For Andy -
It is far easier in terms of bandwidth and power required to distribute sine
waves, and that is the method most used. The sine wave is more easily
transported via coax for long distances with no distortion issues.
I suggest you terminate the output of your oscillator in a nice 6 dB pad to set
the load impedance and to set the source seen by the next stage to around 50
Ohms. The next stage should be a low pass filter of about 4 poles with a cutoff
at about 12-15 MHz.
That will clean up the square wave and get you a good looking sine wave without
much harmonic content and no critical tuning to set it up. Then follow that
with an amplifier to get the level up and to drive the various loads.
This is not the only architecture, but it will preserve the basic short term
stability of your source. A PLL based scheme can either improve it or make it
worse depending upon the design of the PLL and the VCO employed. You would
still need a filter to clean up and filter VCO harmonics (if they exist) and
the output buffer amplifier. Various MMIC chips exist that can amplify a 50 OHM
source and drive a 50 OHM load with outputs up to 20 dBm and gains of up to 19
dB. These are untuned and work from 1 MHz up to several GHZ.
-john k6iql
-----Original Message-----
From: time-nuts-request <time-nuts-requ...@febo.com>
To: time-nuts <time-nuts@febo.com>
Sent: Sun, May 19, 2013 8:15 pm
Subject: time-nuts Digest, Vol 106, Issue 92
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When replying, please edit your Subject line so it is more specific
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Today's Topics:
1. Re: Trimble Acutime Gold PPS (Miguel Barbosa Gon?alves)
2. Re: Time Nut Pickens at the MIT Flea ? (J. Forster)
3. Re: Time Nut Pickens at the MIT Flea ? (Andy Bardagjy)
4. Re: OCXO Adjustment Question (Azelio Boriani)
5. 10Mhz Sine from Square Wave Synthesizer (Andy Bardagjy)
6. Re: Net4501's cheap... (Didier Juges)
7. Re: OCXO Adjustment Question (Frederick Bray)
8. Ovenaire OCXO -- Final Diagnosis Summary (Frederick Bray)
----------------------------------------------------------------------
Message: 1
Date: Sun, 19 May 2013 22:54:39 +0100
From: Miguel Barbosa Gon?alves <m...@mbg.pt>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] Trimble Acutime Gold PPS
Message-ID: <-6084039917996433135@unknownmsgid>
Content-Type: text/plain; charset=ISO-8859-1
No dia 19/05/2013, ?s 22:44, Mike S <mi...@flatsurface.com> escreveu:
> On 5/19/2013 5:03 PM, Miguel Barbosa Gon?alves wrote:
>
>> - Port A (T+) to R+ on the converter
>> - Port A (T-) to R- on the converter
>> - PPS+ to T+ on the converter
>> - PPS- to T- on the converter
>>
>> On the RS232 part of the converter
>>
>> - TXD (pin 3) to computer pin 1 (DCD)
>> - RXD (pin 2)to computer pin 2 (RXD)
>> - GND (pin 5)to computer pin 5 (GND)
>
>> I can see the serial time code on the computer yet the PPS (a long 400 ms
>> one) doesn't seem to reach the computer.
>
> You're trying to have two different signals sourced on the 422 side converted
to 232 outputs. That converter is bidirectional, it converts one signal from
422
to 232, and another from 232 to 422. Your PPS signal is going into an output on
the converter.
Hi!!
I suspected that this could be the case.
I think I'll build the converter whose schematic I posted previously.
I will be entertained for a few days for sure.
Thanks for your help!
Regards,
Miguel
------------------------------
Message: 2
Date: Sun, 19 May 2013 15:05:58 -0700 (PDT)
From: "J. Forster" <j...@quikus.com>
To: "Discussion of precise time and frequency measurement"
<time-nuts@febo.com>
Subject: Re: [time-nuts] Time Nut Pickens at the MIT Flea ?
Message-ID:
<12375.12.226.214.5.1369001158.squir...@popaccts.quikus.com>
Content-Type: text/plain;charset=iso-8859-1
Not me. IMO, the pickings were pretty slim. I think a number of ventors
opted for Dayton.
-John
==============
> Anyone got any Time Nut quality items at the MIT fleamarket today ?
