This page is for articles that I have received from other radio amateurs. Please feel
free to submit your own articles to me!
Today's article was sent in by Keith
Ranger, G0KJK. Keith is a keen QRP operator who lives in Macclesfield. The article is
in "bullet point" form as it was the basis of a talk that Keith gave to the
South Manchester Radio Club on April 24th 1998.
HOW TO BUILD AND OPERATE AN EFFECTIVE QRP STATION
CRITERIA OF SUCCESS
1. Able to make QSOs in reasonable condx, using simple aerials, daily throughout the
sunspot cycle
2. All transmitting/receiving gear self-built, including ancillary equipment and power
supply, using readily available components
3. The entire station assembled at a fraction of the cost of commercially built gear
4. At least 3 Continents and 50 DXCC countries worked with 5W or less RF output power
FOUNDATIONS OF SUCCESS
1. Use of the three HF bands where QRP success is most easily gained and where aerial
demands can be readily satisfied if the operator only has a small garden - 20, 30 and 40
metres. 40, despite the QRM, is beyond doubt the easiest band for QRP QSOs - for example,
a 559 report from a DL station to my QTH in Cheshire, followed by a 100% QSO, was achieved
on an indoor "aerial" at G0KJK of only 3 metres of end-fed wire!
2. Wire aerials will keep you on the air when the beams of others get blown down! (G0KJK
as VS6US in Hong Kong, could keep going during a typhoon when other VS6s took their
aerials down for safety!)
3. Crystal controlled VCO circuitry using toroid coils and a variable capacitor will
generate a frequency stable yet frequency agile signal without VFO stability design
problems if you are inexperienced at home-brew
4. If you are prepared to try non-superhet receiver construction, a carefully designed and
constructed regenerative ("straight") receiver need use no more than four
transistors (as per G0KJK's article in "Sprat" 82) and perhaps an IC chip such
as the LM386 but will out-perform a DC (Direct Conversion) circuit by covering several
bands instead of just one or two and being stable at above 10MHz. Its front-end will also
be typically much more sensitive. FETs make ideal detectors
5. Calling CQ is not the best approach for a QRP station. Listen, listen and listen!
Answer the calls of others and work rare DX before the pile-up gets going (e.g. G0KJK to
JW9JPA in Jan Mayen Island's first CQs before the whole world fell upon him!!). A nice QSL
card confirms that one!
6. Build simple add-on ancillary equipment. A one transistor untuned HF amplifier before
the receiver when condx are poor will enable weak stations to be clearly read. Suitable
transistors up to and beyond 30MHZ are the 2N2369A (cut-off 500MHZ!) and the 2N2222A
7. Simple but reliable Power Supply Units giving up to 2A at 12, 15, 18 and 20V are easily
built using a three pin Regulator (78S12) and Zener Diodes as voltage pedestals
8. Three transistors are all that is needed to build a QSO-effective QRP transmitter (in
G0KJK's case, able to contact PY4PZ and TU2JT for solid QSOs on 15m). Really reliable are
a 2N3904 (exciter), 2N3053 (buffer) and BD139 (PA). Easiest modes for the home constructor
are CW and DSB
SATISFACTION FROM SUCCESS
1. You will feel a far greater sense of pride and achievement if you home-brew!
2. G0KJK has shared his circuits with others. Their response has added to his own fun!
