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RTL-SDR Discussion • Re: Creating Program that Spits Out Messages When Correct Signals are Received.

dangeruss wrote:
Mon Dec 16, 2019 7:05 pm
I'm looking to create a trigger program similar to a garage door except when a device @ 433mhz sends a specific code the sdr / software program checks the signal against a library of pre-generated signals and outputs a message depending on the code sent.

I have 5 rf devices with 3 buttons each, the buttons generates a unique 433mhz code, I'd like to pre-program each signal into a program (say gnuradio) each button will trigger a message to be displayed on a screen.

I have little programming experience but i'm willing to learn. Any ideas would be much appreciated.

Thanks in advance!
Hi buddy, at present on which you are working as of now? ( Practice)

Regards,
Noel Smith

Statistics: Posted by ponef — Mon Jan 27, 2020 6:06 pm


KerberosSDR • Re: Spacing Calc Help

k2gc wrote:
Mon Jan 20, 2020 5:26 pm
Ok, I think I was on the right track.

But, what is the number I put into the Android software then? is that also my .7? or would that be .33?

Also, I am not sure I spaced my antennas correct. Good news, I have adjustments (hard to see in the pic, but I can move the antennas in and out in 1" increments)

I have them spaced based on the red line, but I am assuming now, I need to set them to the yellow line? If that is the case, i am not sure I made my mounting set up big enough.

BUT. I suspect I can put them at the furthest point, and back my calculation back the other way to get the spacing factor I used?

antenna array.jpg

Nice setup :-) i have also two Array build, one my self and the black one by PA8W.

Image
and
Image

Statistics: Posted by theodeurne — Mon Jan 27, 2020 3:22 pm


KerberosSDR • Re: Tracking

ckoval7 wrote:
Mon Jan 27, 2020 11:26 am
how does the gain setting work? please compare to a standard radio for me just to make it easy. I need to understand which way gives me a stronger/weaker signal overall. If I change the gain, do I need to re-sync??
This adjusts the sensitivity of the radio. Think of it as turning the RF Gain knob on an HF radio. I find 25.4 dB to be a good number. It strikes the right balance between sensitivity and managing the noise floor. Chances are, if you can't get the signal at a decent SNR at this gain setting, it's too weak to DF anyway.
Unfortunately, because of the way the RTL-SDR works, you'll have to re-sync every time you change gain or frequency. Honestly though, set it to 25.4 and leave it be.
So to paraphrase - higher the db gain in this setting, will allow more signal in, lower gain lets less in?
ckoval7 wrote:
Mon Jan 27, 2020 11:26 am
Which algorithm would be the best? from what I can tell MUSIC makes it so I have to reverse the antenna, while when using Bartlett, I had more accurate results
I've always had the best luck with MUSIC. I've never had an issue with having to reverse the antenna. Try DFing a NOAA weather station or local repeater that you know the location of to double check your accuracy.
Knowing what I learned last night about the bandwidth, fir and decimation settings (missed the first time around) I am going to 'start all over' and try again. I did use a NOAA station for my initial attempt, and that is when we discovered everything backwards. Our result put us close to 1/2 mile away from the actual transmitter. I am going to try the same station again today with my new knowledge and hope for the best!

ckoval7 wrote:
Mon Jan 27, 2020 11:26 am
While tracking (in the android app) what do the breadcrumb dot colors represent?
Signal strength
I had figured this was the case, but wanted confirmation
ckoval7 wrote:
Mon Jan 27, 2020 11:26 am
Where on the android device, can I find the log files (the csv) I would like to pull them off for potentially further manipulation
Downloads/KerberosSDR if I remember correctly.
Found it! it was actually Download/KerberosSDR - but glad I have it now.

Because our jammer happens during a net where I may find others on the input freq, I have been starting/stopping the tracking software based on my opinion of the signals listening. (ie, is it only the jammer, or am I hearing 2 people). Because of that, we actually ran 2 android apps against the Kerberos, with 2 people operating the stop/start button. a difference of opinion means a bunch.

Nice thing is, now I can merge the files and see what it also looks like as a complete data set.

I also anticipate using that merged file on one device during the next session, as well as start a clean file on another.

This guy has been plaguing us for months now, and its getting quite old. We are much closer, and hopefully after I refine my skills more this week, next Sunday will go even better for us. Especially, as a second Kerberos will also be in the mix.

Statistics: Posted by k2gc — Mon Jan 27, 2020 3:14 pm


RTL-SDR Discussion • Re: Feature request — FM Broadcast signal analysis

ronald001 wrote:
Fri Jan 03, 2020 1:52 pm
There are already some good ( FM Broadcast ) signal analysis meters like: IF spectrum, MPX Spectrum and Audio spectrum.


It would be really helpful and cool if the following tools could be added, for further analysis of FM broadcast signals


- Audio Deviation ( in Khz )
- Stokkemask measurement
- MPX power
- Multipath meter
- Pilot levels meters ( Stereo / RDS )

Curious if more people would like these kind of features?


