70, APRIL 1989
Scanned, OCR'ed, and proofed by Bob "Bacon" Bruhns WA3WDR
10-METRE AM JAMBOREE MAY 5 - 7, 1989
Daylight Shifting Time
Daylight Shifting Time is a more appropriate name for DST, since it does not "save" a second of daylight, but merely shifts one hour of daylight from our morning routine to our evening routine. Some people think it is the best thing that has happened since the advent of radio, while others hate it. Undoubtedly a large segment of the population pays little attention to DST, since many Americans' lives revolve so completely around TV that as soon as the programs begin to come on an hour earlier, their daily routine immediately locks into step without disruption or confusion.
Me, I fall into the group which detests DST. The whole idea of setting the clocks ahead one hour and trying to convince ourselves that it is an hour later than it really is seems absurd, to say the least. Maybe I am one of a dwindling few who actually pay attention to such things as the sun, moon and stars. Whatever the reason, my body's internal clock never quite shifts to DST. The big analog 24-hour clock in my radio room which stays on GMT year round keeps me constantly aware of this exercise in what George Orwell called "doublethink". The bottom line is that I simply have to get up an hour earlier every morning and I hate it. Just when the days finally get long enough that it is actually light outside when I have to roll out of the sack, the time shift occurs and it's back to stumbling around in pitch black dark every morning trying to get ready for work. In my opinion, DST is nothing less than a plot concocted by the "day" people against those of us whose instincts happen to be nocturnal. Does anyone other than me find something stressful about DST? It is always such a feeling of relief in the autumn when the clocks go back to REAL time!
A few years ago, the politicians apparently decided that 6 months of DST wasn't enough, so they moved the time shift from the latter part of April (I remember it used to always occur over the weekend of the Dayton Hamvention) to the first weekend of the month. Maybe someone thought it appropriate that DST should become our national April Fool's joke. Speaking of April Fool's, the proponents of DST have used some rather bizarre arguments in recent years (there is a vocal group who continues to lobby for year-round DST). Supposedly, it saves energy, as if turning on the lights for one hour in the morning somehow consumes less energy than letting them run for the same length of time in the evening. The public has even been told that DST somehow reduces the "crime rate" and the use of illicit drugs! The next thing we'll be hearing is that DST will slow the spread of AIDS. On the other hand, those of us who primarily operate the lower frequency bands are robbed of one hour of nighttime propagation by DST, unless we are part of the small group of hams who get up early in the morning to operate 160 and 75. In midsummer, these bands are just beginning to open when it is bedtime for many of us. Since so much AM activity takes place on the lower bands even during static season, maybe we can blame DST for contributing to the dwindling of AM activity over the summer. (Hopefully 10 metre propagation will alleviate that trend for the next few years.) RF radio propagation is something else that keeps many of our bodily clocks locked onto real time.
Oh well, summer will soon be here and it will be nicer to spend our afternoons outside anyway. Let's get our antenna systems fine tuned and in first class shape for next season, and of course, we need some time to go through the goodies from the season's hamfests. Still, I prefer Standard Time. Happy April Fool's.
New Mailing Address
The AM Press/Exchange has a new mailing address. We have not moved, but the Post Office has renumbered all the rural mailing routes in the county. All correspondence should be sent to:
The AM Press/Exchange
2116 Old Dover Road
Woodlawn, TN 37191
The P.O. will continue to deliver mail bearing the old address, but they have requested that correspondents be made aware of the change as soon as possible.
This is a reader-supported publication, not a business enterprise. We depend almost entirely on subscription fees to cover costs of operation, with little or no advertising revenue. We also depend on our readers for the articles which appear each month. At present, we are only able to accept camera-ready manuscripts for timely publication. Camera-ready means that the manuscript is photocopied directly for publication; we do not re-type the articles. Sometimes minor corrections or alterations are made, but essentially each article is published exactly as received. It is up to the writer to submit copy that is "presentable" and free of typing and spelling errors. Since the editor/publisher is presently severely hampered by time limitation, it simply boils down to camera-ready articles or no more AM Press/Exchange.
Articles for publication may be typed directly to fit on one or more 7" X 8-1/2" pages with at least one quarter-inch margins on each side, top and bottom. They may also be typed on a standard 8-1/2 X 11 inch sheet, with the text (including titles) covering 8" X 10". Text of this latter format is reduced to 75% original size to fit our page size. In the near future an article will explain in greater detail how to put together camera ready articles for publication.
