[time-nuts] WWVB BPSK Receiver Project? (fwd)

[gary]

DC in a transformer raises the low frequency corner a bit. Obviously not 
a problem in your case.

I should point out that every active device Lankford puts in the signal 
chain adds noise since the amp is really just a buffer, not an 
amplifier. You really want front end gain so that devices after the gain 
stage do not add as much to the noise floor. It is input referred noise 
that is significant, and Lankford's design is terrible in this respect. 
Oops, I almost started that pissing contest. ;-)


On 3/18/2012 11:44 AM, Poul-Henning Kamp wrote:
> In message<20120318182440.7cb729c2b018b0b2ca5f957b at kinali.ch>, Attila Kinali w
> rites:
>> On Sun, 18 Mar 2012 13:25:54 +0000
>
>>> Not in my implementation, I have eliminated the input capacitor because
>>> the active element is 3cm from the PCB,
>>
>> Could you explain how the distance of the antenna to the PCB is related
>> to a DC block capacitor? And how do you block current flowing from the
>> input stage of your amplifier into the antenna?
>
> The input to the amplifier is just a piece of metal, there is no need
> for a capacitor in series with it.
>
> The output from the amplifier goes to a transformer which drives a piece
> of "twin-ax" cable back to my lab.
>
> The reason for the transformer is that to go really deep in frequency
> the usual choke to separate the DC supply from RF signal doesn't work.
>
> I the 'cable-side' of the transformer, in both ends, is centertapped
> and that's how I provide power to the antenna.
>
> I have successfully received the Russian "Omega-like" system at
> 9-15 kHz and I have detected but not demodulated the 86Hz submarine
> transmission.
>
> That's DC enough for me :-)
>