Got chance to do the field test with new RX location today, no more radio intereference problem...
The weight without body is 1623g (with AMBrc transponder and 25g balance weight under battery position). With body goes to 1724g, 1g lighter than IFMAR rules. Need to add 5g under battery to meet the rule next time...
for ntc3freak:
I might do small production run (less than 20 I guess) if I can find a good quality with fare price factory to manufacture for me. My prototype doesn't come with good quality and I did lots works to correct the manufacture flaw. I will let everyone know if I can find a good factory for small production run.