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

EWKehren at aol.com EWKehren at aol.com
Thu Oct 22 15:10:51 UTC 2009


Alan, my problem is it has to look half way decent and be acceptable to the 
 neighbors, one time I had to take down a HP Loop for 60 KHz. Did not fit 
the  esthetics of the home fronts and only the front faces Boulder. I once 
tried  forming plastic pipe by heating it with a heat gun while wrapping it 
around an  oil barrel. Still not perfect.
Bert
 
 
In a message dated 10/21/2009 8:03:07 P.M. Eastern Daylight Time,  
alan.melia at btinternet.com writes:

Hi Bert  yes it makes a good "former" if you have it.  I bent some stiff  
wire
(fence wire ?) into a loop of the right size, insulated the ends so it  
didnt
form a "shorted turn" and tiewrapped the multiway cable to  that.......not a
s neat as your method. The point I was making is that the  (Faraday)
screening doesnt buy you much, if anything, at these very low  frequencies.
It is a very different story higher up the spectrum.

I  looked at 1in. white water pipe but it is not easy to form into a loop
:-))  For smaller loops I used hoola hoops from Toys R Us....there is a  
plug
holding them together which is easily removed then I jouned the ends  with a
1in "T" piece and glued that into a plastic box (lots of hot melt  to
water-proof it ......I hope!) where I made the connections to form  itinto a
mutiturn loop.

Best wishes
Alan G3NYK
----- Original  Message -----
From: <EWKehren at aol.com>
To:  <time-nuts at febo.com>
Sent: Wednesday, October 21, 2009 1:53  PM
Subject: Re: [time-nuts] Adret 4101A, the DCF77 and a good  antenna


> Alan,
>  I used a copper pipe because it is  the easiest way to make a round  
loop.
> I have also used PVC but  it always ended up rectangular. If you have a
> better idea please let  me know, because I am considering to fire up my 
old
> Tracor 599  receiver that I modified to work up to 80 KHz. Used it a long
time  on
>  60 KHz.
> Bert Kehren     WB5MZJ
>
>
> In a message dated 10/21/2009 5:19:28 A.M.  Eastern Daylight Time,
> alan.melia at btinternet.com  writes:
>
> 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
> you
> > > 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
>  to
> > > be able to lock to MSF when it was  at Rugby a few  years ago.......I
> havent
> > > asked since it moved   north to Anthorn but I suspect he uses GPS now.
If
> the
> >  > noise  is not a problem these receiver will often work well on  a
> resonable
> >  > wire antenna which is fairly easy  to rig. Or see the PA0RDT  
MiniWhip
> design
> > > for  a very simple active low frequency  antenna. This is used  all
round
> the
> > > world for receiving weak   amateur signals on 136kHz ....it is
broadband
> up to
> >  > about  500kHz, and down to 40kHz Japanese frequency   standard
> transmissions.
> > > It is so small you can  experiment to  find the best quiet position. 
At
> LF
>  the
> > > 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
> future.
>  >
> > Cheers,
> >  Magnus
> >
> >  _______________________________________________
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