Live To Air – National NC-101X

Live To Air – National NC-101X finally back together tonight newly installed coil rack, with the bronze bushings and fabricated band indicator. Slides like it’s on glass, super smooth and low effort.

Listening to the melodious tones of the old Gray Hair Net, using Amplitude Modulation, on 160 meters shortwave. Exact frequency is 1.945 MHz. Not bad for a 80 year old radio, I think the original owner W1KEK would be pleased to know that his treasured set, that he bought back in 1937, has returned to the air.

Very pleased with how this project turned out. The audio is very sweet, with some nice wide bandwidth for hifi AM audio. Just waiting for the electrolytic filter capacitors to finish the project.

Tonight Radio Surgery – National NC-101X

Tonight, Radio surgery.
1937 National NC-101X shortwave receiver.
Replacing 80 year capacitors.
Four down, seventeen to go.
Making ready for another 80 years.

– Bruce

 

 

Collins 30K Series Transmitter Data Site

Collins 30K Series Transmitter Data Site

The purpose of this site is to act as central resource, or clearinghouse, for information, schematics, images, and tech tips on the Collins 30K series of transmitters. Many have been very generous over the last year, sharing tech information, scans of Collins docs, and service information with me, and this is my effort to give back to the 30K community. Thanks to John Dilk K2TQN efforts, the story of my 30K-1 station appeared in John’s “Vintage Radio” column in QST during late 2007. Since that time, I’ve been sent numerous images, photos, and stories from other hams about the 30K series. You can view the complete story at www.w1ujr.net/30k-1_restoration.htm

W1UJR StationOne of the greatest challenges I faced with the restoration of my 30K-1, and now with the 30K-4, is the lack of information. I felt collecting all this information which has been graciously shared with me, would be helpful to other 30K owners, and hams. Unfortunately much information have been lost over the preceding 60 years since the first 30K rolled off the line at Collins Radio. This site is an effort to capture, and share, what remains.

Let me begin with a few words about the 30K series. I have been a Collins fan since I was first licensed in the 1990s, but really fell in love with the 30K when I viewed one at the home of a fellow ham who owned the commercial version of the 30K-1, known as a 30K-5. Very similar in design, the 30K-4 and 5 are commercial models offering two discreet tank circuits for rapid frequency changes but lack the band switching arrangement of the 30K-1.

The 30K series was designed by Collins engineer Warren Bruene in 1945 and was first offered for sale the following year. It was, in some way, a “Hail Mary Pass” for Collins as the war contacts were drying up, and yet amateur radio operation was still banned during wartime. Collins forecast a pent up demand from the return of GIs from the war, and with the elimination of the wartime ban on amateur operation, hoped the 30K would fill the gap. Sales were somewhat limited as the 1946 cost of the 30K-1 transmitter and 310A exciter was $1450, the equivalent to approximately $15,000 in today’s dollars. According to Jay Miller’s, KK5IM, excellent publication, “The Pocket Guide to Collins Amateur Radio Equipment 1946-1980”, less than 100 of the 30K-1 are known to have been built, and few survive today, making the 30K-1 series a rare bird indeed. Less accurate records exist on the commercial variants, suffice to say they are not at all common.

Visually, the 30K transmitter series are most impressive to behold, housed in a cabinet 5 ½ feet tall, finished in black wrinkle paint, and weighing over 350lbs, this is a big transmitter! The design of the unit is pure art deco; vertical and horizontal chrome accent strips, a large window for viewing the 4-125 final tube, and a most impressive meter panel at the top of the cabinet, also housed behind glass. Looking every inch a serious transmitter, the 30K is of robust construction along the lines of commercial broadcast gear. Emission modes are CW and Fone (AM), with the plate input power given as 500 watts on CW, and 375 watts on AM. The 30K-1 offered coverage from 80 to 10 meters using two plug-in output coils. With a tube compliment of 11 tubes in the transmitter, and 10 tubes in the 310A exciter, the 30K station as much a delight to operate, as it is to look at.

In closing, my thanks to those who have taken the time to send in photos, scans, stories, or to share their experiences over the years, please feel free to contact me or forward information which you feel may be of value or interest to other 30K owners.

73 Bruce W1UJR

Yes Virginia, There is a Zorch God

*Circa August 13, 2005

Today in the middle of a FB QSO with K1MVP the plate blocking capacitor in my 32V crapped out.

Collins 32V Transmitter

This was evidenced by an immediate loss of RF, a loud hum and the telltale pegged plate current meter. Even my trusty old buzzard RF indictor, a large neon bulb JS lashed onto to my balanced feedline terminals, showed no glowage, a very bad sign. When something like this happens out of the blue, a thousand thoughts run through your mind. Is it the final tube, did I inadvertently hit some knob, did the modulator transformer give up the ghost? I quickly unkeyed the transmitter thinking my antenna relay had stuck, as Dowkeys sometimes do. A check of the relay showed that all was intact and the fault must lie elsewhere. Switching between bands or from Fone to CW had no effect, still a pegged plate meter. I considered that something may have happened to my antenna or feedline, but transmitting into the dummy load brought the same result.

