The 'YH Bunny: Where It All Began (For Us, That Is) Above: The Bunny (with paper bunny ears and QSL card), pictured just after its completion sometime in early-to-mid 1996. By J. Aaron Holmes, N7OE Welcome, visitor . Almost seven years?  WOW!  ...and it still works?!  Yup.  Not even a fresh charge on the batteries since it went QRT in 1997, and the ol' W7YH bunny sprang to life with the flick of a switch.  <sniff, sniff>  Sigh... the good old days... I joined the Washington State University ARC, W7YH (now unfortunately defunct), as a freshman in the fall of 1994.  I often spent my lunches in the shack working 15/20m CW, and there I ran into Steve, N7VHY.  Steve enjoyed doing his EE homework there, playing Scorched Earth on the club's 386, and fixing the packet node after lightning strikes ;-) In early 1996, Steve, then president of the club, decided that monthly meetings weren't enough to keep people interested.  He wanted to try "bunny hunts" (also often referred to as "fox hunts" or "rabbit hunts"--the radio version of hide-and-go-seek)  ...so we did.  The first two went over well, however the hiders grew tired of giving "ten counts" (counting to ten) on the air.  It sounded an awful lot like CB, and we were all too proud for that! On the morning before the third hunt, Steve declared that he was going to build a transmitter controller.  In what seemed like little more than an hour, he'd produced a breadboard full of jumper wires and other odds and ends.  In the middle of it all was a voice recorder chip from Radio Shack:  The ISD 1000.  When at last it was time to record a message, however, nobody would volunteer their voice!  Finally it was down to me; I cranked up the volume on the club's Icom 751A HF rig, grabbed the Vibroplex, and let loose some CW:   D E   W 7 Y H   B U N N Y   H U N T   S T A T I O N  ...and that was that. Thus, the bunny was born, and it was good. Below is an audio sample of the bunny, direct from bunny to PC.  The audio is a bit clipped, but this is simply how it was originally captured on the chip.  Careful listeners (or those who just crank the volume) will hear Steve say, "Go!" right before the CW begins.  It's a classic, what else can I say?  ;-) Sounds of the ISD 1000:  The 'YH Bunny >> YH_Bunny.mp3 << (Recommend right-click, Save As)   Inspired by the instant success of Steve's bunny, I knew I needed to have a hand in continuing its development.  Armed with a box of ICs from a recent logic circuits class, I set to work on the PTT control.  The result was a block of DIP switches that allowed the user to choose how many message lengths were played on the air and how many off.  It worked out pretty well, and made adjusting the timing easy.  Next, I converted a discarded Fluke hard case into a new home for the otherwise fragile bunny circuit, which continued to live on a breadboard (and still does).  This gave the bunny its distinctive bomb-squad-attracting appearance. Above Left: The "second generation" bunny circuit (circa 1996) with audio and PTT functions on separate boards. Above Right: The bunny box, complete with power switch, indicator LED, and antenna jack. Inside, boards and lead-acid battery were held in place by Velcro strips.  Foam pads on the top and bottom of the case helped secure the host radio (usually Steve's Icom W21AT).  A cigarette lighter socket was later added to allow both bunny and radio to use the same battery, however this created a new problem:  After long hours of operation, the battery voltage would begin to drop sharply during transmission, which led to a humorous "slowing down" effect in the ISD chip.  Many a fine hunting day came to an end in this manner. Following Steve, I served a term as president of the club, and while hunting slowed a bit (I'll blame all the lame "general education requirements" that I put off 'til my senior year--arg!), there was still time to move the bunny circuit onto a single breadboard.  It was the last change made. Above Left: The single-board "second-and-a-half generation" bunny (circa 1997). Above Right: Close-up of the bunny box with indicator LED aglow. Dave, K1ZH, took over as president the following year as I made ready to skip town (with a degree, I was relieved to discover).  He wanted to restore faith in the hunting tradition, and also preferred to use solder when building electronics ;-)  The plan was to build a new, compact version of the bunny.  I did my best to recall why certain component values were used, and together we hacked out a crude schematic. Several weeks later, Dave showed me the result.  It was great!  The whole thing was only slightly larger than the perf board it was built on; it fit nicely in a Radio Shack project enclosure.  Unlike its bigger brother, the K1ZH bunny sports a convenient microphone port, uses external power, and looks a whole lot less like a bomb. Above: Picture of the K1ZH bunny, courtesy of Dave, K1ZH. The new compact bunny figured prominently in the club's hunting activities for several years following my departure.  I never really got to see it in action, unfortunately. Recently, Graylan, KC7YVN, who was a high school student and honorary 'YH member during the "early days" of the bunny hunting, has been trying to awaken the hibernating University of Washington ARC, W7YD.  He's hosted several hunts on the UW campus on behalf of W7YD, the first in April of 2003.  I've had a great time participating in these events, and have been inspired to conjure up some new bunny designs.   FAQ Q:  What's the difference between a bunny hunt and a fox hunt? A:  There isn't one.  Not, at least, that I know of.  But if there were, I'd like to think it had something to do with the format of the hunt.  Much of the time, when people talk about ARDF and "fox hunts", they're talking about driving around in cars covered with antennas and employing fancy equipment to find a distant transmitter.  The hunts we do are quite simple by comparison.  We typically do short hunts on foot.  There are no "prizes", and hunters generally have nothing more than an HT and "rubber duck" antenna.  It's just a fun way to meet up with other local radio enthusiasts for a few good walks around campus and occasionally coffee and/or lunch ;-) Q:  How about a more technical description of the W7YH bunny's circuit? A:  How about we meet halfway?  The ISD 1000 chip has since been replaced by the ISD 14xx series, but the two are very similar.  Everything you need to know to wire up and use these chips can be found in their datasheets, which include schematics for common applications.  After that, you can use a timer IC like a 555 to supply the PTT function for a radio.  The very first 'YH bunny did this.  Second and subsequent versions use an 8-bit parallel-load shift register clocked by the ISD chip's "end-of-message" output.  The register is loaded according to a block of DIP switches when power is first switched on, and the serial output goes to the PTT as well as back to the serial input (this 8-bit "program" is executed over and over until power is switched off).  This allows the operator to, for example, specify that two message lengths will be played on-the-air, and six off.  This design, however, required that the ISD remain looping in playback mode, and thus was not very battery-friendly.  We were goal-oriented students then, ok?! Other questions, comments, etc....?  Feel free to mail me. 73, J. Aaron Holmes, N7OE Page last updated:  November 13, 2003 Go back to N7OE's Transmitter Controller Page. Go back to silicon-arcana.com