The-ugly-weekender-a-homebrew-qrp-transceiver


This video shows my version of a QRP amateur radio transmitter called the "Ugly Weekender" designed by Roger and Wes Hayward and described in the August 1981 and June 1992 issues of QST magazine.

Note: Wes Hayward (one of the designers the Ugly Weekender) pointed out a potential issue with the way I built my rig, having all of the boards in the same box. I wanted to pass along what he said:

"There was a reason for placing the VFO in one box and the PA in another with the original UW transmitter. Oscillators, especially free running LC circuits, are very susceptible to stray RF that might be applied to the circuit. But the susceptibility is only extreme if the stray RF that hits the VFO tank is at, or close to the frequency of the VFO. Stray RF get into the tank by RF conduction through amplifiers and power supplies or by radiation. Buffer amplifiers take care of the conduction problem while decoupling (more than just bypassing) takes care of the power supply coupling issue. The radiation coupling is best handled with shielding. In the original UW, there was a 50 Hz shift in the oscillator when the key was pressed when the shields were in place. The shift became a couple of kHz when the lids were removed from VFO and PA.

There is another way to fix the problem that is even more effective and that is to operate the VFO at a frequency that is far removed from the PA. An especially good design is to operate the VFO at half the output frequency, or the 80 meter band. Then the VFO is frequency doubled before it is amplified and applied to the antenna. My versions of the UW all use frequency doubling. The circuitry is shown in Chapter 4 of Experimental Methods in RF Design. See page 4.27."

So be aware of this if you plan to build this rig, or one like it. I will be looking a adding some shielding to the boards in my version. It is built on three separate PCBs so I think that is feasible.

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