Thank you fellows for your response:
1. The choke used was , as I said, the famous " christmas tree" NATIONAL R
175 or R 175A ( the latter works also on 6 meters as far as I remember?)
used normally as a plate choke in amps. As such as it has a high impedance
on the bands it was designed for and when in paralell with the 50 ohm input
impedance it should have very little effect on receiver sensitivity. This
choke was also described in one of RSGBs handbooks by the way.
2. Yes , of course, the choke reduces charge build - up in my long-wire with
less discharge through the ceramic insulation. But the actual noise in my
loadspeaker was not a cracking or popping noise - it sounded like a
continous noise, and as far as I remember, a hissing noise when there was a
high-static weather overhead. Anyway, it worked and that is was count:
"The proof of the pudding is in the eating ", right? Or as my German
grandma said " Grau ist aller Theorier Anfang............" nicht war?
3. I did not get any answer on Richs statement:" A choke across the load-C
is probably not all that useful because - if the DC blocking cap fails, the
typical load-C is going to arc to ground
>and blow the mains breaker/fuse." Again: What on earth do you mean now? Pse
explain? The world is waiting for your answer Rich.
sooner ................es hej daa de Hans
----------
>Från: "Tom Rauch" <w8ji@contesting.com>
>Till: "sm5ki" <sm5ki@algonet.se>
>Kopia: amps@contesting.com
>Ämne: Re: SV: [AMPS] Re: Static discharge caused NOISE
>Datum: sön 12 mar 2000 01.02
>
>>
>> No Tom I dont think so: When you use an antenna tuner you have ceramic
>> material in the discharge path and do you not get piezoelectric effects?
>> Making a lot of noise? I have much practical experience with a copy of the
>> old Johnsson Matchbox together with a very long longwire. The antenna was
>> connected to the variable capacitive divider in the matchbox and had no DC
>> connection to ground. In summertime I had very often a high noise level
>> that disappeared as soon as soon as I connected my NATIONAL R-175 choke
>> from antenna to ground. Without this choke there was often flash-overs as
>> soon as a thunderstorm was coming up.
>>
>> sooner .......... Hans
>
>Hi Hans,
>
>I certainly agree on what you say. If something IN the tuner or IN
>the radio is arcing or generating noise from a static charge, then
>the choke (or even a leak resistor) will help because it prevents dc
>from entering the system.
>
>But a dc ground does NOT help the noises in the antenna, or the
>corona noises from "snow static" or "rain static" or distant static
>crashes. The choke does not bypass noise, but it can prevent the
>feedline from charging up and making sparks and arcs in the tuner
>or in small components.
>73, Tom W8JI
>w8ji@contesting.com
>
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