[Elecraft] K2 constant-level audio for PSK31 = link to photos

[Don Wilhelm]

Robert,

I can answer that.  "It all depends ..."

   If your soundcard can handle the lower levels from the Product 
Detector, all will be fine, but some soundcards do not.  Notice that 
Alan has wired the tip to one side of the Product Detector output and 
the ring to the other side.  The result is a 3 dB drop in audio signal 
level because most applications only use the left channel input (the 
signal on the tip).  If your soundcard can handle that, then no buffer 
amp is required, but if not, take a look at the W3FPR Fixed Audio Output 
on my website www.w3fpr.com.  That will provide about a 1.5 volt signal 
to the soundcard for an S-9 input signal.
In addition, the takeoff points I have suggested are after the muting 
circuits, so if you want to do recording of the receive signal, you will 
not suffer from the noise during transmit.  The circuit will work fine 
if you change the inputs prior to the muting transistors (the RF board 
J5 connections).

73,
Don W3FPR

On 3/29/2014 6:42 PM, Robert G Strickland wrote:
> Alan...
> I notice that you have an audio out for the K2 that does not use a 
> buffer board. What's your experience with this approach? And to 
> others, this seems pretty straight forward. If so, why use a buffer 
> board?
> ...robert
>
> On 3/29/2014 18:34, Alan D. Wilcox wrote:
>> Hello,
>>
>> Gradually I'm rebuilding my Elecraft site ... and latest is at
>> http://wilcoxengineering.com/2014/03/27/digital-radio/
>> This weekend I put in some photos of the constant-level audio connection
>> I added to my K2 to run PSK31
>>
>> Now I need to show the actual setup and configuration ... next week!
>>
>> Any special photos you'd like to see? Reply off list please.
>>
>> Enjoy,
>> Alan
>>
>> Alan D. Wilcox, W3DVX (K2-5373, K3-40)
>> 570-478-0736
>> Williamsport, PA 17701
>>
>>
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>