ELF to VLF Monitoring

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Dirk_SDR

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My interest are also the frequencies below LF.
Do you think this subforum would be the right place to write about experiences in this area or is there a better place?
 

dlwtrunked

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You do not need to be close to the water. In fact, a USN transmitter for the N Altantic is in N Dakota (LaMoure) on 25.2 kHz. Most is encrypted. However, the USN TACAMO aircraft use 50 Bd 50 Hz shift Baudot RTTY not encrypted but phonetic groups) with unannounced frequencies and times and the Russian sometimes still use some cw (but mostly send encrypted FSK RTTY). WWVB is on LF at 60 kHz with encoded time for clocks--I assume you knew that. I, myself, monitor from VA but once did from OH.
 

Dirk_SDR

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Are you close to the water in order to here these transmissions? Am presuming these transmissions are encrypted?
I'm about 200 km away from the next coast. The VLF transmitters can be received from anywhere.
Yes, the transmissions are encrypted. Modulation is FSK, about 200 Bit/s.
In Minnesota you should at least receive your strongest VLF transmitter FAA Cutler at 24,0 kHz (FSK F1B, 200 Bd):
... and stations from Canada.
 

bearcatrp

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I don't have any radios that go that low. Besides your airspy, what other radios go that low? Just curious. Was stationed by lanstuhl from 92 to 95. Had a great time in Germany.
 

Dirk_SDR

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Yes, I use my Airspy HF+ Discovery also for ULF and VLF. Is a good receiver!

A possibility for reception from nearly DC to 22 kHz is a simple soundcard you probably have in your PC. One possible setup is described here:
PC with soundcard used as VLF receiver (qsl.net)

Another way to receive low frequencies with "normal" receivers is to use an up-converter like this one:
VLF LF upcpnverter - sv1afn.com

For both solutions you will also need a VLF antenna, often your 80 or 160m antennas will also work. A good choice for VLF is also a Mini-Whip antenna.


You were Germany, Landstuhl Medical Center, in the 90ies? Really?
 

bearcatrp

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Actually, baumholder. I lived by landstuhl hospital. Was Army. Was my last duty station before retiring. Thanks for the info.
 

dlwtrunked

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Actually, baumholder. I lived by landstuhl hospital. Was Army. Was my last duty station before retiring. Thanks for the info.

I spent 2 weeks at Baumholder (Army civilian) about 15-20 years ago. I still remember walking from the hotel to a McDonalds that I could see on a hillside some distance away. When I came out, it had turned dark and I could no longer see the antennas that I had noted as reference points. A local got me back to the hotel.
 

pjxii

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I don't have any radios that go that low. Besides your airspy, what other radios go that low? Just curious. Was stationed by lanstuhl from 92 to 95. Had a great time in Germany.

A few older commercial tabletop receivers extend down to 10 kHz, the Bearcat DX-1000 will, the Sony CRF-1 will go lower still. I never had a Realistic DX-300/302 but I have heard that they do indeed receive these VLF frequencies.
 

Dirk_SDR

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A few older commercial tabletop receivers extend down to 10 kHz, the Bearcat DX-1000 will, the Sony CRF-1 will go lower still. I never had a Realistic DX-300/302 but I have heard that they do indeed receive these VLF frequencies.
... or you can use your VHF receiver (125..185 MHz) for ULF..HF..60 MHz with an upconverter.
I found the Nooelec Ham It Up + suitable down to 300 Hz:
Positive: rather stable frequency, good quality, addon: noise source
Negative: attenuates a few dB, up to 10 dB, so you have to compensate for that
 
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dlwtrunked

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I'm about 200 km away from the next coast. The VLF transmitters can be received from anywhere.
Yes, the transmissions are encrypted. Modulation is FSK, about 200 Bit/s.
In Minnesota you should at least receive your strongest VLF transmitter FAA Cutler at 24,0 kHz (FSK F1B, 200 Bd):
... and stations from Canada.

Actually, his strongest signal is more likely USN LaMoure, ND on 25.2 kHz. Also, when you said "FAA", you mean USN.
 

DS506

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With an RTL-SDR dongle, Ham It Up upconverter, and Boni Whip I was able to make out these five in December.
24 kHz Cutler ME
25.2 Lamoure ND
37.5 Grindavik Iceland
40 Ohtakadoya-yama Japan and
40.75 Aguada PR
 

Dirk_SDR

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With an RTL-SDR dongle, Ham It Up upconverter, and Boni Whip I was able to make out these five in December.
24 kHz Cutler ME
25.2 Lamoure ND
37.5 Grindavik Iceland
40 Ohtakadoya-yama Japan and
40.75 Aguada PR
Great!
What about DHO38 (near my location ...)?
DHO38 at 23,4 kHz isn't much further away from Ohio than Grindavik (100 kW) and has much more power (800 kW).
Perhaps the Boni Whip is at its low edge (20 kHz)?
 

Dirk_SDR

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Does anyone know whether SAQ transmits on December 24, 2022?
I don't find any hints on the SAQ homepage.
 
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