Century/21 Hum Fix

From the Ten-Tec Reflector October 10, 2006

Direct conversion receivers are prone to pick up AC 60 hertz hum as the result of modulation of the VFO carrier (which is at the operating frequency in a direct conversion receiver) with the 60 hertz AC in the power supply. The fix is to put .01 uf caps across the power supply electrolytic caps. Electrolytic caps are great at 60 hertz but offer no filtering at all at RF. The .01 uf caps will filter out the RF from the VFO and prevent it from being modulated by the 60 hertz AC. I used to have an HW8 and this fix worked well for the HW8 direct conversion receiver.

Carl Moreschi N4PY

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