#!/usr/bin/env python3
"""
gen_ferrite_tables.py
Generate ferrite_impedance_table.ods — ODS spreadsheet with ferrite core
material properties and choking impedance vs. frequency tables.
TM-CMC-001 Rev A
Uses Python stdlib only (zipfile + xml strings). No external dependencies.
Output: ferrite_impedance_table.ods (same directory as this script)
"""
import zipfile
import io
import os
import sys
# ── Data ──────────────────────────────────────────────────────────────────────
# Sheet 1: Ferrite material properties
MAT_HEADERS = [
"Mix", "µ_initial", "µ_real peak (MHz)", "Loss dominant range (MHz)",
"Curie temp (°C)", "Primary HF use", "Common cores", "A_L FT-240 (nH/N²)",
"A_L FT-140 (nH/N²)", "A_L FT-82 (nH/N²)", "Notes"
]
MAT_DATA = [
["31", 1500, "1-10", "1-300", 230, "160M-6M broadband", "FT-240-31, FT-140-31, beads", 1800, 1000, 570, "Best all-HF choking material"],
["43", 850, "10-30", "10-500", 200, "40M-2M, upper HF/VHF", "FT-240-43, FT-140-43, FT-82-43", 1100, 625, 557, "Best 20M-70cm choice"],
["61", 125, "50-200","200-1500",350, "VHF/UHF (50-1300 MHz)", "FT-50-61, FT-82-61, FT-114-61", 195, 111, 36, "Low loss VHF; use for bead-on-coax"],
["52", 250, "30-100","100-2000",350, "UHF (100-2000 MHz)", "FT-37-52, FT-50-52", 248, 138, 40, "Lower µ than 61; good 100-2000 MHz"],
["77", 2000, "0.1-2", "0.1-10", 200, "LF/160M (0.1-10 MHz)", "FT-240-77, FT-140-77", 7500,4500,1300, "High µ; saturates at lower drive"],
["75", 5000, "0.01-1","0.01-2", 130, "Very LF, 60Hz-2 MHz", "FT-240-75, pot cores", 8500,5100,1900, "Very high µ; avoid above 3 MHz"],
["67", 40, "100-600","200-2000",500,"Microwave (200-2000 MHz)","FT-37-67, small beads", 22, 13, 5, "Nickel-zinc; very low loss VHF+"],
["73", 2500, "0.1-2", "0.1-20", 150, "LF/AM broadcast, 160M", "FT-240-73", 7000,4000,1300,"High µ for low frequency"],
]
# Sheet 2: FT-240-31, 10 turns — impedance vs frequency
TOROID_HEADERS = ["Freq (MHz)", "R (Ω)", "jX (Ω)", "|Z| (Ω)", "CMR @150Ω path (dB)", "CMR @50Ω path (dB)", "Note"]
# FT-240-31, 10 turns
FT240_31_10T = [
[1.8, 450, 2040, 2090, 22.9, 32.3, "160M good"],
[3.5, 750, 3100, 3190, 26.5, 36.1, "80M excellent"],
[7.0, 1500, 3900, 4180, 29.4, 38.4, "40M excellent"],
[10.1, 2200, 3600, 4220, 29.5, 38.5, "30M peak region"],
[14.0, 3200, 2800, 4250, 29.6, 38.6, "20M excellent"],
[18.1, 3800, 1900, 4240, 29.6, 38.6, "17M excellent"],
[21.0, 3900, 1200, 4080, 29.4, 38.4, "15M good"],
[24.9, 3800, 600, 3850, 28.8, 37.8, "12M good"],
[28.0, 3600, 200, 3605, 27.6, 37.1, "10M adequate"],
[50.0, 1800, -400, 1844, 21.8, 31.3, "6M marginal"],
[144, 400, -500, 640, 12.6, 22.1, "2M poor — use ferrite beads"],
]
# FT-240-43, 12 turns
FT240_43_12T = [
[1.8, 80, 700, 705, 13.4, 22.9, "160M poor — use Mix 31"],
[3.5, 210, 2450, 2460, 24.3, 33.8, "80M marginal"],
[7.0, 550, 4200, 4236, 29.1, 38.6, "40M good"],
[10.1, 1100, 5400, 5511, 31.3, 40.8, "30M excellent"],
[14.0, 2800, 5100, 5819, 31.9, 41.3, "20M peak"],
[18.1, 4100, 4200, 5874, 31.9, 41.4, "17M peak"],
[21.0, 5000, 3600, 6153, 32.3, 41.8, "15M peak"],
[24.9, 5800, 2800, 6434, 32.6, 42.2, "12M excellent"],
[28.0, 6000, 2200, 6393, 32.6, 42.1, "10M excellent"],
[50.0, 4800, 800, 4866, 30.2, 39.7, "6M very good"],
[144, 1200, -600, 1342, 19.0, 28.6, "2M adequate"],
[222, 500, -700, 860, 15.2, 24.7, "1.25M poor"],
]
# FT-240-43, 8 turns
FT240_43_8T = [
[1.8, 36, 310, 312, 6.4, 15.9, "160M very poor"],
[3.5, 93, 1089, 1093, 17.3, 26.8, "80M poor"],
[7.0, 244, 1867, 1883, 22.0, 31.5, "40M marginal"],
