Start building spectrum analyser

I need a spectrum analyzer to test my home brew transceivers.
Unfortunately those things are expensive so I Will try to build one myself.

I may build more than one. The first one will be simple. just to check if my creations are performing according to the rules.
The other one will be more advanced. It will include a tracking generator and synthesizer control.
But that is for the future.

I found a TV tuner UDT-401 those things are hard to find. I was lucky to find one.
They can be used from 1 to 500 MHz. That is just what I need. It is enough to check the 2nd and third harmonic of a 144 MHz transmitter.

The tuner UDT-401
The UDT-401 has a few advantages over other tuners. These are.
1-500 MHz frequency range.
No range switching required
Flat response over the frequency range.
IF output at 38 MHZ.
1st LO frequency/256 available.
It has a few disadvantages though.
Hard to find.
2nd LO is free running. No control or output is availability.

Several spectrum analyzer designs exist that use this tuner. I have studied those designs. I can use some parts of those designs. However I want to use a micro controller to control it.
This part I have to design myself.