Vol. 30 No. 01 October, 1994 Ess-Zed Rensselaer Amateur Radio Club ---------------------------------------- Inside... VP's Notes with N2XGL Treasurer Talks Tough with KE4IBF Transverters with WS2B Zed Notes Life with MGEF Continues ------------------------------- THE PRESIDENT'S PARTICULAR PIECE Hello and welcome to this years first installment of Ess-Zed! There's been tremendous amounts of activity with the Radio Club the past year or so, and we're still going at it. Most of you know by now that we have a new building at the same location. It's much bigger than the old building but we managed to fill it up somehow! We have our own home page on the internet now. We're also working on setting up a packet-to-internet gateway and hopefully before that there will be a digipeater at the Shack. This years budget will include three or four handhelds for two meters and 220Mhz as the demand is steadily increasing for club HT's. That means we've got more participation than ever before! I'm also expecting a small community involvement. Pretty soon, the operating stations will be set up in the new building. It looks like we'll have two HF operating points on just about every band. There will also be a room dedicated for VHF work and above. There are more VHF/UHF radios in the budget so we can expand that station. In addition to the two meter and 220Mhz repeaters, Lance's, WS2B, 443Mhz is also up and running at the Shack at about 50 watts. The new Shack has a much bigger Shop and we have some new test equipment in the budget and maybe some coming from the microwave lab. Last year an alumni donated boxes of electronic parts and other stuff to stock the Shop. We're fixing to set up the 10 meter link to the Virgin Islands repeater that once existed at W2SZ. So there's a sample of what we've been up to lately. You should come up and join the fun. It's a great experience to be part of such a cool club and the people who keep it working. Especially if you're a student, if for nothing else it looks pretty good on a resume! Come see us. We're at the Shack just about every Saturday to hang out or fool around with whatever needs to get done. Check it out! -Brett -- N1LAG --------------------------------------- THE VP'S VIVID VERSO Welcome to an exciting year for W2SZ! I need not remind each and every one of you what an amazing thing it is that we have a brand new building for our new shack. It's been quite a while since the fateful car crash. This new building marks a turning point for W2SZ. In days past, the club was a center for social life amongst hams throughout the school. The shack was our clubhouse, the place that we could eventually find each other and find ourselves. The new shack actually already has that mystique. Compliments are due Brett, who through his patience has managed to work just about every connections and every business meeting to the advantage of W2SZ. Without that, we would not have our new shack. The work of everyone involved has resulted in capturing that shack feel in a new building replete with features of our own choosing. There is plenty of space to lounge around. There is a large well-laid-out workshop. Three operating rooms, storage, and a rack room for the repeaters fills the rest of the space. Shelves line the walls; stairs and ramps provide the access. Even the old W2SZ sign graces the front. Our attention as a club now changes to the upcoming events of the semester and the rest of the year. The thing foremost on my mind is the Open House on November 5. The shack looks good, but it still needs a lot of work to prepare. We're sending out 600 invitations, and expect a large portion to stop by on that day. This is a real chance to get involved. W2SZ has always provided a relaxed, enjoyable atmosphere to work in. You can do as much or as little as you want, while gaining the experience that will serve you in the future. What I suggest is this: Stop by the shack and see what it is we're all so proud of. Talk to the people and see what is happening around you. Chances are there is something that interests you. Ham radio prides itself of the aspect of community that it supports. Every ham or ham-want-to-be knows that hams reach beyond the mic to the individual. Stop by the new shack and see what we mean. 73's - N2XGL - Jeff Shykula ------------------------------------- THE TREASURER'S TROUBLESOME TROVE Ok, I think that there are a few things that I must do at the start of this article. Basically, I would like to welcome all of the new members to the club, and would like to say hello to all those who have returned from last year. This has been an exciting time for W2SZ, and with the erection of the new building and the process of moving ourselves into it (while they finish the work) has lead to a few exciting weekends in the past month or so. The club is finally achieving its goal of becoming one in which we can all come up to the station, and not have to really worry about too much, it is a place to hang out and have fun. There is still some work to be done (actually that is a lot of work) but it will get done, and then we will all be able to enjoy the fruits of our labors. Well, that taken care of I can move into