VLF/LF WWVB software receiver　&　LOOP　ANTENNA

Building of a long wave JJY/WWVB software receiver
　　　　

JAPANESE

bitalemon3000

A long wave receiving system using FFT software Spectrum Lab of DL4YHF. 　　　　　　

If antenna connection is carried out to a sound card, it will become a long wave receiver to 96khz.

　jjy/wwvb,whistler, meteor sound and earthquake presage radio wave
　　　　　　

1、　Spectrum　Lab

　 Download Spectrum Lab from the homepage of dl4yhf.
　　　　
　　　　http://www.qsl.net/dl4yhf/spectra1.html

After installation of Spectrum Lab, audio output setting is performed.
　

Audio output setting
　　　　　Quick　Settings
　　　　　Load　＆　Create　user-def'd entries
　　　　　Import　
　　　　　VLF_Stations.usr
　　　　　exit
　　　　Although it became an ELF/VLF receiver of 24khz, since the antenna is not connected,
only noise sound can be heard.
　　　　If a signal is put into a sound card, it can use as a FFT analyzer.
　　　　　　　　

Reception band enhancing
　　　　Options
　　　　Audio settings, I/O device selection
　　　　Audio Processing Sample Rate (nominal)is set as 192000.
　　　　It became the ELF/VLF/LF receiver of 96khz.

Setting preservation
　　　　　Quick　Settings
　　　　　Load　＆　Create　user-def'd entries
　　　　　Save　
　　　　　96Khz.usr

2、Loop Antenna

　　　　　It's the antenna which can be made very easily, but it can be received well.
　　　　　Materials are only an insulated wire and an external speaker.
　　　　　
　　　　　①　Wound the wire around a carton box and it fixes with the packing tape.
　　　　　27ｃｍ×32.5ｃｍ　　35turns　41.7ｍ　0.9mm 32Ω
　　　　　Inductance and Q in 50khz became 915uh and Q=9 in the calculation with WEB.

　　　　　② Remove wiring of a speaker and connect with a loop antenna.
　　　　　

3、Receiving Test

　　　　　JJI and JJY of 40KHZ and 60KHZ were received.
　　　　　 40KHZ in Fukushima was heard clearly and 60KHZ in Saga was heard by a noise mixture.
　　　　　JJI 22.2KHZ in Miyazaki was also heard strong.
　　　　　Reception at the place where it's about 500 km away from Fukushima and Miyazaki.
　

[40khzjjynocap.WAV]

[60khznocap.WAV]

4、Tuned Loop Antenna

　　　　　The resonance frequency of an antenna "is presumed" by Spectrum Lab.
　　　　　The calculation which calculates the value of F＝, L=, and C= uses Excel.
　　　　　

lcf.xls(16kb）

　　　　　①　The capacitor such as 0.01uf(103,10000PF) is connected with the loop antenna.
　　　　　 It searches for the frequency that the signal has strengthened.
　　　　　I measured in 6800pf of holdings. A resonance expectation frequency is ≒ 63.8KHZ.
　　　　　The color of 3 main lines per 60khz becomes red with capacitor and becomes blue without it.
　　　　　They seem to be resonating per 60khz.
　　　　　The inductance which resonates in 60khz in 6800pf is 1036uh.
　　　　　Completion of an antenna for 60KHZ JJY.

　　　　　② An antenna for 40KHZ JJY.
　　　　　The capacitor which makes 1036uh resonate in 40khz is 15297pf.
　　　　　But Q of an antenna is low, so it's substituted in 14700pf of holdings (103+472 and ≒ 40.8KHZ).
　　　　　The signal strength of 40khz is changing.
It becomes red with 14700pf and becomes blue without it.

[40khzjjy.WAV]

5、VLF/LF Tuned Loop Antenna

(1)Inductance measurement.
　　　　　
①　Franklin oscillator was made for inductance measurement.
　　　　　
　　　　

　　　　　
　　　　　
　　　　　②　Loop Antenna 52cm×52cm、1mm Aluminum wire、 16turns、2turns pickup
　　　　　
　　　　　　The loop antenna with the capacitor is oscillated in the Franklin oscillator.
　　　　

　　　　　
　　　　　
③　It oscillates in 76.05khz with 10000pf, and an inductance　is calculated with 438uh.
　　　　　
It oscillates in 24.05khz with 100000pf, and an inductance　is calculated with 438uh.
　　　　　
It is an actual measurement although it seems that it is too accurate.

The result with 420uh had come out when measuring it in summer.

A line is tight and closed in cold time now.

lcf.xls(16kb）

　　　　　
　

(2)Reception band setting
　　　　　
　　　　　The combination of capacitors is chosen with DIP switch.
　　　　　
　　　　　When the value of inductance and the capacitor is input to a yellow cell of the Excel sheet,
　　　　　
　　　　　 the resonance frequency is calculated.

　　　　　

dip.xls(80kb）　　　　　
It resonated from 19.3Khz to 100Khz
　　　　　
by combining 100000pf 33000pf 10000pf 6800pf 3300pf 1800pf 330pf.
　　　　　
The capacitor is not put up to msb.
Reserved for the future use.
That is for the medium wave, NDB, and SAQ 17.2khz, etc.
　　　　　
　　　　　　
　　　　　　

Antenna characteristic graph.

　

　　　　　

Frequency setting chart
Error compensation can be carried out if resonance frequency is measured using the Franklin oscillator.
　　　　　

bcd2f.pdf(6kb）
　　　　　

6、youtube

　VLF/LF　Loop Antenna
　　　　
　　　　http://jp.youtube.com/results?search_query=pobox22cpo