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VK5KLT Australia flag Australia

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QSL Address (direct): P.O. Box 3334 Rundle Mall, Adelaide, South Australia, 5000

Adelaide cityscape

I'm a professional engineer with a strong interest in radio frequency / microwave engineering, electromagnetics, antennas, and the fascinating hobby of amateur radio. I'm a fan of homebrew electrically-small magnetic H−field Loop antennas and other compact and efficient HF radiating structures. There are however no "free lunches" (and few cheap ones) in small antenna design when pushing the inviolable boundaries of electromagnetics and EM radiation; as the free space wavelength has not yet been miniaturized! In addition to small magnetic loop antennas my other favourite HF antennas are the highly efficacious lumped reactance tuned Butternut multi−band HF9V and dual−band HF2V trap−less verticals, and the Comet H422 quad-band trapped rotary dipole antenna. Extensive experiments over time with the Comet dipole show commendable on−air performance with useful directivity on the 40m, 20m, 15m, and 10m bands that belies its relatively compact size / low visual profile. The H422 dipole in either its horizontal or more compact Vee configuration has therefore been found to be an ideal HF antenna for restricted space locations. My favourite manual antenna tuners are the Palstar models AT1500CV and AT5K.

The fickle and capricious Ionosphere and solar cycle play a complex but important role in establishing the viability and efficacy of our HF radio communications. There is very little we can do about these variables; but there is plenty one can do about having a good and efficient antenna system. It is an awe-inspiring concept that a simple wire or aluminium tube antenna structure can transform electrical energy into invisible radio electromagnetic waves that can cross space and vast distances. The magic of radio propagation!

My QTH is located in the North Adelaide / outer CBD parkland circle belt of the beautiful city of Adelaide. Stringent residential zoning restrictions preclude the deployment of tall radio masts and towers with big high−gain HF Yagis / Quads, Log−Periodics, etc; hence the interest in aesthetically pleasing and environmentally sympathetic "covert / stealth" antenna structures having reasonable radiation efficiency and respectable low-angle of radiation DX performance such as well sited and installed verticals, and the small magnetic loops. The Butternut HF9V Vertical is mounted on the 9m high large−area flat galvanized steel decking roof of my residence where the excellent elevated ground−plane is augmented with an extensive set of 60 symmetrically disposed PVC insulated 4mm2 copper un−tuned radials laid out across the entire ground−plane roof surface extending to the four extremities of the building. The low−loss radial wire mat imaging the "missing half" of the monopole fans out from a stainless steel radial plate and capacitively couples to the DC isolated ground plane roof. The vertical monopole radiating structure is fed against the electrically "floating" radial mat with LMR−400 coax and LDF5-50 Heliax to the shack that is decoupled at roof level by a large ferrite core common−mode feedline current choke (DX Engineering DXE−FCC050−H05−A).

I like classic hybrid radios with tube finals, including the Kenwood TS−530S / TS−830S. I also like big HF linear amplifiers of the high-gain tetrode tube variety with lot's dynamic range / head room and conservatively run them well below their rating to achieve spectrally clean SSB signals with very low IMD / IM3 and IM5 + high−order intermodulation products to ensure the occupied bandwidth is directly proportional to and defined entirely by the transmitter's sideband and audio passband filters. I'm particularly fond of the elegantly designed and very well built Emtron DX−2SP model HF amplifier with the ruggedized Russian military Svetlana GU84B / 4CX2500A ceramic / metal tube operating in deep Class AB1 with the plate bias standing current controlled via a tri−state EBS with pre−bias and RF drive sensing. The use of a small footprint desktop QRO linear amplifier easily compensates for the lower gain and directivity antennas to establish a prodigious station ERP comparable to that created by a large multi-element beam antenna. In effect forward link Tx gain comes from the wall socket. A very effectual urban HF station is thereby achieved in a relatively low profile stealth manner.

My primary HF station is Yaesu FT−2000 / DMU−2000 / SP−2000 / MD−100A8X / Bencher YA−1 LP filter based with the option to run an Emtron DX−1 or DX−2SP linear amplifier on rare occasions when a big clean "rock crusher" signal is required. The DX−1 amp uses a single GU74B / 4CX800A tetrode (see photos below). My highly regarded Kenwood hybrid HF radio suite comprising TS−530S / VFO−230 / AT−230 / SP−230 / MC−50 / TL−922 / LF−30A / Himound HK−706 key is also used regularly. The TL−922 linear amplifier uses a pair of venerable Eimac 3−500Z triode tubes. The TS−530S rig is equipped with YK−88SN 1.8 kHz SSB and YK−88C 500 Hz CW narrow IF filters that complement the radio's standard YK−88S 2.4 kHz SSB crystal filter. I believe the old circa early 1980's era Kenwood hybrid radios are among the finest sounding rigs on the air today and still easily rival or exceed modern digital equipment in performance and audio fidelity / voice quality. The radio’s only concession to modern times is the external addition of a BHI ANEM DSP noise reduction module placed inline between the Rx output and the SP−230 speaker to enhance the intelligibility of weak signal DX and eliminate the aural fatigue of noisy band conditions. An external Daiwa RF−550Pro up−converting 10.7 MHz crystal filter based low distortion RF clipping speech processor unit is sometimes used in the rig's microphone line for achieving an efficacious 6 dB increase in "talk power" and improved weak signal intelligibility and noise punch through on transmission.

