GPR - project

[gwzd]

don't be sorry, most people here are very nice and helpful. Many are in one way or another involved in commercial companies as employees or even owners and sensitive information won't be posted here for obvious reasons.
Even though, you will find tons of information here you won't find anywhere else and that's the great value of this forum.
So, welcome to the forum!
I don't post very often because sometimes I just don't find the time, but there are many others always willing to help.
wish you the best
RA

[bajes2008]

sory...

Thanks! I'm right! I'm right!....
well, you know, you share if you want to, that's the whole meaning of the word sharing. It's a voluntary action and if you cannot take a joke then you are in trouble .... dear.
RA

you know ? u r wright....maby im sinsetive too much...im so sory

[gwzd]

You are right dear. But that signs of genius nerves are crazy. If you do not have the intention to partesebate your design in the forum. So why if it comes from the begening. Is it not a subject of nerves?

Thanks! I'm right! I'm right!....
well, you know, you share if you want to, that's the whole meaning of the word sharing. It's a voluntary action and if you cannot take a joke then you are in trouble .... dear.
RA

[bajes2008]

hi..wz

I think you need a beer and some chill out music.
cheers,
RA

You are right dear. But that signs of genius nerves are crazy. If you do not have the intention to partesebate your design in the forum. So why if it comes from the begening. Is it not a subject of nerves?

[gwzd]

I think you need a beer and some chill out music.
cheers,
RA

[bajes2008]

enough is enough seeker

Dear seeker maybe you're a fan of Electronic Engineering, or perhaps be an engineer ... but most of all, you are good at drawing attention and attention. Maybe this is one of the hobbies as well .. but this does not give you the right to manipulate the members of this forum and ridicule them and laugh at them .. it a disgrace .. and I can say with confidence that all members of this forum are enthusiasts for gold traders, but not as claimed by .. and say you will not be published here .. if your design to what all the fuss if it does not? Better to be published here on your site and your friends and not .. and you know that not everyone is supposed to be knowledgeable in electronic engineering in order to build the device you .. or is it the question of individual muscles to the needy members?? If .. I advise you to stop this farce .. and enough is enough.

[gwzd]

Probably because someone, whose name is Franklin, did probably invent this type of antenna array.
http://www.centurion.com/home/pdf/wp_omni_wireless.pdf

Really?! no kidding?

See on page 1 figure a)

This antenna is optimized for 2.4 GHz for an impedance of 200 Ohms. You need a balun to change its impedance into 50 Ohms (WLAN).

I have a prototype of this antenna and it is working well (for WLAN). But probably not convenient for a GPR project.

you've got no clue how a gpr works, do you?

This was not my invention. So there is no need to alter your books.


Aziz

Oh! thanks for that! I was already starting to worry!
RA

[Aziz]

why is it called a Franklin Antenna? I propose from now on we call it an "Aziz antenna"! I'll have to correct that in my books!
RA

Probably because someone, whose name is Franklin, did probably invent this type of antenna array.

http://www.centurion.com/home/pdf/wp_omni_wireless.pdf

See on page 1 figure a)

This antenna is optimized for 2.4 GHz for an impedance of 200 Ohms. You need a balun to change its impedance into 50 Ohms (WLAN).

I have a prototype of this antenna and it is working well (for WLAN). But probably not convenient for a GPR project.

If the reflector is reduced (removing the wings), it could give still a good directional antenna. But then, the antenna has to be recalculated (optimized).
Something like this:

http://www.electronicsinfoline.com/Top_Picks/Antenna/amos_wifi_homemade_antenna_with_semicircular_radiation.shtml

These antennas are also called "Amos" in the web:

http://www.qsl.net/yu1aw/engl.htm

http://www.qsl.net/yu1aw/amos_article.pdf

http://www.qsl.net/yu1aw/invertamos.pdf

This was not my invention. So there is no need to alter your books.


Aziz

[gwzd]

Multichannel gpr systems work in several different ways:

1. can be multiplexed, so no tx/rx pairs work simultaneously
2. can be one antenna transmitting and all the other receiving.
3. can be firing in a sequence, that is alternating, but still no multiplexing like the SIR-20 from GSSI which is a true dual channel unit.
4. can be with directive antennas like 3D Scan from Norway.
5. probably many others more that I just don't know about

Regards,
RA

[miki73]

One more question if im not borring.How that work in situacion with 4.transmither in corner of quad scaned place.This transmiters is sincronius with reciwer too or that method work on some other way?

[miki73]

Thank you!Now i have clearly picture.

Regards too all!

[gwzd]

Here is one of my several developments: a high gain 21 dbi franklin antenna.

model source: http://mitglied.lycos.de/pp4nec2/files/index.html

Aziz

why is it called a Franklin Antenna? I propose from now on we call it an "Aziz antenna"! I'll have to correct that in my books!
RA

[gwzd]

GPR usually works with two antennas, one transmitting and one receiving. The pulses are extremely short compared to the range of investigation. For instance, consider a 100ns (yes, that's right, nanoseconds) range with a 500MHz antenna. The pulse width is approximately 2ns or only 2% of the desired range. And, yes, it is the strongest one and therefore often damped at some extend. In transceivers which has the same antenna transmitting and receiving more advanced techniques are used, but that is out of the scope of this forum.
I guess this helps.
RA

[miki73]

Are somebody know gpr working principe?
Gpr firs transmite signal and then recive..like pi detector,
or contnious transmit and recive,in that case how transmit signal not blind reciver?

Regards!

[epitopios]

GPR - project

Seeker wrote Jun 2006

....The helical antena have many advantages to another types and rotating polarization give us 20dB attenuation between TX and RX signals in straight reception. ....

I dont disagree but also have a look at:

http://www.rozendalassociates.com/datasheets/HORN.pdf