I should mention that this was my Elmer’s, W2UJR – now a Silent Key, former transmitter, so the thought of some major failure made my heart sink. When I obtained the unit from Dick’s estate, I had brought it back to life by replacing a stubborn failed screen bypass capacitor on the 4D32 final tube. Since that time it had run flawlessly, despite the somewhat troublesome reputation of the 32V series. The unit had followed me from Buffalo when I moved to Maine and had become my backup 75 meter transmitter at the office. Rumor had it that Dick only ran it on CW as he did not care for the lack of civility on 75 meter Fone.

Ironically I had just been on the telephone earlier in the day speaking to my friend and fellow Collins enthusiast, Bill K2LNU. Bill shared that, after he had spent countless hours working on them, he was now seriously considering selling some of his Collins 32V transmitters because they were such a project to service. With that cheery thought in mind it was out of the cabinet with the 110 lb transmitter, an exercise which had become an all too common event.

I say common as for most of the proceeding week I had been working on a new acquisition to the W1UJR hamshack. A exceptionally recalcitrant Collins 32V3 which displayed a most troubling linearity fault with the Permeability Tuned Oscillator (PTO). It was only after multiple attempts to diligently adjust the linearity, as specified in the service manual, each involving a trip in and then out of the cabinet, that I discovered that the linearity simply could not be restored to the 50 year old PTO. A returned call from Collins guru Howard Mills W3HM confirmed this and I was informed that some years back Dallas Langford had discovered that the ferrite compound used by Collins in the PTO changed its molecular structure with time. So it seems that unlike wine, ferrite does not improve with age, hence the PTO would no longer track properly. As the PTO was a relatively recent invention at the time, Collins had no way of knowing of this during the initial design of the 32V series. Indeed its doubtful they anticipated their handiwork would still be in used half a century later, so no provision was included in the PTO design to compensate for the ferrite change. Anyway, back to our story.

With my failed 32V on the bench I did a quick check of the mica capacitors used in the output loading network. In the 32V series these capacitors are always suspect and have a high failure rate, especially when used with non-resonant antennas. Still, each of the mica loading capacitors checked fine with the DVM, not a fault among them. This meant that I had to dig digger, or in other words this going to take some time. The next step was to remove the plate connector from the top of 4D32 final tube and see what happened with the plate current. I suspected that the tube had perhaps experienced some catastrophic internal failure. Yet again I was stymied, the tube tested out fine, and I still found pegged plate current with the tube plate capacitor removed.

Curiosity got the better of me and I then removed the tube completely from the socket and applied plate current, same result, pegged plate meter. Since the final tube was entirely out of circuit and I still had excessive plate current, as a quick test I removed the coax connector from the rear of the transmitter, Eureka, plate current was now at zero. I now knew that a fault existed in the output network, but where? The 32V series is one of the most tightly packed and difficult transmitters which I have worked on. Despite Collins excellent manuals and documentation, service on these units requires both a great deal of patience and dexterity.

At that very moment I was on the air with Larry NE1S, yes, multitasking. Carrying out a QSO and checking for plate voltage may not be the wisest course if one wants to enjoy a long life. However, in this case it had a payoff. I described the fault to him and explained my findings. Larry confidently asserted that, given my symptoms, it could only be one thing, a failed plate blocking capacitor. With the transmitter keyed, I checked for plate voltage at the RF connector, 890 volts! Sure enough, the plate blocking capacitor was allowing full plate voltage to show up on the output of the antenna! Instead of blocking the plate DC, it was in fact conducting it! Not exactly a safe thing, in fact it was downright dangerous. If I had not had the tuner in line, full plate voltage would be applied to the antenna feedline and leads, ready to zap some unsuspecting passerby. So with that discovery, the next logical step was to unsolder one lead of the plate blocking capacitor. A resistance check showed that my plate blocking capacitor was now a resistor, reading about 23 ohms on the trusty Fluke meter.

The capacitor in question is one of the older square mica capacitors that you see in transmitter output networks, with two mounting holes and solder tabs on the end. This capacitor in particular was rated at 2500 working volts and 5000 test with a value of .001. It displayed no visual sign of failure, no burn marks, case swelling or discoloration. For all intents it looked like a good capacitor, in fact it looked new.

Collins 32V Transmitter

As I mentioned before, the 32Vs are a real challenge to service.
If you have ever had the joy of replacing the plate blocking capacitor in a 32V, heck if you have done any service at all on these 32V series rigs at all, you know what a project this was. A quick check of the spare parts bin yielded the needed capacitor, those $5 coffee cans of parts dug out from under tables at hamfests sure do pay off.

Failed Collins 32V Plate Blocking Cap

However, finding the capacitor was the simple part. It took me nearly 90 minutes to remove two screws and solder connections on the failed capacitor and install the replacement. The Collins design team had conveniently located the plate blocking capacitor about 3/8 of an inch from a large wound loading coil. Since access to the Phillips head screws which retained the plate capacitor was simply not possible with a screwdriver, I had to settle for turning each screw 1/8 of a turn at a time with a pair of needle nose pliers. So to say things are tight inside the 32V is a major understatement.

Failed Collins 32V Plate Blocking Cap

Curiosity and abundant spare time got the better of me and I decided to open the defective capacitor up for an examination. After all, things that zorch out are often pretty interesting to look at. By examining the exterior of the capacitor I could see a manufacturing molding line around the upper edge of the case.
Using a bench grinder, I carefully ground away the edges of the case, removing the bonding joint of the upper and lower sections. A small chisel was then used to split the case halves open for a visual inspection. It was quickly apparent what had failed on the capacitor. The center section of the mica had been carbonized from end to end, essentially creating a carbon composition resistor. No wonder at all that I measured 23 ohms of resistance across what was once a capacitor.

