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The TAROGE-M observatory is an autonomous antenna array on the top of Mt. Melbourne (∼2700 m altitude) in Antarctica, designed to detect radio pulses from ultra-high energy (over 1017 eV) air showers coming from near-horizon directions. The targeted sources include cosmic rays, Earth-skimming tau neutrinos, and most of all, the anomalous near-horizon upward-going events of yet unknown origin discovered by ANITA experiments. The detection concept follows that of ANITA: monitoring large area of ice from high-altitude and taking advantage of strong geomagnetic field and quiet radio background in Antarctica, whereas having significantly greater livetime and scalability. The TAROGE-M station, upgraded from its prototype built in 2019, was deployed in January 2020, and consists of 6 log-periodic dipole antennas pointing horizontally with bandwidth of 180-450 MHz. The station is then calibrated with drone-borne transmitter, with which the event reconstruction obtained ∼0.3° angular resolution. The station was then smoothly operating in the following month, with the live time of ∼ 30 days, before interrupted by a power problem, and its online filtering has identified several candidate cosmic-ray events and sent out via satellite communication. In this paper, the instrumentation of the station for polar and high-altitude environment, its radio-locating performance, the preliminary result on cosmic-ray detection, and the future extension plan are presented.

TAROGE-M is a self-triggered radio antenna array atop the 2700 m high Mt.Melbourne in Antarctica, designed to detect impulsive geomagnetic emission fromextensive air showers induced by ultra-high energy (UHE) particles beyond 0.1EeV, including cosmic rays (CRs), Earth-skimming tau neutrinos, andparticularly, the "ANITA anomalous events" (AAEs) from near and below thehorizon, which origin remains uncertain and requires more experimental inputsfor clarification. The detection concept of TAROGE-M takes advantage of a high altitude withsynoptic view toward the horizon as an efficient signal collector, and theradio quietness as well as strong and near vertical geomagnetic field inAntarctica. This approach has a low energy threshold, high duty cycle, and iseasy to extend for quickly enlarging statistics. Here we report experimentalresults from the first TAROGE-M station deployed in 2020, corresponding to$25.3$-days of livetime. The station consists of six receiving antennasoperating at 180-450 MHz, and can reconstruct source directions with$\sim0.3^\circ$ angular resolution. To demonstrate its ability to detect UHEair showers, a search for CR signals in the data was conducted, resulting inseven identified events. These events have a mean reconstructed energy of$0.95_{-0.31}^{+0.46}$ EeV and zenith angles between $25^\circ-82^\circ$, withboth distributions agreeing with simulations. The estimated CR flux is alsoconsistent with results of other experiments. The TAROGE-M sensitivity to AAEsis approximated by the tau neutrino exposure with simulations, suggestingcomparable sensitivity as ANITA's at $~1$ EeV energy with a few station-yearsof operation. These first results verified the station design and performancein a polar and high-altitude environment, and are promising for furtherdiscovery of tau neutrinos and AAEs after an extension in the near future.