noise on 166.380

[Glenn Pollock]

I am still fighting noise on 166.380. I know direction of the noise but
can not identify the source.     I understand that my CTT V3 uses sensor
gnome software to set frequency of the funcube pro pulse sdr.   The fun
cube website suggest to use their FCD software along with SDR Sharp.   
I wonder what software sensorgnome is using to control the Funcube. 
What mode is set to decode, upper or lower side band or AM.  If I knew
that I may be able to determine were my noise id originating from.   
Thanks Glenn


Glenn Pollock   6736 laurel Omaha Ne 68104 402 203 5789 Hitchcock nature
Center Creston Iowa. station number 542
--

[Thorsten von Eicken]

(reply copied from slack:)

I'm not very familiar with the FCD firmwares. What I can tell you is:

• the FCD should be running firmware 2.20.03 sampling at 48kHz
• it outputs I/Q samples as a USB audio device
• the SG uses its own software to analyze the I/Q samples and detect Lotek tag pulses
• that software is implemented as a plugin to vamp-alsa-host, which is an audio processing software
• the std fcd app to manage FCDs should be available (presumably /usr/bin/fcd)

Thorsten von Eicken, Santa Barbara, CA, Sensorgnome software dev.

[Glenn Pollock]

On 2/22/2023 6:30 PM, 'Thorsten von Eicken' via Motus Wildlife Tracking System wrote:

(reply copied from slack:)

I'm not very familiar with the FCD firmwares. What I can tell you is:

Thanks you answered my question by these two lines

• it outputs I/Q samples as a USB audio device
• the SG uses its own software to analyze the I/Q samples and detect Lotek tag pulses

Lot of software written by people much smarter than me to make Motus work.  I am just an RF hardware ,antennas, receivers, coax, propagation  and such.    Now if I just can find the source of my noise and then how to stop it. Thanks Glenn

[Thorsten von Eicken]

On Wednesday, February 22, 2023 at 6:08:56 PM UTC-8 poll...@gmail.com wrote:

I am just an RF hardware ,antennas, receivers, coax, propagation  and such. 

I'm not sure I'm interpreting your sentence correctly, but it'f you're into antennas and such... I've added a couple of SAW filters to my Digikey shopping cart:

https://www.digikey.com/en/products/detail/tst/TA0168A/16907020

https://www.digikey.com/en/products/detail/rfmi/SF2170D/12178623

These are pretty narrow 8Mhz respectively 20Mhz filters around 166Mhz. They are just SMD components, so "some assembly required" onto a very simple PCB like

Dunno whether that's up your alley and also dunno whether that ends up helping at all...

Another idea: you're using the old Sensorgnome software, doesn't that have a way to record a WAV file from the FCD? I seem to remember that there's something in the web interface. You could record that and then look on your PC in an audio visualization app whether you can make out the interferer. You're only getting ~30kHz of bandwidth IIUC so you will not see interference that is near enough to desensitize the FCD but far enough not to show up in that recording. Otherwise I'm afraid you need to hook up your laptop to the FCD and run one of the SDR apps that can display the typical spectrum analyzer visualizations to get a sense for which frequencies the interference is on and perhaps what it is. I don't have experience with doing that but perhaps someone else can chime in? (It may be easier to use Laptop + cheap RTLSDR attached to your antenna to do this.)

[Glenn Pollock]

On 2/22/2023 10:51 PM, 'Thorsten von Eicken' via Motus Wildlife Tracking

System wrote:
> On Wednesday, February 22, 2023 at 6:08:56 PM UTC-8 poll...@gmail.com
> wrote:
> I am just an RF hardware ,antennas, receivers, coax, propagation  and
> such.
>

Thanks for information.  I have a spare Funcube SDR and using my lap top
with SDR Console software using it as a spectrum analyzer. So can  see
the noise just do not know the source. The highest level of noise is on
one antenna so have a and idea of what direction the noise is coming
from.   I installed a narrow band low insertions loss .5 db tuned 
cavity filter and had no effect on the noise. The noise causing the
problem must be on 166.380 MHZ since the filter had no effect.   I have
been able to detect four birds so the noise is not so high that receiver
is still functioning. I just like to see it working at its best. The
receiver  system is CTT with V3 software.

I am working with Iowa DNR were two of their CTT receivers  on
166.380MHZ the noise is so high to render them useless.     I do know
that there is natural background noise.

I have been an amateur radio operator for over 50 years and worked as
Biomedical engineering specializing in medical telemetry.

When it warm up my fiend and I will be using a hand help 166.380 MHZ
yagi and receiver and do some hunt for noise source. Now if I do find
the source stopping it may be a bigger problem.

No CTT 434 MHZ 32 bit FSK has no problems.

This has been a fund project for me and another of my ham friends. Keeps
us out of the bars but climbing antenna tower might be a problem.

Thanks Glenn