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

Alan Melia alan.melia at btinternet.com
Wed Oct 21 09:14:02 UTC 2009

Hi Magnus I was not sure whether the 4101A would go up that far. I had not
noticed the news about HBG.  That is a disappointment, particularly with the
number of "radio clocks" around in "domestic" use, and from the "Land of
Clocks" too.

Someone mentioned a screened loop in copper pipe. Screening loops at this
frequency gives little advantage and the extra stray capacitance can degrade
the performance. An open loop works just as well (and is much easier to
build for a trial) the problem usually comes from common mode pick-up on the
feeder to the receiver. This is often best combatted by careful balancing,
or transformer isolation.

Alan G3NYK

----- Original Message -----
From: "Magnus Danielson" <magnus at rubidium.dyndns.org>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Wednesday, October 21, 2009 1:30 AM
Subject: Re: [time-nuts] Adret 4101A, the DCF77 and a good antenna

> Alan Melia wrote:
> > Marco, have you considered that HBG on 75.0kHz might be stronger with
> > from Switzerland??. In a lab or other complex quite often with off-air
> > standards the problem is local noise. I have a friend in Porto who used
> > be able to lock to MSF when it was at Rugby a few years ago.......I
> > asked since it moved north to Anthorn but I suspect he uses GPS now. If
> > noise is not a problem these receiver will often work well on a
> > wire antenna which is fairly easy to rig. Or see the PA0RDT MiniWhip
> > for a very simple active low frequency antenna. This is used all round
> > world for receiving weak amateur signals on 136kHz ....it is broadband
up to
> > about 500kHz, and down to 40kHz Japanese frequency standard
> > It is so small you can experiment to find the best quiet position. At LF
> > secret is the higher the better.
> The TDF 162 kHz is a 2 MW transmitter which is even closer...
> A bit tricker to retriev the timing signal thought, but this is assuming
> the signal can be freely selected.
> The HBG transmitter is going off-air (for good) in a not to distant
> Cheers,
> Magnus
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