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Follow-up-To:rec.radio.amateur.misc Approved:rec-radio-info@ve6mgs.ampr.ab.ca Digest of Articles -- QST, May, 1993 Following are digests of articles printed in the May, 1993 issue of QST. Such digests are being prepared for each issue of QST, and posted periodically. Subsequent issues will be posted one per week until they "catch up" to the current date in mid-1994, thereafter monthly. It is hoped that other hams will volunteer to post similar digests of the other ham technical publications such as QEX, CQ, 73, COMMUNICATIONS QUARTERLY, RTTY JOURNAL, et al. Especially desirable would be digests of publications in other countries, such as the RSGB RADIO COMMUNICA- TIONS and ham magazines in Europe, Japan, Australia, and other countries around the world. We English speakers would especially enjoy them if they were translated into our language, but they would also be valuable additions to the world's knowledge if they were posted in the language of origin. Who knows? Some bi-lingual ham somewhere might translate them into English and re-post them. Worldwide communications are getting better and better. The time has come to make the world's ham press available to all hams throughout the world! The major value of digests is to give readers sufficient information to decide whether to obtain a copy of the full text. If any U.S. reader wants a copy of an article in QST, please inquire of other hams in your own neighborhood. Many have collections of back issues. Anyone who is unsuccessful in finding a fellow ham with a collection should try every library in the area, especially those at universities and technical colleges. If all else fails, a copy can be obtained from the ARRL Technical Department, 225 Main St., Newington, CT 06111-1494 USA for a fee of $3.00 per copy. Remember, it is both cheaper and quicker to obtain one locally. Readers in most other countries can obtain copies from their own national ham organizations, sometimes translated into their own languages. -------------------------------CUT HERE--------------------------------- COPYRIGHT NOTICE: Copyright to all the following material from QST Magazine is held by the American Radio Relay League (ARRL), effective on the date of issue. Permission is granted for redistribution of the following in its entirety, or in part, provided that this copyright notice is not removed or altered and that proper attribution is made to ARRL as publisher of QST, to the authors of the original articles, and to W. E. "Van" Van Horne, W8UOF, author of this compilation. _________ TABLE OF CONTENTS (line number in parentheses - counting from CUT HERE line) TECHNICAL ARTICLES (TA) TA1:Home-Brewing a 10 GHz. SSB/CW Transverter - Part 1 (75) TA2:Single-Conversion Microwave SSB/CW Transceivers (140) TA3:Build the HANDI-Finder! (203) TA4:Add Tracking Side-Tone to Your ICOM IC-765 Transceiver (246) TA5:An Introduction to Amateur Television - Part 2 (284) PRODUCT REVIEWS (PR) PR1:HAL Communications PCI-4000 Clover-II Controller (324) PR2:AlphaLab TriField Meter (386) HINTS AND KINKS (HK) HK1:Build a Quick PVC-Supported Quad for About $50 (421) HK2:Installing a Huskier 160-M Fixed Capacitor in the Ten-Tec (447) Titan Amplifier HK3:Putting Variometry to Work in Matching Networks (464) HK4:When Antennas Should NOT Be Resonant (484) TECHNICAL CORRESPONDENCE (TC) TC1:Expanded Range DC and AC Voltmeters (505) FEEDBACK (FB) FB1:QST Apr 1993 Product Reviews (530) FB2:QST Nov 1992 "Dipoles Above Real Earth" (547) NEW HAM COMPANION (NHC) NHC1:And the Most Popular Frequency is... (572) NHC2:Do You Need an Audio Filter? (603) NHC3:The Doctor is IN (612) NHC4:A Disguised Flagpole Antenna (626) NHC5:VHF/UHF Contesting (634) RADIO TIPS (RT) RT1:What Is AMTOR? (653) RT2:Lightning! (660) RT3:The Ionosphere (672) RT4:Working the World on 10-Meters (681) RT5:Is Amateur Radio Safe? (694) GENERAL INTEREST ARTICLES (GI) GI1:Festing (Notes of a Hamologist) (710) GI2:PHASE 3D - A Satellite for All -- Part 1 (723) GI3 Inspiration N2OVA (779) GI4:Transmitter Hunting: Tracking Down the Fun (797) ------------------------------------------------------------------------ TECHNICAL ARTICLES (TA) Title>TA1:Home-Brewing a 10 GHz. SSB/CW Transverter - Part 1 Author>Lau, Zack - KH6CP Source>QST May 1993, pp. 21-28 Abstract>First of a 2-part construction article describing a 10 GHz. transverter. It utilizes only readily-available parts but to build it requires the builder to have had some experience with VHF/UHF gear and to have access to certain test equipment. Digest>The author has built a 10 GHz. transverter which, when used in tandem with a 2-meter transceiver, will receive and transmit on "X-band", or 10 GHz. One notable thing about this project is that it uses readily available components, nothing exotic or