Crystal Radios Of The 2009 Contest Entrants
Rodney Look, Open Class Entry
Here is a link to theThe Pictures Slideshow for more pictures of the set.
Here is a link that shows the location of the stations copied.
Glen Yarbro, Open Class Entry
Radio : Dave Schmarder's #44
Antenna: 80m trap dipole, 30 feet high
Headphones: 4 k Navy phones
Coils were wound with 24 gauge Bell Wire
O. T. Anderson, Open Class Entry
This crystal set has been modified several times, the dials, Var Caps,and wave traps. Being a ham operator I really liked calibrated dials. Some of the local stations are in red.
The right hand 3 tuning caps are the Hammarlund type. The three caps which are ganged together is a "Tuggle" front end. The detector cap is an old ancient job from a very early radio. I modified it using HDPE to replace old brittle bakelite. I don't know how good it is, but it looks and feels great. It has good band spread down at 1200-1700 kc. The three coils and output Xformer I bought from that good man, "Dave".
The two right and left small caps are a band spread for about one station. It feels good to "rock" these a bit on a weak station. The "S" meter is a real help. A 3 position switch gives a off, normal and high position. I would not built a new set without one. Since this is a "crystal set" I had to put in new (old type) "Cat Whisker". Can you see it? It also has a place for 3 diodes.
My biggest trouble here in Broken Arrow, OK is 1170 kc. That's KFAQ, old KVOO, 50,000 watts. Big 50,000. Has three towers, see them from our house. I have 2 wave traps, one 1170 and the other is 740, KRMG. The switch and stationary caps are at bottom right. Works OK, but 1170 is still in the back ground.
Built up an external trap. It's still there. I accidentally found the trouble moving the set around one day, cleaning up. I nulled out 1170 as I had the set turned around so-so. Apparently the detector coil is a good antenna just like an antenna in a AC-DC radio. So what should I do? Relocate my operating desk, or better yet build a new set patterned after THE LYONODYNE, (which has wave traps on the detector coil).
My wife, Doris, K5BNQ, wasn't crazy about me being back in the shop. She said, when it gets dark, I should come in, build a fire in the fire place, read the newspaper, and have a big cold Pepsi or Mt. Dew. Then maybe she would give me some real good home made chocolate cookies!!! And some ice cream!!!
Who could beat a deal like that?
Mark Hampton, Open Class Entry
My set is a simple double tuned with a Tuggle front end and home brew friction reduction drives. A high/low switch spreads out the band a little further. The "high voltage insulators" are wood toy wheels stacked up and painted white. I thought it would add to the industrial look of the set.
My antenna is a 300' longwire, 30' in the air and oriented NS. The ground is tied to the cattle fencing (welded wire on metal post every 10') that runs all over this part of the county.
The unit is sitting atop my universal match box. The headset is SP units mounted in old Olympus stereo headphones.
The barely visible blue pin is my location on the map.
Garry Nichols, Loop Class Entry
This is the same set used in the 2008 contest, except for a few minor changes:
-I took off the Select-To-Match this year and ran the loop with only the T3/AM-20 transformer (100:100k) and a 107 nA Schottky diode.
-Big can mic elements in series had a 2 uf electrolytic between them and the transformer.
This setup (with short leads) got rid of my FM interference completely, and I did not hear the intermittent hum that I was picking up last year from various orientations of the loop.
Kevin Norton, Open Class and Short Wave Class Entries
Sets: On B'cast I used the K-3 xtalset. It is a 75 ft longwire through a wiperless ceramic 4 gang, then to a 4 ceramic gang wiperless tank ( 660/46 ferrite assisted air coil ). Each var cap is wired so that a 500 gang is bussed to the adjacent 500 gang. So two 500 gangs equal one leg of my cap. The gnd is to the FRAME of the tank var cap (NOT the "cold" stators).
The det tank uses the same coil type and var cap type / wiring layout. There is no det tank connection to Earth or ant tank.
All caps are 6:1 ball driven and have oversized insulated wooden knobs.
A single FO 215 was used fully at the hot end of the det tank. Although single Schottkys HAVE been used in past contests, results were worse this time (for whatever reasons).
The match is 2x UTC A-27s and the phones are David Clark SP types wired in series @1200ohms.
Future K-3 improvements could include raising the match Z by wiring in additional A-27's, changing the benny pot to a higher value and trying various benny caps. Also a set of high band coils should wake things up quite a bit on the high end.
An outboard applied RF bias is available by a weak signal digital B'cast transmitter and coupled to the set by an unterminated litz air coil. This transmitter only covers 600 Kc and up, so an analog Heath signal generator fills in from 530 to 600. Using just a tiny level of (variable) RF greatly narrows the bandwidth. Strong locals are obliterated and signals otherwise NEVER copied come into good audibility. There is an almost "regenny" sound when doing this.
I can find stations by using the analog or digital scales, bias the set into the "supercharged" mode,and then peak all controls. Then I simply shut down the RF, move the bias coil away and wait for a signal to come up into true xtalset passive copy.
The HF set was a simple affair. A wiperless ceramic var cap on 11uH homemade > air dux. There is a two turn ant coil . The tank has no gnd . The det is an unknown diode directly into series xtal earphones.
Overall a good a time, despite a slow start.
Curtis Gamble, Open Class Entry
This is my first passive receiver that was not a bread board set. It includes a Tuggle antenna turning unit with 12 gauge enamel wire rook coil, center of the picture, a 1N34 detector with 14 gauge enamel wire rook coil, and a Triad SP 21 300 Hz to 100Kz response output to sound powered head phones.
The unit to the right is an IC detector with an ALD110900A and BOGEN T725 trans- former to the same sound power headphones. The 160 meter flat top dipole is up about 45 feet, plus I use a 50 foot long wire, and a house copper water pipe ground.
I have two locations I can work, my old home place in Tuscaloosa, Alabama in the same shack I've had for over 50 years, and the home I live in now in Hoover, AL. I worked this contest in Hoover, Alabama. This location has very low noise, and after sunset the local blow torches are not a issue. I normally don't use a trap.
Charles Pullen, Open Class and SW Class Entries
This is the same radio I used in the ’07 contest, with no additional modifications. I call it the Llama, because of the case it’s built in.
The antenna this year was a 40 foot inverted L, about 25 feet above ground. I added two additional ground rods to my ground system this year to compensate for the smaller antenna. I had to make extensive use of the wave traps this time around, the locals at 1080, 820, 770 were totally dominating the middle of the band.
This is a very simple SW loop antenna radio I converted from a QRP 40 meter small transmitting loop I built about 5 years ago, and has been beaten up quite a bit over the years. It consists of a four foot diameter, ½ inch copper loop that is paralleled with a 365 pf air variable capacitor and a 1n34a diode detector.
I hooked it to my copy of Steve Bringhurst’s ultimatch unit for impedance matching and listened in with a pair of philmore xtal earplugs in connected with a radio shack mono y-adaptor.
It has a 30 inch tuning shaft which allows you to sit next to it while tuning. This radio tunes from about 5050 khz up to around 7500 khz in the 41, 49, and 60 meter bands.
The antenna rotates a full 360 degrees to provide selectivity when hearing more than one station, which is quite common, but it generally only needs to swing 90 degrees to get a north-south or east-west azimuth. This year I only logged 5 stations during the contest window, but I’ve heard a lot more stations than that on this radio including 5070 khz up to 7465 khz.
Interestingly enough, it still transmits to nearby shortwave radios (2-3 feet) by simply talking into the xtal earplug.