Problem: Give the parity check matrix H of a [9,6,3] code over GF(7).
Attempt: Well I know that n=9, k=6, and d=3. GF(7) is looked at like an "alphabet" of elements to choose from, but I am just drawing a blank on the construction of this parity check matrix. I am used to working with fields like GF(2), GF(8), and GF(9) - this one proves to be more difficult...
Any help would be most appreciated. Thank you for your time.