Funcube Dongles reset to 0MHz

Hi everyone,

we installed a new receiver station using CTT Sensor Station V3 and Funcube Dongles Pro+ with 150.1MHz antennas. Although the deployment.txt is updated to the correct frequency and I reflashed the FCD firmware following the steps in the guide, the FCD always reset back to 0MHz. It works in the beginning and in the Sensorgnome Interface the Devices show that they are tuned on 150.096MHz, but after some time (a few hours) at least some of the FCD reset back to 0MHz.

Does anyone have any ideas how to solve this problem?


Hi Daniel, how many FCDs do you have attached? It may be that there are too many FCDs causing devices to reset, at least that’s how I would interpret the “0Mhz”.

Hi Thorsten,
thanks for your answer!
Yes, I have quite a few (5 FCDs) and this is probably the problem. I’ve been now also in contact with CTT and apparently more than 3 FCD cause problems. So now I’m trying with only 3 FCD and will see tomorrow if this works.


Hi again,
I tried now with 3 FCD and over the night one of them dropped out again. I’m very confused that I can actually only have 2 FCD. That seems quite little, especially since I saw on the maps stations in the UK with CTT receiver and 4 FCD. Does anyone has any potential solution or idea why my FCD always drop out to 0MHz? I’d be super grateful for any suggestions what to do.
Secondly, I cannot see any data from my test tag, although it is propperly deployed on for much more than 24h in advance and it was for sure activated and sending signals. I was walking with it within the range of antennas where the FCD was working and not dropping out but when downloading the data through R I don’t have any detections of this test tag. The data is uploaded to motus and I waited more than 24h for the processing. Any ideas for this problem? Is it also related to the issue with the FCD dropping out?

Hi Daniel,

I’ll be very interested to hear how you get on testing with 3 FCD so please post results on here.

May I ask if David La Puma or someone else at CTT comment about the problems using more than 3 FCD with a SensorStation? This is concerning news as most of our installed 150 MHz SensorStation based receivers have 4 FCD, and in the next month I am deploying 5 more. For those receivers already in the field is there anyway to spot this problem other than visiting the receiver on site.

Kind regards.

Hi Ewan and Daniel (and others).

This has actually just been observed by a few others.

There isn’t a whole lot of detail available at the moment but we (Motus Central at Birds Canada) along with CTT, Thorsten, and a few others, have been discussing and testing this in the last week or so, and hope to have some solid information and recommendations shortly.

More soon.

I have a script that detects some of the FCD on SS issues and restarts the FCD plus augments the UI. This doesn’t increase the number of FCDs that can be supported but ensures that the ones plugged in work well. This script is not yet ready for wide distribution but it would be awesome to have some more people testing it. Requirements are an internet connected SSv3 with recent software and ready access. Best for SS you’re testing and keep an eye on. Contact me if interested. I will be submitting all this to CTT so they can decide whether to incorporate into their next release.


Thanks for helping with this, your single handed support for SensorGnomes and now SensorStations is amazing and very much appreciated.

I have CTT-V3023D1536C4 waiting for deployment and happy to use this as a test bed.

It’s offline at the moment but can be reactivated for testing from Monday next week. If you can let me have the patch before then I’ll get it installed and we can see what happens.

Again many thanks.

Hi Guys,

Thanks for the update, please let us know what you find out.

Are there any recommendations for SensorStations that will be deployed in the next month or so? As mentioned in earlier message we will 6 to deploy soon and those have 3 or 4 FCD in each receiver. Restricting these to only two FCD will seriously compromise the performance of the stations and won’t be easy to retrofit later.

Hi Thorsten and Ewan,

thanks for your messages!
I tested now again with 3FCD and it seems to work now without any problems of dropping out, however, the framerate decreased from 47.9/48 kHz with 2FCD to 38.3/48 kHz.
Interestingly, now that I have 3FCD again, I cannot see any detections in Live Known Tags in the Sensorgnome Interface, even though I can clearly see the pulses in the Live Pulses window. The only time the Live Known Tags window was working for me was when I had only 2FCD. Maybe just a coincidence…


If the frame rate is more than 1-2kHz lower than 48kHz the tag detections are affected. Lower frame (sample) rate means that buffers with samples are dropped on the floor and that means that pulses that are in those dropped frames will be missed. Depending on the pattern of dropped frames it may be impossible to detect any pulses.

Has the frame rate issue been resolved yet? We have noticed the same issues with >2 FCD, and plan many more stations with >2FCD.

I was also wondering if the issue with the Live Known Tags disappearing has been resolved, and does that impact real detections in the field or not? We also have a station where the live pulses work but not the Live Known Tags with 3 FCDs.

Hi everyone, please see David La Puma’s post about a fix for this that CTT just released.

1 Like