AND …
I will also add that i dont like Leif SM5BSZ test setup …
I see resonant cavity’s that he has built …
If the test had been done with SMD parts and on a proper ground plane PCB design that was similar to manufacturers design … then id be 100% looking for a few PSA4-5043’s … Mini-circuit min order is 20 and at $3.50 each …
I agree, visually his projects are not state of the art but you can be sure that his designs are working. As you may note, he has some problems with assembling SMD components but most of the things he is measuring on the VHF frequencies can be done using the standard non SMD parts.
It may be strange how he grounded the MMICs but the the results are OK. As you can see, there are no oscillations and the measurements are done by the book. Not to forget that you can not find the free SW doing better job than Linrad is doing.
Sometimes it is difficult to understand what he is doing but once you get his Linrad approach to measure the performance it is easy to follow his work. This guy has excellent background and a lot of knowledge and wisdom.
I think the resonant cavity that he built would be in the 7Ghz range …
I don’t think you would see an oscillation at 7ghz when tuned to 400Mhz … it also could be ringing from the 400Mhz input at ~7ghz.
All im saying that i will take that test with a grain of salt until its done with a proper layout …