8m Band-Pass Filter 300W 40-41MHz

8m Band-Pass Filter 300W 40-41MHz will filter any out-of-band signal. Bandpass filter uses high Q coils as well as high Q capacitors. Low loss of filter is achieved with careful design and adjustment. This filter is equally good as a transmitting and receiving with super low loss (0.13dB). The filter will reduce the TVI problem or your problem with neighbors with strong HF, 4m, 2m, or 70 cm transmitters. The filter will eliminate your harmonics.

What is an 8-meter band (40 – 41 MHz)?

The 8-meter band (40 MHz) is the smallest fraction of the very high frequency (VHF) radio spectrum available for amateur radio use. The phrase represents an 8-meter average signal wavelength.

The 8-meter band and the nearby 6-meter band have a lot in common. It does, however, exhibit the improved propagation mechanisms through the F2 ionospheric layer often found at high frequency (HF), which sporadically appears at 6 meters, although it is a little lower in frequency.
On the band, sporadic E propagation, which occurs when radio signals bounce off ionized clouds in the lower E zone of the ionosphere, is typical in the summer.

The 40 – 41 MHz Band-Pass filter is placed in a brass box and equipped with 2 female “N” type connectors. By e-mail request, possible connector options are: “N” male, SO239, BNC, and 7/16 DIN…

 

8m Band-Pass Filter 300W 40-41MHz characteristics:

 

8m Band-Pass Filter 300W 40-41MHz measured insertion loss (S21):

1.8 MHz = -100 dB
3.5 MHz = -85 dB
7.1 MHz = -66 dB
14.1 MHz = -45 dB
21.2 MHz = -30 dB
28 MHz = -15 dB
40 MHz = – 0.13 dB
40.5 MHz= – 0.13 dB
41 MHz= – 0.13 dB
70.2 MHz = – 26 dB
88 MHz = – 37 dB
98 MHz = – 41 dB
108 MHz = – 45 dB
120 MHz (Third Harmonic) = -50 dB
145 MHz = – 55 dB
432.1 MHz = – 84 dB

 

8m Band-Pass Filter 300W 40-41MHz appearance:

 

Maximum power input at SWR:
1:1 = 300 W; 1:1.5 = 210 W; 1:2 = 175 W; 1:3 = 130 W (Intermittence 50%)
300 W transmitting and receiving bandpass filter could be used for outdoor mounting. The price difference is 9 EUR (plastic box “DB” and bracket).

 

All 8m filters are here.