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Guidelines for the observations


The following is just the check-list we use. Informations on how to run a decametric radio observatory can be found in the NASA Radio JOVE Project site and in the Dick Flagg's book Listening to Jupiter

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:


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.

calibrator



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:

How lossy is the antenna coax cable?
For each type of cable (Belden 8241, RG-213,...) the manufacturer specifies the attenuation (dB) per 100 meters or 100 ft but after some time this attenuation can increase because of the exposure at the outside weather conditions. It is worth measuring the real attenuation some months after the installation and replace the cable if the loss is higher than expected.
By means of the calibrator and of a precise attenuator we can estimate the attenuation introduced by the cable. The following is the resulting plot for 25 meters of RG-213 coax
coax

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

The outcome is that our cable introduces an attenuation of less than 1 dB (as from the cable specifications the attenuation for 25 meters of RG-213 is 0.64 dB)

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.

Post processing
The observing session came to its end. Now the received data must be analyzed. HAPPY MONITORING !

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