Simultaneously decoding multiple devices Txing at different frequencies?

[Dag B]

So I am very green regarding rtlsdr and may ask very green questions. But I am also rapidly approaching "old fart" status and can take some verbal abuse...

Here goes:

I have 3 devices transmitting :

1. Efergy Optical (62),  ~433.55 MHz, every ~30 seconds

2. WT450 (33), ~433.73 MHz, every ~60 seconds

3. WT450 (33), ~433.95 MHz, every ~60 seconds. 

The signals are clearly visible in gqrx with 2.4Msps samplerate.

To decode these signals in rtl_433, I must tune the frequency to be pretty much exactly at the Tx frequency. Which may be reasonable given the default sample rate of 250 ksps. Too far from the tuned frequency, and aliasing will kill the signal. But exact tuning for the individual frequencies and default samplerate decodes all three devices nicely. Individually, that is. Only one at the time.

If I tune for 433.55 and increase the samplerate to 1048 ksps, I no longer get any decoded messages from the first device. O...k?

Tuning for 433.73 and setting the sample rate to 1048 ksps enables me to receive the 433.55 transmitter again. Only. And possibly with slightly worse detection than if tuning for 433.55 and default 250ksps samplerate. (missing occasional transmissions). The other two transmitters are not seen at all. Not even the one transmitting at 433.73

Tuning for 433.73 and setting the sample rate to 2.4 Msps still enables me to receive the 433.55 transmitter, device #1. But nothing else.

Tuning for 433.73 and keeping sample rate at the default again enables decoding of device #2

Tuning for 433.85, samplerate 2.4Msps and -R 33 detects nothing

Tuning for 433.85, default samplerate and -R 33 detects ... both the WT450s. Yay! Not #1, though.

Tuning for 433.80 and 300 ksps, -R 33 and -R62 only detects device #2.

Tuning for 433.80 and 960 ksps, -R 33 and -R62 only detects device #1.

*sigh*

I find these results slightly confusing. I must be missing something, I think.

Is it possible to detect and decode all my three devices simultaneously from the same process and hw?

Anyone care to enlighten me? 

Dag B

[Benjamin Larsson]

On 08/31/2016 10:32 PM, Dag B wrote:
>
> So I am very green regarding rtlsdr and may ask very green questions.
> But I am also rapidly approaching "old fart" status and can take some
> verbal abuse...
> Here goes:
>

[...]

> Is it possible to detect and decode all my three devices simultaneously
> from the same process and hw?
>
> Anyone care to enlighten me?
>
> Dag B

What you do should work fine, but tuning to the exact dc frequency for
one transmitter might mess things up. And a sample rate of 1024 should
be able to cover all signals. Lets just assume that the level is what is
messing things up. Try adding -l 0 and try again.

MvH
Benjamin Larsson

[Dag B]

Not at first try, no.

 dagb@ds81 ~ $ rtl_433 -f 433850000 -R 62 -R 33 -s 960000 -l 0

Registering protocol "WT450"

Registering protocol "Efergy Optical"

Found 1 device(s):

  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM

Found Rafael Micro R820T tuner

[R82XX] PLL not locked!

Sample rate set to 960000.

Bit detection level set to 0.

Tuner gain set to Auto.

Reading samples in async mode...

Tuned to 433850000 Hz.

2016-08-31 23:02:16 :   Efergy Optical

        Power kW:        2.160 kW

2016-08-31 23:03:16 :   Efergy Optical

        Power kW:        2.160 kW

Must try more tomorrow. Other suggestions very much welcome.

Dag B

[Dag B]

On Wednesday, August 31, 2016 at 10:59:45 PM UTC+2, Dag B wrote:

On Wednesday, August 31, 2016 at 10:51:12 PM UTC+2, Benjamin Larsson wrote:

On 08/31/2016 10:32 PM, Dag B wrote:
> Here goes:
>

[...]

> Is it possible to detect and decode all my three devices simultaneously
> from the same process and hw?
>
> Anyone care to enlighten me?
>
> Dag B

What you do should work fine, but tuning to the exact dc frequency for
one transmitter might mess things up.

[...] 

Try adding -l 0 and try again.

MvH
Benjamin Larsson

Not at first try, no.

[....]

 

Must try more tomorrow. Other suggestions very much welcome.

Dag B

 

Kept it running overnight with 

rtl_433 -f 433850000 -R 62 -R 33 -s 960000 -l 0

Now getting device #1 perfectly(?) and #2 (most transmissions).

I wonder:

How long after receiving a strong transmission is the automatic gain function impacted by it?

Dag B

[Ian A]

Try a few different gain setting. AGC essentially just means maximum gain in this case which is often not what you want.

[Tommy Vestermark]

Hi,

Increasing the sample rate has some side-effects beyond just increasing the reception bandwidth. Besides potentially letting unwanted nearby signals through, the AM demodulation and pulse detection will also become more noise sensitive. Currently all baseband filters, level estimators, spurious suppression etc. are fixed to the sample rate. This allows detection of faster signals by increasing sample rate, but will at the same time make detection of slower signals more noise sensitive.

