Radio Kit - 2 Tube Regenerative Radio
This radio kit will cover the AM radio band along with the SW radio band. Power for this receiver is 1.5 V DC for the filaments and 45V DC for the plate current. A D cell and five 9V transistor batteries wired in series will work to power this radio. A 2000 ohm headset or an audio amplifier is required. Requires two T-1T4_DF91 tubes (not included).
|Filament Voltage (Uf)||1.5 VDC|
|Headset / Amplifier Resistance||2 kΩ|
|Plate Voltage (Ua)||45 VDC|
|Packaging Dimensions||8.6 in. × 7.8 in. × 3 in.|
|Weight (Packaging)||0.91 lbs.|
|Layout and Schematic||All Models|
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Questions and Answers
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4 answers Can you tell me the approximate frequency coverage of the completed receiver? Thanks!
Asked by Anonymous on August 20th, 2016.
Difficult to tell. I built the kit but there's no way to determine the frequency you are on. I just know that one setting is for the AM band, and the others are for shortwave. I'm sure it covers at least the 5-10mhz portion of the SW bands.
A good way to calibrate this radio would be to find the frequency-time broadcast station WWV - WWVA in Ft. Collins CO, and Hawaii on the lower bands of 2.5, 5, 10 MHz at night, and 15, 20 MHz daytime. It will give you the frequencies to calibrate your radio, plus time of day in Zulu time, plus weather info for mariners and "other related information" according to the announcer at the top and bottom of the hour. WWV announcer id a male voice while WWVA is a female voice There is also CHU in Canada, but I do not have their frequencies at hand. 73's de W4FJF.
1 answers I have a crazy question. I was reading about cold cathode operation. What if instead of a 45v or high voltage source what if I used a quartz ocilator to make a frequency high enough to energize the tube and run it off say 3 volts in a radio circuit instead?
Asked by Anonymous on February 21st, 2016.
1 answers My receiver picked up a lot of AC line hum from the antenna. I solved this by winding 15 turns of wire on a form thinner than the radio's coil, the sliding the thin coil inside the main. The inductive pickup, eliminated the AC line hum. Also used a pair of micro-switches to change bands. In lieu of the HI-Z headphones, you can put together a simple LM386 audio amp and use an 8-ohm speaker, as I did. Uses more current, but I fashioned a power supply out of 45VDC and a 5VAC wall warts. You'll need to filter the 45VDC wart better, and regulate the 5VAC wart to provide 1.5VAC for the tube filaments. The 1.5 can be achieved with a correct value resistor (or variable resistor), but I built a simple regulator using a LM2596. Both chips datasheets show how to do this.
Asked by Anonymous on January 24th, 2017.
This sounds terrific, but the LM386 requires a new set of voltages. How do you handle that? More voltage regulators?
1 answers I am struggling to identify capacitor Beside the 3 ceramic with have a clear 503 label so 0.05 microF The other four are all blue 'ceramic' with no label
Asked by Anonymous on August 16th, 2020.
These capacitors also have a code printed but it can be difficult to read. A magnifying glass and good lighting can be really helpful. If you have a multimeter that can accurately read capacitance, you can use the meter to identify the caps as well.
The instructions are fairly straightforward. They substituted .047 capacitors for the “503” (.05) capacitors the instructions call for. Not enough hookup wire either. Tube socket pins didn’t line up well with what the diagram showed, which made it so some of the leads of the components needed to be extended.
Had to drill a missing hole in the base, and re-drill some of the other holes so everything would line up.
Purchased the sold separately tubes from AES. One is microphonic, but seems to work OK.
All in all, it’s fun to play with together, just a bit disappointed on the quality VS the price.
this is the third kit that I have built .The only problem I have had is winding the coil ,the third time is the charm .I think the tickler coil should be closer to the main coil for better results .It is a great kit ,now how about a two tube amp to compliment it.
I wasn't too thrilled with the quality, which other people have said as well. Holes were not drilled properly, the instructions weren't clear, plus the layout for the foil ground plane and the front label were printed undersized. I had to fiddle to get everything together and wired however when I powered it up it immediately worked. Performance is OK and all bands work.
I had no problem with any of the parts or the wooden pieces. My only complaint is the drawings. The coil drawings are way too dark. Drawing the coil as black and the windings as dark grey in the coil winding instructions - I could barely make anything out. Using black and various grey tones for all the drawings is dumb. Just make it simple and make everything black and white. Thank God they included the schematic.
This was a fun kit to build... a couple of notes to really make this kit sing... you need a long wire... like 75 to 100 feet to hear the short wave bands. Also, these are battery tubes... so don't expect that orange glow... you can see it if you strain your eyes in a dark room, but don't expect that glow to double as a night light. I did add a couple of improvements to make tuning easier: I added a Philmore vernier dial to the tuning capacitor to reduce the speed of tuning - these can be very expensive - almost half the cost of the radio, but we'll worth it! I will also be replacing the 50 ohm regen control pot with a 10-turn 100 ohm potentiometer. Also kind of expensive, but it makes tuning a lot easier. Another thing about battery tubes... you don't have to wait for them to warm up... they started working instantly like transistors.
The wooden chassis and front plate are very poor quality. They are no where near rectangular and the cut is extremely rough. As for the construction, it is not too difficult and goes together rather easily. I was disappointed with the sensitivity of the completed product. I built a similar two tube (also 1t4's) radio when I was about 10 or 12 years old that had much better sensitivity. This was to be a nostalgic return to my childhood, but found it quite disappointing.
Fine kit but there is missing an alligator clip.