[DSP-10] DSP-10 with external Frequency Control
H.G.
[email protected]
Mon, 4 Mar 2002 14:24:43 -0600
Doug:
I placed an inquire to DSP-10 GROUP trying to determine if there more
members that may need the reference changes for EXTERNAL_10MHZ.
I have not seen any response, I wonder if I did not send it properly.
Have you seen my message ?.
Regards
Nando
-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Doug Bade
Sent: Friday, March 01, 2002 10:49 AM
To: [email protected]
Subject: RE: [DSP-10] DSP-10 with external Frequency Control
The input from external references seems to vary depending on
where we get an oscillator (scrounged in most cases). 1 V p-p sine to
5vdcTTL square wave would cover the bases for the most part..
Auto-switching would be preferable in my case, as one less switch to set
wrong...
At 10:24 AM 3/1/02 -0600, you wrote:
>Doug:
>
>I have received page 7 of the schematic and downloaded the LMX1501A data
>sheet.
>
>To be able to insert the external clock automatically the following is
>needed:
>
>A small relay( SPDT) to move EXT_REF ( P106-2) from XTAL (P106-1) to
>EXTERNAL_10MHZ.
>In addition a buffer amplifier and if automatic switching IS WANTED a
couple
>gates to do the job.
>
>All this circuit I am talking about is just a CMOS device like a QUAD NAND
>GATE and possibly a transistor to drive the relay.
>
>Reason why you are having a 1.5 KHZ shift is that the coax cable is adding
>additional capacitance to the XTAL line, causing the 10 MHZ frequency shift
>and with a small relay nearby the local 10 MHZ can be compensated in an
>stable manner and when the external signal is inserted the local 10 MHZ is
>disable and replaced by the external 10 MHZ.
>
>The circuit can be assembled in a small perforated board, so if you guys
are
>interested let me know to proceed.
>
> I will need to know the minimum voltage level for the EXTERNAL_10 MHZ,
also
>if sine wave or square wave
>
>Regards
>
>Nando KC5FDW
>
>-----Original Message-----
>From: [email protected]
>[mailto:[email protected]]On Behalf Of Doug Bade
>Sent: Friday, March 01, 2002 9:55 AM
>To: [email protected]
>Subject: Fwd: Re: Fwd: RE: [DSP-10] DSP-10 with external Frequency
>Control
>
>
>Correction below...
>re-sent due to mail send problem...
>
> >I guess I should have said more specifically, automatic preferred, and
> >switched somehow if necessary. The current scheme requires moving a shunt
> >on the header or replacing shunt with external connection... We wish to
> >simplify this design. Just running a coax loop out and back in causes
freq
> >change to the lo of about 1.5 kHz.. way too much to compensate.. That is
> >the agenda.. Thanks, Doug
> >
>
>
>
>
>
> >At 10:45 AM 3/1/02 -0500, you wrote:
> >
> >>> Here is page 7 of the schematic. The 10 mhz oscillator is
where
> >>> we are talking about. It has an internal and external connection
across
> >>> the header...
> >>>We want to be able to run on board when it can, and the inject external
> >>>for higher stab when available.. Let us know, Doug
> >>>
> >>>
> >>>
> >>>At 09:30 AM 3/1/02 -0600, you wrote:
> >>>>If one of you guys can send to me the schematic and what you desire to
> >>>>do, I
> >>>>will be happy to design the circuit you need.
> >>>>
> >>>>I am an Electronic Design Engineer in areas of R.F. ( from low to
Ghz ),
>as
> >>>>well as DC Circuits and power supplies.
> >>>>
> >>>>Regards
> >>>>
> >>>>Nando KC5FDW
> >>>>
> >>>>-----Original Message-----
> >>>>From: [email protected]
> >>>>[mailto:[email protected]]On Behalf Of Doug Bade
> >>>>Sent: Friday, March 01, 2002 9:20 AM
> >>>>To: [email protected]
> >>>>Subject: RE: [DSP-10] DSP-10 with external Frequency Control
> >>>>
> >>>>
> >>>> 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
> >>>> > > >
> >>>> > > >
> >>>> > > >_______________________________________________
> >>>> > > >DSP-10 mailing list
> >>>> > > >[email protected]
> >>>> > > >http://mailman.qth.net/mailman/listinfo/dsp-10
> >>>> > >
> >>>> > > _______________________________________________
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> >>>> > >
> >>>> >
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