>
> Stan, W1LE Cape Cod
> _______________________________________________
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> To unsubscribe, go to
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> and follow the instructions there.
>
>
------------------------------
Message: 3
Date: Sun, 19 May 2013 18:55:13 -0400
From: Andy Bardagjy <a...@bardagjy.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] Time Nut Pickens at the MIT Flea ?
Message-ID:
<CA+hd4YjLkcdYKBfuCjN1Q1Y=nbbvbt0x-9ush-fwr-xpxpg...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
I grabbed a real nice Leitech distribution amplifier - but I took it home
and it was empty!
I walked back and returned it for a refund, but the seller said he had a
whole stack in his office. I was gonna post to the list when I sort it out
- it was a real bargin, and he said he might be willing to ship them around.
Andy Bardagjy
bardagjy.com
On Sun, May 19, 2013 at 4:42 PM, Stan, W1LE <stanw...@verizon.net> wrote:
> Anyone got any Time Nut quality items at the MIT fleamarket today ?
>
> Stan, W1LE Cape Cod
> ______________________________**_________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/**
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> and follow the instructions there.
>
------------------------------
Message: 4
Date: Mon, 20 May 2013 01:02:58 +0200
From: Azelio Boriani <azelio.bori...@screen.it>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] OCXO Adjustment Question
Message-ID:
<cal8xpmpulxvcaf7ovhu-wdlb46v-j0gdnrisajupidkxpbq...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Usually this type of failure comes from the startup section of the
power supply. Try to locate the resistor and the electrolytic
capacitor of the driver IC. The resistor (in the 68K - 390K range)
connects the V+ bus to this low voltage capacitor and gives the
startup voltage.
On Sun, May 19, 2013 at 7:19 PM, J. L. Trantham <jlt...@att.net> wrote:
> It's nice to have something to do.
>
> Sorry to hear of the 'bad' magic but, at least, it's not the same problem
> all over again.
>
> Joe
>
> -----Original Message-----
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Frederick Bray
> Sent: Sunday, May 19, 2013 12:11 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] OCXO Adjustment Question
>
> Well, I also had some bad magic happen.
>
> Last night, I decided that I would shutdown my HP 8935 so that I could
> move it back to its usual place. When I turned it on this a.m. it
> wouldn't power up. There is a known failure mode in the power supplies
> of the 89XX series. I will probably just do an exchange for a re-built
> supply.
>
> It looks like I will have a new project for next weekend!
>
> Fred
>
>
> On 5/19/2013 9:10 AM, J. L. Trantham wrote:
>> Good to hear.
>>
>> I love it when magic happens.
>>
>> Joe
>>
>> -----Original Message-----
>> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
>> Behalf Of Frederick Bray
>> Sent: Saturday, May 18, 2013 5:55 PM
>> To: time-nuts@febo.com
>> Subject: Re: [time-nuts] OCXO Adjustment Question
>>
>>
>> Thanks to all the people who have commented, I believe that I have
>> recovered the original Ovenaire OCXO. I re-flowed a bunch of solder
>> joints on the PC board(s) and reassembled the oven with the foam. Even
>> without the can over it, it is now stable. I plan to complete the
>> re-assembly and leave it as it presently is after setting it to a GPSDO
>> with a scope. I will save the MV89 for another project.
>>
>> Fred
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
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>> and follow the instructions there.
>
> _______________________________________________
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> and follow the instructions there.
------------------------------
Message: 5
Date: Sun, 19 May 2013 19:30:36 -0400
From: Andy Bardagjy <a...@bardagjy.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: [time-nuts] 10Mhz Sine from Square Wave Synthesizer
Message-ID:
<ca+hd4yj50bsajznx5xjasjv9p4j1tacwbpvfecvpw8diw4h...@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Hi folks, I recently picked up a Symmetricom SA.22c rubidium oscillator.
According to the datasheet, it outputs a square wave with programmable
frequency (well you can pick among some set of frequencies).
I'd like to build up a small circuit locked to the square wave output which
outputs a 10MHz sine wave for use as my "house clock" for my various
instruments (spec an, counter etc). I of course could distribute the square
wave, but am concerned about harmonics, among other things.
The FE-5680A uses a AD9830A DDS to synthesize its output. Is a DDS the
right way to go - in terms of performance, phase noise and so on?
