K7JEB AM Log: 16 Apr 2006 - 05 May 2006 This reporting period starts on Easter Sunday and Taxation Monday -- something about rendering unto Caesar and all that. Had an interesting QSO with Rich, KC9GQ, about telescope-drive motors and controllers. Still hard to see how one can use a geared-down stepper motor to make a telescope track an object without jerking the image, but apparently they do it. I suppose one has the same problem with a commutated DC motor or an AC synchronous one -- uneven drive torque. The band went out before I could explore this subject fully with Rich. Dennis, W7QHO, delved into the intricacies of resuscitating a Hallicrafters SX-42 receiver, his second such unit. Dennis informed me that the SX-42 was the post war successor to the venerable SX-28 and had many of the same goodies as the '28, notably a pair of 6V6's in the audio output stage. I found the SX-42 advertised in my 1949 ARRL Handbook for $300. Ted, WA6TJN, informed us that he has the little brother to the '42, an SX-43, of the same vintage. Scott Johnson changed his call from KC7BGE to W7SVJ, thus joining our club of fellows whose callsigns have their initials in them. He used this new callsign to check into the 2-meter AM net with a "new" Collins VHF201 aircraft radio recently acquired from Bill, N7OTQ. That rig gave him another S unit at my QTH and nice audio to boot. George, W8QBG, was busy getting on DSL with his computer and becoming completely addicted to the higher-speed Internet access. He also successfully interfaced his house alarm to the telephone network by a judicious choice of low-pass filtering to keep the DSL high-frequency junk out of the "normal" telephone equipment and modems. K7SC's article on the Polycomm 2-meter AM transceiver came out in Electric Radio with "my" picture in it. Well, it really wasn't "my" picture, it was Jim's, of his own rig. I just gave it the 'treatment' by blocking out the background and juicing up the contrast a bit. It ended up looking surprisingly like the original manufacturer's advertising photo in my old 1961 Handbook. My thanks to Jim for using it. Lou, KA1MK, checked in on 7293 AM with his Kenwood 940. Took a bit of fiddling around to get the audio right. He was only a couple of miles away from my QTH, up by Cardinal Stadium. Once again I was reminded that making decent AM with a sideband transceiver isn't the piece of cake it is advertised to be. Also heard, on 3855 AM, was Doug, W7IXA, with his Icom 7800 in AM mode. I probably insulted Doug by not recognizing the 7800 as being Icom's top-of-the-line HF transceiver and wondering aloud about its pedigree. Lock, W1ZD, continues to work on his sweep generator to be used for IF alignment of boat-anchor receivers that make their selectivity with those mysterious rectangular tin cans. This led to a discussion of wobbulators -- sweep generators made by having a synchronous motor drive a variable capacitor. This device was a standard piece of test equipment at the transmitter site back in the good old days of television when the usual setup was a low-level modulated stage followed by a string of linear amplifiers, all of which had to be broadbanded to pass the television signal. Shannon, W6SPY, advised that he will be taking up more duties as a substitute teacher out Victorville way. World Radio magazine is promoting a ham-radio cruise and my thought was that it will be the world's worse case of EMI and cross-band QRM if everyone operates from the ship. Dennis, W7QHO, mentioned his problems in that vein operating shipboard from W6LV, the Lane Victory station. I heard about a special-event station that will be on the air from Death Valley, possibly on AM, the second week in May. Andy, KC7KW, is heard from again, checking into the AMI net on 3870. Ron, K0ETD, making a number of trips to and from Kansas, finds time to replace the power transformer on his really neat 6146 homebrew AM transmitter. Had an interesting QSO with David, W6PSS, about Dr. W. Edwards Deming and Total Quality Management. I expounded on my theory of quality control based on Information Theory and Thermodynamics. I don't think W6PSS was impressed but it was fun for me on that pre-net 3870 get-together. Ken, K6CJA, advised