Thursday, September 3, 2015

RX ANT Switching box,    part 1 - BPF

   It is a few years when I want to re-designing the RX antennas switching for Multi-Multi with two independant RX per band. There is our idea: 

High IP preamps in the feed point of each beverage --- long coax --- RX ant switching box

And RX ant switching box design:

Input connector (per ant) --- triband splitter --- two way splitter per band --- switch 1 of X (per RX) --- BPF + notch + ATT + preamp + ATT + diplexer + (high power TX protection)

So this article is about Singleband RX pream board:

PCB and schematic:

   The design: at the input, there is BPF. I have found really nice design from PA3AKE, please have a look at his full project! It is really nice piece of HW! There I added noth filters. I can easyly have stop band over 60dB! So this is the BPF design, than there is ATT, which you can switch ON and OFF and independant switching for preamp. In this case, preamp is done by splitting two W7IUW ones. By this you can obtain higher IP3 - see next post :-) Pream is loaded with 3dB ATT and diplexer.

And there are BPF measurings:




Full preamp ON (G=16dB):

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