How to hook up the other Tvs on my RV

DTV can't use a distribution box.  Please post the model number of the DTV receiver.

H24-700

It worked before.

I'm guessing that your old receiver had an RF Coax output that provided video on Ch3 or Ch4? The H24 does not have that RF Coax output. You'll need an RF Modulator to convert the H24's Composite Video output to an RF signal on Ch3 or Ch4. Or consider upgrading your TVs and distribution equipment to use HDMI instead. 

Thanks

I assume you are still using an 18" round dish. DTV is shutting down the MPEG2 and all local channels on the 101 sat that dish gets so they can still use the 101 sat to broadcast in MPEG4.

OP stated they have an H24 and litzdog911 already told them about an RF modulator.