So, can those more knowledgeable than I, which is probably a good number of you out there, offer up an explanation why this occurred? Operating plate current was normal, perhaps a tad conservative before the failure as this is my Elmer�s former TX and I run her lightly.

Did the 50 years finally catch up with the capacitor, or did the Zorch Gods just decide it was time? Are there other causes for this? If so I’d like correct them so I don’t have to replace another.

Bruce W1UJR

The Zig Zag Loop

Intro
This was written back in the last 1990s when I lived near Buffalo, NY, in a suburb that had zero lot lines, and little space for antennas. A vacant field in back of my home became the antenna field for my station.
– Bruce W1UJR

Where there is a will…

Often, one of the first problems one encounters when first getting onto the HF bands is the antenna. It is now a simple matter to buy a commercially manufactured transceiver, but the antenna still remains the biggest challenge. At times it is the ability to even have an antenna, such in the case of covenant and deed restrictions, or local town ordinances. But often it is simply that newcomer lacks sufficient room to allow the installation of a decent “skyhook”.

Such was my case nearly 5 years ago. I had purchased my home before I was licensed, and as such did not anticipate the need for extra land to accommodate an antenna. Nor, as it turns out, would my homeowners association permit the installation of a tower. After some pondering, and being resourceful, as we hams often are, I was able to use a large undeveloped tract of land in back of my home to erect a 160-meter loop antenna. In part thanks to the natural tree supports, I was able to secure over 500 feet of wire suspended in the air, ready to send and receive RF.

How did work? Well if you read my article last year, you know that it worked great! It was quiet on receive, as loops typically are, and radiated strapping signal with very few RFI issues. You will notice that I use the past tense in talking about my 160-meter loop, as it now no longer exists.

In the name of what goes as progress today, the developer deceived it was time to cut down all of those nasty trees that once proudly held my antenna, and turn the forest floor into a brown, muddy, soupy mess for all the neighborhood to enjoy. Aside from my new eyesore, I faced a more critical problem, critical at least for me as a ham. No antenna. No antenna equals no fun. While I was away in Maine, the contractor clearing the land had cut the wire for my antenna in half. My fault really for not removing it earlier.

So what does one do with 250 feet of wire on a piece of property that measures perhaps 160 feet in depth, by 60 feet in width? I pondered making a large loop antenna that would surround the perimeter, but quickly dismissed the idea in light of the RFI, which would be experienced by my own home, and my neighbors. The beauty of my former loop was that it was in back of my house, and the RF radiated out into the woods not scrambling anyone’s TV or phone, just warming a few chestnuts and squirrels.

I thought for a bit, and then it dawned up me. (I wish that I would say it came to me as a blinding light and a flash of inspiration, but that never seems to be my case. Instead it was only after downing a good part of a pot of very black coffee one evening.) Sure my loop used to be horizontal, but it would also work in the vertical plane, in fact it would radiate irrespective of its orientation to the ground. The wire does not know or care which way it is suspended; it just wants to get rid of the RF, caring not a bit which way it sends it out. Hence the creation of what I fondly term as my “Zig-Zag” loop.

Imagine if you will, a loop antenna where three sides are horizontal to the ground, but the fourth side is vertical. In fact, not just vertical, but “zig-zagging” several times from the tops of the trees, to about 7 feet from the ground. Using my trusty slingshot I was able to launch my antenna support ropes into the trees perhaps 40 feet in the air. I then attached the antenna wire to this rope, pulled it up to nearly its full height. The dangling wire was then tied off about 7 feet from the ground, and the process repeated again, resulting in a series of zigs and zags. This allowed me to fit 250 feet of wire into an area that really would have been hard pressed to allow even a quarter of that. Each 40 foot vertical excursion ate up 40 feet of wire, creating an antenna that was electrically a full wave loop on 75 meters, but physically took up very little room.

How does it work you may ask? In one word, outstanding! I was able to do my first formal check-in on the STARS Saturday morning net last week, and the signal reports were excellent. Perhaps slight decreases from the longer loop, but respectable never the less. As far as loading up with my transmatch, no problem on 75, 40 or 20 meters. I have not tried the higher bands yet, but I suspect the same results. And reception? It is very good, and quite, nearly free of all of the RF hash emitted by the numerous light dimmers, TVs, and other electric noisemakers in my neighborhood.

Is there a lesson in this? Not really, I just had some extra time and owed Terry an article. Of course that is a lesson here, something that we can all learn from. First, when you buy a home, consider the important things, like how many trees there are for antenna supports, will the power service handle that legal limit amp you just built up, and how much space is there to install that beverage antenna you have been dreaming about for the last 10 years. Let the XYL be concerned about the other minor details like local schools, exterior color and price, you need to concern yourself with the important things! Those of us already in a home are often challenged in the amount of space we have to erect our antennas. Do not let this discourage you. Often we think we need to have large elaborate antenna arrays to enjoy the hobby, and to radiate an effective signal. Nothing could be farther from the truth. You can spend thousand of dollars on commercial antennas when a simple spool of #18 wire will at times work just as well, if not better.

