ANT Forum

Hello, I have the Garmin USB Stick and the GSC10 cadence and speed sensor, and the HRM Garmin strap. All goes well in the display simulator until I open two channels, one with HRM and the other with GSC10. At first they work, but after some seconds, the HRM stop to receive, and the checkbox "Receive" is self unchecked. I would like to ask if it can be a problem of the USB stick, if, although there are 8 channels, I can only have one opened at the same time, or if it is defective, or, if you would know there is some problem with the display simulator software source. Thanks for any help.      

Hi,

In your case it seems that the channel frequencies of the HRM and the Bike Speed and Cadence Sensor (both approximately 4.06 Hz) are overlapping each other resulting in continuous channel collisions.This results in the HRM display sensor closing its channel after too many RxFails.

The USB stick is designed to maintain 8 separate channels, so handling 2 should not be a problem.If you could provide some more information about your test results that would help me understand how and why the simulator is failing.

When you say the simulators work at first, does that mean that both Simulators are receiving information from their respective sensors, or are they performing channel searches.
Does the HRM Display ANT Channel Output show any Channel Collision or RxFAil event messages before it stops receiving?
If not, what event messages does the HRM Display ANT Channel Output show before it stops receiving?


Two important documents you should consider reading when dealing with multiple channels are:

- AN15 Multi-Channel Design Considerations (specifically Section 4.5 on Searching and low/high priority searches)
- AN11 ANT Channel Search and Background Scanning Channel

Both can be found in the ANT Applications Notes Section of the Documents Download page.

Regards,

Usama

     

Hello, thanks for your help and sorry because the problem is only that I was pedalling backwards to the stick.

I thought the problem arose when the two channels were open because it happened only pedalling and my trainer position at my room is backwards to the stick. I guess the solution will be just an extension usb cable.

Anyway the memo reported repeated failures and at the end was: Repeated failures. Searching....

And even when it works there are two or three event channel collision and some failures, but they don't affect the overall reading.

Thank you and regards,
skr.      

Yes, this can be a common problem with wireless networks on the 2.4 GHz frequency band as that frequency is easily absorbed by the human body.

The best solution would be change the orientation of your body and the sensor relative to the receiver, so your body is not directly blocking the path between them.