Is it possible to adjust dro lnb for drift by removing cover and if has brass screw going into dro cavity turn to adjust? Frequency adjusted like resitance is with a pot? Then after corrected reseal cover.I noted aprox 4mgz drift wile scanning the tightly grouped 3953-3976V on SES1 101W. I have several replacement lnbf if it gets messed up. And might use it as excuse to justify purchase and replacement with chapparal 1329 and pair of norsats, lol.Is the commercial equiptment realy worth the large $s?