[DSP-10] DSP-10 with external Frequency Control
Rajiv Dewan, N2RD
[email protected]
Mon, 4 Mar 2002 23:04:44 -0000
Yes. I am interested in the EXTERN mod. However, I am early in the
process of getting the systems to work. I ordered the kit from TAPR
three weeks ago and I am still waiting for it to show up. I hope to
eventually use the system for microwave and having an accurate freq
source would sure be useful.
Regards,
Rajiv, N2RD
----- Original Message -----
From: "H.G." <[email protected]>
To: <[email protected]>
Sent: Monday, March 04, 2002 8:24 PM
Subject: RE: [DSP-10] DSP-10 with external Frequency Control
> 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
> > >>>> > >
> > >>>> > > _______________________________________________
> > >>>> > > DSP-10 mailing list
> > >>>> > > [email protected]
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> > >>>> > >
> > >>>> >
> > >>>> >_______________________________________________
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> > >>>>
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