I recently have dissected a defective Morion MV89A oven. Since it is hard to get SC crystals in small amounts, this might be interesting for experimenters. There are many defective Morions from China. I have checked the crystal parameters at room temperature and at the intended temperature. nominal at room temp. F = 4999868.18548896 Q = 2058123.87937723 L = 5.31149294399851 C = 1.90768447144417E-16 R = 81.074358418583 C0= 2.8136087840004E-12 B-Mode at room temperature / 27°C F = 5456268.74855202 Q = 2070228.75819907 L = 5.60406600257822 C = 1.51825777903696E-16 R = 92.8026816958027 C0= 2.50200142407676E-12 fundamental at room temp. F = 1706530.674 Q =12634 L = 2.882184522 C = 3.017798817E-15 R = 2446.1 C0= 3.400172339E-12 Nominal frequency at 87.8°C F = 4999977.73472294 Q = 2210624.24356611 L = 5.31056260615351 C = 1.90793506338953E-16 R = 75.4698598161708 C0= 2.67067707950378E-12 B-Mode at 88°C F = 5445966.6930594 Q = 1559143.3579169 L = 4.56636349264629 C = 1.87033681366853E-16 R = 100.216511187362 C0= 3.02668789364201E-12 Fundamental @ 88°c F = 1706366.18003318 Q = 7829.11559388434 L = 2.67725816365808 C = 3.24941770179082E-15 R = 3666.31393448872 C0= 3.28464263904697E-12 The fundamental is so weak that it does not deserve a trap. The B-mode resonance at +9.5% is nearly as good as the nominal frequency. One might experience frequency hopping if this is not taken care of. The 88°C was produced with a Steinelt heat gun that was sitting on the boom of the microscope. I wonder why my low cost DG8SAQ VNWA can measure this just easily and my R&S ZVB cannot. Simply plug the xtal on port 1. The reference frequency of the VNWA was locked to my LUCENT GPS source. There are some spurii above the nominal frequency and above the b-mode. I did not check them in detail. The time for a sweep is half an hour because of the required settling time and the huge number of measurement points. And it takes a lot of sweeps until one is on the right spot. I you zoom in, the spurii look deeper. The 2 attached plots show some ringing after excitation of the resonance, they are taken too fast. They create nonphysical results because it seems that more energy comes back than is sent by the VNA but it is only energy stored in the crystal. That does not matter here because I used these plots only for locating the resonances and not for the crystal estimator. The Auswahl_005.png plot has some of the experimenting history. Cheers, Gerhard