Saturday, May 21, 2016

Hello, Hello, I'm Here -- Post-Roadtrip

     I went to the Dayton Hamvention yesterday, where there were plenty of vendors despite the rain -- though the ones without tents or awnings in the flea market did knock off early.  That just gave me a chance to check the inside booths, mostly commercial, charitable or social organizations.

     Many of the regulars were there -- Vibroplex, Doug Hauff's American Morse Equipment, and the blend of artistry and engineering Begali Keys has brought to that part of the hobby.  I don't remember the UK's Kent Keys having attended in the past but they were there this year, in a booth presumably staffed by the Kents themselves, Mrs. Kent calmly knitting amidst the chaos.  On the other hand, I never found G-QRP or the Morse Telegraph Collectors, both of them booths I look forward to visiting.  (For the high-speed operator, AME is building their version of the out-of-production WBL keyer paddles formerly made in Indianapolis, one of the best super-high-speed paddles ever made: good bearings, good design and a whole lot of weight; you cannot outrun them but you'd better be prepared to copy that fast, too!)

     Among other items, I purchased a Kent straight-key kit, a Chinese (YouKit) antenna analyzer I have had my eye on for a couple of years, and passed up a couple of short Bud (or Par-Metal) racks with partial projects in them, which I may regret later.

     I also rejoined the RSGB.  I was a member of the Radio Society of Great Britain for several years running but dropped off when the economy worsened just as I became a new homeowner with a suddenly-increased tax burden.  This year they had a special offer, three months free and payment deferred until September.  One of the RSGB staffers joked that he despaired of explaining to non-radio amateur friends just were he went and what he did on Hamvention weekend -- I didn't have the presence of mind to offer that Dayton was where the Wright Brothers hung out their shingle and took powered flight from a stunt to an art, nor that it was where the initiators for WW II atomic bombs were made.  And much as Brits and Americans like to think of one other as being pretty much the same except for our accents, there are wide cultural gaps -- a plain old ordinary security guard walked by with a full "batbelt" and the young woman who was signing me up locked eyes on his holstered sidearm and had difficulty looking away.  (Yeah, it's easy to be snarky about unarmed cops -- but try walking up to a policeman in the U.S. and saying, "I've had far too much to drink and I'd better not drive," and see if he hails you a cab, as I'm told is SOP in the UK.  Different countries, different ways.) 

     Other times, the gaps are not so wide, though the language diverges.  At the Begali Keys booth, I asked after an extra weight for their marvelous "Intrepid" bug.  I purchased one when they were first offered (and the dollars-to-Euros ratio was a little more favorable) and I have to work up to it; the lower end of the speed range for mine is about 15 wpm and unless I'm on the air a lot, my ability to copy code drops to about 10 to 13 wpm.  Begali had an Intrepid on the table slowed down to 10 wpm with a pair of larger weights.  That intrigued me; did they offer those weights as an accessory?  The first staffer I asked was struggling with the American language (the Begali booth is large and the 25+ feet of keys on display is consistently two or three hams deep, either sending code or asking questions; try ten hours of that in a language you didn't grow up speaking and you can imagine how he felt.)  He passed my question on to the ever-stylish (and quite fluent) Bruna,* who apologized that it wasn't a regular item, but she'd ask -- and proceeded to ask Mr. Begali himself!  Piero thought a bit, produced a weight from somewhere and bustled out into the crowd to show me how to add the weight without damaging the key, holding up their demonstration copy.  There's a step milled into the part that carries the second pivot, and a machine screw and a tiny plate clamp the reed and pendulum assembly into place; of course, just about every word for every action and component is different in the two languages and we were venturing into territory where even conversational fluency rarely treads.  Geekery will find a way, and with the device in hand he conveyed the gist far better than I could have managed.  It would seem that when you purchase a key of this quality, you're also getting a level of customer service akin to that of a bespoke luxury car.  (He's also a naturally nice man.  We usually exchange greetings at the Hamvention.)

     One other "lost in translation:" when I bought the Kent key, I jokingly asked if there was, perhaps, a discount for RSGB members.  He thought about it, and said, "Five dollars, that's the best I can do," and even though I replied I was kidding, five dollars off it was.  Kent Keys are Big Engineering, UK-style, with smooth ball bearings, proper springs, coin-silver contacts and no surprises; they are built to last, keys your great-grandchildren will still be using.

