Equipment Tips for Proper Set Up
Here are some tips to getting your equipment set up and operating successfully. Radio Shack part numbers are provided since most folks have access to their stores.
1. One way to confirm that your receiver and antenna are operating properly is to note that there is a big change in audio level when the antenna is connected to the receiver. To check this, disconnect your antenna and set the receiver volume control to the 3 o’clock position. You may hear a weak hiss in the headphones or over the speaker if you have an external amplified speaker. Now connect the antenna (it will likely be very noisy as you are actually connecting the antenna). There should be a very noticeable increase in the noise level with the antenna connected.
2. If you are using a 12 volt lantern battery (R.S. 230-0007 or Ever Ready 732) to power your receiver be sure to check the voltage after 8 hours of use (and every two hours thereafter). Use a voltmeter (R.S. 22-408) or multimeter (R.S. 220-0218) while the radio is operating – just put the leads across the battery terminals. If the battery voltage drops below 10.5 volts the radio may not operate properly. A well-regulated 120 volts AC to 12 volts DC power supply such as the Jameco (www.jameco.com) part number 162996 (about $12 including shipping if paid online) can be used in place of the battery. Given the price and relatively short lifetime of lantern batteries this may be a good option. Some power modules that plug directly into the wall (known affectionately as "wall warts") may work - but these power supplies are often poorly regulated and can cause severe hum problems when used with the JOVE receiver.
3. Audio cables can be a source of trouble. While the two audio connectors on the Jove receiver can drive stereo headphones it is usually a good idea to use mono cables when going from the receiver to an audio amplifier, tape recorder or computer. In particular, stay away from mixing mono and stereo cables and adapters. The receiver audio jacks accept 3.5mm (1/8”) phone plugs. The Radio Shack 277-1008C amplified speaker also takes a 3.5mm phone plug. You can use the Radio Shack 42-2420A six foot 1/8” mono shielded cable to connect the receiver to the audio amplifier.
4. The Radio Shack CTR117 cassette recorder is recommended as the most affordable unit with an ALC ON/OFF switch. Actually the switch is labeled IN/OUT. Select OUT to turn the ALC off. This recorder has two inputs labeled MIC and AUX, each with a 1/8” phone jack. Either input should work – the MIC input is more sensitive. This is a mono recorder with a LED signal strength indicator that goes from –15 to +3 VU (volume units). With the Jove receiver volume control set to the 12 o’clock position adjust the record level to give an indication around –12 VU on the background noise for Jupiter observations and a bit lower for solar observations. A Radio Shack 42-2420A cable can be used to connect the receiver to this tape recorder. When you first set up to record it’s a good idea to record a minute or so of background noise – then play it back to confirm that everything is working and that levels are properly set. Before starting an observing run with a new tape be sure to label the tape on both sides so that you can identify it later. Reset the tape turns counter to 000 when you insert the tape. Your written log of the observation should note events by the time they occur and by the turns count number.
5. Radio-SkyPipe is the recommended software to generate a computer strip chart record of the signals that you receive. If you have an Internet connection then Radio-SkyPipe also supports chat with other observers and will even let you view the signals being received at other observatories. The details of Radio-SkyPipe operation are beyond the scope of this document. You should plan on spending an hour or so reading the Radio-SkyPipe help files prior to using the program. In order to use Radio-SkyPipe with the Jove receiver you must connect the receiver audio output to either the LINE or MIC input of your computer sound card. Your computer has a software audio control panel (often found under Programs>Accessories>Entertainment>Volume Control). There are in fact two control panels – one for recording and one for playback. With Radio-SkyPipe in Stand Alone mode and the Chart running, use the record panel to select the receiver audio source (LINE or MIC input) and adjust the software volume control to obtain a suitable trace level. A good background level is between 1000 and 2000, with a vertical scale of perhaps 5,000 or less depending on how much signal detail you want to see. The vertical scale is set using the StripChart tab under Radio-SkyPipe options. The maximum possible vertical scale value is 32,000 – but this would only be reached by the very strongest Solar bursts. It is important that you set your computer clock accurately as this is the source of timing for Radio-SkyPipe.
