SV: [AMPS] Re: Static discharge caused arcs

[sm5ki]

I am a radio ham and for me it is much more important to have a quite ham
band then receiving bc stations. Although most transceivers have less
sensitivity on the bc bands, signals are very strong and easily readable
anyway.

Rich now said:"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." What on earth do you mean now? Pse explain? 

Have to remind you all what I said months ago, that the rfc choke across the
load C2 is not only there to (eventually) protect the outside world in case
the DC blocking C short circuits. But this C is in series with  C1 and C2 in
paralell from a DC stand point. These condensers are of course charged up in
the DC steady state and may  the maximum voltage across C2 be exceeded with
certain positions of the C1 and C2 unless the rfc was there and discharged
the C1 and C2. The C2 is the one that most likely flashes over because it in
most amps has less spacing than the C1. C2 once flashed over will after that
have  eventually  a less max voltage because of the wound resulting from the
flash over.

Hej daa de Hans 


----------
>Från: measures <2@vc.net>
>Till: "Lamb" <k7fm@teleport.com>, "Carl Clawson" <ws7l@arrl.net>, "Amps
Reflector" <amps@contesting.com>
>Ämne: Re: [AMPS] Re: Static discharge caused arcs
>Datum: lör 11 mar 2000 17.09
>

>
>>
>>Hi Carl:
>>
>>Interesting thought.  Probably should not discuss receivers on the Amps
>>Reflector - but it is simply the continuation of an amp related topic.
>>
>>It makes sense to put the rf choke at the output side of the relay so that
>>it shorts anything that is not supposed to be there to ground - and, as Hans
>>has suggested, improve receiving back-ground noise.  There is one minor
>>caution, though, in that the rf choke will drop in impedance at some point
>>and affect received signals.  A 2.5 mh choke would be fine through 160
>>meters when using a low impedance antenna - but suppose you also use the
>>receiver to receive on the broadcast band or lower - where the antenna might
>>be high impedance.  Thus, it might not be appropriate to hang a normal rf
>>choke across the receiver input of a general coverage receiver.
>
>Agreed.  2.5mH chokes have many resonances in the HF range.  I use a 
>300k-ohm resistor to bleed off any static charge across my Hertz 
>antenna's tuner.  .  
>>
>>Sorry to digress, but it really has to do with design of power amplifiers -
>>and whether the rf choke should be hung on the output side of the relay.
>>There is merit to the suggestion.
>>
>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.  
>
>later
>
>-  Rich..., 805.386.3734, www.vcnet.com/measures.  
>end
>
>
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