[Moon-net] [SPAM] Information req'd on use of copper pipe

[Marko Cebokli]

Hello,

Chris has already explained the problems of round waveguide, but if
you need cheap wg, square tubing of appropriate size will work fine,
for example 8x18 or 10x20mm INNER size.
For low loss, the inside surfaces must be smooth (shiny) ,and you should
avoid ferromagnetic materail or stainless steel.

You can then either make coax/wg transitions on each end, or else
transitions to WR90.
Any wg size transition gradual enough will have a good match.
If you go from wr90 to 10x20mm in 20..30mm, the match will be almost
perfect.
A lambda/4 matching section would be also possible, but does not
really make sense for such a small change in size.

73, Marko S57UUU




On Saturday 23 December 2006 07:39, Charlie Kahwagi wrote:
> Hello all,
>             I am after some help / information.
>
> I am trying to get my station setup on 10m GHz EME completed and as opposed
> to running the TWT remoted behind the dish I had the thought of using some
> copper pipe as W/G .  This would simplify my system and allow me to get QRV
> sooner rather than later.
>
> I have a few questions for anyone that can help:
>
> 1.  Is it feasible / possible to use 1/2 inch or 3/4 inch round copper tube
> as a W/G on 10 Ghz? 2.  If so is there any information on making 
> transitions to  WR 75  or 90   and to coaxial from round copper pipe? 3. 
> What losses can I expect with copper pipe?
> 4.  I plan to run CP on 10 GHz so I suspect the depolarization that would
> occur in the copper pipe is not an issue.Is       this correct?
>
> Any information would be greatly appreciated.
>
> I have my CP  feed  and LNA assembly completed and I only need to get power
> from the TWT to the feed before I can be QRV.
>
> Tnx and Regards to all for the festive season.
>
> VK3NX
> QF21EX
>
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