Isidro,
I am using a pre made unit I bought 2018 or 19. It has a SBL-1 mixer terminated with 3db attenuators, a few band pass filters a limiting circuit and a couple of MMICs. It works well enough without having to go thorough any hoops. It would be simple? for people to build them self or if they don't want to do that spend the 50-60 bucks and buy it. There are ample of sellers on e-bay and Ali express. Of course, since there are at least as many clones out there as there are sellers the results may vary.
John
John Cunliffe W7ZQ