>
>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.
The typical load-C is a 1000v air variable. If the DC blocking cap
shorts, the c. 3000v from the anode supply does not appear across the
load-C because it arcs to ground and shuts the amp down. . .
>
cheers, 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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>
>
- Rich..., 805.386.3734, www.vcnet.com/measures.
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