If you believe you have an idea for a really super article but for some reason cannot submit it typed camera ready, we will accept it, but be prepared to wait months, even a year or more, before it appears in print.
We again express our sincere thanks to those who continue to make this publication possible by submitting appropriate articles.
One final reminder: ads for our EXCHANGE section do not have to be submitted camera ready.
Those $9 Subscription Flyers
Several months ago we were forced to raise the AM P/X subscription rate to $10 to cover the increase in postal rates and increased printing expenses. Lately, we have been getting new subscriptions with $9 enclosed, along with copies of our old flyers listing the subscription as $9.00. Please - whoever is sending out flyers (the only "advertising" we are presently using) - mark through the $9 price and write in $10. So far, we have simply honoured the $9 subscriptions, but if large numbers of these continue to come in, we will be unable to afford any more "bargain introduction subscriptions". We are grateful to those readers who send out flyers to provide us with our only source of advertising; if you are interested in helping out, please write for flyers. These may be distributed at hamfests, clubs and in your amateur radio correspondence.
Nuts and Bolts of AM Operation
Would the author of the article entitled "Nuts and Bolts of AM Operation" please contact us immediately? Your name has become separated from the text of the article, and we have no way of crediting the article to its writer. Contributors, please write your name somewhere on the manuscript - on the back if it is not to be included in the text. Apparently this article got separated from the cover letter, and we generally do not save the envelopes. We would prefer not to run this article anonymously.
BITS & PIECES
By Rick Miczak, K8MLV/0
From Radio Netherlands' "Media Network" program:
FCC has decided to drop its proposal requiring manufacturers of shortwave receivers & scanners to place "WARNING" labels on these devices. These labels were to comply with the infamous Electronic Communications Privacy Act, ECPA, which was signed into law by President Reagan last year, which has set a dangerous precedent to the freedom to RECEIVE any radio signals on the spectrum, which Americans have enjoyed since the birth of real radio! Blame the cellular phone lobbyists & arrogant politicians for this one, folks! Apparently, FCC realizes this to be just another of the many unenforcible laws on the books, and is, therefore, watering it down. But, watch for future attempts by these unamericans to restrict frequency coverage of these devices!!
From "World of Radio" on WRNO-World-Wide Shortwave Radio:
A sample newsletter on HF SSB utility stations is available for a business size SASE to Tim Braun, 2064 Royal Fern Ct. #12B, Reston, VA 20191.
The NAB (National Assn of Broadcasters) experimental anti-skywave project should be on 1660 kcs, call-sign KA2XXB with power up to 5KW as soon as zoning discrepancies are resolved...from Maryland, I think.
From K4GYK on the 14.286 Mcs SPAM group (9PM ET daily):
Todd, WD4NGG, on Hilton Head Island, SC has a 100 mw beacon (CW, I assume) on 1637 kcs that has been heard in several states. I think the beacon ID is ABC. So far, not hrd in Colo! Hey Todd! Are you going into competition with the NAB??!?
West Coast Report
K7YIR, WA7AMI and W7JKY held a SPAM get-together at the Puyallup, Wash. ham swap-meet during March. * W6BM of Berkeley is back on A.M. with a 32V3 after a 15 year absence. * W6HDU of Alameda reports a Collins BC xmtr due to arrive in near future, for 1885 kc. operation. * N6CSW/0 of Durango, Colo. is starting a new radio magazine of interest to A.M.ers, CW artists, collectors, restorers, traders etc. * W6PSS of Chula Vista has MC'd restoration of the Saturday Night Bash - on 7290 kc. Starts around 10PM and lasts until the wee hours. * Note: more West Coast participation needed on 14,286 kc. to balance number of stations east/west. K6HQI and W6HDU holding their end up almost alone. * Central states A.M. heard almost nightly on 1945 kc. but mostly too weak to copy at W6RNC. * Psychological Warfare Suggestion: A better term than "slopbucket" or "sidewinder" is "SSB-A.M.er". After all, SSB is A.M. and I think calling them A.M.ers will really got to them. Besides, it might help elevate our status.