Like the solution to so many other problems, return to the roots. Experiment! Whether you use my zigzag loop, a folded dipole, or other form of shortened antenna, do not give up. Too often if a “textbook” antenna cannot be erected, we give up the battle. The funny, and really delightful thing about antennas is that there is no such thing as a textbook antenna. Each and every QTH is different, and what works for your friend a few miles down the road, may not work for you. Ground conductivities, houses, trees, and other RF reflectors and absorbers all vary with location. Get out there, try and experiment, you will be pleasantly surprised. After all, even the smallest wire can radiate and receive, and something, no matter how small, is better than nothing.

Where there is a will, there is a way!

73 Bruce KG2IC

Why Not A Wire Loop Antenna?

Intro
This was written back in the last 1990s when I lived near Buffalo, NY, in a suburb that had zero lot lines, and little space for antennas. A vacant field in back of my home became the antenna field for my station.
– Bruce W1UJR

As some of you may know, I am an advocate for wire antennas, and have been experimenting with horizontal loop antennas for HF work. I am currently running a 160-meter full wave loop that is suspended about 30-40 feet off the ground. Although the feedline for my loop is currently coax, in future installations I am considering the use of balanced, or open wire feedline for reasons of low loss, which may be the topic of a future article.

One caveat that I should mention before I start. The majority of my operating, and hence my observations, is on the lower bands, typically 160 through 40 meters. At these frequencies, the use of a yagi antenna is often impractical due to size constraints. If you do operate on 20 meters and up, you may find a yagi a better choice than the loop for its gain and directivity. That being said, what holds true for a loop at 160 meters, also holds true at 10 meters, so even those who operate on the “high bands” should find something of interest here.

Wire Loop Antena

The loop antenna has a long and distinguished history, but is often overlooked in light of the current focus on dipoles. However, loops do have some rather significant advantages over a dipole. Since the design of a loop is typically a circle or square form, the need for a long straight run of wire used by a dipole is diminished. A loop is quite forgiving, and perfect symmetry is not essential. It is necessary only to hang it in the configuration providing the greatest enclosed area. As such a loop can be strung up in unusual places and still perform well. Treetop suspension is ideal, but you’ll be surprised how well it works just lying on the roof where nobody sees it. Unlike a dipole that must be center fed, the loop can be feed at any point, allowing a most flexible feedline arrangement.

A loop is an efficient broadband radiator, even when low to the ground. The majority of the amateur bands are harmonically related, typically the 1st harmonic. This is where the loop really shines, as a loop is easily tuned to resonance on all even harmonics of its fundamental frequency. A dipole by contrast is easily tuned to resonance only on its odd harmonics. A loop starts out with 1.2 dB of gain over a dipole on its fundamental frequency, and gains are even higher if the antenna is less than a quarter wave off the ground because that is where the dipole efficiency plummets. For example, in my location my loop is quite close to the ground, only about 30-40 feet up at the highest point. Nevertheless, the antenna both tunes, and transmits just fine.

A loop’s gain over a resonant dipole increases with the increasing frequency of operation, so when used on its harmonics, a loop’s signal advantage over a dipole likewise increases. For a horizontal loop, that’s not the end of the good news, because as frequency rises, radiation angle drops lower and lower, producing increasing DX results that can rival a complex multi-element beam mounted on a 100-ft tower.

The venerable loop is easy for your tuner to match, even when fed with coax. The feedpoint impedance of a loop never gets as high or low as with an antenna that has free ends. Even a 40-meter loop can offer full 80- 10-meter coverage. My 160-meter loop allows me to both receive and transmit from the 160-meter band to 10 meters. Signal reception is also quite good with a loop for a number of reasons. As it is a terminated antenna, it is much less susceptible to atmospheric and man-made noise. As the majority of man-made noise is vertically polarized, the horizontal polarized loop can reduce electrostatic noise as much as 26db when compared to dipoles or verticals, so it is great for noisy RF areas.

The theoretical feedpoint impedance for a full wave loop antenna is approximately 100 ohms, but this does change, and is dependent upon antenna height above ground, near-by structures, and ground conductivity. When used with a 2:1 balun this presents a good match to the typical 50-ohm coax. Due to the low height above ground of my loop, I used a 4:1 balun which seems to offer a wider tuning range (lower Q). With the use of a transmatch (antenna tuner) I am now able to use my loop from 160 to 10 meters.

Loops can be either a 1/2 or full wavelength long. The formula for a full wave loop antenna is as follows: Length (feet) = 1005/fMHz. For example, a loop for the frequency of 3.800 MHz would be calculated as follows: 1005/3.8 = 264 feet. You can now divide 264 by 4 to obtain the length of each of the four legs of the loop. 264/4 = 66 feet each leg.

So next time you need a new antenna installation, consider the time-honored loop. Simple and inexpensive to homebrew, you can put the money you saved toward something really important…like a trip to this years Dayton Hamvention!

-Bruce KG2IC

Special Event Stations – If You Built It They Will Come

Intro
The above work was published in the September 2002 edition of Electric Radio magazine.

