We did it. After 2? 3? years of having other things happening in life get in the way, we assembled the Radio Jove RJ1.1 Receiver Kit, a 20.1MHz radio receiver. It took us about 4 hours to wire and solder together and then about 2 hours to put it into the enclosure and test it. There were over 100 components to solder in and now I can see why the price tag for an assembled receiver is so much more than the kit!
Some of the harder parts of assembly were the identification of some of the smaller parts, with very tiny markings on them, like the picofarad capacitors, the inductors and some of the germanium diodes.
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Luckily they started us off easy, with the soldering of 10 jumper wires first. Followed by the resistors and later on moving into the semiconductors. After a few hours and dozens of connections, Kim was soldering like a pro. When the last solder connection was done, we both inspected the board and touched up any joint that looked suspect.
A short lunch break followed by the assembly of the enclosure. Actually that was supposed to be first but we missed that instruction 🙂
The calibration sequence consisted of finding the 20.0 MHz oscillator signal in the powered speakers by adjusting a variable inductor L5 I believe it was, after a ten minute warmup. We noticed during that warmup, some variance in the tone. After that we, in sequence, adjusted another variable inductor (with a plastic tool to avoid interference), and two variable capacitors. Within a short time we had the strongest signal and powered everything off, cut the jumper wire that supplied power to the test oscillator and reassembled the enclosure.
The last step is to install all of this out in the observatory, cut an RG-6 coax cable to a 1/2 wavelength increment to reach out to the antenna connection, fire it up and wait for Jupiter!
Hmm.. too bad Jupiter is in conjunction with the Sun. Oh well, we can also put up another dipole antenna and study the Sun!
We tried to think back a couple of summers ago when we were watching Mark assemble the North York Astronomical Association radio jove receiver.
All in all it went very well and the next step will be installing it in the observatory and connecting it to the antenna we put up last summer.
Some notes from the assembly manual:
Radio signals from Jupiter are very weak – they produce less than a millionth of a volt (1 microvolt, 1v) at the antenna terminals of the receiver. These weak radio frequency (RF) signals must be amplified by the receiver and converted to audio signals of sufficient strength to drive headphones or a loudspeaker. The receiver also serves as a narrow filter, tuned to a specific frequency to hear Jupiter while at the same time blocking out strong earth based radio stations on other frequencies. The receiver and its accompanying antenna are designed to operate over a narrow range of short-wave frequencies centered on 20.1 MHz (megahertz). This frequency range is optimum for hearing Jupiter signals.
The temperatures have been cool… very cool… so cool that a lot of our plants are behind already and getting farther back. Temperatures remain well below average and the little heater in the uninsulated greenhouse is going full tilt most of the time. Peas went into the ground last weekend as did some beets, but nothing has shown yet. We did get 41mm of rain last weekend in one day alone and 25mm more yesterday. At least the ground is not frozen anymore and letting a lot of it sink in.
