Let's build a Band Reject Filter using just coax!
There are two ways to do this.
In the first video I showed you how to do this with an OPEN stub. This was the easiest way.
In this video, I will show you how to create a Band Reject Filter using a SHORTED stub.
We can get some pretty amazing rejection with it!
Admittedly, they are not not narrow band filters by any stretch of the imagination.
Promised LINKS:
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Smith Chart - Downloadable FREE Complete Smith Chart
www.scribd.com...
SPEED OF LIGHT VALUES
11802.85E6 inches/sec ... 11802.85 mega-inches/sec
29979.24E6 cm/sec ... 29979.24 mega-cm/sec
Time Markers for Your Convenience
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00:05 Introductory Comments
01:38 How do they work?
01:42 Single Stub
03:48 Double Stub
05:43 Designing One
05:48 Know Your Materials
06:42 Determine your Frequency (fo)
06:52 Calculate Cable Lengths
07:45 DEMO: 250 MHz Miscreant Signal
08:12 Designing the Filter
10:26 Cutting the Coax
11:06 The Actual Build
11:18 Creating the Shorts at the end of the Stubs
12:02 Performance
12:31 Tuning the Filter
15:04 Adding Adjustability/Shortening the Stubs
15:31 How?
17:54 How to Design one
18:23 Smith Chart Assumptions
18:48 Two ways to approach the design ...
19:36 DEMO: 90.9 MHz FM Broadcast Signal
20:17 Some good advice ...
20:48 DESIGN with WAY #1: Step-by-Step
24:16 DESIGN with WAY #2: Step-by-Step
28:17 Performance and Tuning
29:51 Final Comments and Toodle-oots
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19 авг 2024