[Boatanchors] Receiver Antenna Input Question

[Al Klase]

Bill,

OK, back to the original question.

There are at least two different antenna input configurations being 
discussed here.  (I couldn't find a 75A-2 schematic.)

1. - Receivers designed for short (high-impedance) antennas, e.g. the 
"ARC-5's" and the Collins R-388, 51J-3/4, etc.:  The antenna terminal 
connects to the "top" of the first-RF-amplifier tuned circuit via a 
small capacitor.  There is no DC path from the antenna terminal to 
ground.  I this case, a gas tube or neon bulb is in order to bleed of 
static build-up from the antenna, and perhaps provide some measure of 
protection from overload.  I suspect there is also a real-world chance 
of a couple of KV of static damaging the coupling cap.

2. - Receivers designed for low impedance antennas, e.g. your NC-303:  
The antenna terminal connects to a primary winding on the input tuned 
circuit.  The other side of the winding is grounded.  In this 
configuration a neon bulb is nearly useless as it could fire under only 
the most catastrophic circumstances.  Any static will bee drained off 
through the primary winding.

Hope this helps,
Al

w0ng at comcast.net wrote:
> Would appreciate some advice here. I have a National NC-303 receiver that I'm restoring. I had a 75A-2 once that had a neon lamp (NE-2 ???) across the antenna input connection to supposedly act as a surge supressor for lightning, strong static charges and strong rf energy from nearby transmitters. Is this a good idea? Does this really work? Is there a better device than a neon bulb? Appreciate any opinions, etc. 73, Bill, w0ng 
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/