The excellent book on transmitters that offer contains 467 pages of information in English about transmitters. Radio Transmitters was published in 1961 by engineers at the laboratory of ITT radio transmission.
Here’s a whole book dedicated to transmitters! Targeted at professional engineers rather than hams, this covers it all from oscillators through power amps, modulators, power supplies, and antenna matching.
Radio Transmitters – Tube power RF Circuits - [Link]
This is a project for a Russian IN-13 bargraph Nixie tube to use it as an indoor room thermometer. It is named “NixieTherm” and is also available as a fully complete kit incl. enclosure as shown at www.Nixiekits.eu
The IN-13 is a special construct of a gas discharge Neon display and works similar to the well know Neon bulb in illuminated mains power switches or as Nixie tubes. But this bargraph has a current depending length of the glow. As all other cold discharge tubes also the IN-13 needs a “little bit more” high voltage to work; at least 120VDC. The current through the tube must be limited, normally with a resistor. In the NixieTherm this is done with a high voltage transistor, as we need a variable current from 0….4.5mA.
Analog IN-13 bargraph Nixie tube thermometer - [Link]
Matt Renaud writes:
It’s time for a little confession: I don’t always spend as much time on my power supply designs as I should. Sometimes I get excited about my latest circuit and after looking for just the right tubes, output transformers, coupling caps, and low noise resistors, the power supply design becomes almost an after thought. Sometimes things turn out ok and there are no problems. Other times I end up with bad voltages, unacceptable power supply sag, channel crosstalk, or worst of all, a hum that I just can’t seem to eliminate. It’s at these times that I always wish I had taken a little more time to get it right.
The truth is, there is no reason to suffer power supply set backs like this. The design of basic tube power supplies is actually very straight forward. And, if we rely on the excellent work of those who’ve come before us (O. H. Schade, N. H. Roberts, D. L Waidelich, H. J. Reich), we don’t even need to tackle any advanced math or taxing mental gyrations to arrive at some truly excellent power supply designs.
Power Supply Design for Vacuum Tube Amplifiers - [Link]
Bruce Heran writes:
This is a project that I always wanted to do, but managed to put off for a long time. It has been over a year in the doing. Partly because there are so many good phono preamps in existence and I was slightly concerned that it was beyond my design skills. It took over a year to get it up to my satisfaction. There were several iterations and lots of frustration along the way. My goal was to make a preamp that would not embarrass the builder with inferior performance. I used a number of commercial products for comparison. My thought was why bother to design and build something that was already available for a lower cost. As it turns out, it was not as inexpensive nor un-complicated as I first hoped.
The Groovewatt Tube (Valve) RIAA Phono Preamp Project - [Link]
adafruit.com writes: [via]
Dan has taken an Ice Tube Clock, added a Roving Networks WiFly (RN-134) module, and wrote some firmware to add some more features to the clock. He has added time synch, weather data display, and even a Twitter display. He currently has it setup to alternate between the time, the weather and a Twitter message.
Wifi Ice Tube Clock – [Link]
This single-Ended (SE) 6550 design is based on a minimonitor constructed by Lars Ohlsson of ElektroAkustik & Music.
The single-ended amplifier circuit uses a 6550 high power tetrode vacuum tube in the output stage. A 12DW7 or 7247 is used to drive the output stage. The 12DW7 / 7247 is a dual section triode, the first section has a gain factor of 20 and the second section a gain of 100. You can think of it as one-half of a 12AX7 and one-half of a 12AU7 in the same envelope. New production JJ ECC832 tubes are a suitable replacement for the 12DW7 and 7247 which are no longer in production. C2 and C3 should be good quality film capacitors. The cathode bypass capacitors C1 and C4 will also have some impact on the sound and good quality low ESR capacitors are suggested.
Single-Ended (SE) 6550 Tube Amplifier Schematic - [Link]
This is a new and improved version of “Warm Tube Clock” – the open source Nixie clock project. Important hardware changes between this new version and the previous one are:
- Timekeeping is more accurate and is done by DS3231 (or DS3232) RTC IC
- There is no DS18S20 temperature sensor – the internal one of RTC IC is used instead
- Backup battery is not powering AVR anymore, but only the RTC IC
- There is no “slide switch” to control the alarm – now it is done in firmware
- Crystal on PCB is optional and can be chosen up to 16 MHz. It clocks AVR and GSCLK pin of TLC59401 IC
- Pin-compatible with previous version of Nixie “shields”
Warm Nixie Tube Clock – [Link]
Gareth Branwyn writes: [via]
To follow the level of radioactivity in the Japanese capital, local makers are building DIY Geiger counters. A popular one seems to be the USB Geiger counter kit sold by Strawberry Linux. It’s a Geiger counter based on Geiger–Müller tube (or GM tube) that can be connected to a PC.
DIY Geiger Counters in Japan – [Link]
Enrico Mathesar writes:
This little gadget will simulate a 500 volt or less Geiger tube when driven by a signal generator of sufficient amplitude, typically 5 volts p-p or greater. The purpose is to generate a steady, precise number of counts per minute so that the Geiger counter’s meter may be calibrated.
Geiger Tube Simulator – [Link]
Seeed Studio is asking for help creating an open source radiation sensor, to help in the wake of the Japanese Tsunami. [via]
Can open hardware community do something to help in this? Seeed Studio is now sourcing sensors, then assemble quick measurement tools, ship as many/fast as possible to Japan.
Since we have no previous experience with such device, your help is needed!
If you have experience in making such device, some quick questions:
1. What would be the right sensor for such detection? Will the education purpose GM tube work?
2. Any recommended peripheral circuits?
3. Does such Geiger counter needs special calibration? Or can we calibrate it with commercial device?
All creations will be open source and donated, thank you for helping out!
Radiation detector, help needed! – [Link]