I run a fully optioned Icom IC−910H multi-mode VHF/UHF basestation rig with TXCO, DSP, SP−23 on the 2m/70cm/23cm bands used in conjunction with a Comet CFX−431 low−loss Triplexer and LDF5−50A heliax coax feed to a high−gain Comet GP−95 tri−band Vertical element array. In keeping with my fondness for tube amplifiers my 23cm linear comprises a parallel pair of Eimac 3CX100A5 / 2C39BA triodes in a homebrew cavity amplifier configuration. I use a Yaesu VX−7R Handheld when operating QRP or portable/mobile on 2m/70cm. I often use a Comet SBB−5 centre−loaded dual−band vertical 1/2 and 5/8 wave ground−plane magnetic base whip antenna on the VX−7R for ensuring solid access to the local FM repeaters. My HF portable station comprises an Icom IC−751A rig and LDG AT−200Pro automatic antenna tuner.

As a recent convert to ancient modulation AM I was fortunate to acquire a couple of surplus ex-broadcast transmitters made by AWA in their Ashfield NSW plant in circa 1969, their venerable tube based vintage BTM-P5 units (virtually a clone-copy of the RCA BTA-1R once used by American AM broadcasters) and converted them for operation on 160m and 40m. Both have their original ovenised crystal Master Oscillators replaced with modern frequency agile DDS digital synthesizers. The P5 Tx has a pair of Eimac 4-400A / 4-250A tubes in the PA and push-pull modulator stages.

I hold an Australian Radio Amateur Advanced Licence (Unrestricted) and am an accredited WIA Assessor of amateur radio examinations for the issuance of AOCP certificates of proficiency required for ACMA licencing. I'm a Member of the Wireless Institute of Australia (WIA) and the Adelaide Hills Amateur Radio Society (AHARS). I am an honorary member of the OH3NE amateur radio club in Tampere Finland. I'm also a member of the IEEE Antennas and Propagation Society (APS) and the IEEE Microwave Theory & Techniques Society (MTTS).

I look forward to hearing your signal on the bands for a QSO. My favourite HF bands are 20m and 40m operating SSB mode. I will promptly reciprocate any direct QSL card received (preferred exchange method), via bureau is also OK. No IRC coupons or green stamps required (optional) when sending your QSL direct, just include a self addresed return envelope.

May the propagation be with you. Patiently awaiting Solar Cycle 25 to arrive with a vengeance. smileycheeky

Alas unremarkable Cycle 24 (July 2017) has now passed and conditions waning  sad

73 de Leigh VK5KLT


AHARS club Website: http://www.ahars.com.au/

(The above URL also contains a technical paper and overview discussion pdf on the subject of small HF transmitting magnetic loop antennas / TMLA) see below link titled "The Underestimated Magnetic Loop HF Antenna"


Other TMLA highly recommended website of VK5SFA Steve:  http://members.iinet.net.au/~sadler@netspace.net.au/

WIA Website:  http://www.wia.org.au/

Professional Invertech Electronics Pty Ltd website:  http://invertech.weebly.com


Photo Gallery:


               DX−2SP HF Linear Amplifier with GU84B tube



             DX−1 HF Linear amplifier with GU74B / 4CX800A tube




                          warm glow of 3−500ZG graphite anode tubes



    GU84B / 4CX2500A in Emtron RF compartment with tank tuning components                                                     GU84B



        GU74B / 4CX800A                  GU84B tetrode tube + air chimney socket                         GU84B


   TL−922 amplifier tank with Eimac 3−500Z triodes


   Ten−Tec Centurion with 3−500Z Molybdenum / Zirconium metal anode tubes


    Pair of 4-400A / 8438 tubes producing RF in BTM-P5 Tx PA


   Kenwood TL−922 HF Linear Amplifier


   Kenwood TS−530S HF Transceiver


   Icom IC−751A HF Transceiver





8239228 Last modified: 2017-07-27 03:49:18, 17173 bytes

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QRZ Logbook Summary for - VK5KLT
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dedateband mode grid Country op
FK4QX 2016-09-11 20m SSB RG37FR43 New Caledonia PHILIPPE BAILLY
KK6ZM/4 2016-08-23 40m SSB EM73xb United States Pat
F4IVV 2016-04-18 20m SSB JN25pg France Didier Crochat
AF6TC 2016-04-17 40m SSB DM13kd United States Mark E Magdaleno
YF3BPL 2016-04-17 40m SSB OI62dv Indonesia Rokhim
2I0FLO 2015-05-10 20m SSB IO74ao Northern Ireland IRENE NICHOLLALSO KNOWN AS RENEE
S58MU 2015-05-10 20m SSB JN76bc Slovenia MILAN PIVK
HB9TWY 2014-05-24 20m SSB JN36gp Switzerland YANNICK ( yan) MATTHEY
G1XOW 2014-05-03 20m SSB IO93ma England Steve Wragge
ON7TQ 2014-04-27 20m SSB JO21of Belgium ROGER STIJMANS
2W0VOW 2014-04-27 20m SSB IO71ls Wales Beth Moore
JG2MQM 2014-04-19 15m SSB PM85md Japan SAKANASHI " SNIPER KEN-ICHI "
S58FA 2014-04-13 20m SSB JN86fn Slovenia Alfred Feher
F4GZJ 2014-04-09 20m SSB JN03qj France HONNONS Christian
VE2ZV 2014-03-22 40m SSB FN25cn Canada Fernand Brulotte

Book Totals: 204 qso's   170 confirmed Get a free logbook at QRZ.COM

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