Welcome to Issue #2 of the Radio-Sky Journal Copyright 2000 by Radio-Sky Publishing All rights reserved. Contents: Announcing Radio-SkyPipe Solar Observing Notes ADC Project Amateur Tips Featured Site(s) Commentary ______________________________________________________ Radio-SkyPipe, an Internet Enabled Strip Chart, is Coming! Have you ever thought of putting your radiotelescope on the internet? I don't mean just pictures of your antenna and images of a couple of your prize strip charts, I mean real-time streaming of your telescope data! Perhaps you are a SETI buff or an HEP (High Energy Pulse) stalker. In that case, it would certainly be nice to correlate in real-time with another amateur, wouldn't it? The problem is that there have been no tools to do this. Web pages, by nature are mostly limited to sending a single text document and associated pictures upon request. I know, there is JAVA and Active-X and what-not now available, but where are the applications which would allow you to put them to use with your radiotelescope? I've go an answer for you. For the past few months I have been developing an internet-enabled strip chart application which will allow you to share your data in realtime with others. For now, lets call it, Radio-Sky Pipe. (You don't know what a struggle its been to find a good un-used name along this line.) In its present incarnation, RS-Pipe will accept sound card or digital input from the MAX187 based ADC featured in this issues project. You can operate in three modes; standalone, client, or server. As a standalone strip chart program, it has an excellent scrolling strip chart with basic editability. In client mode, you log on to the internet or your local area network and accept data from someone else who is using RS-Pipe in server mode. Chances are, unless you work at a university or have your own internet server, you do not have static IP address. That means that every time you log on to the internet, you are assigned a new temporary address for the duration of your session. This can be a problem if you want to serve your data out to others. How will they find you unless you call them up and tell them your address for the evening? The answer is an internet locator server or ILS. ILS is the means used by Microsoft's NetMeeting and other communications programs to achieve this little bit of magic. RS-Pipe has its own ILS which resides on the Radio-Sky Publishing website. When you select the server option from the RS-Pipe program, your IP address, a port number, and some information which you define about your observatory is automatically sent to the RS-Pipe ILS. From then on, anyone who opens RS-Pipe as a client will see your server in a drop-down list on their RS-Pipe window. A click on the server listing and a connection is made directly between the client and server RS-Pipe users. The data from the RS-Pipe server immediately begins streaming in the clients strip chart window where it can be logged if desired. That's it in a nutshell. Oh, I forgot to mention one thing. RS-Pipe will be absolutely FREE! At some point, (who knows when), I might offer a fancier version for a reasonable price, but for now, I simply want as many Beta Testers and users as I can get. Keep checking the website for announcement of the release date and the download itself. I expect to release a Beta version before the SARA conference in July. ______________________________________________________________________ Free Sidereal Clock There is a new piece of free software which you can download from the website. This is a simple clock which sits on your desktop and displays your local mean sidereal time. LMST is the time you use to keep track of celestial objects. Go to the website and you will find a link to the download page and more explanation. ______________________________________________________________________ Solar Observing Notes So far, this has been a less than spectacular sunspot 'peak' year. Nonetheless, moderate to good solar flares and associated radio bursts present some good observing possibilities. Here is a chance to get into radio astronomy with the simplest of equipment. Virtually any shortwave to UHF radio receiver and and antenna can be used to detect solar events. VLF detection of xray bursts may be accomplished by monitoring stations below 100 kHz and looking for a sudden enhancement followed by a gradual decline. The same signature, only in reversed intensity (sudden dip and slow recovery), can indicate a flare when monitoring in the shortwave bands. Shortwave to VHF emissions can be detected directly. Suitable antennas can be as simple as dipoles as they require no tracking and bursts are often quite strong. These radio burts may be categorized by a system developed in the 1950s by early radio astronomers. The following definitions are shortened versions of those found on the Culgoora site: Type I Short, narrow band events that usually occur in great numbers together with a broader band continuum. May last for hours or days. Type II Slow drift from high to low frequencies. Often show fundamental and second harmonic frequency structure. Type III Rapidly drift from high to low frequencies. May exhibit harmonics. Often accompany the flash phase of large flares. Type IV Flare-related broad-band continua. Type V Broad-band continua which may appear with III bursts.Last 1 to 2 minutes, with duration increasing as frequency decreases. If you haven't looked at the Culgoora catalog of spectrographs, you must. There are examples of the spectra of these flare types. It is fascinating. http://www.ips.oz.au/culgoora/spectro/old_cat.html ______________________________________________________________________ Project Time! Over the next 20 to 30 years (just kidding) I will be presenting enough project modules for you to build a simple radiotelescope from scratch. The idea is to work backward through the stages from the output to the antenna. There is good reason to do it this way. From the very beginning, we will be able to check the