Radio-SkyPipe includes a file saving function that will automatically generate a file name based on the current date for you when you save a Radio-SkyPipe data file. It is recommended that you use the file name suggested by Radio-SkyPipe when you stop the stripchart. The file naming format is described in the Radio-SkyPipe help files.
6. You may want to play a pre-recorded cassette tape into your computer sound card and generate a Radio-SkyPipe strip chart. To do so connect an audio cable from the speaker (or earphone) output of the recorder to the sound card input. Adjust levels using the recorder volume control and your computer’s software volume control. When you playback your recording into Radio-SkyPipe, the time marks on the strip chart will be incorrect because Radio-SkyPipe is using the current time on your computer’s internal clock, not the actual time of your observation. In order for Radio-SkyPipe to input the correct time stamps to the strip chart, you can either change the internal clock on your computer before you start the Radio-SkyPipe program (this allows Radio-SkyPipe to read the new time) or you can upgrade to the Radio-SkyPipe Pro version, available at www.radiosky.com, which allows you to edit the start time without resetting the computer clock. In either case you must know the exact start time of your tape to synchronize it with the displayed time on the stripchart.
We have suggested several Radio Shack parts – this is not an endorsement of these specific Radio Shack items over any other – but is provided as a guide to the least expensive readily available parts that should be adequate. Equivalent or better parts by Radio Shack or other suppliers may be used.
Now for a few more specifics about the hardware and software that you may want for a more advanced installation.
Audio Amplifier – A small battery powered audio amplifier like the Radio Shack 277-1008C can be connected to the audio output of the Jove receiver and although it is far from a HI-FI amplifier, it will let your whole observing team listen in to the action.
Tape Recorder – A cassette tape recorder can be used to record the audio output from your Jove receiver. Later you can playback the tape and amaze your friends. You can also play it into a soundcard-equipped computer running Radio-SkyPipe and graph your signals. Unfortunately most cassette recorders are equipped with an automatic level control (ALC) circuit that cannot be turned off. If you try to record Jovian or Solar bursts with a tape recorder with the ALC on the recorder may severely distort the noise bursts – sometimes making them almost inaudible on playback. The Radio Shack CTR117 is probably the most affordable cassette recorder currently available that has an ALC ON/OFF switch. It can be operated either from batteries or the AC lines.
A HI-FI VCR can be used to record audio signals from the Jove receiver. Of course a VCR usually requires 115 volts AC so it may not be suitable for “remote” operation. However, if your observing site has 115 volts available then a HI- FI VCR may be a good choice. There is no ALC switch on a VCR – but these recorders don’t seem to distort the noise bursts. Most are stereo so you could put a timing signal on the second track. The tape is inexpensive and you can make long recordings. It is usually not necessary to provide a video signal (even though it is a video recorder) – just connect the Jove receiver audio to the VCR audio line input and hit record. One drawback is that there is usually no signal level meter (or LED display) to help you set levels, so you should experiment (before you begin observing) with different volume settings on the Jove receiver. By the way – its important to use a HI-FI VCR – if it doesn’t say HI-FI then you may get disappointing results.
A Computer and Radio-SkyPipe software – Using a computer running Radio-SkyPipe, you can graph the strength of the radio noise bursts that you receive. Radio-SkyPipe runs on Win95/98/Me, and NT/2000/Xp operating systems. It will also run on a Mac OS 9.1/9.2 (newer versions not tested) equipped with a Virtual PC emulator. If you are making observations from a remote site with no AC power, then a battery operated laptop computer (with a sound card) is the solution. You could also tape record signals in the field and play them later into a computer running Radio-SkyPipe. An Internet connection is a real plus. Radio-SkyPipe allows you to send and receive charts in real-time over the Internet. With this feature, you can compare your observations and exchange comments about them via an integrated chat window. This is immensely helpful when trying to establish whether what you are seeing on your chart is really Jupiter or the Sun and not local interference. While a high-speed Internet connection is nice, Radio-SkyPipe software can send and receive data and chat over a 56K dial-up modem.