4m 70MHz 300W High Power BandPass Filter Low Loss

4m 70MHz 300W High Power BandPass Filter is Intended for use with transceivers like Icom IC-7100, Yaesu FT-847, transverters, and linear amplifiers with up to 300W output.  Although the intention of this filter is to be used as a transmitting filter, the design allows also it to be used as a receiving filter before wideband LNA to protect sensitive devices from strong out-of-band signals.

 

4m 70MHz 300W High Power BandPass Filter

 

This BPF will suppress any signals from HF 1.8 – 28MHz stations 50-54MHz, FM, 144 MHz, and 432MHz (430 – 440MHz).

The filter will reduce the TVI problems or your problem with neighbors with strong HF, 6m, 88-108MHz, 2m, or 70cm transmitters.

 

Measured data on the assembled filter with HP8753ES network analyzer full 2-port calibrated are presented below.

 

4m 70MHz 300W High Power BandPass Filter Measured Return Loss – S11 (CH1) and Insertion Loss – S21 (CH2).

 

Achieved results on a built 4m 70MHz 300W High Power BandPass Filter:

1.8 MHz < -100 dB
3.8 MHz < -100 dB
7.1 MHz < -100 dB
14.15 MHz = -84 dB
21.2 MHz = -73 dB
28.4 MHz = – 64 dB
50 MHz = -36 dB
51 MHz =- 34.5 dB
70 MHz = -0.24 dB
70.1 MHz = -0.24 dB
70.25 MHz = -0.24 dB
70.5 MHz = -0.25 dB

Harmonics and interfering signals:

88 MHz= -25 dB
98 MHz= -36 dB
108 MHz= -41 dB
140.2 MHz = -54 dB
144.1 MHz = -55 dB
432.1 MHz = -62 dB

These excellent results were achieved by careful selection the of components and design of the filter.
Band Pass filter will suppress any harmonic emission from your transceiver or linear amplifier.

 

4m 70MHz 300W High Power BandPass Filter Measured SWR from 70 MHz to 70.5 MHz:

 

4 Meter Band. The flatness of insertion loss on working frequency:

 

Suppression of harmonics and interfering signals on VHF and UHF:

 

All band-pass filters are here: HF, VHF, and UHF Band-Pass Filters

Link to all 4-meter filters. We have 50 W, 100 W, 200 W, 300 W, 1500 W and 4000 W versions: 4 Meter Band-Pass Filters