Meteor M-N2 Images

Friday, 15 December 2017

Homebrew SDR HF Transceiver - RF Splitter

The RF splitter is used to split the incoming RF into two equal parts. These individual signals are then used as input to the ADE-1 mixers that produce the I & Q signals (90 degrees out of phase). Obviously you don't want to lose too much power in the splitter circuit and you want to ensure that the two output signals are of equal magnitude.

Update: 27 Dec 2017. The splitter design I originally used did not produce zero phase difference. Hence I have updated this page with another design.

I built this splitter based on a design from EMRFD (Experimental Methods in RF Design, Hayward, Campbell & Larkin), specifically the one from the 18 MHz transceiver shown in Fig. 11.14.

The schematic is below:

I used an FT50-43 toroid with 6 bifilar turns.

My built version can be seen in the picture below.

The picture below shows the outputs from ports 1 and 2. They are equal in amplitude and in phase which is perfect.

Next post: Adding the ADE-1 mixers

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