[600MRG] Radio Amateur’s Sub-9 kHz VLF Signal Detected Across the Atlantic [W4DEX - WD2XSH/10]

[Edward R Cole]

Ah, Dex is a well known mw'er, and I understand 
making loaner rigs and being lonely at the 
mw's.  Above 1296 is thus in the "land of the 
midnight sun"!  I plan to build a 3400-MHz 
transverter later in the summer and have a mate 
to build as a loaner (same goes for 10 & 24-GHz). EME is planned for 3400.

Summer lawn mowing season arrived last week (June 
2) so I will be rolling up my chicken-wire 
radials for the summer - so transmitting until 
sometime in Sept.  I have to repair my MFJ 
analyzer to check/adjust tuning taps on the 
inverted-L (maybe I will find time to add 160m tap this fall?).

I have been busy in my "kits made by KL7UW" 
business and repairing my 16-foot dish back-frame 
structure and replacing the bias and control 
panel for my 2m-eme 8877 amp.  Newest addition is 
a Hakko FX-951 solder station making sm work so much easier.

Amazing that one can even make equipment work at 
those low frequencies.  I would think noise reduction a bear.

73, Ed - KL7UW, /45

At 01:15 AM 6/7/2014, Ralph Wallio, W0RPK wrote:
>http://www.arrl.org/news/radio-amateur-s-sub-9-khz-vlf-signal-detected-across-the-atlantic
>
>Radio Amateur’s Sub-9 kHz VLF Signal Detected Across the Atlantic
>
>06/06/2014
>
>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 µW 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. 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. “The signal bearing 
>was roughly west. W4DEX is bearing 285° from 
>here. The S/N is max on a bearing of 315°, which 
>puts the prevailing southwesterly background 
>nearer to the side of the antenna response. This 
>gave the signal a respectable 12.5 dB S/N in a 
>46 µHz bandwidth.” Nicholson said McIntyre’s 
>carrier also was visible during a daylight path in a 23 µHz bandwidth.
>
>Just to confirm that Nicholson was actually 
>detecting McIntyre’s signal, the two 
>experimenters conducted a blind confirmation 
>test. McIntyre changed his transmit frequency 
>slightly, and Nicholson was also able to detect 
>that signal at 8.971.100 kHz at the same 
>strength. An e-mail response from McIntyre 
>confirmed 8.971.1 kHz as the new frequency.
>
>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 said. “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.”
>
>McIntyre expressed his appreciation to 
>Nicholson, “who was convinced this could be done 
>with so little radiated power and for his 
>continuous prodding to give it a try.” He also 
>credited Nicholson’s “amazing weak-signal software.
>
>McIntyre’s transmitter consisted of a Hewlett 
>Packard HP 3586B selective level meter with 
>tracking generator. The low-level generator 
>output is amplified by a Wandel & Golterman 
>A-160 level regulator, which feeds a Hafler 
>P3000 stereo audio amplifier, which has been 
>bridge connected for mono output. In this 
>configuration, the P3000 is capable of putting 
>out 400 W of audio into an 8 W load. McIntyre 
>said the same generator and amplifier have been 
>used on 137, 74, and 29 kHz experiments.
>
>His antenna is essentially the same one he uses 
>for 160 meters and for other LF experiments. For 
>this experiment, however, it was equipped with a 
>gigantic base-loading coil, which contains 
>nearly a mile of wire. “The vertical wire is 
>spaced 1.5 meters from the tower, hanging from 
>an insulator 29 meters above ground,” McIntyre 
>explained. “Top hat consists of about 170 meters 
>of #18 Copperweld. Most of the top hat wires run 
>about 7 to 20 meters over the top of a 
>combination of oak and pine trees. Total antenna 
>capacitance is close to 1200 pF.”
>
>McIntyre also thanked Jay Rusgrove, W1VD, and 
>John Andrews, W1TAG, for their technical advice, 
>Markus Vester, DF6NM, for technical advice “and 
>additional prodding,” Mal Hamilton, G3KEV, for 
>coming up with the term “Dreamers’ Band,” and 
>Stefan Schaefer, DK7FC, for “proving dreams can come true.”
>
>He also expressed gratitude to Warren Ziegler, 
>K2ORS, for the opportunity to experiment on 29 
>and 74 kHz, “and all the other VLF experimenters 
>who posted their results on the RSGB LF Group 
>and the Yahoo Sub 9kHz Amateur Radio group.
>
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73, Ed - KL7UW
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