Kits are available for 10 HF bands , 80, 60, 40, 30, 20, 17, 15, 12, and 10m. This drastically reduces intermodulation problems on the receiver. One must be very careful using other variable capacitors instead of my suggestions here. When I got home from Field Day, I found the power supply to be in perfect working order and it was returned to service at my station. This 6-way band-filter was developed for contest stations which require a comfortable remote control, but ca be helpful at the station at home as well.
Band Pass Filter Fever – The Tangled Web – Part 1
The signal loss is only 0. The bandpass filters used in this receiver are based on the article "the peaked lowpass: Use with mounting fixture for professional quality results. As well, if signals are strong enough they will desense your receiver without causing intermod. So we decided to not include it at all.
Jottings on Amateur Radio: Homebrew SDR HF Transceiver - Band pass filter
The only upside of this design is lower insertion loss which has no practical purpose. These are typically used in repeater instalations to "notch" the frequency of the repeater and reject all unwanted frequencies. The greater challeng e was actually wiring the switching diode to the rotary switch. These filters cannot be beat! I needed a bandpass filter for and did buy the ICE product. Inductors , Voltage , Current. The finished four-ban k RF filter is shown in the photo below.
If the radio already has that design feature, and an excellent set of crystal filters with variable passband tuning, then the SCAF-1 may not bring as much to the party. If you put a 10 dB attenuator between your antenna and receiver, and your intermod goes away, then it is being created in your receiver and filtering will help. I have sampled many different W3NQN filters on a network analyzer, and I have not found one yet that does not match the performance characterized in the above link. There are two circumstances that this happens - either the antennas are in close proximity to each other, or you are running higher power. Third, many times when you add a preamp, the sensitivity of the receiver gets worse, and intermod pops up everywhere. High Pass filters allow the transmission of high frequency transmissions and block frequencies below the design frequency.