[time-nuts] Adret 4101A, the DCF77 and a good antenna
EWKehren at aol.com
EWKehren at aol.com
Wed Oct 21 02:49:25 UTC 2009
Good morning Marco
In the past I had best luck with a loop antenna using a copper tube (one
end insulated) using as many turns as I was able to run through it and tuning
it to frequency. One can also use a multi conductor cable and spice the
ends in such a way that it becomes a multi turn loop. I used a two stage pre
amp split in two parts one in the antenna so that there was no AC/DC
decoupling, the coax did the RF and power.
Bert Kehren WB5MZJ
In a message dated 10/20/2009 10:27:41 P.M. Eastern Daylight Time,
wb6bnq at cox.net writes:
That looks like a really nice receiver. It is a little numb as far as
sensitivity goes, but there are reasons for such. At those low frequencies
atmospheric noise will certainly be quite high. So, one way to to handle
to put the signal preamp out at the antenna, usually a magnetically
similar to the loop used with the Hewlett Packard 60 KHz receiver loop
The loop also acts as an extremely narrow filter.
I wonder if the manufacturer still exists ? If so maybe they could be of
they may still have parts and hopefully their active loop antenna that
Otherwise, you would have to build your own antenna. I highly suggest
designs on the WEB, as others have suggested, concerning magnetically
loops as they help with rejecting local noises.
Good luck with your project !
"Marco A. Ferra" wrote:
> 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.
> 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
> 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,
> a brochure with a few pages ), the DCF77 signal itself or an ideia
> antenna that could be very sensitive to this signal?
> Kind regards, and thank you in advance,
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