I suppose I could do this with a tank or some other analog circuit, but..
Andy Bardagjy
bardagjy.com
------------------------------
Message: 6
Date: Sun, 19 May 2013 18:07:51 -0500
From: Didier Juges <shali...@gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] Net4501's cheap...
Message-ID:
<CAMQqFu=+p6EUQi9iVojK-N3Ny=rCYX134=dra14pafc50ys...@mail.gmail.com>
Content-Type: text/plain; charset=windows-1252
I snatched one for $20 and they are now $59 or best offer.
On Sun, May 19, 2013 at 11:18 AM, Bob Camp <li...@rtty.us> wrote:
> Hi
>
> There are a number of things that a Net4501 could be used for?.
>
> Bob
>
> On May 19, 2013, at 10:45 AM, Jason Rabel <ja...@extremeoverclocking.com>
> wrote:
>
> > Just a heads up, there are some (8+ @ last count) used Soekris Net4501's
> for $29 on eBay (Search for: Soekris)... I submitted a bid
> > for $20 each and it was instantly accepted... Don't know how low you can
> go, from the description the guy wants to get rid of them
> > or they are going in the trash. Seems like a good deal if you are
> looking to make a little NTP server, especially compared to the
> > retail price for a net4501... ;)
> >
> > I'm not affiliated with the seller in any way, I just love those little
> net4501's... I already have 5 of them, I don't know why I
> > just bought 5 more... lol... Now I need more GPS modules!
> >
> >
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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> and follow the instructions there.
>
------------------------------
Message: 7
Date: Sun, 19 May 2013 17:47:34 -0700
From: Frederick Bray <fwb...@mminternet.com>
To: Discussion of precise time and frequency measurement
<time-nuts@febo.com>
Subject: Re: [time-nuts] OCXO Adjustment Question
Message-ID: <519972a6.3000...@mminternet.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Thanks for the info. I had a general idea that it might be something
like this, but it's helpful to know what to look for. I won't have time
to dig into it until next weekend. Unfortunately, HP's documentation is
not generally available so it may take some exploring.
On 5/19/2013 4:02 PM, Azelio Boriani wrote:
> Usually this type of failure comes from the startup section of the
> power supply. Try to locate the resistor and the electrolytic
> capacitor of the driver IC. The resistor (in the 68K - 390K range)
> connects the V+ bus to this low voltage capacitor and gives the
> startup voltage.
>
------------------------------
Message: 8
Date: Sun, 19 May 2013 18:15:04 -0700
From: Frederick Bray <fwb...@mminternet.com>
To: time-nuts@febo.com
Subject: [time-nuts] Ovenaire OCXO -- Final Diagnosis Summary
Message-ID: <51997918.7000...@mminternet.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I may not have mentioned that I think I figured out the underlying
problem with this OCXO lies with the trimpot in the oven control
circuit. (I believe that someone mentioned this as a possibility, so I
can't take credit for finding it on my own.) Some of the other things I
did helped, but adjustment of the trimpot was the final issue. If the
pot is misadjusted, the oscillator will wander all over the place as the
oven temperature swings wildly.
I drilled a second hole in the Ovenaire case so that I could access the
pot. I also monitored the current to the unit with a DVM. When the
oscillator started wandering, I tweaked the trimpot until the current
increased, indicating the oven was activated. I kept adjusting it to
the point that the frequency varies by 0.1 Hz on my GPSDO counter.
Perhaps it is less than that, but I don't have enough digits to say. (I
know that for final adjustment, I will need to use a scope but the
counter does let me see if the OCXO is wildly unstable.)
Now, it is clear that the adjustment is very touchy. I am going to
remount the assembly in the Cushman tonight or early tomorrow and see if
handling it has made it unstable. If so, next weekend I will tear it
down again and figure out the value of the trimpot and the number of
turns. If I can find a trimpot with more turns, I will buy it.
Otherwise, I will just get an exact replacement.
All of this has caused me to realize that the Ovenaire is probably still
quite usable for what it was designed to do. Although I considered
installing the MV89 in its place, the Cushman power supply isn't
adequate to handle it.
Thanks again to all.
Fred Bray
------------------------------
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