[Moon-net] VE4MA type feed

Sergio ik2mmb at email.it
Tue Sep 30 08:34:12 CEST 2008


Hi Ted,
regarding the IMU feeder, I remember that it was early designed with an 
internal diameter of 170mm. Later on it was reviewed to 165mm to achieve 
a better polarization circularity.  Going down to 154 mm it is a big 
change so you would be exploring a new world. I guess you'll probably be 
able to get it to resonate at 1296 MHz meaning to achieve a somewhat 
acceptable return loss on the probes, but I have no idea or rather I 
really doubt that you will be able to achieve good 
circularity/isolation.  This is for a W2IMU with screw polarizer. VE4MA 
with screws it follows the same concept.  These are normally time 
consuming jobs so I'd really suggest you to start with the correct 
diameter if you can. Anyhow GL with your experiments.

regs

Sergio IK2MMB

Ted Barnes ha scritto:
> I have a piece of tubing 0.67 lambda diameter at 1296MHz rather than the
> recommended 0.71. (6" ID rather than 6.5"ID)
> 
> Is it possible to use this with appropriate changes to the feed point etc
> without degrading the feed performance noticeably?
> 
>  
> 
> Regards
> 
>  
> 
> Ted ZL2IP
> 
> _______________________________________________
> Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html
> 
> 
 
 
 --
 Email.it, the professional e-mail, gratis per te: http://www.email.it/f
 
 Sponsor:
 Tomb Raider anniversary. Gioca con Lara Croft sul tuo cellulare!
 Clicca qui: http://adv.email.it/cgi-bin/foclick.cgi?mid=8273&d=30-9

_______________________________________________
Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html



More information about the Moon-net mailing list