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X-TERRA 705 Gold Pack - A simple Solution!

July 01, 2010 11:05am

Kevin Hoagland
Kevin gold prospecting

With the announcement of the X-TERRA 705 Gold Pack hitting the street and forums everywhere I thought I would toss out some results from testing for anyone that has not heard me ranting on about how great the X-TERRA 705 really is. The X-TERRA 705 Gold Pack was a simple idea and solution; really there was no need to reinvent the wheel on this one. Take a worldly proven metal detector add the perfect coil for prospecting and offer it at a good price and we answered one of the most asked questions I receive from nugget hunters.

During the X-TERRA 705 field testing I wanted to test the offset ground balance in one of my old patches in the Bradshaw Mountains of Arizona. This patch is known for extremely bad ground minerals with hot spots of Pea sized iron stone patches from the surface to about four inches that has always caused VLF machines problems. We call the spot Vhell.

Hunting with the X-TERRA 705 in Auto Tracking it was not long until I hit the first hot patch which was mixed in with a number of mostly buried boulder sized rocks. Pressing the Ground Balance button I quickly offset the balance and started shoving the elliptical coil in between the rocks.

For those of you that have time behind the coil, you know that perfect threshold you get when your detector is just right and you are getting the maximum power, sensitivity and depth in the ground? This was one of those times. With the elliptical coil slightly tilted to get it into a tight space between two boulders I got a nice soft signal with no ground noise. Dragging the pick through the dirt I completely covered my magnets in iron soil and little hot rocks. After 4 inches of digging the signal was gone and in the pile of iron dirt and iron peas. The take was a nice 5grain nugget to add to the collection of X-TERRA 7 series gold. About a foot further into the crack, 1gram between 6 and 8 inches down.

This proved to me beyond any shadow of doubt that the digital format coupled with the right coil gave me a metal detector that without making any changes to settings allowed me to work shallow and much deeper in the same swing.

X-TERRA metal detector coil 18.75kHz

During the 705 prospecting field testing we found while sharing notes afterwards that the true digital format of the X-TERRA coupled with the 18.75kHz elliptical DD coil covers the same ground that it would generally take a number of higher and lower freq analog gold detectors to do the same job. Even then, other detectors without offset Ground Balance would have been challenged without lowering the sensitivity to a point where we were uncomfortable.

In fact the digital frequency range of the X-TERRA defies many of the rules we were taught about detecting and frequency. I never travel without it.

I would like to hear from you on how and where you’re using your X-TERRA 705 and if you have had the opportunity to utilize all of its features.

Hope to see you soon, out there.

Kevin Hoagland

X-TERRA 705 Gold Pack product page


I just bought a X-TERRA 705 believing it was 'new' digital signal technology. But reality is, it only has digital electronic 'processing' not digital square wave signal technology. The X-TERRA 705 does use improved analog sine wave frequency capability. I am confused by your statement above that X-TERRA 705 has "digital frequency range". Please explain... Many Thanks...
Posted By: Mitkof on August 07, 2010 11:47am
Hi Mitkof,
The X-TERRA 705 uses digital electronics, called VFLEX to both generate the transmit sine wave and process the return signal. Whilst the transmitted signal is an analogue sine wave it is generated by digital electronics. This is an advantage as digital electronics, unlike analogue electronics, is capable of generating a mathematical perfect sine wave. This is important and improves the detector’s sensitivity because any changes in the received signal are due to the environment (targets, ground and electrical noise) and not due to any imperfections or distortion of the transmitted signal.
Another advantage of the X-TERRA 705’s VFLEX digital circuitry is that the transmitted sine wave‘s frequency is digitally matched to the coils frequency. No two coils are exactly identical, as small physical variations have an effect on the coil’s frequency. If the frequency of the signal from the control box does not match the coil’s frequency then the transmitted signal will be distorted, reducing the detector’s sensitivity. VFLEX uses digital communication between the coil and the control box to determine the coil’s exact frequency. This allows the control box to know the exact frequency of the coil and adjust the frequency of the transmitted signal to match the coil’s frequency. So if the coil’s frequency is 3.049kHz then the X-TERRA won’t just transmit 3.000kHz as an analogue detector would. It will adjust the transmit frequency to exactly 3.049kHz reducing distortion and therefore increasing sensitivity.

Brenton O'Brien
Posted By: Brenton. on August 09, 2010 11:17am
Thanks Brenton, good information especially on the X-TERRA 705 enhanced kHz adjustment unique to each specific coil. That alone will greatly improve sensitivity and threshold if not depth.