available only from military surplus. He has built the transverter as a series of building blocks, each connected with the next through plug connectors and coax jumpers. Thus, each block can be tested independently, or changed in future upgrades. In this first instalment, Mr. Lau supplies wiring diagrams, parts lists including recommended sources, and construction details for the local oscillator building blocks. Near the beginning of the article, he addresses a question that all interested readers must answer for themselves: "Do I have the VHF/UHF construction experience and the test equipment required to handle this project?" It is his opinion that the construction details are not that difficult and he suggests two commonly-available ham publications that give sufficient background information to allow the average construction-minded ham to build the equipment. But the rub comes in tuning the amplifiers, mixer, and filters. He states that it should be possible to accomplish the task with equipment reasonably available to hams, but optimizing the circuits is much easier if one has access to relatively sophisticated bench instrumentation, including a spectrum analyzer. In a side-bar with the article, Rus Healy, NJ2L, senior assistant technical editor, recommends that anyone who has not had the experience of building a lower-frequency transverter should do so before undertaking the X-band project. Conceptually, the transverter is easy enough to understand. On the receiver side, the 10 MHz. signal from the antenna goes through a pre-amplifier, a band-pass filter, and into a mixer where it is heterodyned against a local oscillator signal and converted to 144 MHz. output. On the transmitter side, the r.f. output from the 2-meter rig goes to a mixer where it, also, beats against the local oscillator signal which converts it up to 10 GHz. From the output of the mixer, the signal goes through a band-pass filter, an amplifier, an optional second band-pass filter, and out to the antenna. The "local oscillator" is actually made up of a crystal oscillator at 106.499 MHz., followed by a series of multipliers, each of which is a separate building block and contains multiple band-pass and low-pass filters with sufficient amplification to overcome the insertion losses. The first building block contains the crystal oscillator and the 6:1 multiplier. The output of that block is a spectrally-pure 639 MHz. signal. Following is a quadrupler block, the output of which is 2.556 GHz. The last block within the local oscillator chain is another quadrupler with a 10.224 GHz. output frequency. In next month's issue will be the second, and final, installment. It will describe the preamplifer, mixer, and power amplifier to complete the project. _________ Title>TA2:Single-Conversiion Microwave SSB/CW Transceivers Author>Campbell, Rick - KK7B Source>QST May 1993, pp. 21-28 Abstract>Construction details for a microwave transceiver using receiver and transmitter building blocks described in previous articles, plus other components. The transceiver can be built to operate on any band from 432 through 5760 MHz. On the receiver side, the design uses a crystal-controlled converter to feed an i.f. system at 144 MHz.; that system is, itself, a direct-conversion single-signal receiver. The transmitter side is a phasing-type SSB or CW transmitter. Digest>This is another article by Mr. Campbell who described the "R2" and "T2" PC-board building blocks in his QST articles in the issues of January and April, 1993. This article describes a microwave transceiver that uses them, plus a number of other building blocks, to make a microwave transceiver. The first block is a "no-tune transverter" designed to be used outdoors at the antenna, utilizing a circuit board available from Down East Microwave Company, Troy, Maine. For this article he used one made for the 903 MHz. band; similar ones can be obtained from the same source for use on bands from 432 through 5760 MHz. In all cases, the units convert the received microwave signals to the 144 MHz. band, and the 144 MHz. transmitter signals to the microwave band. Inside the shack, Mr. Campbell's system uses a direct-conversion transceiver with 144 MHz. input and output. The block diagram of the 2-meter transceiver shows, on the receive side, an optional i.f. (144 MHz.) preamp feeding into the r.f. input on the R2 board. A variable- frequency 144 MHz. oscillator output passes through a splitter with one-half of the output going through a 90-degree phase-shift network to the "I" and "Q" inputs of the R2 board. The output of the receiver goes to a headphone jack, or directly to a speaker. On the transmit side, the other half of the oscillator output passes through a similar 90-degree phase-shift network to the "I" and "Q" inputs of the T2 board. The transmitter is