VLF, LF & MF receiver

Discussion in 'The Low Bands - 630/2200 Meters - VLF' started by WA4ILH, Aug 19, 2019.

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  1. WA4ILH

    WA4ILH Subscriber QRZ Page

    When I was in the Navy, 50 years ago, we had a National receiver in an auxiliary radio room that would tune down to about 10 KHz. (maybe lower) It had plug in modules for several bands which you could change by lifting up two little arms at the bottom front of the receiver and pop out the module and plug in another to change bands. The one thing that I thought was really cool was when you moved the tuning dial when it was tuned to about 10 KHz, you would hear a little “woosh” sound as the frequency changed. I don’t remember the model number but it had “National” on the front panel. Wish I had that now for our newest bands. If memory serves, I think we had 3 modules, probably covered 10 to 530 KHz.... ???
    Tom WA4ILH
  2. K9STH

    K9STH Ham Member QRZ Page

  3. WA4ILH

    WA4ILH Subscriber QRZ Page

    trying to copy an image here...

    Attached Files:

    • VLF.jpg
      File size:
      8.5 KB
  4. SM0AOM

    SM0AOM Ham Member QRZ Page

    This is a National HRO-5oT receiver, which is an MF/MF/LF but not VLF receiver.

    The lowest tuning range using standard coils, the quite uncommon "J", is 50-100 kHz.

  5. WA4ILH

    WA4ILH Subscriber QRZ Page

    OK,then I must be thinknig of another receiver. I definately remember copying stations on 24 KHz.
    Tom WA4ILH
  6. K8JD

    K8JD Ham Member QRZ Page

    I have a National HRO/M in the garage with the plug-in coil banks to change bands. I got it well over 30 years ago and could hear Great DX on 10 and 15 M with the only coil set I had for it !!
  7. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Last edited: Aug 22, 2019
  8. KN4WLM

    KN4WLM Ham Member QRZ Page

  9. KN4WLM

    KN4WLM Ham Member QRZ Page

    I was in from 1975-79 onboard a boomer and we used an R-1738 for our broadcast. I think it was a Collins radio.
  10. WA4ILH

    WA4ILH Subscriber QRZ Page

    The remarkable component in receiving a VLF signal "at depth" is not the receiver but the antenna. I was never on subs except as a support ET. (SUBASE Pearl) We used AN/BRA-16s back in the early 70s.
    One thing I find amusing in the film "Crimson Tide" when "sparky" finally got the VLF receiver fixed, the data started coming in at a very high baud rate. Still, it was a good movie.
    Tom WA4ILH

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