"Hoss-Traders" Returns To Deerfield
by Mark Ryan, WA1FAF
The largest ham radio flea market in New England, the Hoss-Traders Tailgate Swapfest, will be held in Deerfield, N.H., on Saturday, June 3, 1989. This is welcome and unexpected news, especially considering the recent history of this event. The purpose of this article is to explain what this swapfest has meant to AMers in the past, and what AMers can do to ensure its future.
So, for those who live outside the Northeast, a brief history of "Deerfield", as it is most often called, is in order. It was started in the mid 70's by Norm, WA1IVB, and Joe, K1RQG, among others, as a small flea market held in Seabrook, N.H., on the Saturday before Mothers Day, in May. After a year or two, the site was moved to the Deerfield Fairgrounds, a large, wooded area. The hamfest was held annually on the second Saturday in May. Around 1980, the hamfest had grown to such an extent that the hams needed to rent out the entire fairgrounds, after having previously shared the area with a horse show. Word was out that "Deerfield" had become a rite of spring. The dealings there were always friendly and low-key, the country atmosphere was refreshing, and it became the largest ham radio related social event in New England.
In the early 80's, a Hoss-Traders flea market was added at Deerfield in mid-October, usually on the Columbus Day weekend. Although the October crowds were never quite as large as in May, this move was met with widespread approval. AMers were especially active at the October Deerfield getting the parts necessary for those winter radio projects.
As the 80's continued, the Deerfield swapfests in spring and fall grew. Fortunately, the fairgrounds were spacious. There was room to camp out the Friday before and kibbitz, and get up on Saturday and have breakfast provided by one of the various clubs that fed the hams for the fest. We were never cramped. In May 1986, 7800 tickets were sold. This included SWLs, YLs and XYLs. That was one of the most memorable Deerfields ever. The weather was unusually warm, sunny, and in the 80s. And as the saying went, "It never rains on Deerfield."
There were signs of trouble among all the successes. The "freebie" pile had to be eliminated. People would leave behind their boat anchors in a selected area, and an alert AM homebrewer could find some pretty valuable parts. But the cost of trash removal became too high for the Hosstraders committee to remove what was left. The fairgrounds committee no longer considered the hams desirable tenants for a number of reasons. In 1986 and 1987, there were announcements made over the public address system that if the fairgrounds committee determined that the hams were not respecting the site and keeping it clean and safe, we would not be welcomed back to Deerfield.
Apparently, the fairgrounds committee felt that the warnings were not being heeded, and in early 1988, what we feared became official. The Hoss-Traders Swapfest would not be allowed in Deerfield. The Hoss-Traders threesome moved the event to the Kingston, New Hampshire fairgrounds. It would be held again on the traditional May date. Almost universally, area hams were somewhat disappointed at the move, but were willing to give Kingston a chance.
Kingston was clearly not Deerfield. The area was wide open and had no trees. That May day was hot and it was uncomfortable for some. Dry areas were dusty, wet areas were muddy. The women were particularly upset that there was no plumbing on the site and portable johnnies had to be used. It was not a place to have a social event. The May hamfest, however, had about 5000 people, a relatively good crowd. Still, it was obvious that practically no one liked the place. The October Kingston was a disaster. It was rainy and cold and the grounds were a sea of mud. At noontime there was a door prize drawing, and right after that was done, the place emptied. This was the earliest end to a Hoss-Traders event in memory.
The questions on everyone's mind over last winter was, "Where will the 1989 Hoss-Traders be?" When Norm, WA1IVB, announced that we would be returning home after a year's absence, joy spread over the land. The traditional May date was unavailable, so this year June 3 was chosen for the big event.
AMers can play a major role in keeping this hamfest where it belongs. Norm wrote me a letter and filled in what the conditions are. Open fires are strictly verboten, since there are a lot of wooden buildings and dry pine needles. Some hams have broken into some of these buildings to sleep in and the owners of these, especially the various food stands, have complained of damage. These are privately owned, not by the fairgrounds. Metal trash is not to be left behind. Alcohol is still allowed, just don't overdo it. These are all reasonable rules and with a little peer pressure, maybe everything will be cool.
There will be a greater presence of uniformed security. However, except for the date, all should be as good as ever. AMers have come to Deerfield from as far away as Pennsylvania and New Brunswick, and no one has left disappointed.
