It have read that Bitcoin Cash uses BIP 143 to generate the signatures and that BIP 143 does not accept uncompressed public keys. Does that mean that you cannot send a Bitcoin Cash transaction using an uncompressed public key?

As a default policy, only compressed public keys are accepted in P2WPKH and P2WSH. Each public key passed to a sigop inside version 0 witness program must be a compressed key: the first byte MUST be either 0x02 or 0x03, and the size MUST be 33 bytes. Transactions that break this rule will not be relayed or mined by default. Since this policy is preparation for a future softfork proposal, to avoid potential future funds loss, users MUST NOT use uncompressed keys in version 0 witness programs. BIP 143