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QCX CW Transceiver Kit

Last weekend I finished my new transceiver for my SOTA (Summit On The Air) activations. This is a single-band TRX with power of 2 - 3 W by QRP Labs. I chose to build one for my favourite HF band 7 MHz.



I have performed a quick measurement of the output power measuring the pak-to-peak voltage across a 50-Ohm dummy load. The results can be seen in the following figure. From the practical point of view when the transceiver is used on battery power, the output power is 2 - 3 W, so a good antenna is needed. :)

23cm Transverter (28 MHz / 1296 MHz) - DB6NT KIT

This week I have finished my new transverter for 23cm amateur radio band. Even though there is still a lot of work on this project, I am very happy that the main part is done. :)

Digi-mode interface for Yaesu FT-897D

I have finished a new interface for my FT-897D which I want to use mainly for VHF contacts using meteor scatter (MS) as the propagation mode. I made this interface very simple. I used two audio transformers 1:1 (600:600 Ohm isolation transformers), one optocoupler (CNY17-1) for PTT and USB to RS232 converter cable (PL2303 Chipset).


144 MHz, Quadruple-Quadlong - DK7ZB design

I have managed to finish my new antenna - Quadruple-Quadlong designed by Martin DK7ZB. The gain of this antenna is 9 dBd. The reason why I have chosen this antenna is simple. I don't have a garage where I could build and store my antennas here in Chesterfield (UK) at the moment, so everything has to be simple, portable and small. I used PVC electrical conduit pipes and designed and printed some parts needed for the construction. Overall I am happy with this antenna and it works very well. My longest contact with this antenna was 869 km during Marconi memorial / A1 contest in Novemeber 2017.

 3D modeling

The brass tubes are fastened by cable ties.


Practical realisation with the 3D printed parts

50 Ohm choke with RG-142



The antenna during Marconi memorial / A1 contest

144 MHz, Yagi antennas 7el., 4x5el., 2x8el. - DK7ZB design

This is a short presentation of my antennas which I built in the past. All of them were designed by Martin DK7ZB. I like Martin's designs as the antennas are easy to build (simple radiator) and work very well. Take a look.

1) 7 element SSB/CW Yagi, boom 3.3m, 11dBd, 28 Ohm, radiator 12 mm, parasitic elements 10 mm

7el. yagi

2) 4x5 element Yagi (Boom 2m, 28 Ohm, radiator, parasitic elements 10 mm, 9dBd) + power splitter, stacking distance 2 m


2) 2x8 element Yagi (Boom 4.35 m, 28 Ohm, radiator 12 mm, parasitic elements 10 mm, 12dBd)  + power splitter, stacking distance 3.2 m

Operation in a contest

Detail of the construction