[DSP-10] DSP-10 with external Frequency Control

Fri, 01 Mar 2002 10:19:50 -0500

         A company I worked  for (20 years ago)  had a 60 hz oscillator on 
a board and would sync it with line freq when it was available. As I recall 
it was a NAND gate with a pullup on the line side inserted in the loop. I 
am trying to rationalize if this approach would work. What I am envisioning 
is coupling the lo on the board a little looser, and if you feed an 
external 10 mhz in, it would tickle the oscillator and drag it on freq. I 
tried the direct approach by connecting both at once at the header and I 
got harmonics and 2 oscillations instead of 1 steady... I was considering 
too a series resistor in the header loop which may allow the xtal 
oscillator to bend a little easier...

         Any engineering thoughts would be appreciated..

         At last case, we could use a 4053 cmos switch and just switch with 
a toggle switch. to manual for my likes...but it should work..Doug KB8GVQ


At 06:26 PM 2/28/02 -0500, you wrote:
>Hi, Doug!
>
>Excellent question; I had wondered about doing the same thing.  It is
>inconvenient here to make the change from the GPS-controlled external
>oscillator (or the Rb oscillator) to internal frequency control, as with my
>box I need to not only open the large outer Hammond box, but also open,
>unscrew, and remove the copper circuit board homemade box housing the EZ-Kit
>Lite to make this change.  And in the course of experimenting, I fairly
>frequently want to make the switch.  So if you come up with a workable
>'front panel switch' solution, please post the details to the list so we can
>all implement it!
>
>Thanks in advance, and
>
>73,
>
>Roger Rehr
>W3SZ   FN20ah
>2 Merrymount Road
>Reading, PA  19609-1718
>http://www.qsl.net/w3sz
>
>
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of Doug Bade
> > Sent: Thursday, February 28, 2002 9:02 AM
> > To: [email protected]
> > Subject: Re: [DSP-10] DSP-10 with external Frequency Control
> >
> >
> >          This brings up a question I have been meaning to ask.. I
> > externalized the 3 connections through rg174 for the 10mhz
> > osc switching.
> > When I jumper loopback external to send 10 mhz back in, the
> > oscillator
> > jumps 1.24 khz off freq due to loading changes of the
> > oscillator with a 14"
> > loop of coax more or less...External input works great, but
> > cannot warp
> > oscillator that far to get on freq.
> >          Has anyone figured out a switch scheme to allow
> > internal/external
> > 10 mhz from the panel? I am considering a mosfet shunted
> > across internal
> > pair on board or similar schemes.. Anyone have a working plan???
> > Doug KB8GVQ
> >
> >
> > At 04:21 PM 2/27/02 -0800, you wrote:
> > >Jimmy W7CQ and I made are first LHL7 Qs with 1 mw or less.
> > >
> > >We have both of our DSP-10s controlled by our external 10mhz - GPS
> > >frequency standards. These standards use the Brooks Shera
> > controller with
> > >an HP 10544A crystal oven.
> > >
> > >If WX holds and I can get the antenna damage repaired this
> > week end, after
> > >our major wind storm here 3 weeks back, will be looking to
> > try other weak
> > >signal modes.
> > >
> > >73
> > >
> > >de KO7N   CN84ia
> > >
> > >Richard Ewing
> > >PNW VHF Society C-075
> > >http://home.teleport.com/~rewing
> > >
> > >
> > >_______________________________________________
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> >
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