actuated by either a key or a microphone, for CW or SSB operation. Its output goes directly to the output terminal. The remainder of the article is primarily devoted to the design details of two alternate "local oscillator" modules. The first of these is a crystal controlled VXO circuit utilizing a 20.6 MHz. crystal. The output of the oscillator is made a square wave, rich in odd-harmonics. Following the output are two cascaded 144 MHz. band-pass filters that select the seventh harmonic. The tuning capacitor in the VXO circuit allows frequency to be varied, providing a 50 KHz. operating range at 144 MHz. The other local oscillator circuit that the author describes is a "premixed VFO". By this, he means that an HF oscillator, in this case with a range of 13.0 to 13.12 MHz., is mixed with a 131 MHz. crystal oscillator to provide the 144 output. The circuitry used in this module is conventional. The author's final comment is: "This article describes one of my favorite applications for the R2 and T2 boards....With the basic transmitter and receiver circuitry contained on a pair of small printed-circuit boards, the possibilities for custom-built radios are limited only by our imaginations." _________ Title>TA3:Build the HANDI-Finder! Author>Leskovec, Bob - K8DTS Source>QST May 1993, pp. 35-38 Abstract>How to build a very simple hand-held direction finder. Digest>This construction article gives full details for building a simple hand-held direction finder for use in "Fox-Hunting". It can be used in conjunction with an HT for locating AM or FM transmitters over the frequency range of 45 to 470 MHz. The unit is completely built on a printed-circuit board. It uses only about a dozen components, one of which is an IC. The antenna is a "bow-tie" made of stiff wire that is supported by screws on the PC board. A handle attaches to the board at the center of the "bow-tie", completing the unit. In operation, the circuit rapidly switches its input from one side of the "bow-tie" to the other at an audio rate. When the transmitter to be found is in line with (i.e. in the same plane of) the antenna, one side of the antenna is closer to it than is the other. It receives the signal a tiny fraction of a second earlier than does the other side. This causes a difference in the phase between the two sides, the result of which is phase-modulation that creates an audio tone in the receiver. The tone is determined by the switching frequency. If the antenna is rotated so that the transmitter is in a line perpendicular to the antenna plane (i.e. "face-on"), then the signal reaches both sides simultaneously and there is no phase-shift, hence no audio tone. This causes a sharp null in that direction, indicating the direction of the antenna. Note that it is the audio tone that is nulled, not the carrier. It is much easier to detect a null in the audio than a null in the carrier, hence the sensitivity of this unit is excellent. Of course, the null is bi-directional and the ambiguity must be eliminated by triangulation, which usually means that the hunter must move laterally to determine which direction is the true one. A kit is available containing all the parts necessary except connectors, battery, and the wire antennas. It can be obtained for $27.95 from North Olmstead Amateur Radio Depot, 29462 Lorain Rd., North Olmstead, OH 44070. A PC board template package can be obtained from the ARRL Technical Department Secretary, 225 Main St., Newington, CT 06111 for a business-size SASE. Address it to Leskovec HANDI-Finder Template. _________ Title>TA4:Add Tracking Side-Tone to Your ICOM IC-765 Transceiver Author>Mraz, Michael A. - N6MZ Source>QST May 1993, pp. 39-42 Abstract>Modifications to an ICOM transceiver to allow CW operators to adjust the sidetone pitch to any desired value while the receiver automatically adjusts the received signal to the same pitch. Digest>In the ICOM IC-765, the sidetone oscillator is fixed at 700 Hz. To adjust the transmitter to the same frequency as a received signal, it is necessary to tune the received signal to zero beat with the sidetone pitch, which requires the operator to listen to the received station always as a 700 Hz. tone. But many CW operators find that tone, or any fixed tone, unpleasant and want to adjust it. The author has designed and built a circuit which generates a side-tone that tracks the receiving pitch within 1 or 2 Hertz. This article gives full construction details. The system that Mr. Mraz designed uses an integrated-circuit function generator to generate an audio tone that tracks the setting on the front panel "CW Pitch" adjusting knob. That knob adjusts a potentiometer which, in turn, causes a varying voltage that can be accessed on the main receiver board. However, the relationship between the knob position and the pitch frequency is