As a starting point I scaled the QRP Homebuilder sine wave generator http://www.qrp.pops.net/RF-workbench-5.asp from 10MHz to 11Mhz since I had an 11MHz crystal in my junk box. Thus I ended up with an oscillator having the following specs for the tank circuit.
L= 3.99uH, C = 39pF fixed plus a 2.7-10pf variable capacitor.
I was able to resonate the oscillator successfully, however the variable capacitor was turned down to 'almost' minimum setting. Reflecting the fact that the fixed capacitor is slightly too big. I decided to leave it as. According to the spec this generator should have the second harmonic down at around -29dBc. I am unable to measure this at this time so I take it on good faith.
A future experiment could be to build a low pass filter say with a cutoff frequency at around 12.5MHz. Inserting this filter between the sine wave generator and the power meter should not result in a measurable change of power reading. Another approach would be to build a pre-selector for the power meter and tuned to the second harmonic at 22MHz. This would be loosely coupled in order to ensure a high loaded Q. The insertion loss of this pre-selector can be measured using the power meter. Yes!
The design includes a 19dB pad in the output circuit of the resonator. This to ensure a good 50Ohm output impedance. I built this pad first and measured the Return Loss using my MFJ259B as the RF source at 11MHz and terminating the pad using Terminator2. The result showed a satisfactory RL=29.3dB. See notes below for details.
Once I had built the sinewave generator I tweeked the emitter current according to the specs. I then connected the generator to the meter and adjusted the supply voltage until the reading exactly equaled the reference voltage of the -10dBm cmos square wave calibrator. 1565mV +/-1mV. All good!
I was now ready to calibrate the meter in full.
|CMOS 10MHz Generator reference point|
|Sine Wave 11MHz generator reference point|
|Sine wave generator frequency 11.058MHz|
|Sine wave generator output wave form. Looking good!|
|Sine wave generator enclosure|