This article was to about last May’s AM Special Event in Portland, Maine, but with my recent move to the state, coupled with my search for a new business the writing was pushed to the back shelf. So when I contacted Barry a few weeks ago I offered a new twist, rather than just tell you about all the fun we had with the station, I wanted to exhort you to set up your own AM Special Event station, and in the process share some of my trials and tribulations, on how to go about getting your station on the air.

Why

Field Day In The Snow

The first question you might ask is “Why set up an AM Special Event Station in the first place?” Which, after working on several of these events, from the Dayton Hamvention to the Buffalo Hamfest, I often ask myself. Why lug a couple hundred pounds of quite valuable gear out of your basement, wrangle with the hamfest committee over operation and placement, round up your contingent of operators, and spend less time operating than setting up the station? Why indeed! The answer is rather simple, because it’s worth it. Sure we can operate from the comfort of our hamshacks at any time, but if you do that you are missing fully half of the fun of this hobby. You see, radio is about people, radio isn’t just about vacuum tubes, feedlines and SWR.

Radio is also about people, their lives, hobbies, and passions. And no mode portrays the richness of the human experience like AM. Alright, I’m biased. I like Amplitude Modulation, in fact like may be too light of a word for it, I am in awe of AM. I have found time and time again that there is no finer mode to bring in listeners like the rich, full sound of AM. I see it time and time again when we run one of these stations, a small crowd will gather around the speaker, listening to our operator hold forth with another station. I can divide this group into two distinct subgroups, those new to the hobby, and those who once ran AM but left the mode decades ago.

 How

The first step to getting a special event station off the ground is get approval from the club hosting the hamfest. Assuming you want to run the station at a hamfest, for nothing prevents you from making your own event, setting your station up for a local Boy Scout troop, church group, or in the neighborhood shopping mall. In fact, as you would not be “preaching to the choir”, it could be argued that these places might be even more effective than a hamfest. But for sake of argument let’s assume you are now trying to justify your stations existence to a local hamfest committee.

The first objection to come up will almost invariably be the concern of RFI to the public address system. Safety, too much power consumption or not enough space are usually next on the list. You can easily handle these objections by having a prepared station layout; photos are idea for this, showing antenna position, power consumption, and RF output. I used to lug the T368 around to fests, but after suffering a hernia –really, I have found that DX-100 power, anything over 100 watts is more than enough to make excellent contacts if the bands are in good shape and the antenna efficient. Our station at Dayton in 2000 was only a DX-100 transmitter and NC-300 receiver, coupled to a dipole fed with balanced line. The entire station, along with AMI and Electric Radio information, fit on a 24” x 36” folding table and while transmitting used well under 20 amps of current. It’s hard to object to a station of that size using that moderate level of power. If you can, bring along a decent external speaker, nothing will draw in passersby like a large public address speaker, at a moderate audio level, reproducing the rich fullness of the AM signal. Time and time again onlookers have been amazed at how good the audio can sound when it is not exiting via the 3” speaker in their solid state rig.

Be sure to mention to your hamfest hosts the attention you station will bring to their event. Often the powers that be are not aware of the significant following enjoyed by AM, too often dismissing it as an antique mode. Prepare ahead of time a ready listing of methods that you will be promoting the station, and their hamfest at hand. Free publicity, with the attendant rise in admission receipts can work wonders for small fest. Be sure to follow up on this, postings on the AM Window and AM Fone websites, as well as mentions in the Special Event QST can make a real difference. Don’t hesitate to let your local new media know about your “vintage station”. A simple press release, faxed to newspapers, radio and TV can do wonders in a small town. (If you would like an example press release just email me.)

Once you have the official thumbs up it is now time to scout out venue well before the operating day. All hamfests are not created equal and it is important to inspect the site for any “skyhooks” to use for antenna supports, power lines to be avoided, and a spot out of the sun to place your station. The obvious safety concerns of feedline placement distance for power lines and such apply, just use common sense. Make a written list of extension cables, coax, antenna supports, and other gear. Such a list assures you a quick station set up on the hamfest morning with a manual of headaches.

Now the easy part. Recruit your help. The effort to set up and operate a successful Special Event station can simple with the right help. I have been fortunate to always find a good number of volunteers who cheerfully chip in to set up and operate the station. Assign two teams, one for setup and breakdown at the end of the event, and another team to operate during the hamfest. I find that I am often too tired to do much operating after night and early morning setup project. Most hamfests last 4-5 hours, so be sure to have at least 3-4 ops to keep the station on the air, allowing everyone to get his or her turn at the coffee, donuts and other hamfest goodies.

I won’t enter into the debate of the “channel” AM operation, but it is important to operate near one of the key AM “windows”. Allow yourself some space, say 10kc as not to interfere with adjacent QSOs. I have found, the hours of the typically hamfest, the 75 and 40 meter bands are ideal. 3.875 and 7.280MC are idea frequencies for your station. Close enough to the AM window to be found easily, but separated by enough space so as not to cause QRM.

Plan for QRM, like it or not, it does happen. Try to find someone with a high power station to act as the “Channel Master” or anchor station and keep the frequency open. It is a good plan to have your QRO station come on at least ½ hour before your station formally goes on the air.

On The Air

If you can, have some, coffee and donuts waiting for your crew when they arrive to set up the station. Be sure to allow plenty of time for antenna and power supply issues. Once you get on the air, or as we say here in Maine, on the “ayah”, log, log, log. Keep a written log of your contacts; make some notes on each QSO for later reference.