     I don't know how far I walked.  By six p.m., despite buying a rucksack to haul my loot, my back was aching, my feet were sore, the Hamvention was closing and it was raining.  Time to drive home.

     Drove back in the rain, too slow for many drivers (65 is plenty for me when cars are kicking up huge clouds of spray.  It's not that I don't trust my tires, I fret about making a too-sudden move), listening to Welcome To Night Vale.  It's a good way to pass the time on a long drive.
* At Dayton, she is the only person in the entire venue who knows how to properly accessorize a company-logo T-shirt, usually with a harmoniously-patterned scarf and tasteful jewelry.  I find this an enviable talent.


Ole Phat Stu said...

Does the Hamvention still have somebody selling T-shirts with circuit diagrams on them? That was WAY back when I was fooling around on top band.

Anonymous said...

I'm jealous of the antenna analyzer, it always struck me as a righteous way to visualize an antenna's impedance.

I do have a broadcast engineering question for you, reading Paul (Thurst - spelling?) radio engineering's blog, he commented on one AM tower set-up seemed to be marginally acceptable for its bandwidth. Since the steel tower structure itself is the driven element, and circumference is usually at *least* 10-12 inches, if not more, with that 'fat' of a conductor, how in the hell is not broadbanded enough for a signal that's only about 15 khz wide?

RandyGC said...

Looks like we missed each other again. I wasn't sure if I was going to make it until Saturday morning. Didn't pick up any gear, but I got to touch bases with lots of friends from all over, which is more and more why I go each year.

One of these times maybe we can to an eyeball QSL here or in Ft Wayne.


Roberta X said...

OPS: Alas, no circuit-diagram T-shirts. Plenty of other kinds for sale.

RandyGC: well, rats! One day, eventually. I think I will try for the Ft. Wayne hamfest this year -- I have trouble getting used to having a dependable car. Tam always laughs at me when I pack a bag with a change of clothes, etc. for a day trip, just in case I get marooned.

Anon: Ah, here's the thing, many MW broadcast towers are not a nice quarter or five-eights wavelength tall. They will often exhibit a complex impedance at the base that must be transformed with a matching network. But the time you've taken the whatever horrible umpty-jillion Ohms + (or -) j-zillion to a nice 50 + j0, you have interposed a tuned circuit of some kind between the antenna and the transmitter, and the transformation is only perfect at the carrier frequency. As a general, hand-wavy kind of rule, the greater the transformation, the farther off it will be away from resonance -- and right there is the very textbook definition of "bandwidth." Even in these dire days of an approximate 5 kHz upper limit for AM audio, you *want* the impedance to be flat across 10 kHz. In a bad situation, you may not get it.

And if that sounds unfortunate, remember in the old days you could set up an AM to have flat audio response from 20 Hz (if the modulator will take it!) to 20 kHz (if you can squeeze it through the tuned circuits, if anyone has that good an AM radio). A big, clumsily-designed matching network, or worse yet multi-tower phasing network, could have wretched R and j curves over the 40 kHz span need to pass that -- I remember one small town directional array in which both plots looked like sine waves! This tends to sound...bad.

(Note that in MW work, we always track Resistance (R) and reactance (j), or the "real" and "imaginary" components of impedance separately. The aim is to get j as low as possible, though many transmitters had slightly better performance with a slightly inductive or capacitive load. The hot app for this it an OIB, an "operating impedance bridge" that will take full power and has essentially zero insertion loss; you'd leave it in the circuit at all times with the R and j dials set for that the transmitter liked and use the "null" meter as a matching indicator. A directional array has a big gnarly phasing/power-dividing network anyway, so over the last 30 years or so, more and more stations added a couple of input-matching controls to it and built the OIB right in. Every slight change in the input impedance of the phasor + antenna array -- weather-related, or the water table rises, etc. -- shows up on the OIB null meter and you carefully tweak only the matching controls for the best null. The high power and wide bandwidth of MW broadcast stations tends to take things that are of little or no importance in a ham setup and turn them into real problems, of which all this is a prime example.)