Guidelines for the observations

Is the system ok?
The first step before starting the observations is to check if the receiving equipment is ok and to calibrate the strip chart:

• Let the receiver and the calibrator warm-up for few minutes.
• Make sure that the receiver AGC is defeated.
• Disconnect the antenna cable from the receiver input and replace it with a 50 ohm resistor. Start Radio-SkyPipe, the plot shows the internal noise generated by the receiver.
• Re-connect the cable (and the antenna) there should be a rise in the noise level. This noise is the background noise.
• Disconnect the cable from the receiver and insert the noise calibrator. Check that the receiver does not saturate when the noise temperature generated by the calibrator is increased. If there is saturation then decrease the receiver's RF gain and/or the soundcard recording level.
• Now that the system has been calibrated run the Get-average-for-view function of Radio-SkyPipe for each calibration step and note the values for later use. Note also the value with the antenna cable replaced by the 50 ohm resistor.

This picture shows the calibration steps as recorded by Radio-SkyPipe. The values on the Y-axis are in arbitrary units, these values can be translated into noise temperatures using the Equation feature of Radio-SkyPipe Pro.
Have a look at the Jim Brown's article in the Radio Jove newsletter(June, 2005) on how to calibrate SkyPipe to plot the display in degrees kelvin.

My RF-2020 calibrator generates the following noise temperatures (kelvin degrees): 38,000 75,000 150,000 302,000 603,000 1,200,000.
The base line corresponds to the room temperature (a 50ohm resistor is connected to the receiver's input) followed by the 6 steps of the calibrator. There are about 3 dB between two steps.

It can happen that after having adjusted the receiver's RF gain and/or the recording level of the soundcard we use the receiver for other purposes so that when starting another monitoring session the levels are not optimized anymore for Sun/Jupiter observations and must be re-adjusted.
For that we use the function of Radio-SkyPipe that performs the averaging on live data and this is the procedure:

• In the Radio-SkyPipe Options (Stripchart tab) there is a "Key Press averaging period" parameter, it specifies the time during which the incoming data are averaged.
• Replace the antenna cable with the 50 ohm resistor (or insert the calibrator) and start Radio-SkyPipe
• Press ALT key and hold it down while pressing the "1" key (if incoming data are on channel 1 or "2" if on channel 2 and so on) on the number pad (Num Lock should be on). Release the keys
• At the end of the configurable number of seconds specified in the Options, the average data value will be displayed in the status bar.
• Compare this value with the one noted when calibrating the system. Even with a well adjusted system do not expect to get exactly the same values, a difference of a few percent is acceptable.
• If the difference is more important slightly increase/decrease the RF gain and start again the procedure.

• Connect the cable to the receiver, disconnect the antenna from the other end of the cable and insert there the calibrator. Set it at, let's say, 151,000 kelvin, check in the Radio-SkyPipe plot what's the corresponding noise value.
• Disconnect the calibrator from the far end of the cable, disconnect the cable from the receiver and replace it with the calibrator (set at the same noise temperature as above), now the plot should show a higher value, this because in the preceding measurement the cable introduced an attenuation.
• We can now measure this attenuation: Insert the step attenuator between the receiver and the calibrator.
• Do not change the noise temperature of the calibrator.Play with the attenuator switches until the plot shows the same value as when the calibrator was connected to the far end of the cable.
• The loss in the cable (dB) is equal to the dB introduced by the attenuator.

The values were averaged for each step using the Get-average-for-view function of Radio-SkyPipe , this gave:

• Calibrator connected at the far end of the cable : Y = 3821
• Calibrator connected at the receiver input (attenuator not inserted) : Y = 3930
• With 1 dB attenuation: Y=3677
• With 2 dB attenuation: Y=3498
• With 3 dB attenuation: Y=3328

The above procedure does not take into account the losses in the connectors.Use high quality connectors, in particular the connector(s) to the antenna, they can undergo degradation because of moisture. Use N-connectors that are water-proof.
If you use F-connectors check regularly that the body of the connector makes a good contact with the shield of the coax. This is very importand because in many cases the degradation of the received signal is caused by lossy connectors.

And now?
Now the system is ready for monitoring the Solar and Jovian storms.

• Have a look at the Jupiter Storms Predictions . Don't forget that the occurrence of a storm is a question of probability. Even though a Jovian storm is predicted, it could happen that nothing is heard. The Jupiter storm emission mechanism is not yet completely understood.

There are no predictions for the Solar storms. But you can find a wealth of sites dedicated to the Sun activity, start with NOAA Space Environment Center and Solar Terrestrial Activity Report.
• Real time spectrograms covering the decametric range are available on the internet. In Europe you can access the Nancay's Decametric Radio Observatory.

Using the Spectrograph software you can access the spectrograms of the University of Florida Radio Observatory (UFRO) and the Windward Community College Radio Observatory (WCCRO).
Looking at these spectrograms during the observations is very useful in establishing if the spikes we see on the chart and the sound we hear are really Jovian/Solar bursts.
• Use Radio-Sky Pipe Pro to plot the data and to record the audio. The Radio-SkyPipe audio recording feature is very useful to exactly correlate the plotted data with the audio. No need to have a tape recorder and complicated procedure to correlate the recorded audio to the plot.

Audio samples of Jovian and Solar storms are available in the UFRO site and in the RadioJove archive.
• The computer clock does not keep a precise time over a long period, it needs to be synchronized with an atomic time standard before starting the observations. Many sites can be accessed (NIST for example) for that. Radio-SkyPipe Pro has a feature to automatically synchronize the clock through internet.

Clock synchronization is needed when comparing the results with other observatories. It is then possible to see if there is a difference in time when a burst is received, let's say, in Europe and in the US East Coast.
• Start Radio-SkyPipe and calibrate the chart. The reference noise temperature steps will allow to measure the temperature of the bursts that will (can) be received.
• And now we have to wait, drinking a cup of coffee to stay awake when waiting for a Jovian storm in the middle of the night !
• The worst enemies during an observing session are interference and power-line buzz. Interferences can be from shortwave stations,TV sets in the neighbourhood,dimmers and so on. Filters can help in some cases.

The power-line buzz can be very strong and destroy a session, this noise is wideband and is caused by arching and lossy insulators in the power-lines.

• Carefully check (by listening to the recorded audio) that the "signals" in the chart are Solar or Jovian bursts .
• Using the calibrated noise temperatures recorded when starting the chart evaluate the temperature of the bursts and using the FluxDensity program compute their flux densities.
• The material collected during the session (strip charts, audio files) can now be up-loaded to the RadioJove archive for the benefit of all the other observers.

Before up-loading a strip chart we put in its Data File Info all informations that can be useful to the other observers (type of receiver and antenna, noise temperatures of the calibrator, time when a burst occurred, noise temperature and flux density of the bursts).