Comprod makes dipole arrays with a screen reflector, at least for VHF, not
sure about UHF. I'm looking in the catalog and it shows a backside null
close to 20 dB down from the main lobe.
The screen reflector should be nominally about 1/4 wave behind the radiator
for maximum forward gain. It could be modeled fairly easily.
How wide of a forward beamwidth do you want? Would a couple of corner
reflectors be a better way to go?
--- Jeff
> -----Original Message-----
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Dan Hancock
> Sent: Thursday, November 19, 2009 11:43 AM
> To: repeater builders
> Subject: [Repeater-Builder] Antenna Pattern Question
>
>
>
> I have a repeater that I need to have as tight a cardiod
> pattern as possible. I have looked at the dipole antennas
> such as the DB-411 and they don't really shut down the back
> door quite enough.
> Does anyone have any antenna modeling software that would
> show the result of adding an 18" wide screen to the back side
> of the mast on the DB-411? Does anyone have any experience in
> home-brewing a modification like this?
>
> Dan Hancock N8DJP
>
>
>
>
>
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