stability and measure the some of the electrical characteristics of the telescope via the computer. Beginning builders, will be able to gain some skills at soldering and wiring before you attempt the more difficult stages. In the end you will have a telescope that operates in or near the lower part of the two meter ham band (144 Mhz). Why this frequency? - You can elect to use a commercial receiver and still gain from other parts of the project. - Commercial antennas are available for those who don't want to build or may already have one. - Most celestial signals are strong at 144 Mhz. - Its a good band to monitor solar disturbances. - At least in my part of the world, the band is little used on the lower end. Of course, some of the stages can be used with front ends for other bands and you may want to veer off to another frequency before we get that far. Since this is a text only newsletter, we have to rely on links back to the website for pictures and schematics. This project won't be for you if you are the impatient type. Its going to take several issues to complete and I am going to be too busy to but out issues on a strict schedule. Still, I will try to stay close to the two month time frame per issue. Project #1 Part 1....A simple ADC This is really not a new circuit. It is one I developed some time back and has been on the website for quite a while. This analog to digital converter uses the MAXIM 187 IC. It has 12 bit resolution with a maximum input of 4.095 volts. The ADC connects to the parallel port of any IBM clone computer and can be controlled with simple software. If you already have Data Collect Lite you have all that you need in terms of software to strip chart from the ADC. The Radio-SkyPipe software mentioned above also supports the ADC so if you can wait for that, there is no need to buy anything. Also I will present a subroutine which you can put in a QBASIC or Quick Basic program of your own design if you are the programming type. You will find the schematic for this ADC at: http://www.radiosky.com/dcla2d.html There are two schematics there. You want the lower circuit that uses the MAX187 chip. I suggest you build this device in a manual A/B printer switch box. I have purchased these boxes new at hamfests and computer shows for less than $10. Its cheaper than a comparable raw project box and with added functionality. They are made of metal, have adequate room, and allow you to continue to operate your printer at the turn of the knob. You won't have to hack out a hole for a DB25 connector. It's perfect for doing this project. Here is the link to the picture page and additional notes to help guide you in construction: http://www.radiosky.com/max187box.html The website also has some troubleshooting notes garnered from experiences past builders have had. http://www.radiosky.com/a2dtroubleshooting.html The BASIC subroutine to query the ADC is at: http://www.radiosky.com/adcbasic.html __________________________________________________________________ These Amateur Tips were submitted by Robert Rolf. Thank you Robert. Amateur Tip #2. Always send regulated power out to a LNB/LNA. The remote amplifier usually has an internal regulator to bring the voltage down to 12 or 9 or 8 volts, but there is still a finite input-output regulation spec (ripple rejection ratio, typically 50dB), but this lack of perfect regulation can easily be seen when you follow up with 60dB of gain. Amateur Tip #3. When sending power to a remote location always have an additional downregulation at the distant point. This improves the voltage stability at the distant point and reduces drift effects. E.G. when sending regulated 18V to a home built LNB boost amplifier, downregulate it to something lower at the board. Always allow for 2-3 V of regulator drop for the LM78xx series, or 1-2 V for 'low dropout' regs like the LM293x series to ensure that the regulators stay in the 'active' region. ______________________________________________________________________ Featured Site(s) Since we focused a bit on solar observing this issue's check out: http://www.spaceweather.com Its a real quick way to view today's sun and keep track of significant solar events. For specifics on recent radio events see: gopher://sec.noaa.gov/11/indices/events Make sure you look at and print off the explanation file at: gopher://solar.sec.noaa.gov/00/indices/events/README%09%09%2B _____________________________________________________________________ Commentary Thanks to all who took time to comment on the first issue, and again I invite your comments, though I cannot promise to fill everyone's needs in terms of formatting and content. I found out that some people do not have word wrapping in their email readers so I have tried to pick a reasonable width and am now introducing carriage returns. If your page has one long line followed a short line, widen the view and things should look OK. It is obvious that this issue of the RS Journal is a bit late. There are a couple of reasons for that. The main reason is that I have been so incredibly busy. In addition to running Radio-Sky, working on new products, and holding down a 'real job', I have been trying to get ready for a move to Hawaii this fall. The fact of the matter is that things are likely to get crazier before they get better, and no doubt the RS Journal publication schedule will suffer other setbacks. So please bear with me until I am settled on the Big Island and can be more attentive to this project. If you have contributions you which to make to the publication, by all means, send them along. This will ease the burden, widen the perspective, and hasten the process. The subscriber list has grown to over 200 which is approaching a significant percentage of people interested in this kind of thing. Your contributions will thus not go unread. Jim Sky, Editor journal@radiosky.com To unsubscribe goto: http://www.radiosky.com/journal.html Click the unsubscribe radio button and enter your email just as it appears on this newsletter. Then Submit it.