Hello Stu2, Some time ago, I had problems with an oscillating (or at the tip of starting self-oscillation) XV432. It manifested in such a way, the XV432 being very sensitive to input power levels and "jumpy" output power when adjusting the power level. Together with a Mirage D1010 (100W 70cm PA) sometimes oscillation at full power has been observed.
In my case I could track it down to 70cm HF being coupled back into the IF (TX IF towards the XV432) causing a feedback. I could eliminate the oscillation by 2 modifications: 1) Added both the Elecraft Erratas to eliminate oscillation on the PA hybrid module (one is about installing a coil and a second one about installing a series resistor). Note that the errata to install the series resistor seems to superseede the coil, in my case installing both of the modifications did improve stability. 2) Install a small low-pass filter in the TX IF input in the XV432, as described here: www.dl7maj.de/XV432-Mod.pdf I installed the filter on board of the XV432, as shown in the PDF above. Note that I drive my XV432 from a K3 with 0dBm power. With the above modifications no oscillation or instability in output power has been seen anymore. I hope this may help. Best 73 de Thomas, HB9XAR Stu2 wrote: > Good day, > > I'm working with the XV432, Flex 1500 and Henry 2004A Amp. The rig, > xvrtr and amp PTTs are sequenced. Hoping somebody might have been down > this path before and has a solution. > > If I connect the transverter output to the amp (or different pieces of > open coax) and key the transverter, the power meter goes full scale and > I see an oscillation on the spectrum analyzer. The frequency of the > oscillation varies with the load. (i.e. amp connected or different > lengths of coax) If I connect the XV432 to a 50 ohm load, no > oscillations and all works well. > > I ran through the alignment procedure again with the XV432 connected to > a 50 Ohm load. All the voltages look right and the tuning is smooth. > (e.g. 20mV Quiescent Current Adjustment, TP3/TP4) It's obvious the XV432 > is happy into 50 Ohms, but not into impedances that wander from 50 Ohms. > > BTW, I have added all the mods as per the Elecraft website. > > Any ideas? > > 73's > Stu2 > W7IY > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
