- Amateur Radio (Ham Radio) Community

Call Search

New to Ham Radio?
My Profile

Friends Remembered
Survey Question

DX Cluster Spots

Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement

[Articles Home]  [Add Article]  

Radio Amateur's Sub-9 kHz VLF Signal Detected Across the Atlantic:

from The ARRL Letter on June 12, 2014
View comments about this article!

Radio Amateur's Sub-9 kHz VLF Signal Detected Across the Atlantic:

How low can you go? A signal on 8.971 kHz has spanned the Atlantic, from North Carolina to the UK. Running on the order of 150 W effective radiated power, very low frequency (VLF) experimenter Dex McIntyre, W4DEX, transmitted signals on June 2 and 3 that were detected by Paul Nicholson, an SWL in the UK. Earlier this year, Nicholson detected McIntyre's WH2XBA/4 Experimental Service VLF signal on 29.501 kHz. McIntyre needed no FCC license to transmit on 8.971 kHz, since the Commission has not designated any allocations below 9 kHz -- dubbed "the Dreamers' Band."

"I'll probably make more transmissions on 8.9 kHz when there is no chance of thunderstorms," McIntyre told ARRL this week. "Then, maybe sliding down in frequency to see how low I can go for Paul to detect the signal." Right now, McIntyre said his priority is to complete a transverter for the other end of the spectrum -- 5.7 GHz. He's also working on a second 24 GHz system as a loaner, "so I'll have someone to work," he noted. "Sure is lonely here above UHF."

Nicholson used sophisticated digital signal processing (DSP) software to detect McIntyre's transmission. The distance was approximately 6194 km (approximately 3840 mi). Nicholson was able to detect the VLF signal during both daylight and nighttime paths.

On June 1 and into June 2, McIntyre transmitted a steady, GPS-locked carrier at 8.971.000 kHz. Between 0000 and 0600 UTC, Nicholson measured a carrier at that frequency in Todmorden, UK, with a field strength on the order of 15 nV/m. He combined the electrical and magnetic field receiver outputs to produce a unidirectional antenna response.

"This brought the signal up to a significant level," Nicholson reported. McIntyre's carrier also was visible during a daylight path in a 23 Hz bandwidth, he added.

Is a two-way sub-9 kHz contact in the offing? "A two-way, transatlantic contact would be a hundred times more amazing than just a simple signal detection," McIntyre told ARRL. "I seriously doubt I will ever have that receive capability. But not long ago I seriously doubted I would be the first to receive a transatlantic or New Zealand 137 kHz transmission. Going down in frequency has been as much fun as going higher. It's all RF." Read more


The ARRL Letter

Member Comments:
This article has expired. No more comments may be added.
Radio Amateur's Sub-9 kHz VLF Signal Detected Across the Atl  
by W7KNA on June 16, 2014 Mail this to a friend!
Very interesting. The Navy ELF operates on 76 hertz. Just above the power line frequency. Good article. 73 Darval N.
Email Subscription
You are not subscribed to discussions on this article.

My Subscriptions
Subscriptions Help

Other News Articles
New IARU Region 2 HF Beacon Coordinator Named:
Amendment to ARRL DXCC Rules Will Expand DXCC List:
Schofield Radio Club Hits New High:
UI Sophomore Reaching for the Stars -- and Getting There:
Frequency Check: Is Your UAS FCC Compliant?