[Lf] A QRP Tx for 136

[Andre Kesteloot]

Steve Rawlings wrote:
> 
> Tom G3OLB wrote:
> 
> > Confirming our contact today as follows:
> > [ . . . . .]
> > Comments: Congratulations Steve on an excellent 5 watt QRP signal and
> > your first LF/QRP QSO!
> 
> Tom, many thanks for QSO and for the e-QSL!  I was very excited
> to make the contact - so I'm sorry that my morse was a bit
> shaky!
> 
> I had been constructing the new QRP TX during the past week, and
> decided to give it a try during the 136 Activity Period this
> morning (Sunday).  The TX uses: a FET VFO (2 x 2N3819 FETs in a
> source-coupled oscillator, using a 4.7 mH RF choke in the tuned
> circuit); FET buffer; 2N2222 amplifier + BC212 keying transistor;
> 2SC2166 driver; 2 x 2SC2166 PA (the two transistors connected in
> parallel, with individual one ohm emitter resistors, each
> decoupled by 22 uF).  As my breadboarded circuit is still without
> a heatsink on the PA transistors, I have to keep the overs short!
> 
> A picture of the TX can be seen at:
> http://www.alg.demon.co.uk/radio/136/pictures/qrptx_1.jpg
> 
> After my QSO with Tom (97 km), I later had more QRP QSOs with
> G3YXM (105 km) and G8IK (101 km) - all using 5 watts RF to my
> simple 12 m vertical (no top loading).
> 
> I believe that a simple low power transmitter for 136 kHz would
> make an excellent club project, with the very real prospect of
> not just making LF QSOs across town - but with other countries
> too!
> 
> Regards to all,
> Steve GW4ALG