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Re: [TowerTalk] 7-16 Din

To: "Tower and HF antenna construction topics." <>
Subject: Re: [TowerTalk] 7-16 Din
From: jimlux <>
Reply-to: "Tower and HF antenna construction topics." <>
Date: Wed, 21 Apr 2010 08:19:42 -0700
List-post: <">>
DF3KV wrote:
> The IEC rating for N connectors is 1KV working voltage and 2.5KV proof
> voltage at sea level, 40-65Hz.
> 10KW into 50 Ohms results in less then 1KV, so that is OK with pulsed
> applications. 

yeah.. and the Amphenol corrugated N is rated at 707 volts, which 
corresponds quite nicely to 9996.98 Watts

And, as a practical note, they work to many kilovolts.  The  connector's 
test condition/spec probably has some "work at altitude" aspect to it, 
as well, so the actual design has air gaps compatible with 700-1000 volt 

Probably the limit is the e field between center conductor and shield.

Emax = V / ( Rinner * LN( Router / Rinner))

Rinner is radius of the inner electrode
Router is the radius of the outer electrode
LN() is the log base e of the argument
V is the voltage between the electrodes


Rinner = .118
Router = .316

Emax = V/.116 inch

Air breakdown is roughly 70 kV/Inch
70 *.116 = 8 kV

The breakdown is likely to occur along a dielectric face, and the usual 
rule of thumb is that the breakdown voltage is 1/3 that of free air, so 
it looks like, by design, the N connector is good to around 2-3 kV.


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