non-linear! Consequently, he had to add circuitry to cause an equal and opposite non-linearity in his sidetone generator so that the two tones would precisely track. The author gives detailed instructions concerning how to perform the necessary "surgery" on the ICOM circuit board. He cautions any would-be follower that, if their transceivers are still in warranty, these modifications would void it. A kit of parts, including etched and drilled circuit board, for building the unit is available for $49.00, plus $2.00 shipping within the USA from LTA, P.O. Box 77, New Bedford, PA 16140. _________ Title>TA5:An Introduction to Amateur Television - Part 2 Author>Taggart, Ralph E. - WB8DQT Source>QST May 1993, pp. 43-46 Abstract>A description of the various equipment necessary or desirable to become active in ATV. Digest>This is the second installment of this description of amateur television (ATV) activities. In this article, the author describes equipment available and other details required in getting started on the air. What he calls an "entry level" ATV setup comprises a TV camera, an ATV 70-cm. transceiver, a TV camera, microphone, an optional power amplifier, and an antenna. The equipment that he describes is manufactured by three companies, AEA, PC Electronics, and Wyman Research. AEA is a well-known supplier of a broad line of amateur gear, whereas the other two are small proprietorships, each run by a veteran of ATV activities. The last two companies both supply crystal controlled transceivers with power outputs from 1 to as much as 15 watts PEP. Their video output signals are double-sideband amplitude-modulated (AM). AEA's latest transceiver produces signals very similar to commercial broadcasting standards. It uses "vestigial sideband (VSB)" AM transmission. This means that the signal is a combination of a single-sideband with a carrier. Most ATV operators use home-style camcorders for their TV cameras, and home-style TV sets for reception. All of the transceivers described produce video outputs switchable to channels 2, 3, or 4 for viewing. In amateur TV, as well as in commercial TV, the audio is transmitted by FM on a sub-carrier which is 4.5 megahertz above, (or both above and below, in the case of AM video) so that it can be reproduced on a standard home-TV set. ------------------------------------------------------------------------ PRODUCT REVIEWS conductor: James W. Healy, NJ2L _________ Title>PR1:HAL Communications PCI-4000 Clover-II Data Controller Author>Ford, Steve - WB8IMY Source>QST May 1993, pp. 71-73 Abstract>Review of a plug-in computer board made by HAL Communications that acts as a data controller for Clover-II communications. A description of the Clover-II protocol is included. Digest>Clover is a new digital mode for HF communications. It was developed by Ray Petit, W7GHM, working with HAL Communications Company. That company is producing the PCI-4000 for use in an IBM-compatible computer with an 80286 CPU, or later, to control a radio transceiver in the Clover Mode. Clover provides much improved data communications in the noisy environment of HF radio, but occupies only 500 Hz. of band-width. It uses four audio tones, each of which is phase- and/or amplitude- modulated in one of 10 schemes. The format with the highest data rate uses 16-phase, 4-amplitude modulation (16P4A), to transmit at a rate of approximately 750 bits/second. Other formats are more robust in resisting noise and fading, but result in slower throughput. There are ten different formats, in all. Clover's most interesting feature is its adaptive operating. Under varying conditions of propagation and noise, it adapts the power level, and also the modulation scheme, to obtain the maximum throughput of data. Faced with an increase of error rate or dropouts in the data, it automatically raises the power output or changes the modulation format, or both. When conditions improve, it reverses the sequence. Clover uses the "Reed-Solomon" coding system which provides forward-error-correcting (FEC). Each block of transmitted text contains "check-bytes" which are used to correct many errors without requiring repeats of the data blocks concerned. This is a major step beyond the older digital modes, AMTOR and PACTOR, which verify the successful reception of data blocks but cannot correct them; they can only ask for repeats. The reviewer found the PCI-4000 easy to install. He used it with a Kenwood TS-820S and found the results were "surprisingly good". On the air, tuning of the signals is very critical. If the transceivers at the two ends of the link differ in frequency by as much as 15 Hz., the link breaks! Consequently, Clover provides a screen display that includes a frequency indicator. It shows the difference between the two signals in Herz at all times. The display also shows a "Receive/ Transmit Status Table". This continuously reports the modulation format in use, signal-to-noise ratio, tuning error, phase dispersion, error-correction capacity, and transmitter power at both ends of the link! Mr. Ford found one weakness in Clover; that is its "Listen" mode does not perform as well as does AMTOR and PACTOR. That is, it does not receive well when "listening in" to a QSO between two other stations. HAL Communications is reportedly trying to improve it. In summary, the reviewer calls the Clover system: "Undoubtedly the most efficient HF digital communications mode yet devised for amateur radio." However, its price is of the order of three or four times the cost of AMTOR and PACTOR. Consequently, it will probably be used primarily for handling large quantities of data transfer on HF bands, such as main-line packet forwarding. _________ Title>PR2:AlphaLab TriField Meter Author>Overbeck, Wayne - N6NB Source>QST May 1993, pp. 73-74 Abstract>A review of a meter designed to measure a.c. magnetic field strength. It was found to be subject to errors so severe as to make it useless in radio work. Digest>The TriField Meter is designed to measure electromagnetic field strength in view of the widespread furor over purported health effects of low-level a.c. fields. It supposedly measures magnetic and electric fields separately and also has a built-in r.f. probe to detect field strength at frequencies of from 50 MHz. to 3 GHz. The reviewer found that, in the magnetic field modes, the meter gave readings that were consistently too high. The well-written instruction sheet accompanying the meter explains why: although its readings at 60 Hz. are supposed to be accurate, readings are a function of frequency and higher frequencies will give higher readings. But there is no way to measure the frequency of the field that the user is measuring, so it is not possible even to estimate how much in error the measurements are! The reviewer's final conclusion was that "...its readings are almost certain to be misleading, creating a false sense of security or - more likely - causing undue alarm. It is not hard to envision groups of concerned citizens armed with these meters patrolling their neighborhoods in search of "radiation" - and finding hazards behind every bush!" ------------------------------------------------------------------------ HINTS AND KINKS conductor: David Newkirk, WJ1Z Sr. Asst. Technical Editor _________ Title>HK1:Build a Quick PVC-Supported Quad for About $50 Author>Evans, Clark J. - WA4DLL Source>QST May 1993, p. 75 Abstract>Construction details for a square loop antenna. Digest>This short item includes a dimensioned drawing and construction details for a square loop antenna, which the author calls a "single-element quad". The spreaders, each 28 feet long, are made of 1-inch PVC pipe stiffened with dowel sticks along their entire lengths. The dowel sticks are 4-feet long. Eight of them are required to reinforce each of the two spreaders since they are overlapped 3-inches at the splice between adjacent sticks. They are attached to the PVC pipe by nylon-tape wraps about every two feet. The bottom leg of the square is horizontal. It is broken at the center with an insulator. Coax feedline is attached at that point. In order to keep the weight of the feedline from causing the lower leg to droop, the author reinforces the spreaders with a 17-foot 8-inch length of 3/4" by 3/4" molding between spreader ends. The author reports that he operates the antenna on 80, 20, 15, and 10 meters through the use of an antenna tuner. As for performance, he reports: "My DX has increased 10-fold". _________ Title>HK2:Installing a Huskier 160-M Fixed Capacitor in the Ten-Tec Titan Author>Lynch, Joe - N6CL Source>QST May 1993, pp. 75-76 Abstract>Step-by-step instructions for replacing a blown capacitor in the Titan amplifier, manufactured by Ten-Tec. Digest>Mr. Lynch reports that, when operating his Ten-Tec Titan amplifier, the 160-meter fixed capacitor in the plate tank circuit blew out, and its identical replacement also blew out. He replaced it the second time with a capacitor obtained from Ten-Tec that is rated at three times higher working voltage than the originals (15 Kv. vs. 5 Kv.) Since the replacement capacitor is larger than the originals, he had to make a modification to the amplifier to mount it. He gives complete instructions of how to do this, and illustrates it with a photograph. _________ Title>HK3:Putting Variometry to Work in Matching Networks Author>Zavarella, Art - W1KK Source>QST May 1993, p. 76 Abstract>Using a variometer (variable inductor) in ham gear. Digest>A variometer is an inductor in two parts, one of which can be moved relative to the other. When the two parts are perfectly in line, the turns of wire in the moveable part add to the turns in