looking for home-made G.P.R.

[gwzd]

Lets tolk about transmit puls.Puls must look like on pic 1. or 2.?

If you are talking about impulse radar, then, neither of them.

How determine transmit power?

Regards!

The transmitted power is a complex function of applied power, antenna losses or efficiency if you like and not the least, how you measure it. If you try to use an ordinary, I'll assume here we are still talking about impulse gpr, power meter then your readings will be ridiculously low because most power meters are designed to measure CW and not peak power. You'll need a little bit more sophisticated device for measuring power from an impulse GPR. There are ways of calculating the output power if you have all the info on your transmitter and antennas at hand. This is most of the time hardly the case.
Regards,
RA

[Valchev]

I do however think your so called "1.6GHz" needs a lot of refinement and work to be able to say it does work as a GPR should. That specially in concrete which has approximately the same properties all over the world, don't you agree? It should look more or less like the attached picture, but it doesn't.

May be it work as metal detector ?

You see, I personally don't have any problems with your other gpr, the one here:
http://m12.hit.bg/gpr_eng.html
It is not top of the line and many things can be corrected, but hey, it seems to work and if your customers are happy then it should not be any problem.

Of course my GPR may be not ideal, but i am absolutely sure that all your antennas FLB-390, HA1000 AND HA2000 are not so suitable for treasure hunting and can not work so deeply as my GPR. You have not enough experience in real condition. If you wish i will explain why your antennas a not so good for treasure hunting. By the way you forgot to write the frequency of your antennas, i can only to suppose that the number is equivalent to frequency may be.

[miki73]

Lets tolk about transmit puls.Puls must look like on pic 1. or 2.?
How determine transmit power?

Regards!

[gwzd]

Hi Valchev,
That was fast! I read your comment and I think for the first time we are able to have an intelligent conversation, you and I.

You see, I personally don't have any problems with your other gpr, the one here:
http://m12.hit.bg/gpr_eng.html
It is not top of the line and many things can be corrected, but hey, it seems to work and if your customers are happy then it should not be any problem.

I do however think your so called "1.6GHz" needs a lot of refinement and work to be able to say it does work as a GPR should. That specially in concrete which has approximately the same properties all over the world, don't you agree? It should look more or less like the attached picture, but it doesn't. This is one of our antennas, I won't be advertising which one, although, I guess I already did so previously, oops!.

My point is that with this post:
http://www.geotech1.com/forums/showp...&postcount=136
I was trying to help you, not to offend you or insult you in any way. It is not my nature to do so, when tickle I tend to react vigorously. It must be my Spanish ancestors blood emerging, but listen, read my post again and you'll find some use there.
Now I have to go, my favorite show is about to start and I don't want to miss it.
As said, have a nice week end, truly.
Regards,
RA

[Valchev]

Really?!
your "gpr":
http://www.youtube.com/watch?v=UFpL5...layer_embedded

a commercial gpr:
http://www.youtube.com/watch?v=wnjvA...eature=related

or even closer:
http://www.youtube.com/watch?v=oNVsSd4K0Zo&NR=1

have a nice week-end.
RA

Before several days i wrote :

I am new in high frequency GPR technology

See post 138 from http://www.geotech1.com/forums/showt...t=10987&page=6

Of course my first high frequency GPR antenna can not to be so good so one from leaders in GPR technology.

But my GPR
http://m12.hit.bg/gpr_eng.html
is very good GPR. Of course it is very good for treasure hunting because in treasure hunting usually ground surface is not flat. For survey on completely flat surface as asphalt, there is more suitable commercial GPRs.





----------------------------------

[gwzd]

Of course this is absolutely correctly and necessary. I am comparing my GPR with commercial GPR in real conditions on real objects . Also, my customers from several continents were compared my GPR with several commercial GPR in real conditions on real objects , and their opinion is that my GPR is perfect.

Really?!
your "gpr":
http://www.youtube.com/watch?v=UFpL5...layer_embedded

a commercial gpr:
http://www.youtube.com/watch?v=wnjvA...eature=related

or even closer:
http://www.youtube.com/watch?v=oNVsSd4K0Zo&NR=1

have a nice week-end.
RA

[Valchev]

The good part of it is that they did check with another commercial GPR to validate their results. A 'reality check' is absolutely necessary when making statements of this kind, specially if people are going to put their hard earned cash into this stuff.
Regards,
RA

Of course this is absolutely correctly and necessary. I am comparing my GPR with commercial GPR in real conditions on real objects . Also, my customers from several continents were compared my GPR with several commercial GPR in real conditions on real objects , and their opinion is that my GPR is perfect.

[gwzd]

The best data for continuous sine wave GPR :

http://rrsg.ee.uct.ac.za/theses/theses.htm.

The good part of it is that they did check with another commercial GPR to validate their results. A 'reality check' is absolutely necessary when making statements of this kind, specially if people are going to put their hard earned cash into this stuff.
Regards,
RA

[Valchev]

Good start is plastic mine detector
http://www.geotech1.com/forums/showthread.php?t=15658
I was tested the original AN/PRS-7 and make the similar devise ,
it is good for non metal objects (cavity) may be to depth 20cm (20cm for big objects), but detect small metal and non metal pieces in ground surface.




.

[Valchev]

The best data for continuous sine wave GPR :

http://rrsg.ee.uct.ac.za/theses/theses.html







.

[miki73]

Thanks Korrigan for your block schematics.
Now I see we can use simply mixer stage for reciving and semling on low freq hf signal.Not need to use sempling method.I thing sempler is dificult to make.Or meybe sempler method give bether result.

Regards too all!

[Valchev]

they will decide for themselves what is right and what is wrong.

With this i am completely agreed.

[gwzd]

You can read english? I wrote FMICW
Young boy you are blind from malice.
Dont dream so much for money, better make test with yours GPR in soil. Most of the soil have conductivity more than 5mS/m. May be in your plase have similar soil 0.1 mS/m but for most of people soil is very different.
Examples with soil conductivity <0.5mS/m are misleading.

The link you mentioned is a paper dedicated to FMCW, besides, the point about it still holds.
I won't continue with this pointless exchange of useless posts with you, it doesn't add any real information for other people reading this forum. Feel free to think whatever it is you want to think. It is for other people here to see what you do and what you say, trust me, they will decide for themselves what is right and what is wrong.
Have a nice day Valchev,
RA

[Valchev]

If that would be the case they would not need the switches for the antennas, a FMCW don't need that. Besides, the antenna development would be a pain and way out of amateur reach because of the complexity of the tuning equipment involved.
RA

You can read english? I wrote FMICW
Young boy you are blind from malice.
Dont dream so much for money, better make test with yours GPR in soil. Most of the soil have conductivity more than 5mS/m. May be in your plase have similar soil 0.1 mS/m but for most of people soil is very different.
Examples with soil conductivity <0.5mS/m are misleading.

[gwzd]

It can to be too FMICW radar. If you are interested from continuous sine wave GPR see: http://courses.ece.illinois.edu/ece4...inal_paper.doc

If that would be the case they would not need the switches for the antennas, a FMCW don't need that. Besides, the antenna development would be a pain and way out of amateur reach because of the complexity of the tuning equipment involved.
RA