Over on Amazon we've recently seen the release of a 978 MHz UAT specialty RTL-SDR and 978 MHz tuned antenna by the flight tracking service known as AirNav RadarBox. The RTL-SDR appears to be similar to their 1090 MHz RTL-SDR version, which contains a SAW filter and LNA onboard the RTL-SDR. Due to the built in filter, this dongle will only work at the 978 MHz frequency. Like the 1090 MHz version, the dongle itself is priced at only US$14.95, and the antenna at US$49.95.
Universal Access Transceiver (UAT) is an alternative to ADS-B that is available only in the USA. It is typically used by smaller aircraft, transmits at 978 MHz, and apart from it's tracking system it has some additional advantages for pilots over 1090 MHz ADS-B, like the ability to receive alerts, weather data and radar plots. With an RTL-SDR and appropriate software these data services can also be received.
In addition they have also released some other interesting products including a 1090 MHz ADS-B with 118-136 MHz VHF airband antenna stacked on top of the ADS-B element for US$49.95, and an external ADS-B 1090 MHz filter for only US$14.95.
As an alternative to an RTL-SDR UAT receiver, we note that the Stratux has a hardware radio based UAT receiver available which has significantly lower power consumption. Although the receiver itself appears to be currently out of stock.
We note that we also currently have our 1090 MHz AirNav Radarbox Antenna + ADS-B optimized RTL-SDR set on sale for only US$39.95 + shipping, which is cheaper than you can find it elsewhere. Visit our store for ordering information.