[TenTec] TT Synthesizer Accuracy (Orion 2)

Jim M. n4be_jim at yahoo.com
Thu Nov 12 16:51:24 EST 2015


I suspect this has already been hashed over in the past, but I need some guidance.  I use the TCXO calbration procedure found on the wiki, i.e. use SubRx, tune to WWV, adjust TCXO for same tone on USB and LSB.  But afterwards, the Main RX seems to be off by 30-50 Hz depending on the frequency/band.  I also use a known calibrated signal source (an Icom TCVR) at various freqs to confirm.  Conversely, if I modify the procedure and instead listen to the known signal source on the Main Rx set for say 14Mhz, all is well for that band but then the Sub RX is off.  Then lets say I use the known source to set the Tcxo when receiving 28Mhz on the O2, then tune the O2 down to a lower band, it will be off by 30-70 Hz depending on how far from 28Mhz I go.  Seems like the O2 synth tracking is amiss.  Is this normal behavior?  My conslusion, unless something is malfunctioning, is DON'T adjust the Tcxo using the Sub RX, but rather using the Main Rx with a calibrated source.  Then maybe calibrate it close to the middle of the HF frequency range, like 14.4 Mhz.

Thanks, Jim N4BE


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