Look what I found: an Atwater Kent Variocoupler!

Discussion in 'Homebrew and Kit Projects' started by KK4NSF, Jan 17, 2019.

ad: L-HROutlet
ad: l-rl
ad: MessiPaoloni-1
ad: K5AB-Elect-1
ad: L-MFJ
ad: Left-2
ad: Subscribe
ad: Left-3
  1. KK4NSF

    KK4NSF Ham Member QRZ Page

    While negotiating a non-radio deal the other day, I noticed this baby sitting on a shelf in the guy's garage. He said he had no idea what it was, it came with the house, and threw it into the package deal. It was still in it's original box, and came with two nice AK Variable Capacitors. Now they are sitting on my desk! I just tested the continuity of the taps and coils... and all of the wires are intact. The only thing that appears to be not prefect about them is a good layer of old grime.

    The AK Variocoupler was used in 1920's style breadboard radios, and when combined with the variable capacitor makes a GREAT front-end for a tube type TRF Radio, or a really good crystal set. If you notice, the coil is tapped with both course and fine taps, and coupling is variable from full to zero.... all I'lI need to do is add a detector, an antenna, and some sort of audio output, and it should tune MF to the middle of the shortwaves!

    The big question now is: what do I want to build? Whatever it is.... it's GOT to be COOL!
    AKvario1.jpg AKvario2.jpg AKvario3.jpg AKvario4.jpg
    Last edited: Jan 17, 2019
    K3KIC, KC8YLT and KA0HCP like this.
  2. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Whatever you build WILL be cool!
    KK4NSF likes this.
  3. W2VW

    W2VW Ham Member QRZ Page


    Looks like a cement mixer. Where is the middle of the short waves anyway?

    Reminds me to fire up my AK-55. Been a while.
    NE1U and KK4NSF like this.
  4. KK4NSF

    KK4NSF Ham Member QRZ Page

    that's right where the BBC broadcasted from!
    Last edited: Jan 17, 2019
  5. W2VW

    W2VW Ham Member QRZ Page

    CU1064.jpg Here's one I dragged out of storage recently:
  6. KK4NSF

    KK4NSF Ham Member QRZ Page

    the pic is quite small.... so I can't see it well. Is it a big tank coil? Cool!
  7. K8ERV

    K8ERV Ham Member QRZ Page

    Great find. If you build it they will come.

    TOM K8ERV Montrose Colo
  8. KK4NSF

    KK4NSF Ham Member QRZ Page

    I spent a few hours last night cleaning and polishing the bakelite and brass parts. It now gleams with possibilities!

    I've been looking over all of my old crystal and one tube radio designs (I used to do the annual CR contests ) and I think I've decided on a project: an MF to low shortwave AM receiver. According to the theoretical calcs, I should be able to cover from 500khz up to ~ 2Mhz with a single 365 capacitor, depending up how much stray capacitance is in the system. Funny, that exactly matches the Variocoupler & Variable Caps I got in the deal! ;)

    It's going to be a simple TRF design, with one stage of detection / amplification. Maybe a 6R7... or whatever is in my box. OR a simple diode detector and one stage of AF...sort of like this one, except I'll probably use an output transformer so it will sound good on speakers:

    KC8YLT and KA0HCP like this.
  9. WD0BCT

    WD0BCT Premium Subscriber QRZ Page

    That A-K Varicoupler looks sooo Buck Rogers! Kool.
    NE1U likes this.
  10. W1BR

    W1BR Ham Member QRZ Page

    That item might bring some serious money to an AK collector. Take good care of it; it is not junkbox parts.
    KP4SX, KK4NSF and NE1U like this.

Share This Page