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QCX Zero Beat

LOC:JO51PL      CQ-Zone:14

The QRP transceiver QCX of ,
QRP Labs,

QCX Dokumentation

is described in detail in a PDF file, "QCX Documentation". I have simple extensions Added:
-   Built-in on / off switch, on the right side, for the
    power supply           

-   Connection of an indicator, green / red LED, for the

QCX, enhanced by a LED SWR indicator and a enclosure manufactured by the company ma BaMaTech (DL6YYM)

I run two transceivers on my dipole. To do this I switch the supply line to the respective device. It happens sometimes that I forget the switch. On the QCX one does not notice that. You kill and there is no RF to the antenna. To be warned, I have set up a small SWR indicator that signals in the transmission case, via a green LED, the HF goes to the antenna, all ok. If the way to the antenna is interrupted, the red LED lights up.

The SWR circuit should have low insertion loss and operate the LEDs directly from the current transformer, so without transistors or OPV's. If the SWR> 1; 1, the red LED starts to light up. It can be estimated from the brightness of this LED how big the SWR is, e.g. 1,5:1 .  



have installed the components in a filter housing of the publisher FUNKAMATEUR. It has a BNC connector and a BNC connector. When the antenna cable is disconnected, both LEDs light up.

The SWR indicator is a Bruene-SWR bridge. Warren Bruene, W0TTK, has long been Collins design engineer. He published the original circuit of the directional coupler in the QST in April 1959.

  Schaltung LED-Spannungen  

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             winding scheme


small hole grid board, 13mm x 15mm, carries the circuit. The toroidal core contains primarily one turn and, secondarily, 33 turns. The secondary side is wound bifilar, 2x15 turns. Wired, yellow color, the board is on the bottom.

The green and the red LEDs have different forward voltages. The red LED lights up rather than the green one. By placing the circuit in a separate enclosure, you do not need to interfere with the QCX enclosure.

  Spannungen LED-Farben  

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  Grüne LED


ou see, the green LED on the left, when sending, if everything is OK. On the right side, the red LED lights up while the antenna cable is plugged in, but there is something wrong on the way to the antenna. Apparently one would send, but nobody would receive anything.
Rote LED

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