Dayton 2000 Log Page 1

Think about your audience, and remember, many of your observers will just be familiar with the standard banter of 2 meter FM, or the quick signal exchanges of DXing, so try to get a fast paced roundtable going. Make notes of the other stations configuration, how long have they been licensed, antenna layout and such go a long way toward showcasing the relaxed mode of AM for those listening in.

Be sure to invite the now gathering crowd to actually operate the station. This tax your persuasive powers for often times your audience will be mic shy. If you find this the case, gently coax and offer them a few questions to ask the op on the other end. If you are lucky enough to have an YL observing, be sure to invite her to operate. Nothing creates a pileup quicker than a female voice. Explain to how to tune the transmitter, how to zero beat the receiver, which may be terms and concepts new to many of your observers.

Goodies

I find it helpful to have handouts at the station. The AMI brochure (contact Dale KW1I for this) or WB3HUZ’s explanation of how to properly run AM on a solid state rig is very good, as are the URLs of various AM and vintage gear websites. You might want to contact Barry to obtain some issues of Electric Radio to sell, and don’t forget the ARRL. The League, which after all exists to promote radio, is an excellent source of many free pamphlets regarding the radio hobby.

Radio parts, old tubes, variable caps, inductors, old QSTs, which many of us have in abundance, are excellent props to have on hand. Show the crowd what a vacuum tube really looks like. If you can, bring in a homebrew transmitter or receiver to show the crowd. People are fascinated when they can see and understand how a radio really works. Today’s equipment, as compact and versatile as it may be, lacks the charisma and “soul” that a nice old tube set has. Open the top of the reviver and transmitter and let your observers see the inside of the radio, the glow of the vacuum tubes, and the purple glow of the 866s. I will wager you that the “ohh” and “ahh” factor will far exceed what you will receive from the stations solid state cousins. If you can, have a small notebook where your crew and spectators can sign in with their name, call and email address. Such a guestbook is very helpful for developing next year’s operation, and provides the hamfest hosts of the station traffic.

Dayton 2000 K4KVY and N2QLS

Keep in mind our three goals; the first is simply to have fun. Lets face it, as magnanimous as it is to want to introduce newcomers to the joys of vintage gear; you are never going to want to make the effort to set up the station again unless you and the other ops enjoy themselves. Our second goal, to borrow a phrase is to be an “AM Ambassador”. This is something that we hopefully practice anytime we are on the air, but at no time is it more important that when operating a high profile Special Event station. Be courteous to those calling in, try to have short chats rather than just callsign exchanges, ask about their station, years licensed and then be sure to thank them for checking in. If you are able to get a roundtable QSO going so much the better, such dialogue really showcases the best of AM operation. Our last goal, and perhaps most important, is to introduce newcomers to the hobby, and to remind those older ops of the pleasures of operating vintage gear.

There is nothing like having an old timer sit down and explain his amazement that AM is still around and relate his experiences homebrewing in the 30s and 40s. Or the new ham, armed only with an HT, which is magically drawn to radios that glow in the dark. Get ready for converts and to hear many memorable stories.

Tying the Ribbons on It

Once your operation is done, the equipment packed away, be sure to thank your hamfest hosts for the space. Chances are your hosts are going to be pleasantly surprised at the turnout and crowd your small station drew. But just in case, be ready to address any concerns that they might have while mentioning that you would like to meet soon to begin planning next year’s station.

Next take your crew of ops, and be sure to invite any new converts, out for lunch and some well deserved cold 807s. This is an excellent time to critique the operation, discuss next year’s station and initiate the newcomers in the world of glow in the dark radios.

Everyone loves to look at photos of the latest hamfest event, so be sure to bring along your camera. Digital cameras are excellent for the ease of putting these photos up on the web. Do your best to shoot a group photo in front of the station, and send off a copy to your crew, aside from reminding you how much fun you had, it will go a long way to rounding up help for next years event.

If you can, scan in your logbook and put it up on the web. Or if you manage to find some very patient and considerate soul, you could even design and mail out your own QSL cards for the event. I still have the very attractive Dayton QSL card that KW1I designed a few years back.

When all this is done, give yourself a good pat on the back. Setting up such a station is not an easy task, but take heart, it does get easier and more enjoyable each time. Know that while you are providing a fun morning diversion for you and your ham buddies, you are also doing a great service for the hobby. Your station can demonstrate the magic of radio to a prospective ham, enrich the radio experience for newcomers, provide an impetus to get back on the air for the inactive, trigger some fond memories in our older hams, and end up costing you no more than a few cold beers. I would say that is bargain indeed! 

 73 Bruce W1UJR 

AM Dictionary and Glossary

AM Glossary

The AM hobby is rich with specialized terms and phrases that mark the unique character of this special mode of modulation. 

Feel free to send me your favorites!
 

