Xterra 705 vid numbers change with new coil?

First thing that I would suggest is a factory reset. With the unit off, press and hold the chevron button while powering it on. It should display FP for a few seconds.

In choosing a different frequency, you need to know how the Xterra target bin segment widths are programmed relative to the various frequencies.
Target segment bin widths are narrower and the lower end of the detection scale and wider at the high end with low frequency coils The inverse is true with high frequency coils. So a silver quarter for example, will give a response that will neatly fit in a segment with a low frequency coil, but might give a response that is too big for one segment with a high frequency coil. The effect of having it be a bigger response for the bin width, is that it is likely to "bleed over" into an adjacent bin on either side, causing it to indicate a "jumpy" ID with multiple tones, making positive ID much more of a challenge (<-read "you'll dig more trash chasing that quarter"). MF coils have the most uniform bin widths across the entire detection range, making them the "most honest", and a good general purpose use frequency.
(check out the illustration below)







Now, understanding all of this, go read Randy Horton's four part blog article titled "Which Xterra Coil Is Best For Me".

Which X-TERRA coil is best for me? part 1
http://www.minelab.com/usa/treasure-talk/which-x-terra-coil-is-best-for-me-part-1
Which X-TERRA coil is best for me? part 2
http://www.minelab.com/usa/treasure-talk/which-x-terra-coil-is-best-for-me-part-2
Which X-TERRA coil is best for me? part 3
http://www.minelab.com/usa/treasure-talk/which-x-terra-coil-is-best-for-me-part-3
Which X-TERRA coil is best for me? part 4
http://www.minelab.com/usa/treasure-talk/which-x-terra-coil-is-best-for-me-part-4

I have the 6" coiltek digger on my 705 and sometimes the numbers are dead on and sometimes one higher

thanks for the replies. I must have just gotten myself confiesed. I was hoping for better discrimination than my ace but it seems like all detectors have some of the same issues with penny/dime overlap and such. I think i just need a lot more time on the 705 to learn the ins and outs. Still pulling coins off the farm I have been hunting so it is treating me right. Found a war nickel in a area I have hunted a ton and have pulle close to two dozen wheaties and no other demoninations of coin befor the nickel. I will keep swinging.

They do change at times but its never good to go by numbers in hard ground .
They change with different freq coils too.

a wheat penny and clad dime will a lot of times hit just about the same ... keep at it and swing low, slow and overlap your swings pretty good ... it's not a race ... the deeper or dry hard ground the more chance for it to be off just a tad ... sounds like you are doing great ... I've got hundreds of hours this year on my 705 and still learning ...

I get out on short half hour lunch hunts and want to continue to work the front yard of this farm until the snow falls. Can you reccomend some settings to cherry pick the yard? I don't have a lot of time to be digging iffy deep signals. I read this in another thread and wondering what you guys think?

"Search hi tones for a while. Dig 30 to 46 tones and 8 to 24 but not on the first pass. I dig hi tones first then swing the same area from the other direction and dig low tones and pick up the hi tones now reveled."

if you don't dig the 2-14 signals you could be passing up gold, and silver war nickels ... just dig solid non iron signals that are repeatable ... if it bounces around pass on it ... your going to dig trash no matter what ... some of the solid signals that wasn't coin #'s turned out to be some of my better finds that wasn't coins or usual coins like my 3 cent trime

thanks much. I will keep at it.

then come spring you will have the best hunting yet to come ... get the shallow easy stuff out of the way then when the ground thaws it will be wet and those very deep iffy hits will be clearer and you will be able to if you want to dig it or not ... from rock hard dry ground in the summer/fall come thaw in spring you will almost get twice the depth ... wet ground is a great conductor ... the wetter the deeper I say