Krystallo's 2010 Entry
Stations Heard: 6
This year's entry was the JB-1 (Junk Box-1) shortwave crystal set.It has a 3 gang 500 pf ceramic var cap. Two gangs are used wiperless. The drive is a 6:1 ball drive w/ a shaft insulator.A large sweeping pointer travels across a cardboard scale.The single coil is homemade air dux with 4 woven string spacers.I use an unknown diode wired at the hot end of the tank.
This set works quite well from around 31M down to the mid broadcast band. Phones were generally series crystal earphones although SP/Uberformer and audio amp'ed 8 ohm PH were also tried.All worked well. The audio bleed pot helped clean up any distortions and any FM QRM.Antenna is VERY lightly coupled w/ a few turns of gimmick cap. This set did not respond well to being grounded.
A good number of stations were logged including some amateur CW, utility stations (WEFAX,data transmissions, et al) along with quite a few broadcasts.Most activity was at or above 49 M.
Most of the listening was casual, but I did make formal logs for a bit of it.Some stations were extremely loud.
Lightning crashes were noted w/ the audio amp, but it is unknown if these were actually ON HF.My feeling is they were from a VLF microphonic mode, despite a lack of ground.
When run wide open several fairly weak FM'ers were noted,especially 106.7.Not a big issue though .Also good results for local AM b'cast when cap was run to rotor along w/ all 3 gangs .Custom jumpers make changing bands a snap.
I had lots of fun fooling around with this set
Log: Straight Crystal Set Mode, no amp-
1. 3215 WWCR Nashville,TN. 2100 EDT 2 Aug 10
2. 3330 CHU Canada Time 2105 " "
3. 5025 R. Rebelde Cuba 2115 " "
4. 5040 R. Havana Cuba 2125 " "
5. 6175 V.o Vietnam 2135 " "
6. 6890 EWTN AL 0100 " 5 AUG 10