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70 – 70.5 MHz 300 W Low Loss Transmitting Band Pass Filter for 4 Meter band
Intended to be used with transceivers like Icom IC-7100, Yaesu FT-847, transverters and linear amplifiers up to 300W output.
Although intention of this filter is to be used as transmitting filter, design allows also to be used as receiving filter before wideband LNA to protect sensitive device from strong out of band signals.
This BPF will suppress any signals from HF 1.8 – 28MHz stations 50-54MHz, FM, 144 MHz and 432MHz (430 – 440MHz).
Filter will reduce TVI problem or your problem with neighbours 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.
Measured Return Loss – S11 (CH1) and Insertion Loss – S21 (CH2). Characteristics of 70 – 70.5 MHz Bandpass filter for up to 300 W Transmitter.
Achieved results on a built 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 of components and design of the filter.
Band Pass filter will suppress any harmonic emission from your transceiver or linear amplifier.
SWR from 70 MHz to 70.5 MHz:
4 Meter Band. Flatness of insertion loss on working frequency:
Suppression of harmonics and interfering signals on VHF and UHF:
Similar VHF band-pass products for 4 meter band:
4 meter band, 70 MHz Bandpass filter (Receiving – Economic) far Ham radio: 70 – 70.5 MHz Eco Receiving BandPass Filter
4 meter band, 70 MHz Bandpass filter (100 W / Receiving) far Ham radio: 70 – 70.5 MHz Low Loss Band Pass Filters for 100 W Transmitters