Come one, come all!! Bring your junque and set up a table. We have a second chance at Deerfield! Let's make it the best ever. As one will hear throughout the month of May, all across the AM window, "See you at Deerfield!".
Editor, AM P/X:
I tried the Bonadio Earth Shunt Wire on my 160 meter antenna which is 67' long (40 m. zepp) and 30' high. The BESW was 115' long - extending some 20' at each end of the antenna. I installed a relay so I could switch the BESW 'in' or 'out' during reception or transmission. I tried it over a six week period during both wet and dry earth conditions. I never saw the S-meter flicker and a friend with whom I have a weekly sked reports the same results on my transmissions. Did anyone else try this idea?
Bob Dennison, W2HBE
Editor, AM P/X:
I read the article by Rick, K8MLV/0 with great interest. Koby, K5MZH is a devoted friend of K5SWK, K5LLK, W5MEU, KA5THB, KF5TC, WD5EHS and many other AMers around the country.
His reasons for operating sideband (he has the best audio of any sidebander, and has taken great and exceptional measures to achieve it, and should be given credit for this fact) is that (1) he simply doesn't have the room for a 500 watt or 1000 watt transmitter and receiver for AM. His small mobile home is already jammed with his living quarters and furniture; (2) additionally, he is surrounded by 250 people, twenty feet from his shack on one side, and 450 people in an apartment building, on another side. The times he's operated AM he's been deluged by harassing telephone calls from these irate neighbors.
I submit that it's far better to have Koby as a friend than to have him operate a Ranger, which I'd never be able to hear, because of his 38-foot-high antenna, or stay off the air, or stay away from us. He's a good buffer to have around in case of malicious sideband interference.
I find the ravings of K8MLV/0 to be slightly paranoid.
Ed Bolton, WA3PUN
Editor, AM P/X:
After reading your comments regarding contesting in the March issue of the AM Press/Exchange, I felt compelled to write to you. First off, I have always loved the AM mode and monitor constantly on the 160, 80, and 20 meter bands. However, because of my QTH, which is located in Center City Philadelphia where antenna space is at a premium, I am relegated to operating AM only on the 10 and 6 meter bands. Even though I enjoy long ragchews on the AM mode, I also enjoy contesting on SSB. I'll admit that there are quite a few contesters who do not follow the rules in as much as they jeopardize the various "windows" and gentlemans agreements. However, many amateurs who do not engage in contesting can't see the point of it all - exchanging 5x9's, etc.
I have no intentions of changing your viewpoints on the subject of contesting especially where 160 meters is concerned, but there are many valid points of contesting to consider whether you approve of contests or not. For one, our great hobby of amateur radio is many things to many people. Just as you may love AM and enjoy long ragchews and rebuilding AM gear, etc, others get their enjoyment from collecting awards, QSL cards, and the like. What better way to accumulate needed states and countries than by joining the contest fray? Unfortunately, many US amateurs are ignorant of the fact that in many countries of the world and especially in the Soviet Union and in the Eastern Bloc Countries, amateur radio is considered a "sport" and not a hobby as it is to us - hence the term "radiosport." As a matter of fact, the winners of major contests hailing from these countries are looked upon as heroes and/or champions by common folk in their homelands.
Another point to consider is this - many of the antenna and propagation experts who write articles in the various ham publications are avid contesters. Much of what they have learned and developed (for everyone's benefit) has come directly from competition. You know, it's funny, for years I could never understand the reason for auto racing. It just seemed ridiculous to me that a bunch of cars would circle a track hundreds of times. It just didn't make sense to me. Then one day by a stroke of luck I sat next to a professional race car driver on a flight from Miami to Philadelphia. I told him my feelings towards the sport of auto racing and he politely pointed out the sport's contributions to society. For example, much of the technology utilized and/or incorporated into todays vehicles are a direct result of auto racing. How so? Take tires for instance. Many of the tires utilized on the racing circuit are returned to the manufacturer and are studied for improvements in tread design, wear, etc. Likewise, amateur radio contesting contributes certain benefits that all of us can share. As mentioned earlier, much of the information relating to antenna design and radio wave propagation as we know it today has come directly from hams who have been involved with contesting on a large scale. A great example of this is the fabulous antenna compendium which was put together by the late W2PV, who was an avid contester.
