[minima] Re: Does the size of the Crystal Oscillators matter?
- From: hcker2000 <hcker2000@xxxxxxxxx>
- To: minima@xxxxxxxxxxxxx
- Date: Tue, 11 Mar 2014 15:27:45 -0400
Nice thanks for the link to the deal.
On Tue, Mar 11, 2014 at 1:27 PM, Sandeep Lohia <sandeeplohia12@xxxxxxxxx>wrote:
> Hope U have got answers Guru, now have it with economic KDS, same I
> suggested U @ 20 yesterday.
> Rather then costly commercial one...
>
> Those not having Si570 yet, even BFO will do...
>
> Good Night, mailed from mobile...
>
> On 11/03/2014, Joe Rocci <joe@xxxxxxxxxx> wrote:
> > Wow...that's even a better deal!
> >
> > I have a Minima product improvement suggestion related to this: How about
> > putting in a jumper so the SI570 output can be put through the crystal
> > filter and then build in a simple detector at the IF output that can be
> read
> > by an A-D input on the AVR chip. With a bit of firmware, this would allow
> > builders to sweep out the filter & IF response & gain.
> >
> > Joe
> > W3JDR
> > ----- Original Message -----
> > From: Adrian Preda
> > To: minima@xxxxxxxxxxxxx
> > Sent: Tuesday, March 11, 2014 1:05 PM
> > Subject: [minima] Re: Does the size of the Crystal Oscillators matter?
> >
> >
> > I bought 100pcs with aprox. 5$ including shipping.
> >
> >
> >
> >
> http://www.ebay.com/itm/100pcs-20-000MHZ-20-MHZ-20M-HZ-DIP-Crystal-Oscillator-HC-49S-New-/251251477769?pt=AU_B_I_Electrical_Test_Equipment&hash=item3a7fc14d09
> >
> >
> >
> > Adrian
> > YO4HHP
> >
> >
> >
> >
> ------------------------------------------------------------------------------
> > From: hcker2000 <hcker2000@xxxxxxxxx>
> > To: minima@xxxxxxxxxxxxx
> > Sent: Tuesday, March 11, 2014 6:48 PM
> > Subject: [minima] Re: Does the size of the Crystal Oscillators matter?
> >
> >
> >
> > Thanks I was just planing on buying a bunch from china in one go to
> avoid
> > paying $8 for shipping on $8 worth of parts. Do you think 20 would be
> enough
> > to get 8 that match?
> >
> >
> >
> >
> > On Tue, Mar 11, 2014 at 10:57 AM, Joe Rocci <joe@xxxxxxxxxx> wrote:
> >
> > I believe what I wrote in my previous is substantially true for any
> > crystal ladder filter; ie, the single most important factor is frequency
> > matching. In general, you should try to match frequencies to be within a
> > range of no more than about 5% of the filter bandwidth. The less
> variation,
> > the better the shape. Since this filter is a bit wider than BITX, the
> > allowable range of crystal frequency variation is also bigger. All of
> this
> > gets more stringent when you're trying to build a narrow band filter for
> CW,
> > which by the way, will be difficult to implement at 20 MHz without
> incurring
> > large insertion loss.
> >
> > Joe
> > W3JDR
> > ----- Original Message -----
> > From: gurudatta panda
> > To: minima@xxxxxxxxxxxxx
> > Sent: Tuesday, March 11, 2014 10:44 AM
> > Subject: [minima] Re: Does the size of the Crystal Oscillators
> > matter?
> >
> >
> > @Joe: That means, there will be lot of relaxation from Crystal
> > Matching in comparison to BITX?
> >
> >
> >
> >
> > On Tue, Mar 11, 2014 at 7:37 PM, Joe Rocci <joe@xxxxxxxxxx> wrote:
> >
> > The filter bandwidth in this radio is so wide that typical
> crystal
> > variations shouldn't have a significant effect.
> > If you want the nicest shape, then:
> >
> > 1) Buy a batch of 10-15 crystals from the same manufacturer,
> > supplier & model. Here in the US, these crystals are available from
> Digikey
> > and Mouser for about $.40/ea., as are higher frequency fundamental mode
> > crystals all the way to 50 MHz.
> > 2) Build a test oscillator and select the 8 crystals that are
> > closest together in frequency. Try to get a set that are within about
> 150 Hz
> > of each other. Absolute frequency isn't so important as frequency match.
> > 3) If you want to get the last few percent of performance
> possible,
> > you can Google ways to match crystals for their Q and loss resistance.
> >
> > The filter in this radio is so wide that only #1 & #2 above are
> > really critical. Random crystals will probably function, but the passband
> > shape won't be optimum. Low profile crystals should work as long as their
> > series loss resistance isn't too high. Even if it is higher, it will
> mostly
> > affect filter loss. In the ones I've looked at, it seems OK.
> >
> > Joe
> > W3JDR
> >
> >
> > ----- Original Message -----
> > From: hcker2000
> > To: minima@xxxxxxxxxxxxx
> > Sent: Tuesday, March 11, 2014 9:45 AM
> > Subject: [minima] Does the size of the Crystal Oscillators
> > matter?
> >
> >
> > Is it ok to use low profile ones?
> >
> >
> > --
> > Mike "hcker2000" Ashcraft
> > http://bigironinteractive.com
> >
> >
> >
> >
> >
> >
> > --
> > Thanks & Regards
> >
> >
> > Gurudatta Panda
> > Jr. Site Engineer
> > R.V.N.L. / KDJR
> >
> >
> > Mob : +91 9777447844 (Work)
> > +91 9778238593 (Home)
> >
> >
> >
> >
> >
> > --
> > Mike "hcker2000" Ashcraft
> > http://bigironinteractive.com
> >
> >
> >
> >
> >
> >
>
>
> --
> http://www.lohiaelectronics.com/sandeep/mimima.htm
>
>
--
Mike "hcker2000" Ashcraft
http://bigironinteractive.com
<http://www.linkedin.com/in/mikeashcraft>
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