The Federal Home Loan Bank Board said effective mortgage rates for fixed-rate loans in early July averaged 11%. That was down slightly from early June, when the average rate was 11.05%. Meanwhile, the California Assn. of Realtors reported that higher home prices and higher interest rates made homes in California less affordable in June than they were in May. The median home price of an existing single-family home rose to a record $137,392 in June, 3.4% higher than it was in May, the association said.