6m 200W BandPass Filter with 8m Notch 40.5 to 40.9MHz

This 6m 200W BandPass Filter with 8m Notch will pass 6m DX band 50-51MHz and highly suppress 40.68MHz (40.5 to 40.9MHz) 8m and all other ham radio stations on the other HF and VHF bands. If you have on the same tower an 8m antenna and also a 6m, 4m, or 2m antenna this filter is for you. There is a high probability that an 8m transmitter will disturb the 6m station or at least desense the 6m receiver.

 

 

Solid power capability, insertion Loss of just 0.35dB, and good SWR handling will enable safe operation in any normal conditions with any 100W transmitter or with a solid SWR 200W transmitter.

Although the intention of this filter is to be used as a transmitting filter, the design allows also it to be used as receiving filter before wideband LNA to protect sensitive devices from strong out-of-band signals.

This Bandpass filter will suppress any signals from HF 1.8 – 28 MHz stations, 40.68MHz 8m, 4m, 2m, 1.25m, and 70cm to pass to the preamplifier or transceiver.
The filter will reduce TVI problems or your problem with neighbors with strong RFI.

 

Measured attenuation on the finished 6m 200W BandPass Filter with 8m Notch

1.8MHz 111dB
3.8MHz 109dB
7.1MHz 100dB
14MHz 83dB
21MHz 70dB
28MHz 58dB
Notch 40.5MHz 52dB
Notch 40.68MHz 59dB
Notch 40.9MHz 48dB
50-51MHz 0.35dB, Input RL -32dB
70.2MHz 42dB
100MHz 64dB
145MHz 83dB
222MHz 64 dB
432MHz 64dB
470MHz 54dB
Maximum power input at SWR:
1:1 = 200W; 1:1.5 = 140W; 1:2 = 115W; 1:3 = 90W

 

Measured characteristics of the 6m 200W BandPass Filter with 8m Notch

 

6m 200W BandPass Filter HF Attenuation

 

6m 200W BandPass Filter with 8m Notch 15m 8m 4m and 3m FM Attenuation

 

6m 200W Filter 8m Notch 10m and 8m Attenuation

 

6m 200W BandPass Filter Measured Insertion Loss and Return Loss

 

High Harmonics attenuation 6m 6m 200W BandPass Filter

 

The 50-51MHz 200W BandPass Filter with 8m Notch is placed in a brass box and equipped with two female “N” type connectors. By e-mail request, possible connector options are: “N” male, SO239, BNC, and 7/16 DIN…

 

All band-pass filters are here

All 6m bandpass filters