Openspot4 not receiving C4FM

darren2589

This is a strange one.
My openspot 4 pro does not seem to be receiving any C4FM from my FTM400 or FT70D.
It's transmitting fine, as I can hear stations on reflectors fine.
The strange thing (with exact same frequency / DN mode / Simplex) is that it works with the 991A, and FTM-500.

When I try transmitting into it from the 400 or 70D, there's no usual flashing LED, just the pulsing green one. (I have checked my frequencies and mode on the openspot)
Im using all the same memories I've used for years, nothings has changed on the radio side.
I've tried doing a factory reset on the openspot (press hold wifi for 30 seconds, which did reset it) but not fix.

It will receive fine on DMR also.
Hardware release 1, Firmware 61

Edit. upgraded to V66beta and still same.
Tried C4FM half deviation too.

thanks M0DUB

HA2NON

Make sure the Half Deviation setting is turned off in your transceiver, and use plain C4FM modem mode on the openSPOT. If there's no such setting in your transceiver's menu, or you can't turn it off, then you have to use C4FM Half Deviation modem mode. In this case, run C4FM Half Deviation AutoCal, or manually adjust the RX offset on the Modem page in +-100Hz steps from -500Hz to +500Hz for the lowest BER. You can verify settings using the openSPOT's built-in local echo service.

If AutoCal does not work for you then the RX offset between the transceiver and the openSPOT is greater than 500Hz. What you can do is to switch frequencies on the openSPOT, but keep the transceiver's frequency. For example, if the transceiver is on 433.900MHz, then test by setting the openSPOT to the following frequencies:

433900500 Hz
433900600 Hz
433900700 Hz
...
433899500 Hz
433899400 Hz
433899300 Hz
...

You can use the built-in local echo service to test your own voice.

If the openSPOT's status LED does not blink green when you press PTT even after adjusting the RX offset, then try setting the deviation DU menu to 177, the default value is 150.