[hpsdr] Excalibur back plate

[Chris Smith]

Hi 

I expect there are others like myself who have become fed-up with Excalibur's two BNC sockets hanging in space in an unblanked slot. I finally decided to do something about it last week-end and thought I'd share my experiences.

The very nice plate that Roger Rehr, W3SZ, supplied about a year ago had no provision for Excalibur. By doing some serious "eyeing" I decided that the 2 BNC sockets on Excalibur lay on the centre-line of the fixing screw slots and that the lower socket was 1" up from the _centre_ of the bottom plate fixing screw hole. The upper socket was measurable as 1 3/16" above that.

Having marked the hole centres, I drilled out 2 x 1/2" diameter holes to clear the BNC sockets by using successively larger drills.

The upper BNC socket is the external reference input (in my case from a Trimble Thunderbolt) and is floating with respect to ground. My drill chuck has a max size of 13mm, or just over 1/2" in old money, and having 1/2" as the largest drill in my possession I used a round file to open the hole slightly before fitting a 1/2" grommet to ensure that the BNC socket shell doesn't touch the back plate..

I found I had to fix the grommet to the plate using a couple of dabs of Super Glue. This was because the BNC socket with it's bayonet lugs needs to be "worked" through the grommet and this invariably resulted in the grommet pulling out of the hole. In fact I had to remove Excalibur from the Atlas backplane, insert the BNC sockets into the new holes and fiddle the plate back into place at the same time re-seating Excalibur into the back-plane. Fine if you have more than the usual allotment of two hands!

Next job is to mount the CCI/Motorola AN762 onto the "front" of Pandora complete with large heat-sink.

Then all I need is Alex ...   :-)

Cheers & 73

Chris G4NUX
 1285851107.0