the other to form a coil with turns count equal to the sum of the two. If the moveable portion is turned by a full 180-degrees, however, then the field created by its turns subtracts from that of the fixed part, reducing the net inductance. Intermediate positions give intermediate inductances. Thus it becomes a continuously variable inductor without coil taps or moveable contacts. Mr. Zavarella shows photographs of antenna tuners that he has built using variometers. _________ Title>HK4:When Antennas Should NOT Be Resonant Author>Aitken, Hugh - W1PN Source>QST May 1993, p. 76 Abstract>If the ends are not plugged, tubular Yagi elements resonate acoustically in the wind. Digest>The writer reports that he erected a new tri-band Yagi antenna but failed to put the plastic end-caps on the elements. Now, when the wind blows the open-ended tubing resonates in the manner of organ pipes! The sounds are very annoying to his family, as well as neighbors. He recommends that others be more careful and seal the ends of all tubing with caps or plugs. ------------------------------------------------------------------------ TECHNICAL CORRESPONDENCE conductor: Paul Pagel, N1FB Associate Technical Editor _________ Title>TC1:Expanded-Range DC and AC Voltmeters Author>Grebenkemper, John - KI6WX Source>QST May 1993, pp. 77-78 Abstract>Construction of expanded-range a.c. and d.c. voltmeters. Digest>The writer provides wiring diagrams and parts lists for contructing either a d.c. or an a.c. voltmeter with an expanded range, more properly termed a "suppressed-zero" meter scale. In other words, instead of reading from 0 to 15-volts, the meter reads from 11- to 15-volts, providing better resolution and accuracy over the operating range. The meters can be accurately calibrated at both ends of the scale with a trim potentiometer to adjust each end. Parts kits are available from FAR Circuits, 18N640 Field Ct., Dundee, IL 60118-9269. A PC-board and meter-face template package is available from ARRL Technical Department Secretary, 225 Main St., Newington, CT 06111 for a business-size SASE. Address the request to the "Grebenkemper DC and AC Expanded-Range Voltmeter Template". ------------------------------------------------------------------------ FEEDBACK (FB) Title>FB1:QST Apr 1993 Product Reviews Author>Ford, Steve - WB8IMY and Jeff Bauer -WA1MBK Source>QST May 1993, pp. 74 Abstract>Errors in Product Reviews in QST April, 1993. Digest>In the April, 1993 Product Review of the AEA DSP-2232, pp. 65-66, the list price should be $999, not $899. Also the Doppler-shift correction feature has not yet been enabled. In the same issue's Product Review of the Outbacker antenna, p. 70,the model reviewed was the Perth model, not the JR8. The Perth has a main shaft of 4-foot length with 3-foot whip, whereas the JR8 is 4-feet overall. On 75 meters, the Perth resonates down to 3.6 MHz., as reported, but the JR-8 resonates only between 3.9 and 4.0 MHz. _________ Title>FB2:Dipoles Above Real Earth Author>Michaels, Charlie - W7XC Source>QST May 1993, p. 78 Abstract>Errors in Technical Correspondence item, page 68, QST Nov 1992. Also, Feedback in QST Feb 1993 regarding this same item wrongly changed Equation 1. Digest>Equations 3-5 of the Michaels letter titled: "Dipoles Above Real Earth" in Technical Correspondence, QST Nov 1992 contained errors. Corrections can be obtained from ARRL's Technical Department Secretary for an SASE. Ask for the Michaels Dipoles Corrections Template. Also, in QST Feb 1993 Feedback, Michaels advised that an error had been made in Equation 1 of the same 1992 letter. He now states that that was incorrect; Equation 1 as originally published in 1992 is correct. ------------------------------------------------------------------------ NEW HAM COMPANION This section is devoted to articles and short features of special interest to newcomers to the ham radio hobby. _________ Title>NHC1:And the Most Popular Frequency is... Author>Mabey, Jay - NU0X Source>QST May 1993, pp. 60-61 Abstract>A study of frequency distribution of repeaters on the 144 and 430 MHz. bands. Digest>This summarizes the number of repeaters on each frequency in the 2-meter and 70-centimeter bands throughout the United States and Canada. At last count, there were 6110 2-meter repeaters and 5059 70-centimeter repeaters! Certain frequencies are much more popular than others. There are 156 repeaters on the single frequency 146.940 MHz. On the 70-centimeter band, things are more spread out. The most popular frequency on that band, 444.500 MHz., has only 23 repeaters. The article also gives data on the number of "continuous tone-coded squelch systems" (CTCSS). These are systems that require a continuous audio tone to be transmitted by any transceiver that is accessing it. In some cases, they are used to prevent access by anyone