Let's face it, contesting isn't going to disappear. Yes, there are problems with certain competitions such as the various 160 meter events because of the various windows and gentlemans agreements which exist. However, you will find that most of the "problems" encountered are usually from the casual operator/contester and not from the hard-core fellows. The hard-core guys know the rules and for the most part respect the windows. Contesting may seem stupid and pointless to some but it is here to stay and is becoming more popular than ever.
Ham Radio is a diverse hobby, so whether your interest is AM, SSB, CW, ragchewing, contesting, DXing, or whatever, we should all respect each other's path to enjoyment and fun. As much as I enjoy AM, I can't imagine how boring ham radio would be if everyone would work the AM mode and engage in hour-long QSO's... blah!!!
Harry A. Schools KA3B
PLAN TO ATTEND THE
APRIL 28,29,30 1989
AM FORUM SATURDAY 2:30
- SPAM Update
- Meet The AMers Slide Show
- AM In The 1990s Guest Speaker - Don Chester: K4KYV
MAKING AM THE GREAT NEW GUY ON THE BLOCK
or HOW YOU CAN GREATLY OVERCOME
POWER LIMITATIONS ON AM
Copyrighted, 1988 by George A. H. Bonadio, W2WLR, Watertown, NY 13601-3829
YOUR 1:1 SWR MAY BE DECEIVING YOU
Years ago you could buy, factory new, E. F. Jonnson's Matchbox Tuners and other designs of tuners wherein you could tap your feeders onto a different reactance. Suddenly, only 6 months after my story was published showing the gross power factor problems with each of these systems, E. F. Johnson Co. had their famous Matchboxes off the market. This is because E. F. Johnson Co. was an honorable company.
Today, however, one popular publisher continues to push the (wasteful) tap down coil tuners. Either the editors do not read other publications (you guess why), or they do not believe stories published in other publications (you guess why), or they did not try the "proof of performance test" (part of "good engineering standards") (you guess why), which I laid out for the readers to do to convince themselves. I do not know why. Do you still use a Transmatch?
Here is the test that I did in many different experiments at two of my different home QTH'S. I ran my full 100 watt output transmitter power into a tuner which put all of its output directly into lighting a 100 watt lamp. I did this on every band of 160 through 10 meters. The bulb dimmed slightly towards the shorter wavelengths.
Each of these times I ran the transmitter through coax, to an SWR bridge, through more coax, to a tuner, to output terminals which could handle a 150 ohm lamp load. In each case I adjusted to an SWR of 1:1.
What I was looking for was an answer to my question: Does the high Q (bell-like "ringing") of a tuner properly handle an opposite reactance placed across only part of one of its own reactive elements? In other words: Will I be able to properly tune out the reactance of an inductive load across a part of a capacitor, or, likewise, the reactance of a capacitive load across part of an inductance of a used portion of a coil?
The Johnson Matchbox places feeders across part of its "differential" loading capacitors. The Transmatch places feeders across part of its used portion of its tapped coil inductor. These arrangements can be inefficient when driving loads of the opposite reactance. In about 40% of practical cases, there might be a very significant power factor problem. There was. There is. It does not go away. You can not tune it out. And this defeating "Power Factor Problem" can still waste substantial power even if your SWR bridge reads a perfect 1:1. Why?
When I went to my tuner and put a feeder of considerable length between my tuner and my dummy load bulb, I quickly had my answer. At some random wavelengths, the bulb was essentially as bright as before, but on others, the bulb was dim to very dim -- yet the SWR was still reading 1:1!
Then, when I changed the length or the impedance of the feeders, the "dim-bulb" bands all changed. Some formerly dim bands were back up to full brightness. One band showed no light at all, although there was some bulb warmth. Different lengths of coax and open wire feeders were tried. Out of six bands I always found at least two bands that were quite poor. Once I had four out of six bands at much less than normal, still all with SWRs reading 1:1!
However, if I took the feeders out, the bulb lit normally and of course best at 1:1, on every band, directly on the tuner terminals. The reactances, produced by the mismatch of the feeders to the bulb, are real and very significant. In one test on 160 meters using a coupler, I was able to quickly (soldering) change back and forth from a tapped coil to a series tuning of the same L & C. The SWR easily and quickly tuned to 1:1 in each case, but the total difference in receiving here was 10dB, and my contact out of town also estimated that I had a 10db signal difference.
