[BC] RF gasketing or not on old CCA

[Mike Rice]

Hi Jerry:

You can get "quarter-turn captive fasteners from McMaster-Carr Supply. 
630-833-0300  www.mcmaster.com                                   They have 
what seems to be all sizes and also the clips  or leaf spring design nuts. 
I have a CCA 25KW rig, and there has also been some pitting around the 
mating surface.  You might try just filing the pits down and cleaning the 
metal. Replacing the fasteners around the cavity should settle things down. 
It would be an interesting experiment to line the edges with wire woven RF 
gasket like Harris uses in a lot of their rigs.  Those CCA rigs just keep 
running and are easy to repair!
Mike Rice
Rice Engineering

----- Original Message ----- 
From: "Jerry Mathis" <thebeaver32 at gmail.com>
To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
Sent: Monday, October 15, 2007 7:33 PM
Subject: [BC] RF gasketing or not on old CCA


> I've got an old CCA 25 KW FM transmitter in standby service. When they 
> built
> these, they didn't use an RF gasket or spring contacts on the RF cavity
> door, they just had bare metal-to-metal contact with the standard Dzus
> fasteners. The door and its mating service are now heavily pitted, and 
> most
> of the Dzus fasteners around the tube cavity section are burnt off. 
> Needless
> to say, the transmitter is not stable operating this way.
>
> Has anyone had success trying to repair a situation like this? What did 
> you
> do? I'm thinking of adding an RF gasket and getting new Dzus fasteners. 
> BTW,
> where can you get these, inlcuding the part that mounts on the cabinet? Do
> they come in sizes? If so, how do you pick what size you need? And what 
> type
> of gasket would you recommend? I've seen at least three different types. 
> I'm
> considering the kind that has wire woven into a fabric. It looks kind of
> like Scotchbrite, or a felt pad.
>
> The transmitter is still very functional outside of this problem, so I 
> want
> to fix this if possible.
>
> -- 
> Jerry Mathis
> _______________________________________________
>
> The BROADCAST [BC] list is sponsored by SystemsStore On-Line Sales
> Cable-Connectors-Blocks-Racks-Test Gear-Tools-Lots More + Now Barix too!
> www.SystemsStore.com       Tel: 407-656-3719    Sales at SystemsStore.com
>
>
>