Sunday, 20 November 2011

Input Switch

Slowly getting there.

This is the input switch of the network analyser. Its purpose is to switch between transmission/reflection measurement and it also provides a switch to choose between spectrum analyser (SA) and vector network analyser mode (VNA).

I decided to mount the SMA connectors in the same style as I did with the other modules instead of letting them protrude from the front panel.

I use 0.2 mm (50 mil) copper sheet for the  perimeter fence. It requires a bit of practise but I found that using one single strip works better than joining two brackets. I used a pair of scissors to cut the sheet.

 Internal shielding. It requires a lot of patience to install the fences. Some of them are made of double sided copper-clad FR4 in order to keep ground planes separate.

 Almost finished. I need to seal the individual sections with copper lids as soon as I get my hand on the missing capacitors. You can see the RF-relay that switches between VNA and SA mode in the lower left corner.

Bottom view. A few power supply jumpers are missing. The three SMA connectors on the top are for the  transmission, reflection and spectrum analyser inputs, the SMA connector to the left below them is the selection output. The semi-rigid coax jumper on the bottom connects two sections.

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