Both circuits gave me an SWR of 1:1, yet one of the circuits lost about 90% of my outgoing and incoming signals. I reported this in my story. It was real.
E. F. Johnson Co. engineers must have had a hot session and then a series of tests. In six months, there were no new Matchboxes for sale. Personally, I have a hard time trusting another "authoritative representing" organization that continues to ignore these discoveries which must be an embarrassment to them. I feel that if they cannot admit this innocent engineering error of omission (I have done much worse), then should I trust their engineering representation of me to the F.C.C.? To ease my troubled conscience, I dropped my A.R.R.L. affiliation, those many years ago.
Avoiding these power factor problems is not difficult if in the original design one observes these Bonadio's Tuner Rules:
-Do not put feeder loads across only part of a tuner reactance that is in the circuit.
-Do not use a "differential" tuning capacitor for connecting feeders.
-Do not use taps onto a coil to connect feeders across a portion of the used part of a coil.
-Either use series tuning, or use parallel tuning in which the feeders connect simultaneously to both inductors and capacitors.
-Never use a fixed link for coupling.
-A swinging link, either series or parallel tuned, resonant at mid-band, with a Q of about 4 at 50 ohms, will adjust the impedance correctly, without excess heating.
-Resonance of the antenna L & C, at a Q in excess of 4, is enough to correct the link reactance also.
-Do not use tinned (the worst) wire, nor bare copper wire, which will corrode; the best being silver plated, even when stained.
-Do not use minimum solder, which is a dozen times more resistive than copper wire, but generously oversolder, or, best, use silver solder (which requires higher iron heat).
-Make sure your SWR meter reads the "Forward" level exactly the same on "Reflected" when the meter is removed and inserted backwards.
-Any finalized tuning that leaves a residual SWR is proof that the tuner is incapable of doing its job as adjusted with your load, perhaps due to too low of an "Operating Q".
-Never operate any tuner in which any turns of any coil are shorted out. Rather than shorting unused turns, just leave the unused coil ends unconnected.
-The best grounding is several grounding wires, from different directions, meeting at the tuner common grounding, which should include a metal case.
-Never power a tuner without a significant load connected to its output. (It may melt turns or arc.)
-An ideal design has a separate link coil and a separate antenna coil, switched in for each band, which can be left all tuned and loaded at the last frequency used on that band.
I have been using all of these except my case is 1/4" pegboard which holds 1/4" rods to capacitors and to swinging links. When we built my shack, I covered all but the window and the doors with overlapping foil. This shielding averages about -30 dB (full screening would be at least -60 dB) in and out.
The heavy duty bandswitch on my tuner includes extra positions which I use for dummy loads, outboard experiments, a lightning-short path (switch to "6 p.m."), antenna via twinlead to home radio, to a CB balun (unused) and a ferrite balun for any shortwave listening via coax.
Don't expect any such tuners on the market soon. It is a real project to build one. However, I run 700 watts of cw carrier through #18 silver plated copper with no significant heating. It has no power factor problem.
The primary problem with a proper tuner is that of finding a good "Q" for each band. Fig. 1 shows a tuner that has a tremendous range of possible loads that can be adjusted for a "Loaded Q" of 4 to 8.
A low Q will require tight coupling with the link. A high Q will need the link backed far out. Switching to parallel tuning as shown, will develop higher Q, as less coil is tapped for use. (Notice that no turns are shorted "out".) Table 4 values may be greatly reduced for most doublet operations.
In a series tuning, a higher Q is developed as more coil is used for resonance. Thus, this circuit is commercial and is designed for no power factor problem. It has a "tremendous" range to adjust for almost any feeders, even a single feeder alone, at a low Q, near 5, at very low losses, at a good medium bandwidth, with small and conservative parts, for economy.
Remember, any tuner that is of this design that tunes very sharply, or which does not reach an SWR of exactly "one-to-one", is not adjusted correctly.
The swinging link is shown in Fig. 2. I use parallel tuning on 160, 75 & 40 and series tuning on 20, 15 and 10. For the new minor bands, use an adjacent band setting.
