where conductance terms and noise are to be taken at the same frequency. Eq.(1) is sup- ported by the RF measurements of transconductance and noise and the electronic temper- ature reported below as function of bias voltage. As electronic temperature depends on current, one can alternatively express thermal noise as S$_{I}$ = 2 eI$_{d}$ ˜ F , by introducing a pseudo Fano factor ˜ F ≲ 1. The limit ˜ F = 1 corresponds to a classical shot noise as observed in vac- uum diodes. The hot electron regime shows up in our nanotube transistor by a full thermal shot noise with ˜ F ∼ 1 at low bias followed by some reduction ( ˜ F ≃ 0 . 7) resulting from Pauli principle and the effect of electronic degeneracy which generally shows up at high bias. The sample (Fig.1(a)) is taken from a batch which was extensively described and charac- terized in Ref.[5]. A symmetric double gate RF design is used (Fig.1(a)) on high resistivity silicon substrate. The high mobility CVD-grown nanotube (diameter d ∼ 2 nm) is equipped with a top gate (length L$_{g}$ = 0 . 3 µ m) deposited on a thin AlO$_{x}$ oxide (thickness t$_{ox}$ ≃ 6 nm). Palladium drain and source metallisations are used for low Schottky barrier contacts. Our high-sensitivity cryogenic setup includes a low noise amplifier fitted to a 200–50 Ohms impedance matching transformer with a 0 . 8 GHz cutoff. Matched resistors are fitted at the input and output lines to obtain a broad 0 . 1–0 . 8 GHz measuring band. The 200 Ohms output load ensures DC voltage bias conditions and serves as an auxiliary white noise source for in-situ calibration. The lumped circuit element description of the nanotube transistor (Fig.1(b)) is used for RF data analysis and the theoretical model below. The gate capaci- tance, C$_{g}$/L$_{g}$ ≃ 0 . 07 ± 0 . 02 fF /µ m, is taken from the room temperature RF probe station measurements [5]. With C$_{q}$/L$_{g}$ = 8 e $^{2}$/hv$_{F}$ = 0 . 4 fF /µ m ( v$_{F}$ ≃ 8 × 10 5 m / s) we deduce β ≃ 0 . 2 [5]. We have used negative drain bias, which shows lower 1 /f α noise and symmetric gate bias conditions. I$_{d}$ and S$_{I}$ are taken by reference to the pinch-off value (at V$_{g}$ = +1 V). Figure 2 shows the radio frequency transconductance g RF m deduced from transmission measurements [5] as function of gate voltage for different bias conditions. The DC con- ductance g DC d and transconductance g DC m are obtained from the I$_{d}$ ( V$_{g}$, V$_{d}$ ) characteristics (Fig.2-inset). Reflection coefficients, and g RF d , cannot be accessed with this setup. The sam- ple shows large g RF m ≃ 30 µ S, typically 3-times larger than g DC m , which suggests AC contact coupling. We observe a small temperature dependence of g RF m (a ∼ 50% decrease between 4K and 300K) which we take as a first indication of a hot electron regime. In Fig.3 we discuss measurements of the transistor in the open state ( V$_{g}$ = − 0 . 5 V) where g RF m ≃ 0. Here the nanotube behaves as a metallic wire with a finite transmission D ∼ 0 . 1, 3