bob's data: Bob's useful electronic data & project plans
One Tube DX Receiver:
This receiver uses the triode portion of a 6AN8 tube as an RF amplifier and the pentode portion as a regenerative detector. Audio output could be sent to crystal earphones or older high impedance ones but it is suggested that this signal be sent to an audio amplifier. A single tuning dial plate serves both the broadcast band from 570 KHZ to 1.83 MHZ and the short wave band from 5.7 MHZ to 18.3 MHZ while utilizing two plug in RF coils. The second hand transformer that was used here produced 53 VAC and 6.3 VAC.

If your transformer produces more than 53 VAC then adjust the voltage ratings on the electrolytic capacitors upward. Antenna length is not critical but should be at least 12 feet long, whereas 30 feet is preferred. This receiver will pull in stations from all around the globe and is very, very impressive in its performance.

The Aluminum front panel was made from 1/8 inch thick Aluminum and is 4 in. high by 7 in. wide. The main chasis was made from .062 Aluminum and is 5 in. deep by 7 in. wide. The small back panel is made from .062 Aluminum and is 1 in. high by 7 in. wide. One inch, thin wall PVC was used for the coil forms. Actually these measure 1 5/16 of an inch in diameter. The BCB coil PVC was cut to a length of 2 in. while the short wave one was cut to a length of one inch. The acrylic pointer for the main tuning knob was cut out and then attached to the back of the knob with epoxy. The black line was drawn with a fine line Sharpie. C4 is a 365 pF variable with all of its plates pulled out except for 8. This produces a 240 pF variable capacitor. With C5, pull all of the plates out, then cut one to a diameter of 7/8 in. and then reinsert it. This will produce a 20 pF unit. To make the coil forms, insert an octal tube socket into a bench vice and then plug a octal tube base into that socket. Now use a belt sander to grind it down to a height of only about 3/16 in. Using a tooth pick, place a small amount of epoxy resin around the ground down tube base and then stand your PVC coil form on top of it. Please use caution when wiring the 120 volt line portion of this receiver.

Home | High Selectivity Crystal Radio with Short Wave | High Sensitivity BFO Metal Detector
Battery Life Chart | Parabolic Microphone | Ultra High Gain Audio Amplifier | Audio Sine Wave Generator
One Tube DX Receiver | Telephone Line Use Monitor | Moisture Detector | Vacuum Tube Amplifier