[Boatanchors] Regen selectivity

[Keith Densmore]

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Generally, what can be done to improve the selectivity of a regenerative
receiver?

For example, I vaguely remember a modification for the Heathkit "Sixer"
that included "tacking" a 22 Meg ? resistor to one terminal of the
regeneration control pot. Or, am I mistaken?

Tnx es 73 de Howie WA3MCK


Regens are not noted for great selectivity but careful circuit design can help 
along with stability and detector pulling.
The most important thing in achieving selectivity is keeping the regen tank 
circuit with as high a Q as possible. This is achieved by observing the 
following.

1 Loosest possible coupling from antenna to detector/oscillator--very small cap 
< 10pf or loose inductive coupling ie, two turn coil near the regen tuning coil.

2 High value grid leak resistor ie 10 megs or more and low value bypass cap < 
10 pf.

3 Isolate the antenna from the regen with a cathode driven, grounded grid rf 
amplifier.

These tricks work on hf regens, not sure how completely they apply to the Heath 
vhf circuits.

73,
Keith ve3gem

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