other than a small group of members. In other cases, the tone signal required is openly published. On the 2-meter band, there are a total of 694 repeaters using CTCSS, 11 percent of the total. On the 70-centimeter band, there are 1131, or 22 percent. The author ends the article with a description of the ARRL REPEATER DIRECTORY, of which he is Editor. He says of it: "It is a complete directory of repeaters in the USA and Canada from 10 meters through 23 centimeters." _________ Title>NHC2:Do You Need an Audio Filter? Author>Gill, Steven J. - KG7YK Source>QST May 1993, pp. 62-63 Abstract>Mr. Gill describes what audio filters are and how they are used. He emphasizes their use in CW operations. He also makes mention of digital signal processing (DSP), but does not discuss it in depth. _________ Title>NHC3:The Doctor is IN p. 64 Author>Various Source>QST May 1993 - p. 64 Abstract>Questions and answers on topics of primary interest to newcomers. Digest>In this issue, the questions include: 10-10 numbers, r.f. feedback; the difference between a duplexer and a diplexer; computers for use in ham stations; the illegality of automatic, unattended station operations on HF bands; and what to do if electronic equipment gets water-soaked. _________ Title>NHC4:A Disguised Flagpole Antenna Author>Parker, Albert - p. 65 Source>QST May 1993, p. 65 Abstract>A description, with photographs, of a vertical antenna disguised as an attractive flagpole. _________ Title>NHC5:VHF/UHF Contesting Author>Ford, Steve - WB8IMY Source>QST May 1993, pp. 67-69 Abstract>A description of VHF/UHF contests, what they are, and when they take place. Digest>The author encourages newcomers to participate in VHF/UHF contests and gives hints concerning how to boost one's scores. He also discusses "grid square" designators and includes a map of the USA with grids indicated. ------------------------------------------------------------------------ RADIO TIPS (RT) These are short items, scattered among the articles in the NEW HAM COMPANION section. _________ Title>RT1:What Is AMTOR? Author>Ford, Steve - WB8IMY Source>QST May 1993, p.61 Abstract>A description of the amateur radio mode: AMTOR - AMateur Teleprinting Over Radio. _________ Title>RT2:Lightning! Author>Ford, Steve - WB8IMY Source>QST May 1993, p. 63 Abstract>Hams are warned to protect their radio equipment from the destructive effects of lightning. Digest>Antennas should have lightning arrestors with low-impedance leads to ground. All equipment should be protected and, preferably, disconnected from the antenna and also the power mains, when lightning conditions occur. _________ Title>RT3:The Ionosphere Author>Ford, Steve - WB8IMY Source>QST May 1993, p. 66 Abstract>A short description of the ionosphere including a diagram of the atmosphere showing the D, E, F1, and F2 layers. Also discusses the effects of ionization on radio propagation. _________ Title>RT4:Working the World on 10-Meters Author>Ford, Steve - WB8IMY Source>QST May 1993, p. 69 Abstract>A description of propagation conditions on 10-meters. Digest>Directed primarily to Novice or Technician class amateurs with HF priveleges, it describes the 10-meter band as a "real powerhouse". Even in the present declining phase of the sunspot cycle, exciting propagation happens unpredictably, and beginners are encouraged to monitor the band for openings. _________ Title>RT5:Is Amateur Radio Safe? Author>Ford, Steve - WB8IMY Source>QST May 1993 Abstract>Purported hazards of electromagnetic fields, including radio waves. Digest>This gives a balanced description of the questions that have been raised about the possible hazards of electromagnetic fields, including radio. Some sensible precautions are outlined for amateurs to follow when working with transmitters. ------------------------------------------------------------------------ GENERAL INTEREST ARTICLES _________ Title>GI1:Festing (Notes of a Hamologist" Author>Apteryx, Ann - W1NG/7 Source>QST May 1993 Abstract>Humor. Digest>This is a humorous article in which the author compares people-watching at a hamfest with bird-watching. Among the posited "bird-types" are the purple dealhunter (hunticus bargainicus), the wandering buynothing (optex non-purchasicus), and the lesser cheapskate (pricens reducensis). _________ Title>GI2:PHASE 3D - A Satellite for All -- Part 1 Author>Jansson, Dick - WD4FAB and Tynan, Bill - W3XO Source>QST May 1993, pp. 49-51 Abstract>A description of amateur satellites launched in the past, their limitations, and the ground equipment needed to use them; a discussion of why so few amateurs are doing so; and a description of the proposed new Phase 3D satellite now being built. Digest>The two authors are Vice President of Engineering and President, respectively, of Radio Amateur Satellite Corporation (AMSAT). In this article, they