[Hallicrafters] AC Bypass Caps in SX-111 MK 1.

[Mack Rogers]

This is just me, here goes. I have never considered AC line bypass caps as being there for any other purpose other than to bypass RF/noise from the AC line, whether that be bypassing RF/noise from entering a rcvr or bypassing RF from inside an xmitter from leaving via the AC line.

Even the modern AC line filters available today still use bypass caps on each side of RF chokes in their design, some use MOVs or SADs plus caps. MOVs by themself measure something like 10k-30k pf (if my memory is serving me well today).

Maybe I'm just lucky but I've never suffered any problems related to using AC line bypass caps, MOVs, SADs, etc. And yes I have had radio gear online during a couple of lightning strikes and suffered no damage that I could relate to the AC line. I've only lost the front end of one rcvr to lightning.

The only downside to using any of these AC line bypass measures is the resulting explosion of all these parts inside a vintage chassis if hit with a big voltage spike/lightning. That's why I use 240vac 30a line filters on all radio gear, hoping any failures of parts will be in these external AC line filters and not inside the radio gear.

N4VGB
Mack Rogers



 

--- On Mon, 12/13/10, Ross Stenberg <k9cox at charter.net> wrote:

> From: Ross Stenberg <k9cox at charter.net>
> Subject: Re: [Hallicrafters] AC Bypass Caps in SX-111 MK 1.
> To: "List Hallicrafters" <hallicrafters at mailman.qth.net>
> Date: Monday, December 13, 2010, 12:36 PM
> Would MOV's be a good way to
> instead?
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