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Simple Shortwave Radio Receiver Designed By N1TEV

I wanted to build a radio receiver designed by N1TEV for a long time. Thanks to my friend Henrik ( DK8HM ) for the PCB he sent me to build this receiver.
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I always avoided this N1TEV radio receiver because it needed two variable capacitors. These days they are not easy to find. I think I may have a solution for that, in a future video when I will come back with another version of this regenerative receiver. Here you have the tests and the initial build. I’m still trying to get used to the regeneration control, as it’s not as easy to use as it is on the Sputnik Regenerative Receiver.

It sounds really nice and has good sensitivity. Maybe a little too much sometimes, as I have to use it with the RF attenuator at 40% in order to have a good modulation for the amateur radio bands. Special thanks to my buddy Hendrik in Germany ( DK8HM ) who sent me to test the PCB board he designed.

THE ORIGINAL SCHEMATIC

The schematic of the radio receiver designed by N1TEV usually includes an LM386 audio amplifier. In this case that was left out. The idea is that everyone can pick the audio amplifier they like. Some people prefer the simple LM386 audio amplifier, others may chose a transistors based audio amplifier. Lately I’ve been playing with a TDA2003 audio amplifier and it sounds way better than the LM386.

The schematic is really simple, but if you asked me twenty years ago, I may had a different opinion. I never had the possibility to measure the variable capacitors I had. Another issue was that I didn’t used the proper NFET transistors and for that reason in the past, this receiver never worked for me. But… it works now, twenty years later.

N1TEV REGENERATIVE RECEIVER SCHEMATIC

Original Image Source tuberadio.com

BUILDING THE RADIO RECEIVER

Most versions of this receiver I found online, were built Manhattan style. I wanted to do the same, until I received the PCB board as a present from Hendrik. So I decided to put it to use and build my test shortwave receiver design by N1TEV. I think the only thing harder to make was the coil. In my case I had four coils instead of the original design. The reason behind that, was that I had an extra coil used for the frequency counter. It did got me a little confused when I had to solder the wires and I had no clue what wire went where.

I built the coil on PVC pipe with the diameter of 31mm. For a receiver that performs well, use good quality components. C3 especially has to be an NPO capacitor for a good frequency stability. For the NFET transistor you can use either an MPF102, J110 or a 2N5457. I used MPF102 thanks to my buddy Nigel who sent me a few.

I forgot to mention in the video, but with the last adjustments, I managed to cover from 3MHz up to 7.4MHz. The only thing I changed from the coil was to use 20 turns instead of 18 or 22 as it seems to have in most schematics online. The variable capacitor used for main tuning, was around 60pF if I remember well.

SENSITIVITY

If you watch the video above, you will hear me saying that the receiver is overloaded with signals. Later on I realized that the receiver was not actually designed to be used with a proper EFHW antenna. A piece of long wire would be ok. In my case I had to set the RF attenuator really low not to overload the receiver with signals. If you build it for one of the amateur bands, this receiver works absolutely amazing.  

Using it for general shortwave coverage is also great and it sounds really nice too. What I did noticed, is that the stability in frequency was not as great as I was expecting it comparing it to other receivers I built. I believe that it can be fixed and make it more stable in the future. As far as I’m concerned, I find the designs by N1TEV to be one of the best shortwave regenerative receivers I found online. If you want to learn and change the frequency of the receiver, down below you will discover the easiest way for me to do that.

When I started playing around with receivers schematics, I did not know how to calculate the circuits to resonate on the frequencies I wanted. I learned the hard way and at first I discovered how to do it by trial on error. Later I discovered that using some really simple online calculators, can save me a lot of time and also enameled copper wire.

CONCLUSION

Unfortunately I do not have a PCB design prepared for you to download and make using the toner transfer method as I usually have. Is because the PCB I received was a present and I didn’t had to work on one. I want to test a few more things and make a few changes to the schematic first. Watch this new video here and there will be a new article as well, based on this regenerative receiver design. I have a good feeling that this can become a really great receiver, both for amateur radio bands, or for general shortwave coverage. Right now I am using this particular receiver for my entertainment, for the shortwave broadcast bands mostly.

73 DE YO6DXE

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11 Comments

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  1. Hi, I have built a N1TEV receiver, as it has no frequency counter.
    I found you have built a excellnet receiver named Sputnik with frequency counter. So I added 3 turns and connected to HP53131 frequency counter, the frequency display is not stable.
    Could you tell me the info of your frequency counter?
    Thanks!

    • HERE is the first one I used. But it may not be anything wrong with the counter. The problem with regen receivers is that they are stable in frequency but it depends on how well is built and also how good the components are ( small tolerances when it comes to the capacitors ). Also if the regen control is not set properly, there may be no reading at all. I noticed that if the transistor is slightly out of oscillation as if would be if we want to receive AM signals, then there is no reading. If the transistor is oscillating as it would be if we want to listen to CW or SSB it works fine. So try to play a little with the regen control and see of you get better results.

      73, YO6DXE

  2. Hello Ciprian,

    I would like to ask you if there is somewhere a schematic and PCB pattern for the frequency display that you get the PCB for from your friend who sent you the PCB for this receiver?

    Thanks,

    Striko

    • I only received the preamplifier PCB, but it didn’t work with the frequency counter I had. So I had to modify the frequency counter and did not used the preamp board at all at the end. Now I use another frequency counter that works like a charm, is small cheap and seem pretty good. Here is a link if you want to buy one. I want to order a few more for me as well.
      73, YO6DXE

  3. El amplificador de Rf, Q1, tiene la base +B atreves del diodo D1… no lo entiendo… ¡Paraque sirve entonces C3!

    • Q1 no es un preamplificador de RF. Amplifica un poco la señal, pero no mucho. Q1 es una etapa intermedia entre el circuito receptor regenerativo y la antena. La etapa de amortiguación detendrá las fugas de oscilación de RF habituales que ingresan a la antena, ya que la mayoría de los receptores regenerativos tienen este problema. C3a en paralelo con L2 es su circuito sintonizado. C3a es un capacitor valioso que lo ayudará a cambiar la frecuencia que desea escuchar. C3b es un capacitor variable adicional para ayudarlo a sintonizar el receptor. C3c es el condensador que forma parte del circuito de sintonización fina del receptor.

  4. Salut!

    Sunt Claudiu, yo8ryb…. felicitari pentru frumoasele realizari!
    As dorii o poza cu rezolutie buna, a cablajului, pentru uz personal!
    Multumesc!

    • Salut Claudiu. Haide că o să fac o fotografie astăzi față / verso și iți trimit. Doar că na… acum e cu toate componentele pe el ). Chiar vroiam să-l demontez ca să construiesc o variantă ușor îmbunătățită. Revin cu un email.
      73, YO6DXE

  5. Hi Ciprian,
    Thanks for sharing your experience with Kitchen’s regen receiver.
    I look forward to seeing any modifications you make to add extra bands and a frequency display.

    73,
    Orville “Alan” Jones, N8WQ

    • Thank you so much Alan…
      I don’t want to mess up the board sent by my friend ( ha ), so I want to build another version of the receiver using the Manhattan style with me pads. My friend Andrei ( YO6TJJ ) from rowaves.com just sent me some of those pads and I will play around with another version of the receiver. I am also curious how that one will work. I will make a video when it’s done and I get to test it a little… just to make sure that I don’t say stupid things in the video ( ha ).
      73, YO6DXE