Abstract: A shock sleeve is positioned above a UBHO sleeve, and both are received inside a substantially tubular sub collar. The shock sleeve is free to reciprocate with respect to the UBHO sleeve and sub collar. A mud pulse transmitter valve is received into the shock sleeve. The shock sleeve is interposed between upper and lower shock springs, which provide compensating compression spring bias to dampen the transmitter valve (as received in the shock sleeve) from vibration or shock forces experienced by the sub collar. At least one shock absorbing compression ring interposed between mating portions of the shock sleeve and transmitter valve also dampens the transmitter valve against vibration or shock. An optional mud filter received over the shock sleeve removes particulate matter from drilling fluid before it encounters the shock sleeve.