# Necessary spacing for 1 kW Gamma Match on 144 MHz

I'm working on a 144 MHz antenna using a gamma match. The best result (resonance 50+j0 at 144.400 MHz) I reached is a 10 mm diameter gamma rod, 15 cm long and a capacity of 10 pF.

I thought to obtain the 10 pF with a 4 mm rod inside the gamma rod (internal diameter 8 mm). The dielectric is air.

Since I will use 1 kW I wonder if this configuration (dielectric air, spacing 2 mm) is sufficient for the power I'll use or I have to find a different configuration (having more spacing at the dielectric).

More in general, how can I esteem the maximum power of a gamma match with air dielectric? Is there a rule to decide the minimum better dielectric spacing in function of the power to use?

$$V = \sqrt{PR} = \sqrt{1000 \cdot 50} = 223.6\,\mathrm{V}$$