[time-nuts] Lucent KS-24361, HP/Symmetricom Z3809A, Z3810A, Z3811A, Z3812...

Bob Camp kb8tq at n1k.org
Mon Nov 3 20:41:01 EST 2014


> On Nov 3, 2014, at 12:00 PM, Arthur Dent <golgarfrincham at gmail.com> wrote:
> GandalfG8 at aol.com GandalfG8 at aol.com Sun Nov 2 09:08:30 EST 2014 wrote:
> "Ooh err, whoops, and oh dear !!
> Arthur, I've only just had a chance to look at your latest photos, and
> unless I've really got my wires crossed, if you'll pardon the
> expression:-),
> your links on J5 are not shown on pins 2, 10, 12, and 15,  but on pins 4,
> 6,
> 11, and 13."
> +++++++++++++++++++++
> Darn-I'm glad someone was paying more attention than I was when I wrote
> that years ago. Apparently when I was documenting what modifications I
> had made I just picked up a 15 pin D plug shell to get the numbers
> instead of looking at the obvious numbers on the RFTG socket connector
> and those connectors being mirror images have the numbers reversed. I
> was out geocaching yesterday and didn't catch up on the new posts until
> this morning so I'm a little late in responding. I also checked to see
> if I had any other scribbles on the changes I made and found this: "If
> pin 2 is held low the 'ON' LED will flash. A pulse low will turn it on.
> The RC timer holds pin 2 low to flash for about 6 seconds so you can
> see it actually happens then pin 2 returns high and the 'ON' LED stays
> on solid."
> So apparently some of the parts I added were to just make the light look
> like they were working correctly (can you spell OCD?) and may not be
> necessary. As I originally said, this was a hack and I wanted others to
> duplicate what I had done to see if any of it made sense to them. At
> least it appears that by adding the circuit I came up with and/or adding
> jumpers you can get the RFTG-u REF 1 unit to work without the slave unit.
> I just ordered another RFTG-u REF 1 and will see if I can modify that and
> get it to output 10Mhz instead of 5Mhz like my original unit.

The 15 MHz “chain” in the units is *much* cleaner than what ever they did to get 10 MHz. It looks like the 15 MHz has some sort of push pull amp driving a fairly involved filter. Best guess is they have a 3X stage and a fairly involved filter to take out the 5, 10 and 20 MHz signals. Turning the 3X into a 2X (assuming you can find it) should be fairly easy. The doubler should be cleaner than the 3X, so less filtering would be needed. Working out their filter circuit might be easier than it looks. Right now it looks pretty complex to me. 

> Sorry about the screw up on the numbers.

Sorry I could not find any of these when you first posted about them….

> -Arthur
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