Thanks, keep up the good work.....
Hi buddy, I completely agree with this. Even I would love to get this add ons.

Regards,
Noel Smith

Statistics: Posted by ponef — Mon Jan 27, 2020 3:10 pm


KerberosSDR • Re: Tracking

how does the gain setting work? please compare to a standard radio for me just to make it easy. I need to understand which way gives me a stronger/weaker signal overall. If I change the gain, do I need to re-sync??
This adjusts the sensitivity of the radio. Think of it as turning the RF Gain knob on an HF radio. I find 25.4 dB to be a good number. It strikes the right balance between sensitivity and managing the noise floor. Chances are, if you can't get the signal at a decent SNR at this gain setting, it's too weak to DF anyway.
Unfortunately, because of the way the RTL-SDR works, you'll have to re-sync every time you change gain or frequency. Honestly though, set it to 25.4 and leave it be.
Which algorithm would be the best? from what I can tell MUSIC makes it so I have to reverse the antenna, while when using Bartlett, I had more accurate results
I've always had the best luck with MUSIC. I've never had an issue with having to reverse the antenna. Try DFing a NOAA weather station or local repeater that you know the location of to double check your accuracy.
While tracking (in the android app) what do the breadcrumb dot colors represent?
Signal strength
Where on the android device, can I find the log files (the csv) I would like to pull them off for potentially further manipulation
Downloads/KerberosSDR if I remember correctly.

Statistics: Posted by ckoval7 — Mon Jan 27, 2020 11:26 am


KerberosSDR • Re: Problems starting processing

Hi again,

So - I did not get around to the actual rtl_eeprom command as I expected it to work - hint - it didnt hehe, sorry for the long wait! rtl_test works just fine, but rtl_eeprom doesnt play along:

CODE:

# rtl_eeprom -d 1 -g realtek_oemFound 1 device(s):  0:  Generic RTL2832UUsing device 1: Failed to open rtlsdr device #1.
Not sure how to proceed with this? :-) Thank you so much so far for the help!

Statistics: Posted by cowboymonkey — Mon Jan 27, 2020 10:00 am


KerberosSDR • Re: Spacing Calc Help

Oh - i see the note in the startup guide saying it was changed in the latest version.... Oops.

Statistics: Posted by k2gc — Mon Jan 27, 2020 5:54 am


KerberosSDR • Re: Spacing Calc Help

After watching a couple of the videos, i need to clarify.

My yellow line - that measurement is what I put in for the spacing factor???

I got the impression it would be the .33?

I worry I have the wrong # entered, and that is part of my issue getting an accurate track.

Statistics: Posted by k2gc — Mon Jan 27, 2020 5:48 am


KerberosSDR • Tracking

Ok, so I purchased my Kerberos, because we are trying to track down a local jammer who keeps messing with our net on sunday nights.

I am having 'so-so' luck so far with tracking (been working with a fixed station) and i have a couple questions.
  • how does the gain setting work? please compare to a standard radio for me just to make it easy. I need to understand which way gives me a stronger/weaker signal overall. If I change the gain, do I need to re-sync??
  • Which algorithm would be the best? from what I can tell MUSIC makes it so I have to reverse the antenna, while when using Bartlett, I had more accurate results
  • While tracking (in the android app) what do the breadcrumb dot colors represent?
  • Where on the android device, can I find the log files (the csv) I would like to pull them off for potentially further manipulation

Statistics: Posted by k2gc — Mon Jan 27, 2020 4:02 am


RTL-SDR Discussion • Re: Finding a Weather Balloon

I'm getting your intentions and it looks pretty cool.
You could build a multi element yagi antenna cut for your APRS frequency. The more the elements, the more directional it would be.
I've built several yagi's that work on 2 meters all the way up to wifi frequencies. Used a simple fiberglass pole for the boom you use to mark property boundaries, driveway edges in the winter. And the elements made of things like 10 gauge romex to brass tubing you get from the hardware and crafts store. There are a few yagi calculators freely available on the 'net to help design one.
Of course after building one to test using an sdr receiver you check if it works first. Then fire up the APRS transmitter and start checking the range and how directional it is. It would be a bear to locate the transmitter with one antenna. Better with 2, and of course with triangulation the best with 3. Perhaps tackle a few lessons on the field trip spree.
I didn't dig real deep of the data logging done with your device. Certainly if the data were stored onboard, retrieving it in the field would take a pc and all the stuff needed.
The balloon will burst at a particular height. Weather stations using radiosondes pump in a finite amount of helium, hydrogen in them for a definite ascent per minute.
I'd think that for you if you didn't want to retrieve the device a bazillion miles away, you would pump the balloon up pretty tight for a fast ascent but low altitude burst. Those balloons are extremely flexible for a purpose.
Another thing to help find it would be an 'if found please contact' tag and streamers that that would spool off from a roll hooked to little army men parachutes. Remember, there's no perceived wind when a balloon goes up. Once it starts dropping under gravity, look out!

Statistics: Posted by Arlo — Mon Jan 27, 2020 1:18 am


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