the introduction of myself. My name is John Barenys, KE4IBF, and I am a fourth year Electrical Engineering student here at RPI. I will, hopefully, be graduating from here this spring. I am also the treasurer of the club (other wise I would be in another section of the newsletter). Now that I have changed to the subject of the treasury, let us move on. W2SZ is one of the clubs that is funded by the RPI Union, and this means that we do actually have a nice budget with which to make purchases for the club. This means that we actually do have to follow a budget. So, although many of the purchases that are to be made this year have already been mapped out in the current budget, there is still room in it for things that we had not considered. This means that if you have some interest in acquiring something, then I would be the person that you could approach with this. Well that about does that. I think that the next topic I would like to touch on, is what is in the budget for this year. Budgets are presented to the executive board of the Union in the fall, and then once they are approved they are given to the club. This means that this is the semester where we do most of the spending of the moneys that have been allotted to us. This year we can expect to see the following arriving at the new building: Tektronix dual trace oscilloscope Fluke digital multimeters Bird Wattmeter Hy-Gain medium duty rotor Yaesu satellite Az/El rotor 1000 ft. RG-214/U coaxial cable Tilly 40 ft ladder Climbing belt Icom IC-2SAT 144Mhz handheld radio Icom IC-3SAT 220Mhz handheld radio Mirage 144Mhz 100W amp Kenwood 144Mhz base radio Misc. shop and building supplies These are only some of the arriving things, but they are something to look forward to once we are up and running again. Well, I think that this will about do it for me. Before I go I would like to thank all of those people who have been putting time in at the club to get it going again. This is something that all of us will appreciate once we have left RPI (we do have a good alumni following), and it could not have been done without you. Finally, if there are any questions or concerns please feel free to contact me. My number is (518) 276-4555, and my e-mail address is barenj@rpi.edu. I can also be found (usually) on the 146.82 machine. 73's de KE4IBF. ------------------------------------ TECH NOTES (please note than in the text version the diagram do not appear, if you would like a print copy of the newsletter please contact W2SZ). With Lance Lascari What is a transverter? Why use one? How does it work? These are questions that usually arise when I mention the word transverter. I'll try to answer these questions in this article. For those who are more interested in detail, I will describe a real transverter application and implementation in a future article. If you dissect the word transverter, you see remnants of the words transmitter/transceiver and converter. Well, that pretty much describes what a transverter does, it is a radio frequency converter or translator if you wish. Unfortunately, to many the transverter is a black box where magic occurs. I will try to explain how the translation works without getting bogged down in mathematics and implementations. There are many reasons to use a transverter. Hams generally use transverters for microwave frequencies, because you can't buy radios for this nosebleed region of the radio spectrum. Another reason is cost, in most cases one can build a transverter for a fraction of the cost of a commercially produced radio ( a 2m all mode radio for instance might cost 5 times the cost of building or buying a transverter). Another way of looking at cost savings is this: If you were to invest in one radio, like a loaded HF radio with filters and the works, then you could use transverters to make this one radio (with all the nice features) cover not only the HF bands, but 144 MHz, 220MHz, 432 MHz, etc. Transverters are almost like "band modules" for some transceivers, where you buy the base unit, and add frequency coverage by buying modules. Other people use transverters just because they like to build things. Think about this, if we were allocated a new band of frequencies tomorrow, who would be the first people to utilize them? The answer is people who build transverters, i.e. before the commercial guys even get a product conceived! Transverters are USUALLY used to convert a low frequency radio up to a higher frequency radio. A common example of this is a 10 meter to 2 meter transverter. Here is how you would hook it up (see next page). The architecture of a transverter is made up of three fundamental blocks, the receive converter, the transmit converter, and the Transmit/Receive switching apparatus. The switches are just that, they select which converter you're using at any given instant. Frequency translation? You've got to be crazy, you tell me that I can pump a signal in this connector labeled "gozinta", and when it reaches the connector labeled "comesoutta" it will be the same signal, but shifted to a different frequency? Yep, that's what happens. (image missing) In order to explain this, I will introduce some terminology. In our example, a 10m