Can we develop a new detector..?

[6666]

Pulse can you write software for PI detector ?

What chips are you useing, can the TX freq (100-500 pps)and pulse width , and sample delay and pulse widths be altered with pots ?

[rajesh]

new detector

Perfect, this can detect 100 tons of metal, mostly aluminum, flying above your head. Otherwise nothing to do with metal, especially gold detection, this is airband AM receiver. At a price of purchased parts, second hand scanner or ham radio equipped with airband can be found. Or even this, on junkyard:

hi actually i'm not suggest device i mean to say the frequency 460 m h z band this is very sensitive to gold ......................

[Davor]

I heard about that. Maybe with appropriate Rx antenna that will balance-out far field signal it will be possible to use such receiver as a detector. However, I guess it will be possible to work as all metal detector. It surely will not discriminate them.

Anyway, i like Hanumanji's picture in your avatar.

[WM6]

460 mhz band this is very sensitive to gold .....................

.

In air.

Regretfully, gold is located mostly in soil, not in air.

[Davor]

There is a significant penetration of LW into ground. Perhaps 460kHz would also work. As far as I know the idea is not new.

[WM6]

There is a significant penetration of LW into ground. Perhaps 460kHz would also work. As far as I know the idea is not new.

Yes, but rajesh is talking about MHz.

[Davor]

Ah! I see.

[rajesh]

new detector

Yes, but rajesh is talking about MHz.

hi wm6 actually there are a possibility The high power pulsed transistor part number
ILD0506EL350 is designed for P-Band systems operating
at 480-610 MHz. Operating at a pulse width of 15ms with
a duty factor of 33%, this push-pull MOSFET device
supplies a minimum of 350 watts of peak pulse power
across the instantaneous operating bandwidth of 480-610
MHz. Fabricated with all gold metal contact, wire bonding
and package for maximum reliability. All devices are
100% screened for large signal RF parameters in the
broadband RF test fixture across the entire specified
operating bandwidth with no variable or external tuning.

[Davor]

Errr... but why? You'd surely need some serious permit for such operation, and the existing services will not be too happy about it. I know, i dealt with a paging system (ERMES) ina 2m band that made too many services unhappy. Boy did I have trouble with EMC compliance, cavity filters and stuff. I invented a PSpice method of assembling filter batteries in a process. It was that bad.

There are other ways of finding gold.

True, 70cm is famous for good penetration into buildings, including wire mesh, but unless you transmit in a PMR band, and obey power restrictions there, your rig will surely be illegal, or you'll have to invent some creative way of licensing it.

[rajesh]

new detector

Errr... but why? You'd surely need some serious permit for such operation, and the existing services will not be too happy about it. I know, i dealt with a paging system (ERMES) ina 2m band that made too many services unhappy. Boy did I have trouble with EMC compliance, cavity filters and stuff. I invented a PSpice method of assembling filter batteries in a process. It was that bad.

There are other ways of finding gold.

True, 70cm is famous for good penetration into buildings, including wire mesh, but unless you transmit in a PMR band, and obey power restrictions there, your rig will surely be illegal, or you'll have to invent some creative way of licensing it.

hi dear not serious but surely
frequencies, gold would effect the operation of the AM receiver more than any other
metal than Iron. We did not pursue this any further. We did not use a coil head nor
a metal detector design. just a freak thing we noticed one day while working with
an AM radio. I mentioned taking it to a digital level. I almost think that "Fuzzy logic".
which is cheap if you know how to do it: could change this metal detecting into
a more accurate field. I truly believe that each metal has a signature of some sort
hidden within the disruption of EMF , like DNA. Fuzzy Logic allows people to
sort out signatures without having to know what the signature actually looks like.
I do believe that until more work is done, that 32 to 64 bit processors with stored
EPROM signatures of EMF reactions and comparisons to saw tooth wave form and
slope detection, including inductance and capacitance changes occurring during EMF
distortion is the most promising. Pulse detection has its place and seems to be
trying to retrieve more data from EMf returns, However, with pulse one also has
harmonic distortion and needs to watch out for false information returns.
AT this this time , I am using off the shelf big name brand 32 bit waveform analysis
detectors from well know metal detecting companies to find coins. I am not interested
in gold hunting. If you live near a big city, or the beach, gold rings maybe be your thing.

[Davor]

mujhe mAlUm nahin
You are confusing me with AM service in 70cm band. WHAT exact band did you notice this discrepancy? Multi-physics are not new, but AM service in 70cm band is not common.

[rajesh]

new detector

mujhe mAlUm nahin
You are confusing me with AM service in 70cm band. WHAT exact band did you notice this discrepancy? Multi-physics are not new, but AM service in 70cm band is not common.

mujhe sab maloom hai tum kya chahte ho com my place indore mp or delhi office....

[Davor]

(Carl is going to kill us)
javab to sirf kripaya - what made you use AM at 70cm with all other services using FM???
Are we talking 70cm at all? Or we mixed kHz with MHz?

[Pulse]

Hi friends,



thank you all, i am using freescale for todays. i want to make a digital pulse detector. Also, if we will make a vlf detector, we wil need a sinus osc. Could you give me some advice for mcu control sinus osc.

6666, yes I can write. I am using freescle and arm.

[Davor]

It is easy, especially if you do not need to tune frequency continually. You'll synthesize it using some even number of steps (NRZ). In such case you'll have a zero crossing a well defined one. You may also adjust granularity of steps in a way that they step at some nice phi values, say 7° etc. Thus you'll have no problem sampling Rx at proper times.
This approach generates harmonics, but who cares? They'll be nicely wiped out by the tank capacitance. Using only a few steps you can effectively reduce harmonics up to, say, 5th or 7th to zero by adjusting step values alone, and your drivers need not be in linear regime at all. And it will swing from rail to rail.

Using DDS is a possibility, but expensive one.