[time-nuts] Discussion of precise time and frequency measurement

Ronald Held ronaldheld at gmail.com
Mon Dec 17 21:14:52 UTC 2007


Since the moving option is out, perhaps I need to investigate whether
I currently can get any inside or outside signal. Is ther3=e an
inexpensive way given that I do not have any circuit assemble skills?
The complex will allow dishes as long as the are completely inside the
balcony(I speculate that it is at the behest of the local cable
company). I do not recall seeing any dishes on building in my complex.
If I can get a signal inside or outside, what then?
                                               Ronald

---------- Forwarded message ----------
From: time-nuts-request at febo.com <time-nuts-request at febo.com>
Date: Dec 17, 2007 12:00 PM
Subject: time-nuts Digest, Vol 41, Issue 61
To: time-nuts at febo.com


Send time-nuts mailing list submissions to
       time-nuts at febo.com

To subscribe or unsubscribe via the World Wide Web, visit
       https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
or, via email, send a message with subject or body 'help' to
       time-nuts-request at febo.com

You can reach the person managing the list at
       time-nuts-owner at febo.com

When replying, please edit your Subject line so it is more specific
than "Re: Contents of time-nuts digest..."


Today's Topics:

  1. Re: re low noise regulators (Bruce Griffiths)
  2. Re: re low noise regulators (Magnus Danielson)
  3. Re: time-nuts Digest, Vol 41, Issue 56 (James Maynard)
  4. Re: Antennas in apartments (Hal Murray)


----------------------------------------------------------------------

Message: 1
Date: Mon, 17 Dec 2007 11:19:05 +1300
From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] re low noise regulators
To: Discussion of precise time and frequency measurement
       <time-nuts at febo.com>
Message-ID: <4765A459.5030902 at xtra.co.nz>
Content-Type: text/plain; charset=ISO-8859-1

SAIDJACK at aol.com wrote:
> Hi Bruce,
>
> The capacitors' microphonic sensitivity may actuallyy be more of a factor
> here.
>
Are electrolytics microphonic?
Ferroelectric (X7R, Z5U,Y5V, X5R, etc but not NP0/C0G) ceramic caps are
microphonic
>
>
>> It still helps to have as low a noise as possible before using  such
>> brute force filtering to get that extra few dB of noise  reduction.
>>
>
> It's not just a few dB, it's -3dB at 17Hz already, and that drops  at ~-20dB
> per decade. At 170Hz it could theoretically give -23dB already,  or in other
> words if the noise floor was entirely due to the supply voltage  noise, then
> the difference would be between say -140dBc/Hz and about  -160dBc/Hz at 170Hz -
> this could be a very significant improvement.
>
> You are absolutely right, it is very difficult to get low noise  <10Hz.
>
> bye,
> Said
>
Bruce



------------------------------

Message: 2
Date: Sun, 16 Dec 2007 23:50:44 +0100 (CET)
From: Magnus Danielson <magnus at rubidium.dyndns.org>
Subject: Re: [time-nuts] re low noise regulators
To: time-nuts at febo.com, bruce.griffiths at xtra.co.nz
Message-ID: <20071216.235044.1957269467.cfmd at bredband.net>
Content-Type: Text/Plain; charset=us-ascii

From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] re low noise regulators
Date: Mon, 17 Dec 2007 11:19:05 +1300
Message-ID: <4765A459.5030902 at xtra.co.nz>

> SAIDJACK at aol.com wrote:
> > Hi Bruce,
> >
> > The capacitors' microphonic sensitivity may actuallyy be more of a factor
> > here.
> >
> Are electrolytics microphonic?
> Ferroelectric (X7R, Z5U,Y5V, X5R, etc but not NP0/C0G) ceramic caps are
> microphonic

All caps is more or less microphonic. Even a pair of plates with vacuum between
them are microphonic. However, the higher capacitivity of the dielectrum, the
higher microphonic sensitivity can you expect. You can as always reduce the
microphonic aspect through mechanical design, including wise use of symmetry,
but the effect will always be there. The point being, the effect is always
there, but the coupling degree may be stronger or weaker.

Traditionally electrolytics have not been the main concern thought. But they
are not always the best choice for many other reasons, as you are fully aware.

Cheers,
Magnus



------------------------------

Message: 3
Date: Sun, 16 Dec 2007 18:08:12 -0800
From: "James Maynard" <james.h.maynard at usa.net>
Subject: Re: [time-nuts] time-nuts Digest, Vol 41, Issue 56
To: <time-nuts at febo.com>
Message-ID: <709LLqcHm6314S07.1197857292 at cmsweb07.cms.usa.net>
Content-Type: text/plain; charset=ISO-8859-1



------ Original Message ------
>Received: Sat, 15 Dec 2007 05:53:00 PM PST
>From: "Ronald Held" <ronaldheld at gmail.com>
>To: time-nuts at febo.com
>Subject: Re: [time-nuts] time-nuts Digest, Vol 41, Issue 56
>
>My apartment is in a reinforced concrete building, not near the roof.
>Many years ago I tried a Garmin handheld and could not get a lock.
>Recently, I tried a GPS watch near the window, and could not get e
>lock, even though it did lock up outside(cold) after a few minutes.
>that is why i do not think I can use a GPS disciplining option.
>  Since my unit already gets no worse than 1 millisecond when locked
>up, i would want no worse than 1 microsecond in phase over long
>periods of time. What non GPS options are there with the electronic
>building skills I do not have?
>
Does a cell phone work in your apartment? If so, you might consider
an oscillator that gets its frequency discipline indirectly:
GPS receiver disciplines oscillator at cell phone tower,
then CDMA cell phone network disciplines oscillator in your
apartment.

See <http://www.endruntechnologies.com/frequency-standard-lowcost.htm>
for an example.

James Maynard, K7KK
Salem, Oregon, USA







------------------------------

Message: 4
Date: Sun, 16 Dec 2007 22:57:49 -0800
From: Hal Murray <hmurray at megapathdsl.net>
Subject: Re: [time-nuts] Antennas in apartments
To: Discussion of precise time and frequency measurement
       <time-nuts at febo.com>
Message-ID: <20071217065750.CCE78BE32 at ip-64-139-1-69.sjc.megapath.net>
Content-Type: text/plain; charset=us-ascii


> i  thought of tha balcony option. The balcony as an overhang which
> effectively  blots out the other half of ths sky not covered by the
> building. I cannot  hang any antenna over the railing or on it(in my
> lease and enofrce;I  asked), plus there are birds and squirrels which
> would get into it. Any other suggestions?

You said " I cannot  hang any antenna over the railing or on it".  Does that
mean you can put things out there as long as they are not visible from the
outside?  Try it just inside/below the railing.


Talk to your building superintendent.  Offer to provide NTP service to the
whole complex if he will help you setup a GPS antenna.

What do people who want satellite TV do?

I like the hide-it-in-a-bird-feeder suggestion.  Are plants and bird feeders
prohibited?



--
These are my opinions, not necessarily my employer's.  I hate spam.






------------------------------

_______________________________________________
time-nuts mailing list
time-nuts at febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

End of time-nuts Digest, Vol 41, Issue 61
*****************************************




More information about the Time-nuts_lists.febo.com mailing list