Smith Charts: DEMO 1 - Parallel Stub Match Design & Build (00h8)
ฝัง
- เผยแพร่เมื่อ 9 ก.ย. 2024
- In this video I will be designing, building and testing a parallel stub match to match my perfectly horrible load to a 50 Ohm feedline.
The main purpose of this is to cover more of the practical aspects of the whole process than to go over the design process in detail.
I will show how even the most carefully designed and built stub match may require a little adjustment to dial it in to what you want. Unfortunately, real life and theory rarely agree 100% ... but they CAN be quite close.
00:05 Introduction
02:09 Start the Process
02:22 STEP 1 = Measure the actual Impedance
03:51 STEP 2 = Know Your Coax (Measuring the Velocity Factor)
04:19 Measuring coax Velocity Factor with a VNA
06:57 All the Facts in One Place - What are we working with?
07:35 STEP 3 = Normalize your measured Impedance
08:00 STEP 4 = Plot the Normalized Impedance on the Smith Chart & draw the SWR circle
09:17 STEP 5 = Convert the Impedance to Admittance using the Smith Chart & read lambda(load)
10:53 STEP 6 = Move to the G = 1.0 Circle & read Admittance(a) here and lambda(a)
12:35 STEP 7 = Calculate coax length from Load to Stub (Impedance Transforming)
14:33 STEP 8 = Determine the lambda(Stub)
17:35 STEP 9 = Calculate the length of the coax for the Stub (Reactance Eliminating)
18:49 CONSTRUCTION BEGINS - Introduction
19:51 On the bench - important things to remember in construction
22:52 How to make the SHORTED end of a SHORTED Stub
23:53 How to make the OPEN end of an OPEN stub
24:07 The completed Stub Match - A Tour
24:35 Initial Test Results and final adjustments
27:34 Final comments and Toodle-oots :-)