signal (28 MHz) gets translated up to a 2m signal (144 MHz), and vice -versa. The convention is to call the 144 MHz frequency the "RF" or Radio Frequency, and the 28 MHz signal the "IF" or Intermediate Frequency. Since we are converting one frequency to another, it makes sense to consider one of these two frequencies as intermediate. If you look at a receiver in the simplest form, the signal comes in the antenna on one frequency, and gets demodulated and converted to audio directly (reverse process with the transmitter of course). On the other hand, when using a transverter there is an additional translation that occurs, requiring an Intermediate Frequency. Don't let this confuse you, both RF and IF signals are radio signals by nature, it is just that we have to make a distinction between them. This just happens to be the convention. To review our example, RF=144 MHz and IF=28 MHz (equivalently, with the same converter you have RF=145 MHz and IF=29 MHz). So this leads to the conclusion that the frequency is being translated by 116 MHz. 28 + 116 = 144 transmit 144 - 116 = 28 receive Ok, addition and subtraction are easy...but we're dealing in the frequency domain... how could this work? What component makes this possible? There must be some component that does this, otherwise every TV or radio signal in the air would add and subtract with every other one. Think what the radio spectrum would look like if this just happened without some special phenomenon. The component in the system that allows these type of operations is the mixer. The mixer has three ports, RF, IF, and LO. RF and IF should look familiar to you, but LO is new. LO stands for Local Oscillator, but we can think of it as "translation factor input". The local oscillator in a transverter is a low power source of radio energy for "local use", and is usually on the order of a few milliwatts. Now the question arises, "Are there "add" mixers and "subtract" mixers?". The answer is no, the mixer always does both at the same time. I suggest you consult a text if you are interested in what goes on inside the mixer. Here is the basic example of how a mixer is used, and a diagram of what the system block looks like: RF Port Input LO Port Input IF Port Output 144 MHz 116 MHz 28 & 260 MHz RF Port Output LO Port Input IF Port Input 144 & 88 MHz 116 MHz 28 MHz (image missing) Now if you look at the chart if mixer inputs and outputs, you notice that there are frequencies that we never intended to see! How did this happen? As mentioned before, the mixer always adds *and* subtracts, that's where these nasties came from. If we are trying to transmit on 144 MHz, the we don't want to be transmitting on 260 MHz as well! In a transverter, there are bandpass "filters" to eliminate these "spurious" (unwanted) signals, more on bandpass filters later. So, we've hopefully made it through the hard part without too much confusion. Trust me, it might take a while for this to sink in, but hopefully it eventually will. Now we have all of the basic building blocks except for the filters. Bandpass filters are filters that allow only a "band" of frequencies to pass through them, they stop all other signals from passing to some degree (an ideal filter is impossible), graphs below depict filter performance. (image missing) For this transverter, if we wanted it to cover from 144-145 MHz, we would build two types of filters. The first filters would be at RF frequencies, i.e. the bandpass would be from 144-145 MHz, the second filters would be at IF frequencies, i.e. from 28-29 MHz. Now, we have touched upon all of the building blocks in the transverter except the amplifiers, which I think are already understood. The lineup of components to replace the converter blocks in the simplified drawing would look like this: (again, image is gone) With the addition of preamplifiers and a bandpass filter (on RX) and high power amplifiers ( on TX), this is all there is to a transverter. Well, that's it in a nutshell. I hope that I have explained the why, what, and how of transverters. Feel free to ask me questions about things that are still unclear by email, phone, or in person at the shack. In my next article, I will give an example of a transverter that I designed this summer ( and am still working on) for the 6m amateur band. Feedback on the article, questions, and suggestions for future topics to write about are requested. See me at the shack, give me a phone call, or write me some email. -Lance Lascari, WS2B x4565 lascal@rpi.edu ----------------------------------------- Mount Greylock Expeditionary Force ADVENTURES AT MT. GREYLOCK (by John Barenys) Some of the people reading this may be familiar with the effort know as MGEF (Mount Greylock Expeditionary Force) but to many it something that is not quite understandable. So what is MGEF? It is a group of hams getting together under the sign of W2SZ/1, going to the top of a hill for a weekend and contesting in the VHF and UHF sweepstakes that take place three times a year (actually, one of the contests is strictly UHF and above). So. you ask what is so different about this. Well the answer is a simple one. Most people do not truck gear 50 miles from home to spend