In original construction, the link is disconnected completely, and if in series, temporarily connected in parallel. The link is adjusted for mid-band resonance and never retuned in operation. It is connected either in series or in parallel, as designed, at a Q of about 4. Either series at 4 x 50 ohms = 200 ohms reactance, or 50 ohms / 4 = 12.5 ohms in parallel tuning links.
Table 3 shows values of L & C for parallel links on 160, 75 & 40 and for series tuning on 20, 15 and 10 of Fig 2. Table 4 shows maximum values of L & C to have in Fig. 1. The high choices of ranges for Fig. 1 are needed in order to find the proper loaded Q at the resonance which will be found at different taps, for extremely hard to tune systems.
TABLE 3: 50 Ohm Swinging Link Design, Q of 4
|160||1 uH||8000 pF||Parallel|
|75||0.5 uH||4000 pF||Parallel|
|40||0.25 uH||2000 pF||Parallel|
|20||2.5 uH||60 pF||Series|
|15||1.8 uH||45 pF||Series|
|10||1.2 uH||30 pF||Series|
TABLE 4: Antenna L & C Maximum Values
|BAND||SPLIT L||C & C DUAL|
|160||100 uH||3200 & 3200 pF|
|75||50 uH||1600 & 1600 pF|
|40||25 uH||800 & 800 pF|
|20||13 uH||400 & 400 pF|
|15||9 uH||300 & 300 pF|
|10||6 uH||200 & 200 pF|
The leftover turns of coils must not be shorted out for the same reasons that you do not short out unused windings on power or audio transformers. These "hot" ends will not corona.
The large values of C may be made up from ceramic capacitors of 6,000V ratings, if each ceramic is not over 0.001 uf or 1,000 pf in a KW path. A series and parallel of these C's will handle 4 times the power before baking open, at the same C value but for twice the voltage ratings.
At powers under 500 watts, ceramics which operate warm enough to melt their wax should be replaced with two of the same voltage but each of half of the C value. Give them air space on both sides.
I used large compression capacitors of layers of mica, and inserted leaves to build up for my peaks. I bought extras and used two layers of mica between plates, and put them in series.
On voice peaks at the legal maximum power, the peak to peak r.f. voltage across the parallel link C's can reach 1,000 volts.
The coils themselves should be of large turns and relatively short. Long and slim coils look great but have poorer Q's than coils which are wider than they are long. This is why choke pies are wider than long, in spite of what you can find in a radio handbook.
These tuners will tune and load beautifully, broadly and with great efficiency. I would like to see a manufacturer produce them. Six tuners will cover 1.8 to 30 MHz and will be bigger than most "modern" tuners. I do not see any need for "automatic tuning" of this unit. I hear them and I work them easily on every band with this tuner; so can you.
Norm Scott, WB6TRQ, PO Box 27, Potrero, CA
ARRL Proposes Its Own Amateur Rules
(Newington, Connecticut) The American Radio Relay League (ARRL) filed comments with the FCC in response to the FCC's proposed reorganization of the Amateur Radio rules (PR Docket 88-139). Annexed to the League's comments, prepared by Counsel Christopher D. Imlay, was a complete rewrite of the rules developed by a committee of the ARRL Board of Directors.
The League's rewrite was developed over a seven-month period. In addition, the committee digested countless comments of individual League members. The final document represents the interests of the broadest majority of amateurs, while protecting the needs of minorities with special interests.
The FCC had succeeded in reducing the length of the present rules from 30,073 words to 24,397. The League's rewrite further reduced the length to 17,045 words without eliminating necessary substance by further editing, and retained the basic structure of the rules as proposed by the FCC.
A look at the League's new rules reveals no changes in issues which AMers face, such as AM for novices and 1KW AM transmitters. It makes one stop and think which minorities the League is protecting.
AM Forum at Dayton Hamvention
(Dayton, Ohio) On April 29, 1989 at 2:30 PM, Dale KW1I has put together an AM Forum. As a part of this forum, Dale needs 35 mm slides of your AM stations to be used in an AM slide show, "Meet The AMers."
I wish to thank Dale for all of his hard work in organizing this great event. We AMers are very fortunate to have people like Dale who are willing to give their time to help promote AM.
New Membership Rules for SPAM
(Potrero, CA.) The SPAM mailbag is overflowing, due in part to the ad in QST and all of the AM activity on the 10 meter band.
