Fine-tuning the Yaesu FT-891 Reference Oscillator
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- Опубліковано 15 жов 2024
- I shot a previous video about fine-tuning the reference oscillator against WWV, in case you don’t have access to a frequency counter. In fact, I shot a video showing how to check and adjust the reference oscillator for both the FT-891 and the FTdx5000MP Limited. I had several questions regarding the previous videos, so I assume I wasn’t very clear and concise. A apologize. Hopefully this video will help. Hint: you can set menu item 14-05 to 2Hz to obtain an even more precise reading. Assign your ZIN to button A. Press and hold to hear the spot tone. Adjust the main volume knob until the received audio matches the level of the sidetone. You can adjust the VFO in 2Hz increments to ascertain the exact frequency where the two tones match. On my FT-891, I had to set the reference oscillator to +25 (maximum) in order to get mine to within 2Hz accuracy.
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73, de N4HNH
This helped a ton. My FT-891 is better then it's ever been. Sharing with my dad who also has one.
I’m so glad you found the video helpful. Thank you for letting me know. 73, de N4HNH
It works great. Same rig as yours. Thank you for sharing.
You’re very welcome! I’m glad you found the video helpful.
73, de N4HNH
That's great Doug. Thank You
Is it possible, somehow, to connect this oscillator to an oscilloscope?
Sure. There are test points that technicians can use to measure various voltages, signal level, etc. But the easiest thing to do is use a frequency counter. However, if the frequency counter isn’t calibrated to the NIST, you are probably better off checking against WWV, as my video shows. The BFO might be off 1 Hertz at 300Hz, but that is plenty accurate enough.
I had trouble with my ft-891 lining up the reference adjustment I went as far as I could go and it still was not exactly on frequency so at that point you have to go into the service menu and adjust the reference oscillator but you must put the radio oscillator back to zero before you go in and adjust the oscillator from the service menu I had to do the same thing one time with my ftdx1200 the reference adjustment from the main menu was not wide enough to correct it this is because of the factory they're not critical on testing the frequency accuracy
Hi Roy! I have two FT-891 transceivers. I recall having to go as far as -22 or maybe -25 to get it within 1 Hertz. I can’t remember the exact number but I remember I didn’t have much adjustment left.
I aligned many, many radios during my years with Motorola. We didn’t have the ability to fine-tune the oscillator via firmware. We had to open the radio and adjust a variable capacitor. I’ve done that with my IC-725, my FT-890, and my FT-920, neither of which offer the option to adjust from the front panel using the menu.
Yes, you will want to zero the firmware adjustment before opening the radio to adjust the more coarse capacitor adjustment. Remove the cover so you can get to the variable capacitor and then place the cover on again, without the screws. Power on the radio and let it warm for 30 minutes. Remove the cover and make the adjustment. Return the cover and check against WWV. Repeat this procedure until you get within 1 to 3 Hertz accuracy and stability. Replace the screws and fine tune with the menu adjustment. It is always important not to make an oscillator adjustment until the transceiver has been powered on for 20 to 30 minutes. I prefer 30 minutes.
73, Doug