150Khz Antenna question

Sounds like one of those "Boost your gas mileage" scams:

o 13.8V sounds like an automotive operating environment. o Fluid density less than that of watr sounds like gasoline (0.784 gm/cm^3). o Low electrical conductivity also sounds like gasoline. o Circular fluid pipe of 1/4" to 1/2" sounds like a fuel line.

Sounds like one of those "Boost your gas mileage" scams:

o 13.8V sounds like an automotive operating environment. o Fluid density less than that of watr sounds like gasoline (0.784 gm/cm^3). o Low electrical conductivity also sounds like gasoline. o Circular fluid pipe of 1/4" to 1/2" sounds like a fuel line.

I did not say it :))

I can not argue the project validity, I am just trying to answer to my customer request the best I can.

I must admit I also do not think it's a viable gadget, and yes it sound like a scam.

Bye Jacques

In that case, anything will work. Safest would be to have it do nothing - which is what it would be doing anyways.

RL

oduce

h to

it?

There have been some good articles about this in rags like "RF Design" over the years. There are those who say, reasonably, that it's more complicated than the simple formula you gave in a posting further down the thread. I don't generally have to worry about it much, so I'd have to go scrounging through my archives to dig out articles. As noted, a tiny box like that dealing with a nearby sample is reasonably called a "transducer" but probably not an "antenna" in any sense I'd use.

Cheers, Tom

ike

If it is to go in a car there are very strict regulations ensuring that it won't interfere with other systems. I wouldn't touch it with a bargepole. I hope you you have plenty of professional liability insurance.

Leon

ANY change will void the car's warranty. Read the fine print.

...Jim Thompson

And knowingly generating an RF field on a frequency that is not endorsed ISM can be construed as gross negligence. Which PLI may not cover. Just assume Jacques designs it, it goes into lots of cars and then those cars that are operated in large cities trigger all kinds of RF problems. To be honest, I would not touch that project with a ten-foot pole either. For various reasons.

Thank very much for all your recommendations.

I must admit I was not very hot on that project. I nearly refuse to take it at first, but now I think I will simply stop working on it. I did told the customer that this project can be a problem with many regulations, but he ask that I look at it any way.

I have many other projects to work on, and this one did not appear to worth much more attention.

I any way, all the help you give me here may be use in other situation, it's never bad to look around, it often rise many good ideas.

Bye Jacques

Look at the Atmel U2270. (RFID frontend) It is made for 125 KHz, but it is not hard to alter.

I could reasonably easy get 100V p/p in a simple aircoil / capacitor resonant series circuit, this from 5V. Boosting the signal would not be that hard. As you will not be doing RFID (I guess) the Q can be a lot higher, and as such the peak voltage.

Alter? And then a huge green van stops in front of the building, a few guys in battle dress hop off, some commotion is heard from the stairways, sirens can be heard coming closer ...

Then you know the circuit works adequately :-)

Be careful concerning small fluid pipes, especially flat ones. Fluids tend to "stick" on the walls and thus create turburlent flow meaning a higher than expected resistance and lower than exected flow rate.

For emitting a few mW of 150kHz? What sort of place do you live at?

robert

Jacques mentioned this in his first post: "150Khz square wave of 140Vp-p approx."

I would not do that.

in battle dress hop off, some commotion is heard

approx."

I wanted to say "Unless he has a big antenna 150KHz isn't going far even at this power level and it is unlikely anyone would even notice at 150KHz."

Than I noticed it says square wave. At least some hams would probably take notice, might cause some radio/tv interference very locally.

The ERO 'European table of frequency allocations and utilisations covering the frequency range 9 kHz to 275 GHz', available from

Probably wouldn't want to interfere with one of them!

Chris

Considering the presumed application, the results might be construed as evidence that the device is working as intended!