Uputronics is a UK-based manufacturer and distributor of radio and Raspberry Pi related equipment; they're big into filtered preamps, online shop offers several varieties for popular applications, such as Weather satellites, 2m band, AIS and many more. USA distributor is airspy.us, charges same price.
All preamps come in the same metal case. I've been intrigued by their range, as they have a good reputation, so contacted the company, and was talking to the designer, Anthony within minutes. He's an actual radio user, his personal website is worth a visit for high altitude baloon fanatics.
Originally, the design was for a small LNA for balloon tracking, then things got constantly improved for alternative uses.
Their 1090MHz filtered preamp for $45 is popular in the ADS-B community, and is the subject of this review. My sample had the SAW filter fitted, a version with ceramic filter for high-noise environments is also available for nearly double the cost.
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Tracked delivery to Ireland from UK took 5 days, doubtlessly due to heavy Christmas postal traffic. Nice cardboard box, two layers of foam on top and bottom, metal case in plastic bag. This is not just another eBay purchase, packaging conveys the suggestion of a much more expensive product - the last time I had the same impression was when opening the $300 HackRF.
Package contains description and datasheet, part of it included here with the manufacturer's permission:
Feel, fit and finish shouts pro gear, the best I came across from any RTL-SDR related radio manufacturer. Unit is massive and heavy, if "Icom" was written on it, you'd say 200 dollars well spent.
Aluminum case with tough-looking screws, SMA female connectors with nut and washer, Mini-A USB connector for external power AND the option of bias-T. Preamp can be used with any radio device.
Remove screws, PCB slides out easily, interior of case with wall case thickness below (green is Thumbnet N3, blue is aftermarket Nooelec case):
PCB is huge and sparsely populated, components properly named:
It's good to see that Uputronics did not went down the "smaller is better route", this preamp is designed for 24/7 use, and heat dissipation is better with a larger PCB and finned case. As a result, preamp stayed constantly cool, no sign of thermal issues. All in all, an overwhelmingly positive first impression. $45 for a preamp seems a lot, but you get excellent build quality and easy power.
Two options: via coax called bias-T, which only works with a suitable dongle, like rtl-sdr.com v.3, or any other SDR with bias-T (e.g. AirSpy, RSP2, HackRF). Alternatively, via common USB Mini-A connector. No pads, no need to solder, but the option is on the PCB.
Preamp is usable with any RTL-SDR dongle, only cable and power supply e.g. smartphone charger, or any other device with 5V out required.
Two identical Raspberry Pi 3 microcomputers running PiAware in a ModMyPi Starter kit with an outdoor-mounted FlightAware antenna and splitter, coax length 5m, preamp at receiver to keep things simple.
Results reflect my location, your mileage will vary.
Unsurprisingly, with two rtl-sdr.com v.3 dongles, adding a filtered preamp resulted in significantly more position reports:
One day's polar plot, plain vs with preamp:
For the discerning ADS-B enthusiast, this preamp, preferably mounted at the antenna is a good solution.
Ubutronics's 1090 MHz filtered preamp is a great product. Build quality is excellent, power options make operation plug-n-play, and it delivers when push comes to shove.
Would I buy one? Yes, receivers constantly get improved, but a filtered preamp will always remain a filtered preamp no matter what magic comes out in September - quality never gets old.