Minikits in Australia ( https://www.minikits.com.au/ ) makes a nifty little low noise RF amplifier for a VHF weather satellite receiver, such as the Meteor satellite on 137 MHz. Note that SatDump is very much improved now - it is all the software you need to see that it is raining outside, without looking out the window. Some careful soldering is required, but it is not difficult to build. When I test an RF circuit, I run it from a 12V sealed battery - my noise free power supply . Once tuned up carefully with a nylon screwdriver ( the little spatula that you get with epoxy glue! ), it can provide up to 20 dB gain, but on average over the band, expect about 5 to 10 dB. With some patience I eventually managed to eek out 7.6 dB at 137 MHz . This may not sound like a lot, but a radio receiver is more dependent on the Signal to Noise and Distortion Ratio ( SINAD ), than the actual signal level. The LNA is a tuned single transistor amplifier with a linear power supply and a bias-T c
In a moment of boredom/inspiration, I thought about making a patch antenna for my ADS-B aircraft tracking system. One can make one-off patch antennas from garden variety glass/epoxy FR4 board, but the result will have relatively high loss and it will not be repeatable. In order to simply order batches of antennas from any PCB factory, one needs to use high quality, low loss, controlled impedance board stock . The side slots in this design increases the bandwidth a little, but it also reduces the operating frequency, so I'll have to see how it turns out and trim it. There is a variety of RF board made by various manufacturers ( Rogers , Isola , Panasonic ... ) and the RF parameters are different, therefore once you designed your spiffy new antenna for Rogers 4003C , then you cannot change your mind and manufacture it from Isola I-Tera MT40 - you need a new design. I therefore made a simple design in KiCAD and submitted it to three PCB manufacturers ( Eurocircuits, Ourpcb, Pcbon