One additional question on X-TERRA 705 MD: Do you know the depth increase for a target, between the 10.5" round coil... to the 10x5" coil? The 5.5" additional width of the round coil should increase signal depth on a DD coil. But, by what percentage??? Searching for nuggets the additional 5.5" width might make a big improvement. Thanks.
Posted By: Mitkof on August 13, 2010 01:17pm
It is very difficult to give a general percentage to compare the two coils because conditions such as target size, target material, ground mineralization vary and all play a part. So I have gone to one of our physicists to get a definitive answer to your question.
There is a performance difference between the two coils, which is, as you say due to the different coil widths. The elliptical shape of the 10 x 5 coil means that the two ‘D’ shaped windings are narrower than the D shaped windings on the round coil. The D shaped windings on the elliptical coil therefore have more windings to give them the same electrical properties (inductance) as the D shaped windings on the round coil. This results in a more intense magnetic field close to the elliptical coil (less than 6cm), but the field dissipates over a shorter distance than the round coil. So to answer your question, yes the round coil does give more depth, but it sacrifices sensitivity close to the coil.
Posted By: Brenton. on August 17, 2010 02:10pm
Hello, While doing some testing with the 10X5 coil that I purchased from Gerrys detectors I noticed that in the coin mode it hit very good on a dime, quarter, nickle and one cent coin but wanted to blank out a silver dollar and it did this on most of the disc. modes-any thoughts on thi?
Posted By: Idaho Al83226 on August 21, 2010 12:13am
I apologize for the delay in responding I have been off the grid in Alaska for some time, just recently returning to the land of internet connectivity.
To help clarify my post a bit, After performing field testing and hunting with the detector in a few of my favorite nugget patches and finding targets that were ranging in the 1.5-3 grain range I turned to testing in my garden.
I have an extensive test garden with targets of differing conductivity levels, size and of course depths. I have also imported a large amount of iron rich black sand soils and added it to the mix to replicate some of the hottest patches I have detected over the years.
There are a number of targets buried in my garden that are extremely hard to locate with lower frequency technologies due to the physics of frequency and response for very these targets. These targets range in the 2-5 grain range and are buried and different depths and with varied levels of mineralization.
In the past these targets in my garden have been best found if found at all, with detectors ranging in the 40 kHz - 75 kHz range. It is very important to note here that there four targets that I have in the past only found with detectors in the 60kHz - 75kHz range.
I was astonished to find that with the X-TERRA 705 with the 18.75 kHz 5 x 10 inch elliptical and the 6 inch round coils these four targets were not only present to the detector but had exceptional response.
On one target I actually dug the test cylinder up to make sure that there were no additional targets that had contaminated the test area.
With those test completed I will share that the technological differences in the X-TERRA line of detectors is a clear advantage to any VLF single frequency detector I have used over the last 30 plus years of detecting.
I hope this helps with my statements as to what I am finding in the field and in my garden as Brenton in my absence has expertly and thoroughly shared the technology advantages of the X-TERRA Series of detectors.
See you out there.
Kevin Hoagland
Posted By: Kevin Hoagland on August 23, 2010 10:05am
Excellent question and one I am familiar with. In the factory preset mode of the four discrimination patterns you will see on the far right hand side of the screen that there is a rejected signal (blacked out vertical bar) this is where most large American silver coins fall into the discrimination scale.
Using your plus (+) button move your curser over the rejected mark and press your accept/reject button to clear the mark.
Please remember to do this in all of the four pattern modes.
I do not know the exact reason for that particular area to be rejected from the factory but I have a speculation that I will share.
Minelab is a global company building machines for just about every country on the planet. That being said, over the years I have been given and found a lot of trash targets from around the world that were very similar to silver in conductivity. Very much like a pull tab and some gold rings are very close to the same conductivity signal.
Since the large silver range can be easily added back in for our hunting and a few other countries that have good signals in the same conductivity range it makes sense, at least to me, to reject that range from the factory.
Again that is just speculation and I have after all these years sent an inquiry to one of the X-TERRA design team for more clarification. I will post it as soon as I receive a response.
See you out there
Kevin Hoagland
Posted By: Kevin Hoagland on August 23, 2010 11:09am
A question rather than a "comment":

I can't afford a seperate detector for beach use so my X-TERRA 705 is it! I've only used it on one beach hunt and need some help with settings that will allow me to have more success. Before you ask, YES, I had it set in beach mode. The wet sand gave me lots of problems. What settings do you suggest for the X-TERRA 705 and wet sand?

Posted By: TomboyDgr on August 31, 2010 07:51am
No worries we can get you sorted out, just a matter of setting your detector to the ground around you.
Beaches offer some of the most challenging and rewarding hunting areas anywhere. And the time spent learning these areas has always been rewarding to me.
I would first ask you to take a look at your sensitivity setting and match it to the ground and not use the preset.
To do this, go into your menu and select the sensitivity icon.
Hold the detector about one inch above the ground; listen for background noise within the threshold that causes the threshold to be slightly erratic. Using the (-) touch pad lower the sensitivity just to the point where the detector becomes stable. Press the Pinpoint Detect pad to return to your hunting mode.
This should take care of your settings for you. And do not worry that you are detuning the detector. It is just the opposite. By setting your sensitivity to the ground you are working you are optimizing the detectors performance capabilities.
If you still have a little noise and are working between dry and wet sand take a look at your manual and use the Ground Balance offset feature to allow you a seamless transition between the two soils. There are also a few videos posted on concerning offset balance, just type in X-TERRA 705 in the search field.
Posted By: Kevin Hoagland on September 01, 2010 11:52pm
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