VLF Receiver?

[JBrock]

Has anyone ever built and operated a VLF receiver? The idea has always fascinated me. Can you offer any construction ideas or design tips? Can you describe what you heard? Can you direct me to any schematics or articles on the internet?

Thanks!

 

[Leftyretro]

Has anyone ever built and operated a VLF receiver? The idea has always fascinated me. Can you offer any construction ideas or design tips? Can you describe what you heard? Can you direct me to any schematics or articles on the internet?

Thanks!

There are tons of LF links on the web, with lots of them in the ham radio world. One word of caution, practical antennas are very inefficient at these frequency and receiving long range weak signals with the normal high noise levels in this band requires a lot of attention in design and construction.

On the receiver end a good solution is to use a up converter mixer stage and use a normal shortwave or ham band receiver.

Lefty

 

[MikeMl]

Another idea: most aircraft owners are pulling ADF receivers out of their aircraft. These are fine receivers that tune 190 to 1600kHz. Hang around an airport, and someone will give you one.

 

[Mikebits]

Most common use I know of for VLF is underwater comms for subs. They usually drag about a mile of wire behind the boat... Word of caution, if you do build one, don't use a switcher supply or you will get birdies at the switch frequency and all its harmonics.

 

[Leftyretro]

Most common use I know of for VLF is underwater comms for subs. They usually drag about a mile of wire behind the boat... Word of caution, if you do build one, don't use a switcher supply or you will get birdies at the switch frequency and all its harmonics.

The minuteman missile base I served in had a VLF command communications system in the underground launch control facilities as well (they had HF and local UHF as well). Something about the ionized atmosphere after possible overhead nuclear explosions left VLF as the only reliable RF communications channel available to send launch control permissions

Lefty

 

[Mikebits]

The minuteman missile base I served in had a VLF command communications system in the underground launch control facilities as well (they had HF and local UHF as well). Something about the ionized atmosphere after possible overhead nuclear explosions left VLF as the only reliable RF communications channel available to send launch control permissions

Lefty

Did not know that, makes sense though.

When I worked at Cubic Comm, we made a VLF receiver, when I tuned around the dial with it all I ever heard were blips and beeps, I doubt it would be a worthwhile project.