an extended weekend setting up many towers and then proceed to tear them down that Monday leaving the mountain top no worse of for wear. >From this point on I would like to tell the "story" of one such weekend. This one is the most recent sweepstakes that took place in September. ---9/8/94--- It is Thursday afternoon and people begin to arrive en mass (i.e. four or five of them) at the General Electric Earth Station Laboratory in Schenectady, NY. A few of the die hard individuals have already been there since the early morning. One poor fellow has not yet eaten that day and is dependent on the kindness of his fellow compatriots to stop at a fast food location and bring him a bite to eat. Lunch arrives and the fellow seems to be in low spirits. Through a stuffy nose he mutters "I have a code, and all the medication is doing some funky things to my body. I think that I need a nap." In the meanwhile the fearless leader of the group has left the Lab to make copies of the contact schedules that he will have to try to keep to during the contest. He has been heard muttering that he would like to do them on a word processor, but does not have the time at the moment. So, what are all of these people doing? Simple really. They are loading two trucks and a van with radio equipment, and are preparing to head up to Mount Greylock, in Massachusetts, to do unspeakable things (all of which are non- permanent) and create some severe visual eye sores (to the untrained eye that is). So, what is it? It is the September VHF/UHF radio sweepstakes. It is something that this sorry, or was that merry, group of individuals take to heart. A proof that one can be number one, and a constant reminder that one must bust his butt to do it. Also, it is a time to have a good time with people who share common interests. Back to the ESL, the sleeping beauty (one could say the number two in command) is awake and now feels about 73% better. He is heard saying that he would like to be heading out by about seven in the evening. His chances? Not great, but not fully gone. Yet. As for the leader of the bunch, he will most likely be taking his truck to the mountain at some obscene hour of the night. Well something is going right, the first wave departs the Lab circa 7:30pm, but after a quick stop at the new W2SZ shack they realize that it was too easy. Fate would not allow for this. It is discovered that one of the members' car is not in any condition to go anywhere (blown alternator), so it is time to reorganize a little and move on. The second truck, dubbed the White Elephant, finally leaves the Earth Station late at night and makes a rather uneventful trip up "the hill" that is Mount Greylock. Late at night atop Mount Greylock we see the bulk of the equipment that will take over part of the hill top this weekend. The White Elephant is there, as is Wilfrid (the first truck to depart), the Blue Whale (the van), three trailers with antenna hardware, and other assorted vehicles. The people are finally getting some sleep. A long day awaits them. ---9/9/94--- Ah, Friday. That means that it is the end of the work week, time to relax, right? WRONG! Not as far as our heroes are concerned, today is a day of hard work, followed by more on the weekend and then on Monday. But it is a torture that they are all used to, and in some strange all seem to find mildly pleasurable. Of course, life can not be that nice, mother nature had decided that she is going to make the times a bit more interesting for the crew. It manages to rain heavily for a good part of the morning, now the setup will be in the soggy grass. The group has no option but to wait her out in the comfort of the Bascom Lodge, a place to eat, sleep, relax, and take care of nature's callings. By late morning the sun has finally decided to show its face, and it is time to get cracking. As the vehicles are unloaded there is muttering of how they are behind schedule, and that there is no time left. But as the day progresses the once serene and timid hill top becomes transformed into a forest of metal towers that will eventually hold the antennae. By mid-day to early afternoon tensions are now back to a normal level, and the work is actually a bit closer to being on schedule. Others have arrived and are now ready to assist those who have been there for the day. All is actually kind of peaceful. After a nice dinner the crew returns to the work at hand, by about 10:00pm most of the members have had enough. They head off to bed, plenty to do before 2:00pm on Saturday. Of course, not all of the people stay at the lodge, some of the more energetic (or maybe a better word would be loony) participants head down the hill to stay at the campsite. The small band of campers will want a little more entertainment before going to bed. After collecting wood, having a campfire, consuming some perishables, and having had a jovial time, some of the members of the band reflect on the fact that it is actually Saturday and that they will only get a nap before having to "get back to it." They then clamber off into their tents for some deserved sleep. One figures that after some many years, they would learn. Maybe in time to come. ---9/10/94--- A