that the high gas prices are impacting his Corvette driving around the high desert around Hesperia. He also commented that he has had good luck with vertical delta loops on 40 and 20, probably the first positive comment I've heard about anything 'vertical'. Martin, K7BDY, pulled our collective leg about throwing away his Gates BC-1G transmitter. Instead, he actually sold it to Bob, W6OOQ out in Escondido and we can expect to hear it on 160 from there once the transportation issue is resolved. I took some pictures of Max's hamshack for the website and pasted some into a page for him: (HTTP://WWW.ARIZONA-AM.NET/PHOENIX/K7CAX). At the same time, Bob, NA7RH took some photos of his setup and e-mailed them to me for his page: (HTTP://WWW.ARIZONA-AM.NET/PHOENIX/NA7RH). I guess I'm back in website-editing mode now. Added some scanned-in copies of the schematics of Bob's RF chain and modulator as well as copies of the original Handbook articles. Anything to fill up the website disk, I suppose. I was informed that both KO6NM and WA6JUS received my audio-CD recordings of their transmissions. Lotsa fun. Gordon, W8QAQ, continues to troubleshoot his Ranger while putting out a nice, strong signal from his DX-60/Amplifier combo. Gordon and Max have this unnatural attraction to model trains, to the detriment of their ham-radio time. Randy, W7CPA, repaired/restored a Collins 75A4 receiver for someone, encountering weird AGC problems in the process. He finally located the difficulty in the most inaccesible coupling capacitor in the radio and replaced same. That's always how it happens. His Kenwood twins continue to pump out very good-sounding AM and, with the help of an Alpha amplifier, pin my S-meter over here on the West Side. Part of the 'secret sauce' audio-wise was revealed to be a W2IHY equalizer that, when switched out, left the CPA's audio rather flat-sounding. Damon, W7MD, gets a birdbath on-line at his QTH but is still struggling with contractors to get a decent garage built. Part of 21st Century pioneering, I suppose. I related my sister's difficulty getting her house built in Silver City -- same deal, bad contractors. More 2-meter AM stuff: K7SC puts a good-sounding Lafayette HA-1200 on the air; W8QBG has problems with the Xtal in his Clegg, too high in frequency and won't pull down to 144.45; Ernie, W7CCC and Jim, K7SC experience 'sticker shock' at the gas pump; Larry, KO6SM, has a granddaughter who finishes in the top 50 in Oprah Winfrey's essay contest and is invited to the show in Chicago; Lock finishes the mechanical work on his sweep generator. April 26 - 28 found me in Las Vegas attending the NAB convention, courtesy of a friend who provided a place to stay and a badge to get into the exhibition hall. Highlight of the show was the amateur-radio mixer Wednesday night where I met Mike, KO6NM, and Dave, WJ6W, in person. I took a few pictures on the convention floor, mostly of Jack Sellmeyer, AD5VO, and whatever caught my fancy. I was fascinated to discover that they use a set of tiny yagi's cut for 2.4GHz to downlink video from helicopters. These yagi's are gyro stabilized so that they always point at the receive site and are behind a radome to protect them from the slipstream. Also noted, a couple of 50 kW MW transmitters from Broadcast Electronics and Nautel that are completely solid-state and no bigger than a double-wide refrigerator. The BE transmitter has a 15-inch LCD screen on it's front that displays, among other parameters, the impedance at its output on a Smith chart over a 50 kHz bandwidth. The pictures are on the Arizona-AM website at: http://www.arizona-am.net/test/nab/index.html On the way back from Vegas on Friday, I caught the AM net on 7293 from my mobile, but with difficulty. I had an intermittent connection to my Texas Bugcatcher loading coil with the alligator-clip jumper. It cleared up when I switched to the jumper with the blade connectors on it. I then worked WA6TJN, W7MD, W7XH and W1ZD from just north of Kingman. Funny thing happened driving into Kingman; I began noticing more and more people on Harley-Davidson motorcycles heading in the same direction. When I got to Kingman, the place was flooded with them. A discreet inquiry revealed that