AM Amplitude Modulation, a method of modulation that utilizes two sidebands and a carrier. Know for it’s full, rich audio quality, and personal interaction. AM offers a fraternity unique among the various divisions of amateur radio hobby
AMer One who uses the AM mode. Often technically inclined, using home-brew, or modified transmitter. Uses words like “Yellowly, PW and Strap”.
AM Window A fictitious invention of the ARRL. 
AM operation is legal anywhere in the Phone area of the band. 
B.A. Abbreviation for ball assembly. “That guy’s voice was so low, it sounded like he had a third BA.”
Crapped Out Failed in service, Gave up the ghost. Usage: My modulator tube just crapped out. Lesser version of zorch. 
Crapstal  Small piece of X or Y cut quartz that oscillates at a given frequency when current applied. Used to generate stable frequency of Amplitude Modulation transmitter. Hams using other modes often refer to them as “crystals”.
Cunt’rent A substitute term for current.
Deerchester The site for one of America’s fabled Amplitude Modulation oriented hamfesters. Originally held in Deerfield, NH, it was later moved to Rochester, NH. Hundreds if not thousands of AM’ers congregate in motor homes, campers, motorsickes, etc. to  swap lies and gear for two great days. Happens twice a year, in October and May.
Deyellification The process of modifying a transmitter to beless “Yellowly”.
Draining the Log Gone for a leak.
Drilling and Blasting Extensive modifications to a rig.
FECES A less than honorable name for the Federal Communications Commission (FCC). 
See also FECES Magic.
FECES Magic The formula used by the FCC to calculate AM Power limits. 
When is 375 watts of AM carrier output equal to 1.5K SSB? When it is FECES Magic!
Gimmick Capacitative device, usually a 1 inch wire protruding from the chassis plane, to be bent to shape for best results in getting the correct L/C ratio in a RF circuit, or as an aid in neutralizing a wild stage, etc.
Grid Leak Drip Pan A wonderful little pan to be slung under the grid leak resistors, to catch the excess drip. Used as give aways by Sangamo, IRC, etc. during the halcyon days of AM ham radio, when men were men and wimmen were wimmin, and amchurs built their own rigs and wound their own xfrmers. 
Intrascent Interesting, but only to AM’ers. 
JN Abbreviation for Johnny Novice. Used to describe a newcomer to AM, or radio or a youngster (sometimes highlighting the lack of knowledge or experience).“Yea, my wife had to drop the JN off at the babysitter.” Or “Back in 73, I thought I could put up a 80 foot mast without guys. What I JN I was!
JS “Jock Strap”. A temporary method of securing a device. Often becomes permanent. Usage: Just JS that fan to the back of the rig.
Loop Modulation From those exciting days in the dawn of AM radio when one would couple a single or two winding loops to the final tank coil, using a carbon microphoniumin series. Preferably one with a NON-METALLIC housing. Definitely not hi-fiaudio.
Microphonium A term used for microphone. Usage: How does this new microphonium sound?
Maul Big transmitter or signal
Monkey Transmitter or modulation meter, as in “Swing Monkey!” (making the modulation meter move upwards).
Old Buzzard Older operator, not so much related to age as to state of mind. See Piss and Moan.
Old Buzzard   
Transmission
A very e-x-t-e-n-d-e-d transmission, often punctuated by tuning up the rig on the air, incessant ramblings about matter of personal health and hygiene.
Olene A liquid hydrocarbon distillate that explodes when an electric spark is introduced into a closed compartment where the OLENE is introduced in vapor phase. Several of these compartments are arranged as an “engine”, which in turn propels the AM’ers automobile down the road towards a desired destination, like SorryExcuse, NY or Pissburg, PA.
Piss and Moan A mode of conversation often engaged in by Old Buzzards.
Piss Weak or “PW” Low power transmission or transmitter. Usage: You are Piss Weak here. Or I am running the PW rig tonight. 
Rectumfier Obvious reference, rectifier, diode.
Rubberizing Padding a crystal it with a small variable cap to pull it freq. a small amount to one side or the t’othah. Could also squeeze the crystal’s nuts by threading in a small shaft/plate/knob combo to apply pressure against the xtal wafer thereby changing the freq.
SBE Abbreviation for sideband eliminator. An AM rig with large amountsof incidental FM. The contantly moving carrier tends to drive away slopbuckets since they can’t zero beat it. The highest form of SBE technology is a modulated self-excited oscillator.
Scrot Scrotful – derivation of scrotum. Used as a round about way of saying something has balls, i.e That’s a scrotful transmitter.The antonym is scrotless.
Shock Modulation Cupping one’s hands and yelling against the cover of one’s presumably unstable VFO, thereby EFF-EMMING the bloody thing and causing at leastsome degree of intelligibility
Sing for (its) Supper Running a tube(s) or transmitter at or over its specified ratings.“I’m running 4kV on the 833’s and they are singing for their supper.”
Slop-bucket A sideband station, esp. one that is interfering with, or crowding into the AM window. Usage: A slop-blucket just straped you.
Strap A sophisticated monosyllabic expletive used by seasoned AM’ers to denote a signal that swamps/demolishes/buries another signal. May be used as a straight out primitive male macho statement, as in putting your signal on top of another’s, and yelling “STRAP” or, more politely, putting thesignal on and then inquiring, “Am I STRAPPING this guy?”
Talk-back That fine sound when the mod xfmer laminations rattle awayyy
TimTron Tim WA1HLR, very well know Maine AMer. Originator of many of the fine phrases on this page.
Vomit Meter A volt meter. 
 