The maximum distance between your three signals is appx. 400 kHz, so I would recommend to try with a sample rate of 500 kHz and set the tuning frequency in the middle => 433.75 MHz. Due to the I/Q sampling, the detection bandwidth will be equal to half the sample rate at each side of the tuning frequency (433.50 MHz to 434.00 MHz).

The "gain" of the automatic level detection is cleared after each reception, but will decrease sensitivity (raise the threshold) if the base noise level is high. You may get some insight into reception quality by enabling the pulse analyzer '-A'. If the reception is noisy, you will get a higher number of shorter pulses than expected.

Tommy

[Adrian Stevenson]

Thanks for the posting DagB, I was struggling with trying to do this.  Its also nice to see someone else is benefiting from my Efergy Optical work.

 rtl_433 -d 1 -f 433850000 -s 960000 -R 62 -R 19 -F csv

time,model,id,battery,channel,temperature_C,humidity,power

Registering protocol "Nexus Temperature & Humidity Sensor"

Registering protocol "Efergy Optical"

Found 2 device(s):

  0:  Realtek, RTL2838UHIDIR, SN: 00000001

  1:  Realtek, RTL2838UHIDIR, SN: 00000002

Using device 1: Generic RTL2832U OEM

Found Rafael Micro R820T tuner

[R82XX] PLL not locked!

Sample rate set to 960000.

Bit detection level set to 8000.

Tuner gain set to Auto.

Reading samples in async mode...

Tuned to 433850000 Hz.

2016-10-16 10:33:19,Efergy Optical,,,,,,0.112

2016-10-16 10:33:39,Nexus Temperature/Humidity,74,LOW,2,11.900,81,

2016-10-16 10:33:49,Efergy Optical,,,,,,0.112

Regards

Adrian

[martin swanepoel]

Did you manage to find a solution?

Thanks.

[Robert Terzi]

On 11/18/2016 1:17 AM, martin swanepoel wrote:

Did you manage to find a solution?

The bandwidth that is covered is a function of the sample rate.  So you can cover more bandwidth with a higher sample rate.  However, there are some issues that I don't recall the details of when using a sample rate other than the default.   I seem to think it affects FSK decoding and I think the Efergy might be one of the few FSK devices.  Check for messages from Tommy Vestermark in this and/or related threads.

Also, how sure are you of the center frequencies your devices are actually transmitting on?   Unless your RTL-SDR has a temperature controlled oscillator, the frequency error will change as the dongle heats up.    When you make measurements, make sure the dongle has been running, not just plugged in, for at least a few minutes.

It's also possible that decreasing noise, a better antenna and/or location might help if it isn't the actual distance in frequency between the devices.

--Rob

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[martin swanepoel]

As soon as i move it from 4335000 it's gone. Doesn't matter what sampling rate I use. I actually use it to monitor my weather sensors so it's running all the time. 

No success:

rtl_433 -f 433600000 -s 300000 -R 36 -R 12

Registering protocol [1] "Oregon Scientific Weather Sensor"

Registering protocol [2] "Efergy e2 classic"

Registered 2 out of 70 device decoding protcols

Found 1 device(s):

  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM

Detached kernel driver

Found Rafael Micro R820T tuner

[R82XX] PLL not locked!

Sample rate set to 300000.

Bit detection level set to 0 (Auto).

Tuner gain set to Auto.

Reading samples in async mode...

Tuned to 433600000 Hz.

^CSignal caught, exiting!

Success:

rtl_433 -f 433500000 -R 36 -R 12

Registering protocol [1] "Oregon Scientific Weather Sensor"

Registering protocol [2] "Efergy e2 classic"

Registered 2 out of 70 device decoding protcols

Found 1 device(s):

  0:  Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM

Detached kernel driver

Found Rafael Micro R820T tuner

Exact sample rate is: 250000.000414 Hz

[R82XX] PLL not locked!

Sample rate set to 250000.

Bit detection level set to 0 (Auto).

Tuner gain set to Auto.

Reading samples in async mode...

Tuned to 433500000 Hz.

Power consumption at 110 volts: 691.42 watts

Power consumption at 115 volts: 722.85 watts

Power consumption at 120 volts: 754.28 watts

Power consumption at 220 volts: 1382.84 watts

Power consumption at 230 volts: 1445.70 watts

Power consumption at 240 volts: 1508.55 watts

On Wednesday, August 31, 2016 at 10:32:11 PM UTC+2, Dag B wrote:

[TheLaGmAn]

4 years later i find this thread and im having the same issue. trying to use acurite and efergy signals in one rtl_433, were you able to find a solution?

[Benjamin Larsson]

Den 2020-05-15 kl. 02:05, skrev TheLaGmAn:
> 4 years later i find this thread and im having the same issue. trying to
> use acurite and efergy signals in one rtl_433, were you able to find a
> solution?
>

You have to play with the frequency, gain and sample rate. There might
be a combination that works with all devices.

MvH
Benjamin Larsson