I had driven into the thick of the annual Laughlin River Run. Interesting experience. Good thing I opted for Route 93 rather than 95 through Laughlin and Searchlight. NA7RH revealed that his work at Moto involves 2.4 GHz power amplifiers, definitely making him an RF type. Ken, K6CJA, tells me he will be at the Williams swapmeet in July, pretty much sealing-in my participation at the event. I'll give it one more shot. Williams is still a bit of a difficulty with its hot, dry wind and unremitting sunshine, but the little town is nice to get around in at night and much friendlier than Flagstaff. Had an interesting QSO with Skip, K6LGL, in the early-morning hours of May 1 about single-ended triode hi-fi amplifiers running Class A. Skip has a couple of mono blocks that each run an 811 in the output and he assures me that the sound is excellent from them. It's the kind of hi-fi setup a boat-anchor aficionado could well appreciate -- hard-vacuum tubes with color on the plates, monstrous output-transformer and power-supply iron and technology thoroughly planted in the 1940's (except for silicon diodes in the power supply). Incidentally, Skip was using a Globe King 400 on 3885 and it sounded wonderful -- full audio and good signal strength, but, alas, crystal-controlled, at least for the time being. Looking forward to hearing this beastie on the AMI net soon. Got an e-mail from Rich, KC9GQ, in Flagstaff advising me that his XYL had been in the hospital over the week of 4/24 - 5/1 with a perforated bowel, but is now on the road to recovery. Best wishes for her, Rich. Tom, AE8O, out in Rio Rancho, NM, regaled us with tales of woe in getting his swamp cooler on-line for the summer. That thing is a whole technology in and of itself. Coping with the effects of our uniformly hard water here in the Southwest seems to be the major maintenance headache. Willis, W9FGJ, gave the daily 7293 gathering a call with a very nice sounding Hallicrafters HT-37 running barefoot. He insisted that this was his fall-back mode and will continue to operate his Ranger into his SB-220 for his main rig. Notes from 3870: Wayne, W6IRD, was elected "DXer of the Year" for the Visalia convention. W7MD enlightened us as to the magnitude of this honor. There is an AMI barbeque in the works for June 10 by WA6HCX. I heard a K7JUB checking in from Tucson and realized we are going to have mass confusion between us if we are on the same frequency. Breaks of the game, I suppose, just have to emphasize the middle letter there. I participated in the "celebrity celebration" with K9EID, WJ6W and KO6NM over the NAB doings, much to the disgust of K6CJA. George, W8QBG, finishes his conversion of his HP-200 audio oscillator into a low-distortion, high-output speech amp and uses it to drive the socks off one of his BC610's. It does sound great and only cost $5 for the "parts only" HP-200 at a local swapper. One could bemoan the demise of an instance of electronic history in the HP-200 (the multi-section tuning cap becomes the loading control for one of George's HB amplifiers), but there are so dang many of those 200's out there that I don't think they'll ever be an "endangered species". My reliance on old ARRL Handbooks led me to have my 1956 and 1961 editions rebound into hardcovers the way libraries do it. I called the Glendale Public Library and asked who did it for them and they gave me the following name and address: Roswell Bookbinding 2614 North 29th Ave. Phoenix, AZ, 85009 phone: 602-272-9338 I used them and had good results, except that they labeled the 1956 edition as 1961 and vice-versa. Note to self: don't send them two books at the same time that look identical. A dab of white paint and a Sharpie pen fixed that problem. Damon, W7MD, explained in great detail what makes Avian Flu so deadly after being asked about it specifically. We are going to have to start paying Damon for this medical advice one of these days. AM HONOR ROLL... W8QAQ KO6SM K6CJA W7XH W6BCN W7IXA WA6TJN K0ETD KC7KW WA6HDY K6BW K7BDY NI6Q KA1MK KB7LOQ W8QBG K6LGL WA6JUS W7MD W7QHO NY6L KA6VEC W9FGJ W1ZD AC6AJ W6SPY K7VZP W7CCC W4QCU W6PSS K7AK K7CAX W0OGH K7EWE K6UA K4KCL K7JUB K2DLZ KC9GQ AE8O W7GMK N7WEK K7SC W7CPA KO6NM W7SVJ (ex-KC7BGE)