Cut it half size and 1/4 size and connected it. The final length is 73cm (25cm+50cm=75cm but 2cm is a connection portion) . The maximum diameter was set to 140cm as a result. Since the form of dish was made into 12 square shapes instead of a circle because of ease of making, the diameter of the minimum size is set to about 135cm. F/D is set to 0.342 , so that a Patch antenna can be also used. The following figure was as a result of calculation. Dish would be made according to these parameters.





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