[14.0, 1244, 2267, 2587, 24.8, 34.3, "20M good"],
[21.0, 2222, 1600, 2736, 25.2, 34.7, "15M good"],
[28.0, 2667, 978, 2841, 25.6, 35.0, "10M good"],
[50.0, 2133, 356, 2163, 23.2, 32.7, "6M good"],
[144, 533, -267, 596, 12.0, 21.5, "2M marginal"],
]
# Stacked FT-240-31 + FT-240-43, 8 turns
STACKED_31_43_8T = [
[1.8, 486, 2350, 2400, 24.1, 33.6, "160M good (sum of individual)"],
[3.5, 843, 3189, 3298, 26.8, 36.3, "80M excellent"],
[7.0, 1744, 5767, 6025, 32.1, 41.6, "40M excellent"],
[14.0, 4444, 7367, 8679, 35.3, 44.8, "20M outstanding"],
[21.0, 7222, 5200, 8889, 35.5, 45.0, "15M outstanding"],
[28.0, 8667, 3178, 9234, 35.8, 45.3, "10M outstanding"],
[50.0, 6933, 1156, 7029, 33.4, 42.9, "6M excellent"],
]
# Sheet 3: Snap-on beads — impedance per bead and N-bead stacks
BEAD_HEADERS = [
"Freq (MHz)", "|Z| Mix31 1pc (Ω)", "|Z| Mix31 6pc (Ω)", "|Z| Mix31 12pc (Ω)",
"|Z| Mix43 1pc (Ω)", "|Z| Mix43 6pc (Ω)", "CMR Mix31-12pc @150Ω (dB)",
"CMR Mix43-6pc @150Ω (dB)", "Recommended config"
]
BEAD_DATA = [
[1.8, 195, 1170, 2340, 60, 360, 23.9, 7.6, "12× Mix31"],
[3.5, 270, 1620, 3240, 115, 690, 26.7,12.7, "12× Mix31"],
[7.0, 430, 2580, 5160, 190, 1140, 30.7,17.6, "12× Mix31 or 6× Mix31"],
[14.0, 545, 3270, 6540, 360, 2160, 32.8,23.2, "6× Mix31 adequate"],
[21.0, 590, 3540, 7080, 520, 3120, 33.5,26.4, "6× Mix31"],
[28.0, 600, 3600, 7200, 600, 3600, 33.6,27.6, "6× Mix31 or Mix43"],
[50.0, 600, 3600, 7200, 672, 4032, 33.6,28.6, "6× Mix43 better at 6M"],
[100, 510, 3060, 6120, 735, 4410, 32.2,29.4, "6× Mix43"],
[144, 480, 2880, 5760, 750, 4500, 31.6,29.6, "6× Mix43 excellent"],
[222, 400, 2400, 4800, 680, 4080, 29.8,28.7, "6× Mix43"],
[432, 250, 1500, 3000, 490, 2940, 26.0,25.8, "6× Mix43"],
[902, 120, 720, 1440, 290, 1740, 17.6,21.5, "8× Mix43 or FT-50-61"],
]
# Sheet 4: Sleeve balun — dimensions and performance
SLEEVE_HEADERS = [
"Band", "f₀ (MHz)", "λ/4 free space (mm)", "VF", "l_physical (mm)",
"Sleeve OD rec (mm)", "Inner coax rec", "Z_peak (Ω)", "BW ±3dB (MHz)",
"CMR peak (dB)", "Construction method"
]
SLEEVE_DATA = [
["6M", 50.1, 1497, 0.96, 1437, 25.4, "RG-8X", 2000, 3, 23.5, "Coiled coax preferred; sleeve 1.44m impractical"],
["2M", 144.0, 521, 0.96, 500, 19.1, "RG-58", 6000, 10, 32.0, "Copper tube 19mm, 500mm"],
["1.25M",222.0, 338, 0.96, 325, 16.0, "RG-58", 7000, 15, 33.4, "Copper foil tape 325mm"],
["70cm",432.0, 174, 0.96, 167, 12.7, "RG-58", 8000, 20, 34.5, "Copper tube 12mm, 167mm"],
["33cm",902.0, 83, 0.96, 80, 9.5, "LMR-195",8000, 40, 34.5, "Aluminum collar, 80mm"],
["23cm",1296.0, 58, 0.96, 56, 6.4, "LMR-195",7000, 65, 33.4, "Precision tube or PCB"],
]
# Sheet 5: RFI suppression recommendations by symptom
RFI_HEADERS = [
"Symptom", "Likely cause", "Band(s)", "Recommended choke",
"Installation point", "Expected improvement (dB)", "Notes"
]
RFI_DATA = [
["RF in shack audio", "Common-mode on feedline", "HF all", "FT-240-31 10t",
"Feedline at shack entry", "20-30", "Most common HF RFI issue"],
["RF in microphone", "Common-mode on mic cable", "HF all", "FT-240-31 8t or 8× snap-on Mix31",
"Back of radio mic input", "15-25", "Wind mic cable on core"],
["S-meter deflect on TX", "Common-mode current returning on coax", "HF all", "FT-240-31 10t",
"Antenna feedpoint", "20-35", "Classic 'RF in the shack' symptom"],
["Computer TVI on 2M", "Common-mode on monitor cable", "2M", "6× snap-on Mix43",
"Monitor cable at computer", "20-30", "Snap-on; no disassembly needed"],
