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VK2ZRG > TECH 10.10.08 05:08l 61 Lines 2736 Bytes #999 (0) @ WW
BID : 2721_VK2ZRG
Read: GUEST
Subj: 13cm horn (not from a Pringles can)
Path: IZ3LSV<IK2XDE<DB0RES<DK0WUE<7M3TJZ<F6CDD<F6BVP<VK2TV<VK2AAB<VK2WI
Sent: 081008/1045Z @:VK2WI.#SYD.NSW.AUS.OC #:3170 [Sydney] $:2721_VK2ZRG
From: VK2ZRG@VK2WI.#SYD.NSW.AUS.OC
To : TECH@WW
VK2ZRG/TPK 1.83d Msg #:2721 Date:08-10-08 Time:10:49Z
This end is open. A 2.45 GHz HORN ANTENNA
Signal comes out here. (Not from a Pringles can)
|----- 159 mm diameter ------|
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ ------ A Dick Turrin (W2IMU SK)
³ ³ | dual mode horn with 12 dBi
³ ³ | gain. This design can be
³ ³ | scaled to another frequency.
³ ³ |
³ ³ 166 mm long
³ ³ |
³ ³ | This antenna has very low side
³ ³ | lobes making it very suitable as
³ ³ | a feed horn for a dish antenna.
³ ³ | The F/D ratio of the dish should
³ ³ | be between 0.5 and 0.6 (0.55 opt)
ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´ ------
\ / It is basically two circular
\ / ³ waveguide sections joined with
\ / ³ a 30 deg conical flare section.
\ / ³
\ / ÀÄÄ Flare angle = 30 degrees
------ ÃÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´
| ³ ³
| ³ ³
| ³ ³
98mm ³ ³
long ³ ³ÃÄÄÄÄ¿
| ³ ÄÄÄÄij³ ³  Female `N' connector with probe 28mm long.
| ³ ³ÃÄÄÄÄÙ ³
| ³ ³ 43mm spacing from end cap
------ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ Á
/ |------87mm------|
/ diameter
³
ÀÄThis end is closed with an end cap.
The simple probe feed may be replaced with a half wave dipole mounted at
the centre of the end cap. Adjust the spacing and length for best match.
The 28 mm probe length is measured from the wall of the 87 mm tube.
The horn is of all metal construction. It may be possible to find some
suitable metal containers such as paint cans, food or beverage containers
etc, for the main parts. I made a 23 cm version of this antenna from
1.2 mm thick aluminium sheet. The flat sheet was rolled into circular
forms and rivited together. It matched to better than 1.1:1 VSWR with
the probe feed.
The design comes from the ARRL UHF/Microwave Experimenters Manual, 1990
edition. See page 9-31.
73's from Ralph VK2ZRG@VK2WI.#SYD.NSW.AUS.OC
P.S. To G8MNY You may not re-issue this in your tech bulls without my
permission.
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