Please, see 40M High Power BPF made in a smaller enclosure.
Recommended Band Pass filter applied power with antenna VSWR <1.5:
- 100 CFM fan installed – 3000W CW/SSB (2500W RTTY)
- 50 CFM fan installed – 1500W CW/SSB/RTTY
- Without fan installed – 1000W
Enclosure is Hammond 1411ZU :
- Without Fan – 17 x 4″x 5″ (42.5 x 10.5 x 12.5 cm)
- With Fan Installed – 18″x 4″x 5″ (46 x 10.5 x 12.5 cm)
In general, schematics is the 5th order Chebyshev inductor-coupled BPF.
- Insertion Loss < 0.32 dB
- Band Isolation ( 80M > 60dB, 20M > 70dB, 15M >100dB)
- VSWR < 1.1 (RL > 26 dB)
VSWR and Insertion Loss inside the 40M band:
Doorknob capacitors used allow to use it up to 4500-5000 PEP output power but I was able to test it with 3000 watts.
On a picture below you can see 40 and 80 meter band BPFs. 80M BPF box twice deeper than all other band BPF boxes.