How to detect the transmitter frequency ?

"Rodo"

Non contact systems typically use X- band microwaves - ie 10 GHz.

Could it be ultrasonic instead of RF ?

In both the above, you ain't gonna see it on a scope or hear it on any scanner.

....... Phil

Assuming that the Tx power is in the milliwatt range, just connect the antenna to the input of a sensitive frequency counter. No antenna lead? Get a smallish coil of a few tens of uH and place it in close proximity to the Tx module. Connect the coil leads to the counter input. You might have to play with position and orientation of the coil, but it should give you a solid count somewhere around the module.

Something like this:

"DaveM"

...... Phil

"DaveM" wrote in news:yYqdnYkkBaf-k2_YnZ2dnUVZ snipped-for-privacy@comcast.com:

Or use a spectrum analyzer and antenna. Optoelectronics used to make low-cost receiver/counters for this sort of thing;are they still in business?

I'm sorry I didn't make it clear that the Tx/Rx modules are not the one reading the water level. That system is an ultrasonic meter. The Tx/Rx modules are connected to the output of the ultrasonic meter and transmit the info to the base unit. Someone suggested a BK Precision counter. This sounds like a pretty good option. I think the model 106 will need to be because I'm almost certain the info is digital (on-off stuff)

Thanks

"Rodo"

" We have a Tx/Rx system at work that measures water level in a huge tank. "

Top posting D*****ad !

A transmission must be * 100% continuous * to use a counter obtain the frequency.

A radio scanner is still your best, low cost bet.

...... Phil

ISTR there's a way to use a grid dip meter to get close.

This may not be an engineering issue. If you cannot guarantee that you can reverse-engineer the mfgr's specs _including safety margins_, whose ass is on the line if the system goes t*ts-up and the tank fails; just yours, or the owner's?

I know it sounds like a fun problem, but the phrase "CYA, remove and replace" exists for a reason.

Mark L. Fergerson

It's not his fault you misunderstood him. The rest of us didn't have that problem.

You are wrong. The B&K 106 only needs a 250uS burst to measure.

Yeah right. Stick with audio Phil.

"Anthony Fremont = Asinine Cunt "

Now, go shove you pointy, totally f*****ad head back up you slimy arse.

........ Phil

NO, it's entirely your problem for jumping to the wrong conclusion and thinking it's the OP's fault.

Well, most didn't.

That isn't all of them. At any rate, it only has to last for a maximum of two gate times on "the vast majority of counters".

_I_ just gave you one. If you need a confirmation, look it up.

I guess you cut the rest out and put it up on your bathroom mirror.

Can't you be more clever than that? If you don't like being treated like a dick, stop acting like one.

"Anthony Fremont = Asinine ASD F***ed Cunt "

Enjoy.

...... Phil

For God's sake phil, are you _physically_ paralyzed too?

In case you don't believe that, here's the datasheet:

"Anthony Fremont = Asinine ASD F***ed Cunt "

Shame if the pulses are shorter than 250uS.

The OP already has a radio scanner with no such limitation.

Piss off - you vile, autistic donkey f***er.

....... Phil

I never said it was. I suggested the cheap one first. I'm sure it will fit his needs just fine. I referenced the other one just to set you straight. Different problems, different tools.

What kind of baud rate do you think they're using Phil? Maybe it's DSS?

Fat lot of good that will do him with transmissions

Come back again when you need some more learnin'

Yes. AT the low end of their line, the "Cub" covers

Ed

If it's manufactured or sold in the US, the law requires an FCC ID plate affixed to the device somewhere. Check this number against the FCC Database.

Other governments have similar requirements. Even if not in the USA, you may find this model was sold there, and may still luck out.

Also, in the US, if you don't have a special FCC license for them, it's a pretty good bet they operate in one of the ISM bands (Industrial, Scientific and Medical, of which there are many.)

A listing of ISM frequencies can be found here:

Otherwise, a spectrum analyzer should give you the answer, regardless of the modulation used.

-mpm