[time-nuts] 10 MHz Band-Pass Filter Needed (Roberto Barrios)
sar10538 at gmail.com
Thu Jan 8 23:18:04 UTC 2009
Congratulations! On your very first visit here, you have hit the Bruce
Effect. Do not be alarmed! Just place your filter in a temperature
controlled oven regulated to a change of 1E-99C for external temp
changes of -100C to +200C and you may be alright, I did say "may".
But then, for ham purposes, the phase/frequency changes should make no
difference to you. If you were NIST, well that would be another
matter. But this is a time-nuts forum and people here think in the
1E-16 range. Some of us here just strive for the best and find that
some of our needs are easily covered with much more modest equipment.
That does not mean we are happy to accept this limited capability for
projects we may wish to do in the future.
You have made a wise choice coming here, it has low noise (accept for
my posts) and some of the best minds contributing. Keep watching this
space and join in to ask question and give ideas. Do not be put off by
any comments on what you post, there are high ideals here and some may
not be the most tactful people when they make their comments. You will
learn a great deal here and you will certainly get the time bug.
73, Steve - ZL3TUV & G8KVD
2009/1/9 Bruce Griffiths <bruce.griffiths at xtra.co.nz>:
> Roberto Barrios wrote:
>>> The GPSDO I want to use has an output rich in harmonics. In some> cases that is good, but Murphy rules and in the application I have> today, it is not good.> > I need a 10 MHz Band-Pass Filter, Bandwidth is not critical, something> small with SMA connectors would be ideal, but I can live with BNC.> > Anyone have such a beast or know where I can get one ? I checked Mini-Circuits> and choked on the price !!> > Thanks, Dick, W1KSZ>
>> Hi Dick,
>> There are plans for a simple nine section low pass filter here:
>> You can also use (I did) a filter from an old 10mbit ethernet network card, as suggested here:
>> I joined this list just yesterday, so hello to everyone. I live in Madrid and I'm interested in frequency measurement for HAM purposes. Not understanding most of the things you guys discuss here, I thought I would never have the opportunity to give my 2 cents... I´m currently working on a simple GPSDO that (luckily) some of you may find interesting. I'll send you details in a few days so I can get your opinions and (hopefully) it inspires/helps someone.
>> Bests Regards & 73's
>> Roberto Barrios, EB4EQA
>> Madrid, Spain
> But what is the filter phase shift tempco?
> In the presence of temperature changes the filter phase shift variation
> is equivalent to phase and frequency modulation of the output of the filter.
> One cure is to use low tempco filter parts and place the filter in an oven.
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Steve Rooke - ZL3TUV & G8KVD & JAKDTTNW
Omnium finis imminet
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