[ARC5] BC-453B dial calibration (again)

[J Mcvey]

If c-10a and C10B have changed value, why not replace them with new micas?There may be other issues with them as well , such as silver migration or high ESR witch will affect performance.The original cap is still there with it's problems.

Even though you now tune beginning to end, the dial tracking is not completely linear.The LC combo has to be precise to get proper dial tracking. It's a real pain in the butt! Been there.Adding or subtracting capacitance may get you in the proper range, but is only masking some underlying issue such as compromised caps. It definitely won't help the dial tracking.

 

    On Friday, June 23, 2017 12:06 AM, Waldo Magnuson <magnuson at mac.com> wrote:
 

 I've had a few suggestions (thanks) and ended up putting a 0.0047 uf capacitor in series with C10A, C10B and the variable C9.  C10A & B should be 690 pf but apparently have grown fatter like people and C9 was not able to bring the dial calibration in at the lower end (210 kHz).  I can now adjust both high (520 kHz with C4E) and low (210 kHz with C9).  
Still puzzling is that my 365 kHz DPY NDB still comes in at 370 on the dial.  I'm beginning to think that must be as good as it gets with my BC-453B.
Skip W7WGM
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