[Top] [All Lists]

[AMPS] How much screws on top cover of 2m W6PO 8877 amp?

To: <>
Subject: [AMPS] How much screws on top cover of 2m W6PO 8877 amp?
From: (Steve Thompson)
Date: Fri, 26 Feb 1999 18:45:26 +0000
In message <>, Carsten Esch
<> writes
>I build some W6PO 2m linears with the 3CX1500A7 in the past but was
>always wondering on how to decide how many screws (what distance between
>screws) I should use to get the top cover closed (regarding RF).

On a 19" x 12" panel, screws round the edge at 70mm centres killed
radiation up to 1GHz. As supplied the box had 210mm centres on the
screws and there was significant radiation above 500MHz. It also depends
on the quality of metal-metal contact along the edges. I've been cursing
a unit with about 100 screws, one every inch along machined faces on
7/16" Al panels. Some goon didn't understand that one every 6" would
have been plenty!

>What if I use perforated metall for the top cover? What would be the
>'maximum' size for these holes? 

10mm is .5% of a wavelength - should give minimal leakage.


FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>