[Speedy68]

Hello

Can i see the RF efficiency on WeatherDuino Pro 2 ?
I have the Problem with outside Temp and Hum. The RX only 3 or 4 Times read new Data at day.

But i am not sure, i have problem in Transmission.

http://sternenfreunde-eichsfeld.de/wetter/trends.htm

Regards

[danner]

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[danner]

Here are some obligatory software pattern plots of the antenna.

The first two are in free space.




And this is the pattern mounted 6 feet up over real ground.

[AllyCat]

I now know that the two transmitters were too close in frequency and that is what caused the severe dropout in RF efficiency from TX0.

Hi,

I don't understand that comment, nor how you are getting such "clear" spectrum analyser results in your other thread.

The whole point of the 433 MHz ISM band is that transmitters can (or even should) use the same frequency and the different "messages" (data packets) are discriminated by time sharing.  Each transmitter should only transmit the radio signal for a very short period of time, which is why I'm surprised that you are getting such a detailed spectrum graph.

Have you modified the Weatherduino boards (or program) in some way so that they are transmitting continuously?

Cheers,  Alan.

[danner]

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[danner]

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[werk_ag]

The relay transmit antenna is mounted only a few inches from the main receive antenna so the receive antenna is getting the RF from TX0, TX1 and the relay transmitter. With a transmit antenna only a few inches away from a receive antenna that's a hostile RF environment.

Just my too cents on this:

When the Pro2 PLUS relay a signal, the receiver is disabled, or by other words it is not listen for any incoming signal. So having the two antennas close to each other should not be a problem.

Turning off the relay function recovered some RF efficiency from TX0, so there has to be some interaction/interference. Separating the antennas recovered even more RF efficiency from TX0.

This may happen, but perhaps by other reasons. Everything we do takes time to execute, disabling the relay function, allows the main receiver to be a little more time listening for incoming signals.

And if you watch closely you can see when there are transmissions from TX1 and TX0 that the relay transmitter does not transmit. I'm guessing that means the receiver didn't receive either TX1 or TX0 at that specific point in time. Does that make sense?

Yes, makes sense. The relay only transmits, after it receives a valid data packet from any of the TX units.

There is also another thing I don't clearly understood... You have referred somewhere that you had changed a transmitter module because its frequency its on top of the other TX unit. My understand on this, is that the best situation is exactly when all the transmitters are transmitting in a frequency very close or top of each other. Collision will ever happen, no matter if the frequency of each transmitter is on top or not. One thing already observed is that the receiver will get more datapackets when the frequency of each TX is closer to each other.

Currently I think I should never had implemented that thing, I call "RF Efficiency", mainly because its usefulness, it's to be seen in a completely different way, than it is seen.
Trying to get 100% or 90% "RF Efficiency" is like searching for the "Holly Graal"
And yes, the more TX units, the less the "RF Efficiency" shown for each one. The idea is reach a good balance between them, having two or three at 90% its almost impossible. Having two units, each other running at around 60 to 70% ensures a reliable operation of the whole system.

Another little bit... perhaps it helps to look for the problem from another point of view. Some times the problem is not having a week signal, is having a too strong signal. Those modules are able to give an output of around 25mW, think of it. Recently one of our Test / Developers (meteoestarreja) as managed to receive a signal from one of these modules, 2Km away (open field) from the transmitter.

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[danner]

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[danner]

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[werk_ag]

Dan, please doesn't understand my words as something "against" you or "against" anything you are doing or writing, is was greatly appreciated, and anyone is free to express its opinions and observations.

What I wrote was exactly with the same sense: expressing my observations along the time.

You can find on the forum pictures of some constructions, that are using two TX units side by side even sharing the same enclosure, and they possibly are transmitting more signals than your units, as some have the soil / leaf interface and the solar / UV interface too.

I'm not an RF experts, but fortunately I have a friend which also makes part of the Test /Developers team (usually he doesn't participate in the forum) that is an expert on this matter, so we also know where and when some problems can occur,  and mostly of the times the solution is so simple as playing with the antenna positions, other may be more complex and can pass to power the different TX modules with different voltages (always the idea is making that the signals reach the receiver almost with the same power). The higher the voltage the higher the transmitting power (also higher the drift, from the announced frequency).

One more time, please don't misunderstand me. My English is not the best, some times I take more than an hour just to try to write a single answer, trying that it will be minimally understandable.

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