Re: VMARS RA17 product detector modification
Lock in occurs when the IF input signal causes changes in the BFO frequency.
Due to coupling between signals.
Dosen't need much to upset , especially when both signals nearly same freq.
The 6BE6 has perhaps 20 Db isolation , ring mixer has twice this , plus another 10 Db due to extra audio gain.
The audio out is clean sine wave down to 20 c/s.
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