"You do realize that 2 pf is a HUGE amount of capacitance at 2.4 GHz, right?"
"Also, does your PC board have a ground plane on the backside??"
Unfortunately the ground plane is unconnected.I would say so, see attached image.
Lol.Unfortunately the ground plane is unconnected.
All three devices I demonstrate in the video below have a continuously emitted RF signal but I am not sure if cell phones transmit the same way.
As I mentioned, seems that the detector works at 2.4GHz.
As I mentioned, seems that the detector works at 2.4GHz. I see that you didn't remove the 50 ohms at the input. That will improve a bit the sensitivity of the detector. You can replace that resistor with a 0.1uH RF choke (the same as in the 2nd schematic in link that I posted above).
Cell phones in 2G mode transmit bursts with duty cycles varying between 1/8 and 4/8. In 3G and 4G modes there is a continuous transmission during a call.
In cell phones, their output power vary from -50dBm to about +24dBm in 3G and 4G and up to +33dBm in 2G. So the power is not constant during a call as in your cordless phone or RC transmitter.
As I do have a CNC machine I will go all out SMD on this one and see what results I get. I have ordered a few MGA-86563 MMICs to use as the front-end LNA.But this layout is far from ideal. By shrinking the layout and using proper RF layout technique, the detector could be much more sensitive.
I see the "ground plane" problem much more important than the SMD/THM problem.As I do have a CNC machine I will go all out SMD on this one and see what results I get.
From an RF point of view, that is a complete disaster. You really need to understand the concept of wavelengths then closely look at the tracks around the RF front end. The track carrying signal from the antenna is almost as long as the antenna itself.
This Antenna came off of a GPRS Shield v1.0 running a SIM900 module and works on the 850/950/1800/1900 bands. 850Mhz to 1900Mhz seems pretty "wide" to me. Additionally, it works "exceptionally well" at 40Mhz and 466Mhz. Similar to how an AM wavelength is in the range of 300 meters but you can still hear it on your radio without a 150m or a 75m antenna attached to your house I would have thought I would pick up at least something THAT close to the transmitting source.Also consider the antenna is hardly wide bandwidth and you are asking for a detector covering at least 27MHz to 2,400MHz.
A full schematic of your board would help with diagnosis.
Brian.
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