pleasant morning atop Mount Greylock, that is until the breakfast bell is rung. A that point the crew from W2SZ/1 seems to come out of the woodwork while they stampede for the dinning hall. All consume their share, and another day is under way. During the activities of the morning, there is realization that 2:00pm, the start of the contest, is nearing. Utterances like "Less talk more work," and "I don't have time for this," are commonly heard. Setup is rather uneventful, other than the fact that some of the pieces of equipment are enjoying themselves back at the Earth Station. Looks as if they decided to take a vacation this year. Oh well, looks as if the art of improvisation will be at hand once again. By about 1:45pm all seems to be nearing completion, other than a few stragglers, the antennae are set up and are ready for power up. Gentlemen, and ladies, start your engines! The Chernobyl, as it is affectionately called, is brought one line at the two meter station. 1.5kW and four yagis, check! Next is the 223 station, 1.5kW and four yagis, check! On to 443, 1kW and four yagis, check! 6M? A kilowatt and four yagis, check! Hmmm.... starts to get repetitive, eh? Well looks as if the Wilfrid's operators will be in fine form, not meltdowns so far. The operators in the White Elephant are not so lucky, one of the amps for 900 is having a bit of a time, but otherwise all seems to be going along smoothly. The contest progresses into the afternoon, and the operators are feverishly logging contacts, swearing (not on the air of course) at the competition, and over all attempting to kick some butt. Not much has gone wrong this time, only one amp with a problem, and only a few components emanating that oh so familiar aroma. A normal Saturday for W2SZ/1. Dinner time rolls around, and there is a rotation of operators in an attempt at keeping all the stations manned at all times. Once dinner is over, it is back to the radios. One of the members of the club announces that the specialty "Buttocks Brown Ale" is now being served, and there is much rejoicing. Operations continue long into the night, and finally most of the stations are now empty. The operators are not getting some rest, so that they can jump back into it in the morning. ---9/11/94--- After the usual flocking to the dinning hall for breakfast, the operators are back in place. This day will be spent making Q's and hopefully avoiding problems. The day progresses rather uneventfully, and there really are no major problems with the "works". The occasional remark is made here and there, to which the group responds with laughter and more rhetoric. By the end of the contest (midnight), there is tension, scores are a bit lower than usual. What could we have done better? This is something that is always asked. On the radio the other contest stations gather. Scores are tallied and exchanged.... oh oh, this one is going to be a close one.... this is not looking good... but wait.... yes! the competition was pulling a joke... YES YES YES!!!!!... MGEF has managed, yet again, to win another one (at least so they think, it will be a while before the official scores are out). But it is not by a great margin. They will have to try harder to keep the lead next time. All seem relieved. ---9/12/94--- The crew takes down all of the antennae and towers and packs them back into the trucks. They then proceed to head back down the hill and for home. It has been a long, yet exciting, weekend for all. As usual, the will all be back to do it again next year. --------------------------------------- ZED NOTES - Check out the new W2SZ Home Page on Mosaic. You can get there from RPI's Home Page. - Remember the Capital District Amateur Radio Council Bulletins on 146.82 every Monday night at 1915 and Thursday 1700. - Check out all the local news on our newsgroup at rpi.union.ham-radio. - FCC Exams held in CII 3051 on campus Saturday, October 8 and November 12. Show up at 8:15 a.m. Contact is Bud Hovey (WF2B) at 283-3227. - Check out the Commuter Net on 145.330(R) every weekday at 0600-0900 and 1500-1800. - Saratoga RACES meets Monday, October 10 at 7:30 p.m. Contact Ed Barnett (N2RKA) on the Commuter Net listed above. - For other club info, see Jeff Shykula (N2XGL). ================================ Ess-Zed Editor in Chief: N2XGL Jeffrey T. Shykula President: N1LAG Brett Mellor Vice President: N2XGL Jeffrey T. Shykula Treasurer: KE4IBF John Barenys Secretary: KA9WZO John Karcz Equipment: WB2NOW Cesare Mancini Repeaters: KB2HEL John Muller Trustee: W2HKM Dr. R. Athanasiou Submissions to this monthly newsletter of W2SZ, the Rensselaer Amateur Radio Club, are due by the last Wednesday of each month. Submissions should be double spaced type, or in electronic format to: Jeff Shykula - Editor in Chief W2SZ: Ess-Zed 06 Sunset Terrace, Troy, NY 12180 jshykula@charon.phys.rpi.edu Or Call 518-276-6578 for Questions, Comments, Criticisms, Advertising or Concerns. ---------------------------------------- W2SZ holds its General Meetings the First Saturday of every month at 1:00 p.m. at the shack. Talk in is available on 146.82(R), 224.42(R), and 443(R). Ess-Zed A Publication Of W2SZ 06 Sunset Terrace Troy, NY 12180