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GM7HUD > TECH 11.10.08 01:29l 68 Lines 2965 Bytes #999 (0) @ WW
BID : AE5252GM7HUD
Read: GUEST
Subj: Re: 13cm horn (not from a Pringles
Path: IZ3LSV<IK2XDE<DB0RES<DK0WUE<7M3TJZ<ZL2BAU<GB7PZT<GB7MAX<GB7SYP<GB7ESX
Sent: 081010/1930z 23349@GB7ESX.#31.GBR.EU $:AE5252GM7HUD [Witham, Esx]NNA V3.1
VK2ZRG wrote:-
>
> 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.
But he didn't say I couldn't resend it. Welcome to fair use Ralph :-)
73 de Andy GM7HUD
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