GPR - project

[Functional]

GPR - Project

Seeker,

I don't think that your .9-2.4 GHz antenna will be of much use for anybody trying to look deep into the ground. It could be a nice through-wall imager.

Here is a nice article about a similar GPR system developed as a NDT tool.
http://www.ndt.net/article/ndtce03/papers/v090/v090.htm

Just thought I'd mention a webpage, titled "How Deep Can GPR See?":
http://www.georentals.co.uk/gprsee.htm

A nice page of science and physics bookmarks, with some GPR links:
http://home.comcast.net/~scottxs/ScottsBkmrks.html

And an interesting article from the website of the Microwave Journal, (I'm not a registered member, so I couldn't read all of it):
http://www.mwjournal.com/Journal/art...?HH_ID=AR_1398

Back to the little discussion. I'm not quite certain what the reason is for wanting to see through walls, unless your trying to find treasure in your neighbors house.

As for the GPR topic, I wish I was enough of an electronics guru to build one, but if I was, I'd probably have torn my old cordless phones apart by now, so I could salvage the 900 mhz and 2.4 ghz antenna's and circuitry, in the hope of using it to build a GPR. Well, at least I know which end of the soldering iron is which, (hint: the pointy end it hot).

F.

[Seeker]

Seeker,
You might be interested in this Master's Thesis on the development of a Stepped-Freq GPR transceiver.
http://www.rrsg.uct.ac.za/theses/msc...son_thesis.pdf

Geophyz,
thank you for link. It is interesting abstract work,but without practice benefit and ornate with theoretical deductions. This is not applicable for homebrew GPR. The diagram is unduly complicated with two sythesizers and IQ-transforming.
So, I think it is good work for Master's degree , but it's not for GPR-amateurs.

Regards

[Geophyz]

Seeker,
You might be interested in this Master's Thesis on the development of a Stepped-Freq GPR transceiver.

http://www.rrsg.uct.ac.za/theses/msc_theses/gfarquharson_thesis.pdf

[Seeker]

Seeker,
These types of step frequency GPR systems have been around for a while. Georadar Inc produces a step frequency GPR system commercially called GeoRadar Model 1000B and it also uses spiral antennas.

http://www.georadar.com/

They also own the patent for such devices in the USA.

http://www.freepatentsonline.com/6225941.html

I don't think that your .9-2.4 GHz antenna will be of much use for anybody trying to look deep into the ground. It could be a nice through-wall imager.

Here is a nice article about a similar GPR system developed as a NDT tool.
http://www.ndt.net/article/ndtce03/papers/v090/v090.htm

Geophiz,
I have not claims to found "hot water" , the princip of FM in radiounits is in use from long time. For example some radioaltitudemeters and low power radars work with FM continuous waves. Spiral antenna is more suitable then other types and this is close to mind.

About patens - everyone can patent what he desire, especially well-known things.
My wish was to show the way for unexpensive homebrew GPR . Too many guys wants to do that and I will help them. Ofcourse I don't publish end schematics.

In fact , 0.9-2.4 GHz is not the best band, but is enough for GPR for 4 m depth.

Best regards

[Geophyz]

Seeker,
These types of step frequency GPR systems have been around for a while. Georadar Inc produces a step frequency GPR system commercially called GeoRadar Model 1000B and it also uses spiral antennas.

http://www.georadar.com/

They also own the patent for such devices in the USA.

http://www.freepatentsonline.com/6225941.html

I don't think that your .9-2.4 GHz antenna will be of much use for anybody trying to look deep into the ground. It could be a nice through-wall imager.

Here is a nice article about a similar GPR system developed as a NDT tool.

http://www.ndt.net/article/ndtce03/papers/v090/v090.htm

[seagsm]

Ultrawideband Ridged Pyramidal Horn Antenna

Abstract:
We report the numerical analysis and experimental
characterization of an ultrawideband (UWB) antenna designed
for radiating short microwave pulses. The antenna consists of a
pyramidal horn, a ridge, and a curved launching plane ..........
http://www.engr.wisc.edu/ece/faculty/hagness_susan/li_IEEEAWPL_03.pdf

I think , we can use it for GPR...

[aft_72005]

Hi seagsm

Thanks for this link, seem as good practical
Idea in the matter.
Best regards .

[seagsm]

UWB radar

A practical hands-on description on how to build a prototype of an ultra wideband (UWB) radar
http://www.uniroma2.it/fismed/faculty/Stadero/papers/osee.pdf

[schatzsucher]

Sorry, I can not read German.

thank´s at google
http://translate.google.com/translat...language_tools

or other translater-engien

Hi, for 20-30cm inside wall you can use 10GHz band for good resolution, the diagram is same as 2,4GHz. You can use modified sat. converter at 10GHz as TX .Output power is about 40-50mW , but it is enough to penetrate through concrete or stone up to 50 cm and return to RX module.
DARPA had some developments to detect people behind wall at 10GHz.
So, the "low-frequency" is function of deviation of TX by modulated frequency and form of signal. You can make experimen to define deviation and "low-frquency" in your case.

Thank you Seeker.
I will try to use a "gunnplexer" from a motion control ( 10GHz ). There is a small problem : Tx and RX are complanar .

[Seeker]

can i use an emp-source for transmitter?

Hi, what is emp-source?

[Seeker]

thank Seeker for all the info.
The RF part seems easy: 2.4GHz transmitter, power ampli,
diversion module , antenna.
RX: opposite polarisation antenna, mixer (from antenna and diversion module).
Now can we have some more info about "low frequency"
circuit? ( sensitivity, band-pass, etc)
PS I need to "see" only 20-30 cm inside a wall.
Any idea appreciated.
Thank to all
Paolo

Hi, for 20-30cm inside wall you can use 10GHz band for good resolution, the diagram is same as 2,4GHz. You can use modified sat. converter at 10GHz as TX .Output power is about 40-50mW , but it is enough to penetrate through concrete or stone up to 50 cm and return to RX module.
DARPA had some developments to detect people behind wall at 10GHz.
So, the "low-frequency" is function of deviation of TX by modulated frequency and form of signal. You can make experimen to define deviation and "low-frquency" in your case.

[schatzsucher]

can i use an emp-source for transmitter?

High resolution -low range GPR

. Is your electronics sistem also adaptable for higher frequencies (higher resolution, lower range)? For uses like probing walls, etc..

Hi Leto,
are you working on something to see inside walls?
Paolo

GPR prototype

thank Seeker for all the info.
The RF part seems easy: 2.4GHz transmitter, power ampli,
diversion module , antenna.
RX: opposite polarisation antenna, mixer (from antenna and diversion module).
Now can we have some more info about "low frequency"
circuit? ( sensitivity, band-pass, etc)
PS I need to "see" only 20-30 cm inside a wall.
Any idea appreciated.
Thank to all
Paolo