discuss the satellites that have been launched over the past 30 years and the ones that are in orbit now. They describe the different modes and methods of use that have been utilized in the past and speculate on why so few amateurs have actually tried to use them. They conclude that one reason is that many hams perceive that the technology is too difficult and/or the equipment too expensive for them to be interested. Another seems to be that many hams who are active in VHF and UHF are put off by the fact that satellites do not handle FM. The authors' rebuttal to the first objection is that the technology of operating through satellites is no more difficult or more expensive than other aspects of amateur radio operating. Regarding FM, they point out that if a satellite were designed for FM repeating, the power requirement would be prohibitive and the number of stations that could access the satellite at any one time would be so severely limited as to make it impractical. They make an adequate case that CW and SSB modes are necessary in satellite operations. Next, they discuss the kind of station equipment that is needed to take full advantage of the current satellites, especially the high-altitude ones. These, specifically OSCARs 10 and 13, provide nearly world-wide communications to amateurs throughout the world. They are in orbits in which the apogee (the point in the orbit that is farthest from earth) is so high that the satellite appears to move very slowly across the sky and stays visible for several hours each day. They make it possible for hams all over the northern hemisphere to communicate with each other. Finally, they discuss the new Phase 3D satellite that is under construction at this time. Oscars 10 and 13, the present "high-altitude birds", are reaching the ends of their operating lives. The Phase 3D will be the largest and, by far, the most sophisticated one ever launched. Because of its high-powered transmitters and extra-sensitive receivers, it will be possible for hams all over the world to access it using simpler equipment than is required with Oscars 10 and 13. Furthermore, it will be possible for ground-based repeaters to link with other repeaters long distances away via the satellite! The result may be hams communicating with each other over inter-continental distances using HTs! Next month, in Part 2 of this article, the authors will discuss design details of the Phase 3D satellite and its orbit. _________ Title>GI3:Inspiration: N2OVA Author>Lorito, Philip - WB2HDY Source>QST May 1993, pp. 52-55 Abstract>The true story of how a terminally ill boy became a ham in his final months on earth. Digest>This is a human-interest story about a young boy who was suffering from a terminal illness. His strongest wish was to become a radio ham. The author, and many other individuals, as well as the FCC, cooperated to make the boy's dream come true. His name was Jason Longboat, and his ham call was N2OVA. He received his license in early 1992, and died in November of that year, but his last months on earth were made distinctly happier through ham radio. _________ Title>GI4:Transmitter Hunting: Tracking Down the Fun - Part 2 Author>Moell, Joe - K0OV Source>QST May 1993, pp. 56-58 Abstract>Second installment of a description of radio direction finding as a competitive activity. Digest>In this article, Mr. Moell discusses details of organizing "Fox Hunts" and also describes different kinds of direction-finding equipment. In sidebars included with the article, there are discussions of several different types of RDF instruments that use something other than beam antennas to indicate bearing. One of these is a "homing set". The authors state that a homing set uses a pair of vertical antennas and a control box with a "right-left" indicator such as LEDs. However, they do not describe the principle of operation. Another type is the time-difference-of-arrival (TDOA) system. This uses two antennas that are switched in sequence at an audio rate. It is the same principle as was discussed in the article: "Build the HANDI- finder!" by K8DTS in this issue. The last type system described is doppler systems. These are usually mounted on vehicles, since they use multiple antennas (typically 4 or 8) which are rapidly sequenced to simulate a rotating antenna. As the putative antenna rotates, the received signal shifts up and down at an audio rate. The receiver detects this as an audio signal, the phase of which indicates the direction of arrival relative to the heading of the vehicle, and is often displayed on a CRT. This system is capable of giving instant display of heading from a short burst of transmitted signal. However, it is much less sensitive than beam antennas and cannot be carried on foot. ------------------------------------------------------------------------