Register now to gain access to all of our features. Once registered and logged in, you will be able to contribute to this site by submitting your own content or replying to existing content. You'll be able to customize your profile, receive reputation points as a reward for submitting content, while also communicating with other members via your own private inbox, plus much more! This message will be removed once you have signed in.
Search the Community: Showing results for tags 'Filter'.
Found 2 results
Selfmade RF frontend for Video signal (Analog, DVB-T, DVB-T2, CATV) amplification in a 75 Ohm system. The RF frontend contains the following building blocks: 4-Way Wilkinson power combiner - combines the signal from 4 antennas (~6dB gain) bandpass filter - eliminates the interfering radio signals (FM...) low noise amplifier with a voltage regulator - for sensitivity improvement (~21dB gain, NF~1dB ) Interconnections: 4 F type connector 75 Ohm inputs (antenna) 1 F type connector 75 Ohm output (receiver side), requires a bias voltage in the range of 6-20 VDC and ~60 mA (for example: ZS300 antenna power injector ) Technical data: Frequency range from ~460 to ~880 MHz Noise figure >2,5 dB (including insertion losses) Gain <25 dB (including insertion losses and combiner gain) P1dB ~19dBm Max Pin 17dBm Size ~250x120x25 mm The use of this RF frontend is recommended in one of the following scenarios: the picture is pixelated but you are already using a high gain antenna and amplifier you are in a high power RF environment, Amateur Radio, FM radio is attenuated by more than 80dB ... you want to combine the signal from multiple directions to a single cable (signal quality will/can be reduced) Basic knowledge in antenna (phase) arrays is recommended to exploit the benefits of the RF frontend. Protective housing not included. Antennas not included. Power injector not included. Coax cable not included. Test results (scenario with a pixelated picture and high power RF environment) DVB-T2 Transmitter side cordinates 45,89938 N; 15,94786 E; DVB-T2 Reciever side coordinates 44,47105 N; 17,97297 E; Link distance ~225 km, no line of sight. Receiver side 2x2 antenna array with Triplex Loga Iskra P-47N (without an amplifier, marked on radio tower picture), connected with ~1m RG-6/U coax cable (length variation between antennas <1cm) to RF frontend. Received signal strength (SNR) above the threshold including fading effects (SNR range 29-37 dB). Successful elimination of interfering radio signals (see measured transmission response) on the receiver side (4 FM station with 400 W ....) Free worldwide shipping with DHL.
It's been a long time. I was not active due to health problems. Now I'm slowly coming back. I have added a notch filter in the attached picture. This filter is produced so that the two RF systems working side by side do not interfere with each other. 1 watt rf transmitter in the 915 mhz band and 1200 mhz rf video receiver are used to avoid interference. This filter is to protect 1200mhz rf video receiver from noise from 915mhz rf transmitter. If this filter is not used, noise appears in the image. Should I do to build a pcb filter like this?