Many stations requesting membership in SPAM only operate on 10 meters. This is a problem, because due to the nature of the band, we have no SPAM nets on 10 meters, and therefore these stations can not check into a SPAM net as required to qualify for membership. Many SPAM members have written to me, requesting a change in these rules.
Membership in SPAM will be simplified as follows:
Application for SPAM membership shall include the names and calls of three SPAM member stations that the applicant worked while operating AM.
The names and calls will be checked against the SPAM roster and we will then issue the membership certificate.
All SPAM members can recruit new AMers with this new rule change, so go get them going.
(Names removed, past copy.)
WANTED: Collins books: "The First 50 Years, History of Collins Radio" and "Amateur Single Sideband". Also wanted Collins 180S-1 antenna tuner, any condition.
FOR SALE: Collins 75A4 with filters $175 plus UPS. Tubes 814 $10, 1625 $2, 813 $20, 807 $3, 805 $20. Inquire on others. Components, H.V. transformers, 15 amp 110 powerstat variac $50.
WANTED: Harvey Wells TBS-50A (or any series) transmitter with tubes, in good physical condition (not required to operate). Meissner Signal Shifter, model 9-1077/80 (plug-in coil type) in good physical condition (not required to operate).
FOR SALE: Hallicrafters HT-4I (same as BC-610I), extra 250TH finals, 100TH modulators, plate coils, grid tuning units. BC-614 speech amp and manual included. Excellent condx $300. R-392 general coverage receiver, power supply, speaker, manual, excellent $125. Hammarlund HQ-129X, manual, excellent $75. Hammarlund HQ-100 $95. Hallicrafters HT-33 linear amp uses 4CX300A's in final, manual, excellent $400.
WANTED: Top cover for R388/51J receiver.
WANTED: Dial drum or drum paper for 75A-4, mechanical filters for 75A-4, 2.1, 2.3, 6.0 kc, Central Electronics Linear Amp 600L, 7360 tubes.
FOR SALE: 1989 Kenwood TS-440S transceiver, 160 thru 10 metres, AM with SSB and CW. 100 watts output, solid state and brand new still sealed in sealed plastic cover. $925 delivered.
WANTED: Hammarlund HQ-215 service manual or copy.
WANTED: CHROME knobs for a Heathkit Mohawk receiver. Can be from Heathkit Apache transmitter.
FOR SALE: Two Collins VFO's (PTO), 70E-18 and 70E-15. $20 each including shipping or best offer.
WANTED: Audio transformers U.T.C. LS-49 and Chicago BD-2, or equivalent 30 watt driver xfmr to match push-pull-parallel 2A3's to class-B grids.
WANTED: Schematic and/or manual for a Sargent 8-34 communications receiver circa 1934 and a Stancor 440M modulator kit.
HAVE FUN ON 20 METER AM! Convert a Radio Shack TRC-218 AM CB handheld to 14286 khz., the 20 meter SPAM frequency. RF output 1-2 watts, receive sensitivity 0.8 uv. Just plug in 2 crystals, change capacitors only, and tune up. $79.95 check or money order.
FOR SALE: Heath Apache and SB10 sideband adapter, both working and very clean. $75 each or $125 for both. Hammarlund HQ-129 receiver with speaker $75.
WANTED: A good Heath DX-60B and VFO.
WANTED: Manual for a Heath DX-35. Will pay for shipping.
WANTED: 6 & 9 mc xtals for 50 cents to $1 apiece, frequency ranges 6.038 - 6.055, 6.233 - 6.247, and 9.032 - 9.057 mc. Will accept xtals a few hundred kcs out of these ranges.
This is the AM PRESS:
An amateur radio publication dedicated to Amplitude Modulation.
This is the AM EXCHANGE:
Offering FREE ADVERTISING to enhance the availability of AM equipment and parts.
DISPLAY ADVERTISING: Rates upon request.
Edited and published by Donald Chester, K4KYV
NOTICE: The purpose of this publication is the advancement of Amplitude Modulation in the Amateur Radio Service, and there is no pecuniary Interest. Therefore, permission is hereby expressed for the use of material contained herein without permission of the publisher, with the exception of specifically copyrighted articles, provided that The AM Press/Exchange is properly credited.