Do you live near an AM broadcast station? Trying to use an SDR (or other receiver with a wide front-end) to receive VHF and UHF, but keep getting desense’d by that strong AM signal? Or maybe you just want to keep receiving on VHF/UHF while operating HF from your own shack.
The Halibut Electronics BCI Filter for VHF/UHF is the device for you!
The Halibut Electronics BCI Filter is an in-line receive filter that blocks the AM broadcast band from overloading your receiver’s front end, while allowing VHF and UHF to pass through with minimal insertion loss.
- Blocks the AM broadcast band at better than -60dB
- Less than 0.1dB insertion loss across most of VHF (worst case: 0.2dB at 6 meters)
- Less than 1dB insertion loss across most of UHF (worst case: 2dB at 2.74GHz)
- Better than -20dB Return Loss up to 1.5GHz, better than -10dB up to 3GHz (worst case: -9.5dB at 2.74GHz)
Download the .s2p Touchstone file here.
This graph shows the insertion loss. Note that it is zoomed in to 0.5dB per division. (Full resolution above in the product gallery.)
This graph shows the return loss. (Full resolution above in the product gallery.)
It has SMA connectors, and comes with either Female/Female for use with cables, or Male/Female for use in-line with an existing setup. It can come as an unassembled kit, or you can have Halibut Electronics assemble it for you for a nominal fee.
But why? There are many BCI filters already out there.
Most Broadcast Interference (BCI) filters are designed for HF radios, where the strong AM broadcast signal is much closer to frequency you’re operating at, and your radio’s front-end filtering may not be sufficient. Because the frequencies are so close (AM broadcast ends at 1.6MHz, 160m starts at 1.8MHz, and 80m starts at 3.5MHz), the filters have to be many poled (read: have lots of components) and made using very precise (read: expensive) components. Those larger value components for HF don’t perform well at VHF or UHF, creating too much insertion loss (loss in the pass-band.)
This filter is optimized for use at VHF and UHF:
- 1.8MHz to 50MHz is a long slope, allows for a simpler filter design, fewer components, very common values.
- A simpler filter allows us to optimize for passing VHF and UHF frequencies. Small SMT components, short leads, impedance matched transmission line.
Jesse KZ9G –
Fantastic little filter. Little to no attenuation outside of the broadcast band. This filter had 45db more reduction than any other filter I was able to test including ones sold by one of the major sdr manufacturers.