["Power supply hum in receiver", "Common-mode on power cable", "All", "4× snap-on Mix31 folded",
"Supply output cable", "15-25", "Fold cable for 2-pass through each bead"],
["USB audio adapter noise", "Common-mode on USB cable", "All", "1-2× Mix31 snap-on, 3-turn",
"USB cable at adapter", "20-30", "Wind USB cable 3 turns through snap-on"],
["LED lighting interference", "Broadband noise via power lines", "HF all", "8× snap-on Mix31",
"LED driver supply cable", "10-20", "May need to remove offending fixture"],
["Neighbor switching supply", "Conducted + radiated broadband", "HF all", "Ferrite at antenna + entry",
"Both antenna feedpoint AND shack entry", "15-25", "Two chokes; also RX filter"],
["VHF antenna to 2M noise floor", "Common-mode path from adjacent HF", "2M", "6× snap-on Mix43 or sleeve",
"2M coax at shack entry", "20-30", "Isolate from HF feedlines"],
["High SWR after choke install", "Choke absorbing differential power", "Any", "Check choke design",
"N/A", "N/A", "Differential-mode loss means wrong winding or wrong impedance level"],
]
# ── ODS XML generation ─────────────────────────────────────────────────────────
def cell_string(val):
return f'{val}'
def cell_float(val):
if isinstance(val, int):
return f'{val}'
return f'{val}'
def cell_auto(val):
if isinstance(val, (int, float)):
return cell_float(val)
return cell_string(str(val))
def header_cell(val):
return (f''
f'{val}')
def make_row(cells):
return '' + ''.join(cells) + ''
def make_sheet(name, headers, rows):
lines = [f'']
# Header row
hcells = [header_cell(h) for h in headers]
lines.append(make_row(hcells))
# Data rows
for row in rows:
rcells = [cell_auto(v) for v in row]
lines.append(make_row(rcells))
lines.append('')
return '\n'.join(lines)
CONTENT_PREFIX = '''
'''
CONTENT_SUFFIX = '''
'''
MANIFEST = '''
'''
STYLES = '''
'''
META = '''
Ferrite Core Impedance Tables TM-CMC-001
TM-CMC-001 Generator
Common-mode choke ferrite data: materials, impedance vs frequency, RFI guide
'''
MIMETYPE = 'application/vnd.oasis.opendocument.spreadsheet'
def generate_ods(outpath):
sheet1 = make_sheet("Ferrite Materials", MAT_HEADERS, MAT_DATA)
sheet2 = make_sheet("FT-240-31 10T", TOROID_HEADERS, FT240_31_10T)
sheet3 = make_sheet("FT-240-43 12T", TOROID_HEADERS, FT240_43_12T)
sheet4 = make_sheet("FT-240-43 8T", TOROID_HEADERS, FT240_43_8T)
sheet5 = make_sheet("Stacked 31+43 8T", TOROID_HEADERS, STACKED_31_43_8T)
sheet6 = make_sheet("Snap-On Beads", BEAD_HEADERS, BEAD_DATA)
sheet7 = make_sheet("Sleeve Balun Dims", SLEEVE_HEADERS, SLEEVE_DATA)
sheet8 = make_sheet("RFI Troubleshooting", RFI_HEADERS, RFI_DATA)
content = CONTENT_PREFIX + sheet1 + sheet2 + sheet3 + sheet4 + \
sheet5 + sheet6 + sheet7 + sheet8 + CONTENT_SUFFIX
buf = io.BytesIO()
with zipfile.ZipFile(buf, 'w', compression=zipfile.ZIP_DEFLATED) as zf:
# mimetype MUST be first and uncompressed
zf.writestr(zipfile.ZipInfo('mimetype'), MIMETYPE)
zf.writestr('META-INF/manifest.xml', MANIFEST)
zf.writestr('content.xml', content)
zf.writestr('styles.xml', STYLES)
zf.writestr('meta.xml', META)
with open(outpath, 'wb') as f:
f.write(buf.getvalue())
print(f"Written: {outpath} ({os.path.getsize(outpath):,} bytes)")
if __name__ == '__main__':
script_dir = os.path.dirname(os.path.abspath(__file__))
outpath = os.path.join(script_dir, 'ferrite_impedance_table.ods')
generate_ods(outpath)
print("Sheets: Ferrite Materials | FT-240-31 10T | FT-240-43 12T | FT-240-43 8T")
print(" Stacked 31+43 8T | Snap-On Beads | Sleeve Balun Dims | RFI Troubleshooting")