Wednesday, March 10, 2010

Colt receiver part 1

I found a book as an E-book at the university library: Radio and Electronics Cookbook that was published by the Radio Society of Great Britain in 2001. I have skimmed through it briefly and it seems to cover both some  radio theory and some interesting projects. I do have a lot of  "maybe" and "should be" projects in my head (that I will cover in later blog posts) and now I think I decided, apart from getting the softrocks built (as they are already on my desk), I would like to build a hardware defined receiver.  A very basic one to really try to understand how a radio works.

In this book, I found one called the "The Colt 80 m receiver" that I liked, because it´s built in modular steps and quite thoroughly explained. It starts with the audio amplifier and then adds mixer (NE602) and VFO to become a direct conversion receiver. The last part is to add an IF stage to become a superhet.

What worries me a bit is that I can´t find any reference to this design when I google it. Or maybe blogs and so on wasn´t that common 2001 and earlier or this design is named something else elsewhere? A bigger problem is the availabilty of parts. Variable capcitors to be used in a VFO can´t be bought new, but I´ve have asked around in the club and I think that will be solved.

Then there are some specific inductors from Toko:
  • Toko KANK3334
  • Toko KANK3333
  • Toko YHCS11100AC (tuned inductor)

For the two first ones I have found a guide at the GQRP club (that I by the way have joined; Sprat is a great magazine), so I can make those inductors with toroids. But the last one, I have no clue. Any ideas someone? There´s also a part number for a crystal filter, but I think I can use another one for 455 kHz.

We will see if there will be a part 2.


  1. Hi Eric,

    Try Googling JABDOG or this small company here in the UK supplies lots of great components for radio Amateurs interested in construction like yourself.
    Enjoy the Hobby.

    73 Ian MW0IAN GQRP 12387

  2. Hi Ian,

    Thank you for your comment. I will check their website to see if there are any supplies of these components there.


  3. JAB does have these parts

    Toko Part JAB Part

    YHCS11100AC2 EZ-11100
    KANK3333R 10K-3333
    KANK3334R 10K-3334

    MuRata Part
    CFM455JI CFM455JI