Of course, equal credit must be given to VK2DDI for having a system good enough to hear John's signal all the way down on Berry Mountain, New South Wales, Australia! It is there that David has set up a fine LF station, 500m above and overlooking the Tasman Sea.an ideal location for weak-signal LF work.ĭavid's receive antenna at the time, feeding and SDR-IQ receiver, was a simple non-resonant 90' vertical wire, with no ground radials and no tuning. John's system does indeed work well.just last year at this time, his 630m signals were copied by KL7L near Anchorage, Alaska. "As far as my system is concerned, I am the poster child for "If I can make it work, anyone can!" These days RX antennas are the VE7SL multiturn loop or the TX vertical, both of which have their own merits depending on the conditions at the time." IF Rig on 630m is typically a Yaesu FT920. Scope match is used to resonate and match the the impedance.
I power the amps with a pair of BK Precision 30V 6Amp variable power supplies (variable current limit threshold also). I filter the output with the W1VD KW LPF that was built by Dave Robinson G4FRE (ex WW2R). The W1VD Ø degree hybrid combiner brings them together in phase for close to somewhere between 200 and 250 watts TPO depending on how hard I drive and how close I match the TX levels entering the combiner. I use a GPSDO for the LO and use that signal to drive two parallel GW3UEP amps with max power at 125 watts each. I have two of those boards, one is a backup. The other way is via the MF Solutions transmit downconverter, developed by John Molnar, WA3ETD/ WG2XKA. I can do CW with a very nice waveform using the GW3UEP VFO/Driver coupled with a GW3UEP 100w amp with waveform shaping. "I have a few ways of making RF in the shack. Like most LF stations, John's is mostly homebrew. A check of evening WSPR activity will often reveal dozens of stations actively spotting what they are hearing. Although two stations may each spot each other, it is not considered to be a valid two-way QSO.
WSPR is not a QSO mode but strictly a one-way 'beacon' mode. The WG2XIQ beacon was operating in the WSPR mode, which has become very popular amongst 630m experimenters as well as those just interested in listening-in.