https://www.ebay.com/itm/265907234575, select 2-port, $235.95

73,

David N1HAC

On 3/10/25 8:45 PM, Jim Lux via time-nuts wrote:

hi Jim,

You might want to take a look at the Furuno GPSDO offerings. They offer both PPS and a programmable clock, which Furuno calls GCLK. Boards are nicely compact and run from a single 5V supply.

I got myself a surplus model GF-8704 for IIRC €40. Pictures and some ADEV measurements I have here, let me know if interested.

Wilko

On Tue, Mar 11, 2025 at 6:39 AM Jim Lux via time-nuts
time-nuts@lists.febo.com wrote:

I have a number of the Leo Bodnar devices to sync various radios and
other devices that need odd-ball clocks.  But it's a bit of a nuisance
and strikes me as inelegant to have to run all these GPS receivers
when I have a very good 10MHz signal sitting right next to them.

Anyone know of a device similar to the Leo Bodnar boxes that take
10MHz and produce a high quality RF clock output referenced to the
10MHz input? (I think all my devices are 25-250MHz)?

We addressed that 20 years ago by locking a 1GHz narrow band resonator
followed by
a quality DDS like AD9912. This is close to an Xtal in performance, but
generates 0-400MHz.
Boards may still be available at various places.

http://www.qslnet.de/member1/on4iy/CJ2009f.pdf

If you only need < 40MHz a locked 100MHz Xtal osc + DDS should do the
job at much lower cost.

br

Christophe

On 11/03/2025 10:37, Greg Maxwell via time-nuts wrote:

If you want to build something, the Analog Devices AD9552 might be of interest. 
I have not personally used one so I can't offer advice other than providing the P/N.

Wes  N7WS

On 3/11/2025 2:37 AM, Greg Maxwell via time-nuts wrote:

 
I assume you mean as a "standalone module" of some sort (Plenty of folks have used the venerable 3325 for this kind of thing, although, true, it doesn't go up to 250 MHz).

There are "clock chips" out there that do what you're asking - they have a PLL and a DDS all in the same package.  The PLL based CDCM7005 clock generator chip does something like this, too, You can independently set the divider for the output and the input going to the phase frequency detector.

On Tue, 11 Mar 2025 09:37:45 +0000, Greg Maxwell gmaxwell@gmail.com wrote:

On Tue, Mar 11, 2025 at 6:39 AM Jim Lux via time-nuts
wrote:

I have a number of the Leo Bodnar devices to sync various radios and
other devices that need odd-ball clocks. But it's a bit of a nuisance
and strikes me as inelegant to have to run all these GPS receivers
when I have a very good 10MHz signal sitting right next to them.

Anyone know of a device similar to the Leo Bodnar boxes that take
10MHz and produce a high quality RF clock output referenced to the
10MHz input? (I think all my devices are 25-250MHz)?
 

SImilarly, you can get a little board from Aliexpress for $21 that has a AD9910 on it.  I don't know if the 9910 will take a 10 MHz input. 
But it's basically what was described in the previous post - multiplies up to 1GHz and has a DDS with all the modern bells and whistles to do spur reduction.
 

On Tue, 11 Mar 2025 21:06:30 -0700, Wes via time-nuts time-nuts@lists.febo.com wrote:

If you want to build something, the Analog Devices AD9552 might be of interest. 
I have not personally used one so I can't offer advice other than providing the P/N.

Wes  N7WS

On 3/11/2025 2:37 AM, Greg Maxwell via time-nuts wrote:

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
 

Skyworks, it seems, has ended up with the Silicon Labs product line of timing products and oscillators.

The successors to the Si5351 run with VCO frequencies as high as 13GHz.  After locking with the fractional-N synthesizer, followed by its internal dividers, the specifications are impressive. The Si5340 series parts have multiple outputs. While they're, if memory serves, around $40 one part might generate some or all of your desired frequencies. You'd want a good reference for minimum phase noise.

At the sacrifice of one output, those could be used with an inverse phase locked loop to slave a ln arbitrary reference with a 10 MHz input. That would allow the freedom to use the best oscillators you can lay your hands on while minimizing or avoiding the internal reference multiplier.

Most of my (lower frequency) needs can be met with things that can be done with fixed dividers that are simple enough to breadboard. Don't overlook the possibility of using a dual modulus divider that might offer a divide by 7 or 8 strapped for a single modulus. Following a divide by 7 with a divide by 4, and dividing a 10MHz by 10 to come up with something like a 28MHz PLL would be quite easy. Paul Wade offers a board you can populate and add jumpers to if the parts used provide low enough phase noise for your needs.

From: Jim Lux via time-nuts time-nuts@lists.febo.com
Sent: Wednesday, March 12, 2025 3:51:50 PM
To: time-nuts@lists.febo.com time-nuts@lists.febo.com
Cc: Jim Lux jim@luxfamily.com
Subject: [time-nuts] Re: Flexible synthesizer boards? Was: US source for Leo Bodnar or equivalent

I assume you mean as a "standalone module" of some sort (Plenty of folks have used the venerable 3325 for this kind of thing, although, true, it doesn't go up to 250 MHz).

There are "clock chips" out there that do what you're asking - they have a PLL and a DDS all in the same package.  The PLL based CDCM7005 clock generator chip does something like this, too, You can independently set the divider for the output and the input going to the phase frequency detector.

On Tue, 11 Mar 2025 09:37:45 +0000, Greg Maxwell gmaxwell@gmail.com wrote:

On Tue, Mar 11, 2025 at 6:39 AM Jim Lux via time-nuts
wrote:

I have a number of the Leo Bodnar devices to sync various radios and
other devices that need odd-ball clocks. But it's a bit of a nuisance
and strikes me as inelegant to have to run all these GPS receivers
when I have a very good 10MHz signal sitting right next to them.

Anyone know of a device similar to the Leo Bodnar boxes that take
10MHz and produce a high quality RF clock output referenced to the
10MHz input? (I think all my devices are 25-250MHz)?

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com

YMMV, I would not take that route and multiply 10M directly
to DDS clock frequency drive or use these nasty built-in clock
frequency multipliers that are broadband. It may mess up the
phase noise pretty bad, depending on the initial 10M quality
and the internal VCO.

It pays to make a quality 10M-locked 100M or 1G and distribute
that as sysclck to all DDSs needed.

I have seen these AD9910 boards appear as well, I am puzzled,
since the AD9910 is still 75$ in singles. If am not mistaken these
25$ boards are only MCU and the DDS itself is still much pricier.

Also, these use a cheapo 10M xtal on board and multiply, exactly what you
should NOT do. And don t get me started on the power supply
subsystems of many of the DDS and PLL boards and the layout.
The ONLY boards I have seen reach close to chip spec are the
AD demo boards.
We "reworked" a few of these boards to bring them to spec in
https://on4cdu.net/agile-sources-based-on-the-adf5355-microwave-wideband-synthesiser-with-integrated-vco/
... but it was just as much work as doing a good initial design.

There is absolutely no sense in using all the advanced features of these
chips to come to quality output if you don t get the basics right and
with respect, these aliexpress boards "don t care".

But then if one is below 50M output, it s all good I presume.

Xtof on4iy

On 12/03/2025 21:57, Jim Lux via time-nuts wrote: