Your opinion about this GPR Image...

[Abdullah]

I would really appreciate your opinion about this profile.

-Antenna: 250 MHz
-soiltype unknown; but it's very dry (see 5Th picture)

Thank you in advance for your efforts.

Abdullah

 

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[samorano]

Hi abdullah the soil you are working in looks like black dirt low conductivity you are penetrating very good the anomaly is very shallow it looks like the stones are making that high contrast maybe some kind of foundation I would dig it up it helps us for future exploration, I would like to see your settings I also have the ramac unit 250,500,800mhz antennas with the 250mhz antenna I was missing small objects like the one gallon objects in my opinion the 500mhz antenna is a better choice it depends on what you are looking for, I just ordered the new 3D software from mala quick3Dsoftware its mostly for presentation but I think it will help to get a better idea of what you are looking at don't forget you have to make a grid X,Y

 

[Abdullah]

Samorano,
I thank you that you took the time to answer me here. It's good to read that from a professional !
Send you the measurement info per pm...

Here's a new profile I would like to show you. There are anomalies; do you think they come from a metallic object ?

Abdullah

 

[samorano]

Yes there small metal objects from the surface, I am not a professional in GPR I don't have a degree in geophysics I am only a treasure hunter like you train to learn more

 

[samorano]

Please send me the measurements I just realise where mite be the problem but need to check it first in my GPR I think the point interval is not right

 

[Abdullah]

Samorano,

thank-you again for the reply.

Here is the measurement.info from this profile:

Antenna: 250 Mhz shielded
Sampling Frequency: 2573.1 Mhz
Number of samples: 506
Number of Stacks: 16
Antenna Separation: 0.14 meters
Time Window: 196.7 ns
Trace interval: 0.049 meters


Abdullah

 

[tagasilay]

Hi Abdullah and Samurano,

I also use a ramac with a 200mgzh antenna, i assume depth measurement is in ft, if that is the case, the wavelength of the gpr is only reaching around 3 ft. As for a metallic object, i see no hyperbola that would indicate a solid hit based on your pics, but don't give up, maybe Samurano can recommend the proper settings that would allow the wave to go deeper, im a bit rusty with the formulas, it has been awhile since i have been "out" with the machine.

happy hunting.

 

[Abdullah]

Hi tagasilay,
no, depth is in meters. Yes, the gpr didn't penetrate deep at this place. The 250 MHz Antenna can go deeper. I think it's true what samorano wrote, the stones make the high contrast. Even without any contrast used in GroundVision the profile looks "overcontrasted".

I'll attache another profile from there. It also looks like I made the contrast to high, but it's just a little contrast.
Does someone "see" anything important there ? And if there is something, where exactly is it ? Need to know this because I want to dig it up.

Abdullah

 

[tagasilay]

Hi Abdullah,

The blurry part and the wave "spikes" are possibly noise or outside interferance ie cellphone ringing or you might have a handset radio with you. again there is no hyperbolic reflection in the pic. If the blurry part is consistent then it might indicate ground disturbance. the ramac cx monitor gives you to post filter images, are you using the same?

 

[tagasilay]

Hi again,

at 4.5 horizontal and 2 meter down, there seems to be a small break and hyperbola, run it again till you think its consistent enough.

 

[Abdullah]

Hello Tagasilay,

yes, there is very much noise in this data and I'm wondering why. There is no cell phone network outside, no power lines, absolutely nothing.

I don't have the ramac monitor, I use a laptop with Ground Vision. During measuring it's possible to use filters and I use them. I also put on some filters on the data I posted here.
Next week I'll go there with my fisher two box, because I think gpr doesn't work there. Will also check at 4.5 horizontal as you said in your post.
The two box gave me a lot of false signals in the past. Once the only thing I found where stones, huge stones. Perhaps this happens because of the soil or stones ? Think so...

When I'm back I'll let you know what I "found" there

Greetings
Abdullah

 

[tagasilay]

Happy hunting! keep me posted (-;

 

[UXGeophysicist]

Hey Abdullah and All,
With regard to your GPR images, 10m is way too deep for a 250MHz antenna to penetrate. I would start with 3 meters (4 tops). I usually use 120ns on with my 200MHz antenna and end up cutting data off the bottom. If you cut down on your sample interval (depth) and keep the same number of samples you may also improve your data quality. If you are trying to locate smaller items or concerned about data density, I would decrease my trace interval also.

The features that are "ringing" are most likely caused by small metallic features at the surface. You may also see similar features when the antenna is lifted off the ground or bumped due to uneven terrain... you need to pay attention to that during data collection. You can also see "ringing" features when you collect data over a vertical pipe (e.g. abandoned well), although they are usually more defined in that case.

I suggest turning the gain down in the top 1-2 meters of your profile and turning the gain up in the lower portion.

Not all metallic objects will result in a Hyperbolic anomaly. Hyperbolic anomalies are seen when you collect data over a cylindrical object perpendicular to its access. In real life even cylindrical objects (i.e. 55 gallon drum) may be damaged or rusted out which could distort the GPR anomaly. When looking for small metallic objects you should pay more attention to sharp contrasts.

I am more familiar with GSSI and MALA GPR systems so I apologize in advance for setting discrepancies, although my advice was pretty general. What software do you use for processing?

What are you looking for anyways? I imagine that you would be more productive if you invested in a magnetometer or some EMI device. Hope this helps, Good Luck!

 

[tagasilay]

Hi UXG,

what would be your recommended frequency for a 120ns setting, i am a bit rusty now but i use a x3m monitor with a 200mgz antenna . If it would not be a burden i would appreciate if you could advice me so i could have pre-set setting for fast, slow, and medium ground
conditions, i use to tape the formulas beside the monitor lol.

God bless,

Jose.

 

[AUVnav]

Abdullah,

Does your laptop have a setup for a wireless network? If so, try turning that off....

Auv