CRYSTALFEST 09
"Was held" OCT 10-11 in CAVE SPRINGS, ARKANSAS
[posted 10/12/09]
Attending: We forgot to take a group picture this year. Last year's pic is shown at right. Attendence was about the same, a solid dozen, a few different attendees. A great time was had by all!
A number of crystal sets were displayed and discussed at length, see below. Mark Rotsch's work on making high Q coils with stacked flat ferrites was discussed off and on during the whole day. Check the various boards for a discussion of this idea and his work. We tried to dip and drag Litz wire with a solder pot Phil brought along. Conclusion was that the pot was not hot enough, only at about 700 deg F! Mark H provided pizza for lunch from the local "Greek." Em good. We also broke up - with a hammer - some chunks of galena; some call this "sparking." Parts trades were numerous, of course!
Our host, again, was Mark Hampton of Cave Springs. Thank you Mark!
Evan's (NØGMR) tube radio is shown at right. Really crisp and clean, nice layout, and worked very well. Note the 6E5 "tuning eye" at upper right.
Back view of unit is at far right. Big speaker produced fine audio. "Metal" tubes fill out this AM set.
Mark Rotsch's (Alton, IL) ferrite rod set and antenna tuner are shown at right. Mark Hampton had strung a long wire to the south out of the "old" Cave Springs city hall building where we met (nice space!). The antenna tuner was adjusted to maximize antenna curent reception. It was then moved left or right to adjust coupling into the rod shown at center. The main LC tank is shown at left. This set tuned very sharply and copy was solid. Mark's audio matching box was at left, not shown. Sound-powered phones were used and increased volume was noticeable. Nice job Mark!
Mark brought along his HP-4342A Q meter and we measured Evan's Litz basket-weave coil from his DX Contest Winning Rig. Q was measured at 1230. This was a confirmation of Phil's Trap Q Measurement Method (50 ohm system) used last year to measure the same coil, getting 1200.
Charles Rogers of Rogers AR attended for the first time. His "breadboard" jig is noted at right. He had it set up as a regen. We'll see you next year Charles! He also brought a B&K signal generator and 465 scope in and we wired up an LC circuit to demonstrate the increase in voltage one gets at resonance between the L and C. We also demonstrated how to measure the Q of this arrangement using the half-power bandwidth method. Q was low (15) of course due to the 50-ohm impedance at the output of the generator. Hence we demonstated that the Q measured also predicted the increase in voltage between L and C from that at the generator.
Mark Hampton's "Bottle On a Stand Regen" is noted in the picture at right. The circuitry is buried in a carved out cave on the bottom side of the wood stand. Of course this is because we were in Cave Springs. Hi!
Phil, WØXI, brought along his ultrasonic toys: the Ultra RX1 receiver and the Ultra-QP transceiver. Phil and Mark H spent considerable time outside listening to the bugs "eeekin & buzz'in" in the grass and trees. A bat DX-pedition with Pat, Phil, and both Marks was attempted at sundown by the lake up the street but no bats reported in, perhaps too cold or too early. Click here to read about these devices. Listen to this windows media file of bugs and beetles chatting in the lawn and trees.
We had a great time at Crystalfest-2009. Join us next year! Bring your stuff for show and tell.
[posted 081008] Cave Springs is just south of Bentonville and in the NW corner of Arkansas.
In the summer of 2006 Josh Young of Springfield MO invited folks to his garage for a meeting. A small but enthusiastic number attended and decided summer was too hot. In October 2007 attendance doubled and it was decided to continue this fun-filled event. Our goal for this year is 30 plus!
The 2008 session will be hosted by Mark Hampton at the Cave Springs Community Center from 9:00 AM until Dark:30PM. The event will be very informal and free although Mark is asking us for donations to defray costs.
Activity will include whatever you want: coil winding, Q testing, showing off, DX listening, repairing test equipment, radio building, horse trading, idea and knowledge sharing including this year some words of wisdom from Grampa Phil (WØXI) on Saturday afternoon, including beginner, intermediate, and advanced projects/ideas.
Litz wire and an winder with mandrel will be available to wind a basket-weave coil. We've included a bench of equipment to measure the Q of that coil, using the Trap Q Measurement Method.
There will be plenty of table space, electricity available and a vacant lot next door with big trees for antennas. Bring some sets and stories for show and tell; and, bring the soldering irons, small toolbox, and parts for mak’in stuff. Don't forget to bring stuff to trade!
Of course, all attendees will be expected to pay proper homage to the Crystal Queen upon entrance to the Community Center.
Please contact Mark or the Queen (Patricia) to let us know you will attend.
Local Hotels:
Days Inn Suites, 3408 S Moberly Lane, Jct 71 bypass & 71 Bus, Bentonville, AR, 72712.
ph 479-271-7900, about $50/day.
Travelodge, Bentonville, AR, 479-273-9727, about $50/day.
Super 8 Bentonville, AR
Super 8 Rogers/Bentonville, AR
