Useful links

Antennas

• 250-400 µH variometer (G0MRF)
• 472 kHz small loop experiment (VK1SV)
• Antennas for 136 kHz (ON7YD) ^*
• A short antenna tuner (HB9DUL)
• A small 500 kHz vertical antenna (G0MRF)
• A versatile 630m antenna (VE7SL)
• Implementing an effective ATU for 630 meters (KB5NJD)
• LF-MF antenna notes (N6LF)
• Tee vertical antenna for the 630 m band (VK2XV)
• The PA0RDT Miniwhip antenna (PA0RDT)

Books

• LF Today (G3XDV) A guide to success on the bands below 1MHz
• MF Down Under (VK5BUG) An edited VK-compendium of articles and projects for the 630m and 160m bands

Commercial rigs

• JUMA TX500
• TVTR1 630 m transverter

Measuring

• 630 m antenna matching measurements using an oscilloscope (VE7CNF)
• A long-wave SWR meter (HB9DUL) ^*
• LF VSWR meter (G0MRF) ^*
• LF-HF reflection coefficient bridge (G0MRF)
• Modifying an MFJ-259B antenna analyzer to operate on 630 meters (KB5NJD)
• Tuning aids for the 136 kHz and 500 kHz Bands (M0BMU)

Modes, modulation

• Basic forward error correction (FEC) schemes (Mark Watson)
• Extreme narrow bandwidth techniques (ON7YD)
• The principle of forward error correction (Paul Nicholson)

Propagation

• Propagation 101: The case of the X1.6 flare on 9/10/14 (KB5NJD)

Receiving

• 136 kHz LF and 472 kHz MF Pre-amplifiers (G0MRF)
• 500 - 515 kHz preselector (W1VD)
• 518 kHz elliptical 50 Ohm low-pass filter (W1TAG)
• A simple bandpass filter for 475 kHz (VK1SV)
• Making a 472 to 479 kHz bandpass receive filter for 630 m (VK5ZVS)

Software

• Argo (I2PHD) a DFCW and QRSS viewer
• Freeware for radio amateurs (DL5WSB, sk) mini Ring Core Calculator, mini dB Calculator, ...
• Opera (EA5HVK) Opera receiving and transmitting software
• QRS (ON7YD) QRSS & DFCW transmitting software
• Spectrum Lab (DL4YHF) Audio spectrum analyzer with waterfall display, for QRSS & DFCW reception
• Winrad (I2PHD et al.) SDR amateur radio program
• WSJT-X (K1JT) JT4, JT9, JT65 and WSPR receiving and transmitting software
• WSPR (K1JT) WSPR receiving and transmitting software
• WSQ (ZL2AFP, DL4YHF) WSQ2 receiving and transmitting software

Transmitting

• 0,5 kilowatts 500 kc (630 m) MOSFET PA (DJ0ABR)
• 0-500 kHz linear exciter (VK2XV)
• 100 Watt CW transmitter for the 500 kHz band (N4ICK)
• 100 Watt MF CW TX (GW3UEP)
• 25 Watt 472 kHz PA (GW3UEP)
• 400 watt FET amplifier for 630 meters (W7IUV)
• 472 kHz transmitter (M1GEO)
• 472 kHz transverter (G3XBM)
• 500 kHz Class-D 500-Watt RF deck (W1VD)
• 500 kHz CW transmitter (M1BMU)
• 500 Watt 500 kHz transverter (PA3BCA)
• 500 Watt output 4-400A linear amplifier for 600 meters (W5JGV)
• 630 m 5-15 W amplifier (IW3SGT)
• 630 m Wilkinson power combiner (VE7SL)
• 6AG7/807 transmitter for 472 kHz (VK1SV)
• A 300 W Class D amplifier for 630 m (G0MRF)
• A simple amplifier for the Ultimate 3 for 136 & 472 kHz (HB9ASB)
• HF to LF/MF linear transverter with 500 kHz Class D EER power amplifier (M0BMU)
• LF/MF, flexible, efficient, non-linear, transmit converter (VK1SV)
• Long-waves and medium-waves dual-band kilowatt CW transmitter (HB9DUL)
• Medium power linear power amplifier for LF/MF (G4JNT)
• Modifying an IC735 for the 630 m band (SQ5BPF)
• SoftRock RXTX - Modification for 2200, 630 and 160 metre operation (VE7VV)
• Third-Method Narrowband Direct Upconverter for the LF / MF Bands (G4JNT)
• Transverter for the 630 m band (VK6YSF)
• Using the Ultimate 2 on 472 kHz with an external PA (G8AGN)
• VXO controlled transmitter for the UK 500 kHz Experiment (G3YMC)

Other

• A survey of the 630-meter band for amateur radio (KB5NJD)
• The 630 meter band (VO1NO)
• The ARRL 600 meter Experimental Group (W5JGV et al.)
• Twente WebSDR (PA3FWM et al.) Wide-band WebSDR, includes 472-479 kHz
• You, too, can work 630 meters (WD8DAS)

The missing link

Do you know one or more links that should be in the above list? Feel free to contact .
Broken links can be reported to the same e-mail address.

^*: Can be used for 630 m as well