[Boatanchors] Cheap & Easy Selectivity

[J. Forster]

The term 'gimmick' is more usually applied to a pair of solid, insulated
wire (like hookup or magnet) twisted together fairly tightly. One pair of
ends are the capacitor terminals. The other ends are just cut off.

The capacitance may be adjusted down by snipping bits off the unconnected
ends, or by untwisting a bit.

-John

=================



> Its also called a "gimmick" capacitor. Its even used in commercial radios.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "rbethman" <rbethman at comcast.net>
> To: "Boatanchors" <boatanchors at mailman.qth.net>
> Cc: "AI2Q" <ai2q at roadrunner.com>
> Sent: Thursday, August 20, 2009 2:51 PM
> Subject: Re: [Boatanchors] Cheap & Easy Selectivity
>
>
>> The Handbook say to use a "short wire", attached to the grid, and add a
>> small amount of capacitance, creating feedback by bring the loose end in
>> near proximity to the plate lead.
>>
>> This is a paraphrased condensation of the several paragraphs.
>>
>> Bob - N0DGN
>>
>> AI2Q wrote:
>>> Sounds like what a Q-multiplier box does.
>>>
>>> Vy 73, AI2Q, Alex
>>>
>>> ----- Original Message ----- From: "rbethman" <rbethman at comcast.net>
>>> To: "Boatanchors" <boatanchors at mailman.qth.net>
>>> Sent: Thursday, August 20, 2009 2:19 PM
>>> Subject: Re: [Boatanchors] Cheap & Easy Selectivity
>>>> The 1948 ARRL handbook hits it in Chap 5,  High Frequency Receivers,
>>>> Improving Receiver Selectivity, IF Amplifiers, then under a minor
>>>> heading:  Regeneraton.  pp115-116.
>>>>
>>>> This is essentially ADDING Regen to a Superhet.
>>>>
>>>> Bob - N0DGN
>>
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