Spectrum of RFID tag

The spectrum of a group of 2.4GHz RFID tag , it is supposed to be frequency hopping but the spectrum doesn't looks like that. It's center frequency is around 2.48GHz and bandwidth approximately 1MHz.

Spectrum analyzer upgrade

The first step of going to 2.4GHz development is to look for a way to see the 2.4GHz signal. After checking in online store, I picked some cheap used mixer that have a frequency range of 300-4300MHz. Today the mixers just arrived, I tried to hook it up with the signal generator in the LO port, tuned to 1.9GHz and plug in an antenna to the RF port, attempting to receive a nearby the 2.40-2.48GHz bluetooth signal. As seen from the screen of spectrum analyzer, the signal is downconverted to 500MHz~580MHz. By doing this downconversion, the old 1.8GHz spectrum analyzer is successfully upgraded to a 2.4GHz, in a very low cost. Not a bad start.

Gilbert cell active mixer board

Just got the Gilbert cell active mixer board, it looks smaller than expected.

Can this mixer works? can this goes to 27MHz?  if so, it can replace the expensive and power hunger ring-diode mixer. I don't know, need to test.

Upgrading 1.8GHz spectrum analyzer

Just brought this, may be I can convert my 1.8GHz spectrum analyzer to cover 2.4GHz with this and signal generator as LO.

2.4G RFID

Meanwhile we are working on an 2.4G active RFID project, a colleague told me this : "The RFID is using 13MHz"

me: it's 2.4GHz

colleague:  "I use a wire loop and checked on oscilloscope, it's 13MHz same as RFID card, the MEGAHERTZ it using is also 13MHz"

me: you cannot not use an oscilloscope to see a 2.4GHz stuff...

A double conversion, PLL 433MHz receiver

The first 433MHz receiver of mine, double convert from 433MHz to 10.7MHz then 455KHz, the phase noise of PLL dominate the noise floor. took sometime to improve the phase noise of PLL but still the dominating factor. No demodulation, just have a series of LED indicate the RSSI.