KeyFob has better radio reception than BLE112

Can you be more specific on what HW you run SensorTag and KeyFob. It supposes to be antenna difference.

I run the same program on BLE112 and KeyFob and there is a difference between radio.
So i guess a trace antenna is better than SMD antenna ?

Hi Drave,

As YK states, Antenna design plays an important role in RX sensitivity. Did you run the same test using different SW on the same keyfob?

Best wishes

Hello, i meant the TX power of the two modules BLE112 and KeyFob, they are different with the same Software, the KeyFob has more power, like 10-20dBm.

Hello Drave, 

The performance of PCB antenna has been observed to be slightly better than ceramic antenna, but difference of 10 dB in output power is not expected.

How are you measuring the output power? Good way to isolate if the antenna is causing output power to drop is to do a conducted power measurement using a spectrum analyzer.

It is possible that antenna is not tuned to the desired frequency band causing drop in output power on BLE112. If this is the case, it can be tuned using discreet components just before antenna. Also, it is important to follow layout guidelines provided by the module manufacturer including providing good ground plane where needed and sufficient clearance in ground plane under the antenna. 

Regards,

Yes you right, i found a BLE112 Development Board and compared it to the KeyFob and the TX Power of KeyFob is slightly better than the BLE112 Dev. Board. But then i compared all three Boards, KeyFob, BLE112 Dev and my own PCB. My own PCB was like 15dB worse. That's really strange, because i have no ground plane at all, i just have traces. But wait, on the other PCB side, at the area where the antenna is, there are some pads, maybe this this is the bad influence, mhm...Ok in the next PCB the anetenna are will be completely clear.

The SW examples of BLE stack use 0 dbm as TX power by default. If you don't change it on different tests, the TX power difference must be caused by different antenna designs.