Transmission distance problem

Hardware
1

Hi,

I tested the transmission distance of my Standalone Industrial Vibration Temperature Sensor (PR55-67A) with the wireless USB modem (PR55-17A). I found that no signal was received by the USB modem when the distance exceeded 80 meters. However, i observed the “RS” indicator light inside the modem did blink during the test.

80m is significantly less than the claimed transmission range of 2 miles (3218.688 meters).

Below is the test environment (Outdoor, no obstacle)

Distance 80m(1)
Distance 80m(1)1046×846 87 KB

Google 地圖

Could you please help me identify the issue? How can I increase the transmission distance? I have attached my node-red flow (JSON) for your review. Thanks.
Node red flows 2_9_2024.json (21.0 KB)

Best regards,
Howard

2

are there any objects around the vibration sensor ?

3

IMG-20240902-WA0004
IMG-20240902-WA00042000×1500 365 KB

Please refer to the picture above. I attached the sensors to a lamppost at the pier, and the area around the sensors is quite open. Thanks.

Best regards,
Howard

4

can you point the sensor towards the receiver?
are there an cell phone tower near by ?

5

Alright, I will position the sensors so that the top faces the receiver and conduct the experiment again.

Based on what you’ve mentioned, it seems that the direction of the sensors does affect the signal transmission power. Please explain more about this. And could you please provide the antenna pattern for the Standalone Industrial Vibration Temperature Sensor (PR55-67A)?

Additionally, the nearby cell phone towers are shown below, with the closest one to the pier located approximately 500 meters away.

cell phone tower nearby
cell phone tower nearby706×645 165 KB

Thank you.

6

the antenna is on the top of the sensor and its recommended to keep the sensor vertical to earth or 45’.

Put a USB modem with external antenna near by the sensor and just power it on.

7

Thank you for the information; it has helped me understand better. Would you mind sharing the antenna pattern for the Standalone Industrial Vibration Temperature Sensor (PR55-67A)?

Additionally, could you please review my Node-RED flow? I would appreciate any feedback or suggestions you may have.

8

Hi @howardcairs I’ve tested your flow locally, and it works well.

test2
test2781×278 24.5 KB

You have successfully included sensor data and correctly added battery percentage and RSSI. The file name is based on the timestamp;

test1

However, you might consider formatting this timestamp to convert it to a human-readable date to make it easier to identify the file’s date.

While it is just one option, overall, it is effective.

Let us know if you have any questions.
Thank you,
Eduardo M.

9

Thank you for your suggestion, Eduardo.

Howard