Hello, I have a K3 with the K3EXREF, K144REFLK and K144XV.
Let me start by saying that the K3EXREF performs as described. It keeps the K3 tuned to a frequency within about plus/minus 2 Hz. However, I don't think it operates the way I thought. I initially thought that the K3EXREF adjusted the actual 49 MHz reference frequency to stabilize it to an external reference. After some testing, it appears that the 49 MHz reference frequency from the oscillator is never changed by the K3EXREF. It appears that the offset between the 49 MHz actual frequency and the 10 MHz reference is compensated for in firmware. I have monitored the 49 MHz reference and it continues to drift like it always has. At the same time, the tuned frequency of the K3 stays within 2 Hz of the actual frequency. The reason for the research was the continued inaccuracy of the K144XV frequency after the installation of both the KEXREF and the K144REFLK. The K144REFLK does lock the LO of the K144XV to the 49 MHz reference. It reduces the "large" uncompensated drift of the K144XV down to between .5 and 1 PPM. That is, it will drift in the neighborhood of 100 Hz AFTER warmup. This appears to follow the spec of the 49 MHz reference oscillator. This DOES NOT track the K3EXREF compensated stability. I would have expected the K144XV to stay within about plus/minus 6 Hz when stabilized to the K3EXREF. I called tech support and they seemed to confirm my analysis. The K3EXREF only works from 160 to 6 meters. The firmware has not been written to have it work with the K144XV. So right now, the K3EXREF will stabilize the frequency of the basic radio; however, it will not stabilize the frequency of the K144XV. It is my understanding that the firmware for the K144XV is "in the que". 73, Tim K8XS ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
