[Lowfer] HC-49 Crystal on 1856 khz

[Bill Ashlock]

You mean "pull it down to the 185.3 watering hole", right?  :)    Also, you might try a little series inductance if parallel capacity won't get you low enough. Seems that the Q of the inductor has to be high, so watch out for certain ferrites that will kill the oscillator.

Bill

> From: pulsarxp at embarqmail.com
> To: lowfer at mailman.qth.net
> Date: Thu, 5 Aug 2010 21:02:10 -0500
> Subject: Re: [Lowfer] HC-49 Crystal on 1856 khz
> 
> I guess you could "pull" the crystal slightly too with a cap to change the 
> frequency slight. from 185 Khz.  I just looked at my crystals from Dan.  I 
> have 6 of them, so maybe they were 6/$1.00.  Can't remember but they cost 
> next to nothing and are bright and clean unused with 1 inch leads.
> 
> Lee
> 
> 
> 
> ----- Original Message ----- 
> From: "Bill Ashlock" <ashlockw at hotmail.com>
> To: <lowfer at mailman.qth.net>
> Sent: Thursday, August 05, 2010 8:55 PM
> Subject: Re: [Lowfer] HC-49 Crystal on 1856 khz
> 
> 
> >
> > Lee,
> >
> > Another advantage to your Xtal approach is that you can add FM modulation 
> > to that Xtal osc by simply connecting a series 2pf - 5pf cap to the hot 
> > side of the Xtal and a GP rectifier diode to gnd (cath to cap) at the 
> > other end of the cap. The modulation is applied via a ~1 meg series 
> > resistor to the diode. The diode acts as a poorman's varricap but you will 
> > find there is plenty of freq change on a typical QRSS30 screen with a 
> > simple 1N400X and will likely have to increase the value the resistor to 
> > keep it under a deviation of 1Hz.
> >
> > Bill
> >
> >> From: pulsarxp at embarqmail.com
> >> To: lowfer at mailman.qth.net
> >> Date: Thu, 5 Aug 2010 20:14:17 -0500
> >> Subject: [Lowfer] HC-49 Crystal on 1856 khz
> >>
> >> A short while back I ordered some parts from Dan's Small Parts and Kits.
> >> Among other things, he has HC-49 crystals on 1856 khz.  The price is
> >> 5/$1.00.  I ordered 5.  They look great but I have not tried them.
> >>
> >> I was thinking, if you want to make a Lowfer transmitter without an Epson
> >> osc, you could use one of these crystals into a divide bye 10 chip and 
> >> come
> >> out with a Lowfer freq signal.  You can hardly beat 5 for a buck.
> >>
> >> Lee, w0vt
> >>
> >>
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