[time-nuts] Adret 4101A, the DCF77 and a good antenna

[Marco A. Ferra]

Hey time-nuts people,

First of all, let me start by saying that I follow the time-nuts mailing 
list for some time and it's a great source for trading experiences.  Perhaps 
you can help me on this one.

We have in our laboratory, in Portugal (near Lisbon), an Adret 4101A 
Frequency Receiver Standard, and we are trying to pickup the DCF77 signal 
from Frankfurt, Germany.  I wasn't sure if the unit was working properly (it 
seems quite old), but by injecting directly a 10mV 77,5 kHz sinusoidal 
signal in the BNC antenna input I got the "level" and the "locked" green 
leds to lit (it seems good news).

However, I believe that the DCF77 arrives very weakly in Portugal, and I 
thought on constructing a passive or active, but very simple antenna to 
connect to the Adret 4101A.

Do you have any experience on this equipment (we don't have the manual, just 
a brochure with a few pages [1]), the DCF77 signal itself or an ideia for a 
antenna that could be very sensitive to this signal?

Kind regards, and thank you in advance,

[1] 
http://www.adret-electronique.fr/appareils_adret_metrologie/4101a/4101a.pdf