Difference between revisions of "SSB6 Design"
Jump to navigation
Jump to search
Blwikiadmin (talk | contribs) |
Blwikiadmin (talk | contribs) |
||
| Line 36: | Line 36: | ||
==== Dishal Values ==== | ==== Dishal Values ==== | ||
| + | |||
| + | * Impedance = 195.9 | ||
| + | <pre> | ||
| + | RefDes Dishal RefDes W7ZOI | ||
| + | Ck12 87.3 C3/C9 82 | ||
| + | Ck23 110.9 C4/C8 100 | ||
| + | Ck34 114.4 C6 100 | ||
| + | Cs1 110 C2/C10 120 | ||
| + | Cs3 369.5 C5/C7 470 | ||
| + | </pre> | ||
[[file:Dishal-sim-01.PNG]] | [[file:Dishal-sim-01.PNG]] | ||
Revision as of 22:39, 16 October 2021
Contents
Design
- 6 element filter
- W7ZOI Crystal Filter paper has several crystal filter designs
- Narrow bandwidth bandpass filters for SSB
- Used for transmit/receive
- 9 MHz nominal frequency
- 50 Ohms in/out impedance
- Bin crystals using Colpitts Crystal Oscillator
- Hand select close values from a pile of crystals
- Can get much closer than 10% of bandwidth with 50 crystals
- W7ZOI Filters on Kits and Parts Boards
- Other filter builds
- 5 or less crystals
W7ZOI SSB6 Schematic
- Response curve
Build
- SSB6 filter is too big for Kits and Parts board (5 crystals limit)
- 2500 Hz bandwidth
Schematic
Dishal Values
- Impedance = 195.9
RefDes Dishal RefDes W7ZOI Ck12 87.3 C3/C9 82 Ck23 110.9 C4/C8 100 Ck34 114.4 C6 100 Cs1 110 C2/C10 120 Cs3 369.5 C5/C7 470
3D Image
Measured Crystal Values
Number Freq Delta from average 09 8.997791 -7.7 12 8.997791 -7.7 41 8.997793 -5.7 06 8.997794 -4.7 21 8.997798 -0.7 38 8.997798 -0.7
Enclosure 80x50x20
- Fits in 80x50 extruded enclosure
- Material: Aluminum
- Color: black
- Size: approx.80*50*20mm
- Thickness: approx.1mm
Performance Measurements
Overall
- NanoVNA
- 2.5 KHz / div
Detailed
- 1 KHz/div
- Bandpass looks about 2500 KHz = good
- Left freq = 8.99762 MHz
- Right freq = 9.00005 MHz
- Delta = 2.43 KHz
- Center frequency = 8.99885 MHz
- Implies crystals are properly matched?
- Insertion loss at "best" point (red marker) -5.14 dB = OK
- Deep skirts = good
- Ripple looks bad
- Right side low
Compared to SSB4
- 1 KHz/div
- Skirts much deeper on SSB6
- -90 dB on SSB6 at window edges
- -60 dB on SSB4 at window edges
- Passband much flatter on SSB4
- Insertion loss lower on SSB4
- SSB4
References
- Crystal ladder filters – Software
- Crystal Ladder Filters for All - ARRL QEX
- DISHAL software by DJ6EV
- A Practical Test Set for Comprehensive Crystal Testing
- Crystal characterization and crystal filter design
- Crystal parameters Written by Hans Summers (QRP Labs)
