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IQ4DF - CRBR Activity Page (experiences report) page 1 of 2 - goto page #2 20 Feb 2006 - CRBR headquarter, 7m antenna radiating lobe evaluation @ 10Ghz using the Sun as a source.
Click on the above images to enlarge them. The above radiating patterns were taken @ 10GHz using the 7m antenna with the Sun being the signal source. The idea came from the fact the we noticed some slight distortion in the radiating lobe, a thing that we liked to evaluate. The third graph on the right it is very sharp at the top, this sharpness it is untrue and it is just the result of the interpolation of the samples taken; this third graph is basically the 90° offset representation of graphs 1 and 2. The samples were taken automatically by a noise sampler designed and created by Gianni IW4BYP. We scanned a 4 x 4 degrees area but the above presented graphs are cut to a 2 x 2 degrees size. Some mechanical works were then done on the cassegrain reflector as well as on the feeder to better shape the radiating lobe. Thanks to Vico I4ZAU for the sampling job (and everything else) and Sergio IK2MMB for the interpolated graphs. These are the manufacturers specifications of our 7m antenna (Scientific Atlanta)
15 April 2006 - Rubidium standard installed in the shack (by Riccardo IK4PNJ) The funny thing about this rubidium standard is that it was found and bought by Riccardo IK4PNJ on a flea market being sold as a quartz oven (hihi !!!) . Well, it now made it to IQ4DF and it serves wonderfully as frequency reference even if at present the 10GHz LO it is not yet locked to it (it will be). It has a 20MHz sine output which it has been divided by 2 and filtered (to restore the sine shape) to serve us properly. It is a 'cheap' unit that normally sells for 6500 US$ circa, so its performance is not ranked 'super' but it is certainly still a rubidium osc. The box in pictures 4 and 5 is the 10GHz LO with its adj. pot. See here some pictures of the IK4PNJ arrangement, Thanks Ricky. Click on the images to enlarge them.
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