Doug
Searching GPSPASSIONS News section I found this. Maybe it will help.
"Static Navigation requires some explanation. When standing still, the GPS unit "wanders" from fix to fix within the error circle. For the BT 338, that's about 15 meters. As each fix is calculated, it can be as much as 30 meters from the last one 95% of the time, and maybe even further for the other 5%. Of course, it could be exactly the same place, too, but that is unlikely. In early mapping software, this wander shows up when you are stationary, but the map jumps around. If you have "heading up" display, the display will shift all around, too, as it sees the movement from one fix to another as a heading change. Some software packages dampen out these minor changes, particularly if you are in a navigation mode, assuming that if you are stopped, you are probably not jumping around that much. What GlobalSat did was do that dampening in the receiver, invoking Static Navigation. Basically, if you are traveling less than 3 mph and if the distance from the original "stopped" fix to the current fix is less than 50m, the unit doesn't report a change in location or heading. This function makes the unit appear to be rock solid when you are sitting at a traffic light. However, it has a side effect of also dampening out movement when you are walking with the unit, particularly if you are geocaching with it and not moving very far or fast with it. I can also see a problem with hiking and skiing where if you are moving slowly, say uphill, you won't see movement in the GPS until you have traveled more than 50m, which is a long way. SN could NOT be turned off in the early units. GlobalSat received numerous complaints and now has agreed to disable this function in the factory. I could not find a commitment from GlobalSat to enable the user to select SN on/off through the utility software, but I am told that SirfDemo (google for it) may be able to control that function. I couldn't test it as my early unit has SN on and non-changeable. GlobalSat also says that they will not be releasing a firmware upgrade utility for the early units, so early units will have SN on all the time. Again, buyer beware in the used market and eBay.
How that affects the X don't know for sure. Lot's of info in the "news" on these ever changing chipsets. The Sirf III seems to be a good one but with know issues.
My antenna is a GPSGEEK amplified. He's got a Ebay site as well as GPSGEEK.com. Cheaper on his ebay site. It's a Gilsson brand. I haven't had any problems with the wire. The mcx does sit off to the side some because of the depth the jack is set in the case. I have used it without the band but don't trust it while hiking. Lobster band does a nice job.