I have never looked inside the AMB transponders. The only photos I could find were for the RC4, and it uses an MSP430 processor. The photos are here:

https://apps.fcc.gov/oetcf/eas/repor...id='NXYRC3'

I searched the FCC site for the number printed on the old transponders, "NXYAMBGP2", but came up with nothing.

If you send me the links for the photos of the older AMB transponder via PM, I'll post them.

P.S. That's a lot of parts in the RC4!

I sent you a PM with the direct links to the FCC data.

I do not know anything about the RC4 ID formats... sorry.

Looking at the FCC data, it appears that they're using the standard 7 digit numbers they've always used. However, looking at the internal photos, and the new microcontroller, I'm guessing that the packet payload was significantly changed. It won't be easy to duplicate...

I'm not at all interested in the new data format, so that's no big deal.

Thanks for the links. Here's the link for the devices marked "NXYAMBGP2":

http://apps.fcc.gov/oetcf/eas/report...'NXYAMBGP2'

There's a whole lot of extra active devices in this one too, other than the PIC microprocessor.

EDIT: It looks like a 5 MHz resonator or crystal, so there's no way the PIC12C671 is generating the carrier by twiddling its pins.

What kind of resonators are those? They look like fuses...

Yes, that's an interesting package. And the RC4 has a metal can that looks like it's either a crystal or a complete oscillator module.

looks like a 5 year old soldered that AMB...

Here's a quick update on the code compression. I've done 20 numbers so far, and it definitely looks like the PIC12F683 will hold at least 32.

For the moment, I'll simply step to the next selection when the jumper block is present on power-up.

My own efforts at hand-soldering surface mount components are quite entertaining! That's the reason I'm using through-hole components on this design, at least for the moment. My last RC project, a dynamic timing module for use with ESCs that don't have the feature, was surface-mount, and it was a real challenge for my shaky hands.

You are probably looking at a prototype; these are usually hand-soldered. The only thing that would be hand-soldered on production units would be the power wires.

The test results show that the RC4 radiated emissions were just 2.9 dB below the limits at 560.5 MHz. That's a bit too close for comfort!

Any idea where that frequency component would originate? not a square wave harmonic surely? would be the 56th harmonic. Unfortunately I know less about this than I would like.

I might be able to talk my way into some time in an area setup for vector network analysis, where I know they have a very nice spectrum analyser.

I do service repairs for portable recorders/mixers...

There's nothing like soldering LEDs/resistors 2x the size of salt under a 10x microscope

I could do better on that AMD freehand without any magnification...


I repaired this not to long ago...
This is a $7k mixer/recorder that someone plugged into 48v(18v rated) and left it fry
more pics
http://s272.photobucket.com/albums/j...und%20devices/

My earliest posts showed a strong second harmonic component in the output field of the older AMB transponder, most likely due to driving the tank single-ended. The RC4 probably also uses a single-ended drive. This would give plenty of even-order harmonics.

At higher frequencies, even short conductors become excellent antennae!

My head hurts

Do you think this would be improved by reducing the slew rate on the driver? If I am not mistaken the maximum frequency component (ideal) would be 6.25MHz. so even a 2nd order LPF would have no issue at all killing off the higher frequency component. or am I missing something entirely?

Thanks