Re: Re: Discriminator tap question

OldOne <[email protected]> Wed, 06 Mar 2013 16:52:54 +1030
Newsgroups gmane.recreation.radio.hardware.uniden.bc780xlt
Message-ID <[email protected]>

   I normally use a 1K resistor as an isolator incase some one plugs a 32 ohm 
earpiece into the socket and almost shorts the discriminator point to ground.

Also do not use a 0.01 uf cap as DC blocking if you want a clean data waveform 
out as it will phase distort the low frequency squarewaves output for data 
decoding.   If you must block the DC use a least a 1.0 uf  50v monolithic cap 
when feeding into a 10k load of the sound card input.



On 06 Mar 2013 08:57, Bigjed wrote:

--- In [email protected], Don <stb55@...> wrote:
>>
>> Usually it is advisable to use a small value ceramic cap like 0.01 uf to
>> block DC - no resistor needed - that would drop the signal some.
>>
>> Doesn't hurt to use coax like RG-174 but not really needed. Depends on
>> how much you want to put into a project labor wise. Also I always think
>> about resale value - like putting holes for switches on a front panel.
>>
>>
>> Thanx Don.I've seen a couple of conflicting articles re this.Some recommend the resistor with coax,some just a wire from the tapping point straight to a phono socket on the rear of the radio.I've not seen the ceramic cap mentioned yet tho'.is that just connected in series,like the resistor would be?
>>>
>>
>
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