40 meter 4000 W High Power Band Pass Filter

High power 40 meter 7 – 7.3 MHz band pass filters for BIG GUNS.

Band pass filter is perfect for multi-station environment like special events, field day, portable operating to protect receivers from excessively strong out-of-band signals. Our 40 meter filter is designed to have extremely low loss from 7 – 7.3 MHz (40 meter band) and it is 0.12 dB! Out-of-band interference is extremely suppressed. The filter is ideal to be on both reception and transmission. The 40 meter band pass filter is declared at 4000 W, but filters is designed for more power than presented. Band pass filter is placed in a powder-coated aluminum box. Silver-plated SO239 connectors and excellent filter design enable extremely low losses through 40 meters band and high attenuation of out-of-band signals.

Specifications
Frequency Range	7 – 7.3 MHz
Insertion loss	0.12 dB
Input Return Loss better than:	-32 dB
Attenuation on nearest band:	35 – 55 dB
Nominal input impedance:	50 Ohm
Maximum power input at SWR 1:1	4000 W
Maximum power input at SWR 1:1	3200 W
Maximum power input at SWR 1:1	2500 W
Maximum power input at SWR 1:1	2000 W
Connectors:	SO239 or “N”

External look. 40 meter band pass filter is placed inside powder-coated aluminum box. SO239 connectors are silver-plated.

40 meter band pass filter Top Side Look

Measured data with HP8753ES full 2-port calibrated is presented below.

1. Out-of-band measurements with graph.

Ham Radio Bands	Attenuation (more than)
160 meter	45 dB
80 meter	45 dB
20 meter	45 dB
15 meter	35 dB
10 meter	40 dB

Out-of-band measurements on 40 meter filter

2. Return loss (S11) from the 40 meter 4000 W band pass filter.

Return Loss from 40 meter filter - S11 and S21 Measurement

3. S21 Measurement from filter. Points: 7 – 7.3 MHz. Flat line and extremely low loss is shown:

S21 Measurement. Low Loss and Flat curve from 7 to 7.3 MHz

4. Actual box size 40 meter band pass filter. The filter is placed and closed with a strong aluminum box. The filter is designed and adjusted together with the box so that the shown and measured characteristics are identical.

Actual 40 meter box size. Silver plated connectors and powder-coated aluminum box.