Woodolene Forest fuel. Small chunks of properly dried arboreal matter which, when tossed judiciously into a WOODOLENE STOVE and ignited, will heat the AM’ers shack/kitchen/living room to a comfortable level during those cold winter nights, and stimulate that special feeling of AM camaraderie which hams using other modes can only envy.
Yellowified State of extreme agitation or anger. Also used to describe your reaction to a bad situation, “I hit the high voltage switchand all I saw was sparks and smoke. Man was I yellowfied.”
Yellowee Poor sounding rig, characterized by restricted audio respone or hum or distortion or some combination there of. Also used to describe a bad thing or situation e.g Joe: “I went to the hamfest and all I saw was computers.” Bill: “Errr, hyellowee!” Derivation, deyellowfy- to modify a rig for better audio quality. Comment: The ultimate bad signal is one that is piss weak and yellowee.
Zorch To burn out, or smoke in a spectacular fashion.Usage: I just zorched my feedline. Also known as “Letting the smoke out.”

AM Geography

Buffoonalo Buffalo
Cuntnecticut Connecticut
Filthadelphia Philadelphia
Kenfucky Kentucky
Massolechewits Massachusetts
New Hamster New Hampshire
Penissylvania Pennsylvania
Pissburgh Pittsburgh
Plymo Plymouth
Poontiac Pontiac
Porkrot Rockport
Rottenchester Rochester
Sorry Excuse Syracuse
Tennesemen Tennessee
Verminmont Vermont
Waste Coast West Coast

Credits: Bruce KG2IC, Y.A. Feder W1UX, Steve WB3HUZ, Ed VA3ES

AM, What Is It?

AM Is Hardly “Ancient Modulation”!

Although at times it is jokingly referred to as “Ancient Modulation” by its detractors, AM is “Angel Music” to those who enjoy this special mode of modulation. AM refers to the method of modulating the RF carrier, in this case, Amplitude Modulation. Amplitude Modulation (AM) was the first voice mode used in amateur radio, and is now very much alive at it enters the 7th decade of its life. AM is a well-regarded specialty within the radio hobby, and its operation offers a warm, rich audio quality that provides for more personal interaction. AM is rich with tradition, and the time honored tradition of elmering and homebrewing equipment are no exception. AMers often build and maintain their own antennas and transmitters. The simplicity of AM circuit design encourages hands-on restoration, modification and homebrew construction to an extent no longer found among contemporary radios. 

AM Culture

You may find AM culture is a bit different than what you are used to. Often QSOs tend to center around technical discussion, especially relating to tube type gear. Antennas are also a popular topic, and different styles and methods of feedline construction are often debated. Transmissions tend to be more extended, and VOX is rarely used. In fact, the pace of AM QSOs is often quite leisurely. AM slang is very descriptive, do not be surprised to hear some rather interesting terms, from some quite interesting people!

Technical items are not the only issues discussed however, and established nets deal with topics ranging from UFOs to historical events. Two of the more interesting nets, in this authors opinion, are the “Future Net” found on 3.875MC Sundays at 4:00 PM and the “Gray Hair Net” on 1.945MC Tuesdays at 8:00PM. Not to be missed is the “AM Swap Net” on 3.885MC Thursday at 7:00PM, where equipment and parts are exchanged in a “tongue in cheek” fashion. Locally look for the “Sunday Morning Brunch” net on 3.815MC around 9:00AM, the “160m Early Morning Net” on 1.885 which starts around 6:00AM and the “2m AM Net” on 144.450MC Sunday evenings at 8:00PM.

AM activity can be found on a variety of other frequencies both day and night. For daytime operation check around 7.290, 14.286 and 29.10 MC. Evening and early mornings 1.885, 1.888, 1.945, and 3.885 are your best bets. Most AM operators will gladly welcome newcomers to the mode, give it a try!

Transmitter Setup

That’s it; you’re ready to get on the air on AM. If you are running a solid state rig, you will want to reduce the RF output to about ¼ of the maximum valve. For most of today’s rigs this equates to 25 watts carrier. You might also want to reduce the mic gain somewhat from what you are running with SSB. These settings may not be exactly right but this should get you close. Once you get on the air, ask for an audio report to determine to determine if you need to do any tweaking. If you access to an oscilloscope, by all means, use it to adjust your mic gain. Using a scope, you can determine your percentage of modulation and if you are “flat-topping”. Flat topping refers to the distortion that occurs when a transmitter is driven past its max power output. Distortion, and splatter onto adjacent frequencies occur during flat topping, something that you want to avoid.

If you run your transceiver into an amplifier, follow the same steps with the linear in line. One important thing to remember is that your amp will be running at about 20 -25% efficiency, and what does not go up the antenna as RF is given off as heat. So, you may want to get your calculator out and determine how many watts you can run without exceeding the plate dissipation rating of your linear. Remember that AM is a 100% duty cycle mode, as opposed to 30-50% for SSB. So the tubes and the power supply in your amp will be working much harder. You may not want try to squeeze every last watt out of your rig. The difference in received signal strength is just not worth it. Err on the side of safety.

An Invitation

The AM mode can be a tremendous bit of fun. Although it is most often associated with older, tube gear, modern day transceivers can produce some very good sounding AM when properly adjusted. Whether you were an active AMer in the past, or new to the AM mode, by all means get on the air and give us a call. Welcome aboard!

-Bruce W1UJR