Hmmm ... There seem to be different flavors of static. My reference was
to what is often called "precipitation static" [rain, snow, maybe hail]
and which can sometimes also be caused by wind blowing sand/dust past
the antenna. It sounds like bacon frying in the receiver. Each drop or
snowflake acquires a minuscule charge falling or blowing which
discharges into the antenna on contact. The typical semiconductor
devices in radio front ends these days exhibit a nearly infinite
impedance to "ground" and a tiny capacitance. The constant little
pulses from the static charge that capacitance with essentially no
discharge path. That's what fried the 1st 760 II and then, predictably,
the second one.
There is also the combined "static" caused by distant thunderstorms.
INT QRN: "Are you troubled by static"
QRN: "I am troubled by static"
which is different than "static" caused by corona or leakage on a high
voltage power transmission line.
73,
Fred ["Skip"] K6DGW
Sparks NV DM09dn
Washoe County
PS: For those about to tell me "nearly infinite" is a meaningless term,
save the BW. I know, I hold a math degree. Just using a little
editorial license.
On 10/31/2018 3:10 PM, ab2tc wrote:
Hi,
It's a dead short circuit for DC and low frequencies thanks to the SWR
bridge (it has a voltage transformer directly across the antenna terminals).
There seems to be different opinions on what is meant by "static". To me it
means a slowly varying DC voltage caused by static buildup in the clouds
during or before thunderstorms. The K3(S) is perfectly protected against
these. Some people include the transients that are caused by actual
lightning strikes nearby in the definition of "static". The K3(S) is not
protected against these as they have very strong high frequency content. For
these extra protection is needed as discussed several places in this thread.
I have a number of Alpha-Delta switches in my antenna system and they have
gas discharge tubes, but frankly I have no idea how effective they are.
AB2TC - Knut
wayne burdick wrote
On Oct 30, 2018, at 12:50 PM, Fred Jensen <
k6dgw@
> wrote:
Does my K3 have a static bleed across the antenna terminal(s)?
Yes.
Wayne
N6KR
<snip>
--
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