DIY DC Blocking Capacitor for oscilloscope
Something really small (maybe that could be assembled between two close-spaced side launch connectors) and that has low enough impedance at your low end frequency not to affect the 50 ohm load too much. 

So if Xc = 1/(2*pi*1E4*C) = 1 ohm, Cmin ~= 15uF. 

You can get 1210 10uF X7R caps. One or two of those in parallel- check the impedance curves at your highest frequency and parallel with lower values if required. If you need much more than 50V-63V it will become more difficult.