Radio newbie Salil Tembe has designed a low-noise amplifier (LNA) to be used with software-defined radios (SDRs) — and gives a walkthrough of the method, from half choice and schematics to the PCB and testing.
“There are many amplifier designs out there on-line. You’ll be able to merely buy one and be accomplished with no matter you intend on doing,” Tembe writes. “Nevertheless, designing your individual low-noise amplifier will be enjoyable. For somebody into ham radio, you may need come throughout climate satellite tv for pc LRPT [Low-Rate Picture Transmission] reception utilizing an RTL-SDR. Receiving photos from a satellite tv for pc could require low-noise amplifier. Alternatively, somebody into radio astronomy positively requires a really low-noise amplifier to obtain the hydrogen line frequency emanating from the Milky Approach.”
In the event you’ve ever questioned what goes into the design of a low-noise amplifier (LNA), Salil Tembe has the venture log for you. (📷: Salil Tembe)
Reasonably than selecting one thing up off the shelf, Tembe opted to design his personal — aiming for a noise determine beneath 1dB. The Mini-Circuits PGA-103+ monolithic amplifier, rated at a typical 0.6dB at 1GHz rising to 0.9dB at 2GHz, was chosen because the half round which the LNA could be constructed, together with a bandpass filter concentrating on the frequencies required for satellite tv for pc imagery reception and the 2m newbie radio band.
Tembe’s construct log walks by means of the design of a circuit for the PGA-103+, a bias tee, and a bandpass filter, earlier than the schematic is translated right into a PCB design and despatched off for manufacturing and meeting. The subsequent step was, after all, testing — which Tembe carried out utilizing hobbyist-friendly instruments together with the NanoVNA vector community analyzer and TinySA Extremely spectrum analyzer, plus a real-world take a look at related to an RTL-SDR software-defined radio.
The design is examined utilizing hobbyist-grade instruments, proving that you do not want an enormous funds to play with radio applied sciences. (📷: Salil Tembe)
“The low-noise amplifier is not an advanced design,” Tembe admits of his creation, “but it surely takes fairly some effort to design, assemble, outline assessments, and really conduct assessments to show it is working based on the design.”
The total construct log is accessible on Tembe’s web site Nuclear Rambo, whereas the maker is promoting the LNA itself on Tindie for $20.