Jump to content

Multi Frequency Coils For The Minelab X-Terra 705


GB_Amateur

Recommended Posts

On 1/28/2017 at 0:22 PM, Steve Herschbach said:

The 705 can be had stock in 7.5 kHz or 18.75 kHz versions, and customized via coil options to run at 3, 7.5, or 18.75 kHz. This seems impressive but in real life has not been a huge factor with the X-Terra because having to change coils to change frequencies is cumbersome.

Cors (aftermarket independent coil manufacturer) has made coils which are advertised as operating at all three frequencies.  I couldn't find anything regarding this at their website, which either means I'm not good at finding web info or they've discontinued making them (temporarily or permanently).  At least one Ebay seller has them -- here's an example ad (they were making them in various configurations):

http://www.ebay.com/itm/CORS-Scout-12-5-x8-5-DD-Search-Coil-Minelab-X-Terra-All-Frequencies-/291652981609?hash=item43e7df5369

These cost 1.5 to 2x what you pay for a single frequency Cors coil of the same general design (size and config) but if they really do work at all three frequencies then it's about a factor of 1/2 what you'd pay for three coils.

Real time multifrequency detetectors such as the Whites V3I and VX3 and Minelab 3030 give you more options (and don't require a coil change) but at considerably higher initial prices.

I already have two 3 kHz DD coils (Coiltek 6 inch and 15 inch, both DD) for my X-Terra 705 plus the stock coin & jewelry 7.5kHz 9 inch concentric.  Later this week I'll be receiving an 18.75 kHz 6 inch round DD Minelab coil, but I'll likely be on my way to the Southwest US by then so won't have a chance to try it out until I get back mid-February (weather permitting :wink:).  It will be especially enlightening to compare the performance of the two 6 inch DD's because the 'only' thing significantly different is the operating frequency.

Personally, changing coils hasn't been an issue for me because I usually am hunting with one purpose (e.g. coins or nuggets) and typically you know which coil you want to use, at least which frequency.  Also I often am within close proximity to my vehicle in case I want to do a change.  I understand that backpacking your swappable coils is more hassle than just walking over to your vehicle.

 

  • Like 1
Link to comment
Share on other sites


5 hours ago, Jackpine said:

The multi-freq coils seem to work well on the 705.  detectingMo has some vids on the 6x10 Mars sniper.

Multi freq Mars coils

I read through that thread -- good info and thanks for that.  Is this you youtube video you refer to?

Interesting that someone else said changing the channel (small frequency shift to minimize EMI) actually reduced wraparound.  Another thing I need to try when it gets warmer.

Link to comment
Share on other sites

Good info guys, thanks. My comment was not intended as a slight of the X-Terra 705, just more a offhand comment intend more for the newbie detectorist. Despite what all us hardcore users think most detectors never get used with anything other than the coil that comes with them. For more casual users the ability to change frequencies via a coil change has therefore been more of an unexploited option. In theory the Minelab method is superior because the coils are specifically tuned at each frequency. From a marketing and sales perspective however it has put Minelab at a bit of a disadvantage with less knowledgeable potential purchasers. This detector brand you can change frequencies with the flip of a switch - this brand requires you buy another coil to access each available frequency. You can see the problem from a sales perspective.

Anyway, these coils provide a workaround to all that, though there must be one frequency these coils work best at, with somewhat less than perfect performance on the harmonic frequencies.

Link to comment
Share on other sites

4 hours ago, GB_Amateur said:

I read through that thread -- good info and thanks for that.  Is this you youtube video you refer to?

Interesting that someone else said changing the channel (small frequency shift to minimize EMI) actually reduced wraparound.  Another thing I need to try when it gets warmer.

That's one of them.  He has several videos on his channel using the multi-freq coils..

What was amazing is how close the 6x10 was to the 10x13 in depth.

 

Tom

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...