For 1420 MHz (the hydrogen line), the best ferrite toroid material
For 1420 MHz (the hydrogen line), the best ferrite toroid material is not a typical low-frequency ferrite (like #43 or #61) — these are optimized for lower RF or broadband suppression. At this high frequency, you are in the UHF to L-band range, and standard ferrite materials tend to be too lossy or ineffective.
Instead, consider these options:
✅ Best Choices for 1420 MHz:
1. Fair-Rite Type 67 (Material #67)
- Frequency Range: 200 MHz – 2 GHz
- Optimized for: VHF and UHF
- Use: Baluns, chokes, impedance transformers at UHF
- Example: Fair-Rite 2673002402
- Toroid Size Example: FT50-67 (or FT82-67 if you need higher power handling)
2. Fair-Rite Type 61 (Material #61)
- Frequency Range: 200 MHz – 1 GHz (can work up to ~1.5 GHz)
- Use: RF transformers and chokes
- Example: FT50-61 or FT82-61
- Note: Slightly less efficient at 1420 MHz than #67, but still usable if you can’t find #67.
❌ Avoid for 1420 MHz:
- #43 Material – Too lossy above 100–300 MHz
- #31 Material – Designed for low MHz EMI suppression
- Iron powder toroids (T-series like T50-2) – Not effective at GHz frequencies
Application Tips:
- If making a balun or impedance transformer for an antenna or feedline at 1420 MHz, #67 is ideal.
- Use short leads and tight windings to minimize parasitics at high frequencies.
- Consider air-core coils for certain matching networks at these frequencies — they often outperform ferrites in this band.