[time-nuts] Lucent KS-24361 15 Mhz and 10 Mhz

Tue Dec 2 02:05:35 UTC 2014

Hi

My *guess* from looking at roughly how the circuit runs from the OCXO to  the 15 MHz power amp and then over to the output connector:

1) There is a fairly complicated filter on the output of the amp. It might have traps in it for 5, 10 and 20 MHz. No need for all those parts in a doubler….

2) What ever is turning 5 into 15 MHz is doing a good job. If it can be tweaked to double rather than triple that could move things forward quite a bit.

3) If the 15 MHz is used by the “rest of the box” it’s not on any of the pins I poked. There are a lot of pins, so I could have missed something. 

Obviously my hope is to find a magic IC and move this pin or that pin to somewhere else. Now it doubles rather than triples. The rest of the box runs fine. Then you start pulling out coils or caps in the output filter. 

Lots to dig into. 

Bob

> On Dec 1, 2014, at 7:54 PM, paul swed <paulswedb at gmail.com> wrote:
> 
> Bob
> I really have the board setup now for digging in. You are right the 10 Mhz
> going into the 74act14 pin 1 is dirty. By this I mean transistors 208 and
> 209 that amplify the 10 Mhz are over driven and thats intended. The second
> harmonic is only 20 db down. The actual 5 to 10 Mhz is Q202. Following the
> collector, goes through a number of filters. At the top of the filter a
> inductor 150J and another R22J goes to a small coupling cap and ultimately
> to Q209.
> 
> To the side of the coupling cap away from Q209 the 10 Mhz signal is 500mv
> pp and the other signals are 39 db down. That looks like an interesting
> point to work with.
> 
> As sugested it would be good to leverage the output amplifier of the unit
> and that seems like a pretty reasonable thing to look at. Plus there would
> be no need to drill another hole for a connector.
> Need to figure out how to snitch a bit of the 10 Mhz signal and then buffer
> and isolate it.
> Regards
> Paul
> WB8TSL
> 
> On Mon, Dec 1, 2014 at 6:37 PM, Bob Camp <kb8tq at n1k.org> wrote:
> 
>> Hi
>> 
>> Yes, one of the “great unanswered questions” about the KS boxes is how to
>> quickly and easily switch them from a nice clean (useless) 15 MHz output to
>> a nice clean (useful) 10 MHz. The circuit appears to be all discrete
>> analog. That suggests that a “jumper this, swap that” approach might work.
>> 
>> Bob
>> 
>>> On Dec 1, 2014, at 10:11 AM, paul swed <paulswedb at gmail.com> wrote:
>>> 
>>> To address the one question Ref1s have no 10 Mhz. Just 15 MHz.
>>> I have reversed out the various paths but it seems so have others. Must
>>> have missed that thread. I do see the 5 to 10 doubler is in the q200-q203
>>> region. I can't speak to the qualities of the signals and still have not
>>> found the magical X+Y= 15 Mhz.
>>> So what are folks doing that just have ref 1s?
>>> Is this the discussion on buffering the 5 Mhz and doubling?
>>> Regards
>>> Paul
>>> 
>>> On Mon, Dec 1, 2014 at 7:43 AM, Bob Camp <kb8tq at n1k.org> wrote:
>>> 
>>>> Hi
>>>> 
>>>> Given the level of phase noise on the Ref-0 10 MHz output, I would not
>>>> *want* to use the same pin they get that off of ….
>>>> 
>>>> Bob
>>>> 
>>>>> On Dec 1, 2014, at 6:25 AM, Götz Romahn <goetz at g-romahn.de> wrote:
>>>>> 
>>>>> @ Paul
>>>>> yes pin 1 of U206 is the input of a schmitt-trigger ( xxACT14 ) where
>>>> the rectangular 10 MHz output on the Ref-0 Modul is generated.
>>>>> 
>>>>> @ David
>>>>> 10 MHz is not available on the Ref-1 module, the one with antenna input
>>>> (yea, but it is still at pin 1 of U206).
>>>>> 
>>>>> Götz
>>>>> 
>>>>> Am 01.12.2014 04:09, :
>>>>>> OK so it was not as hard as I thought getting all of teh screws out.
>> The
>>>>>> harder part is getting the actual board to slip out of the back.
>>>>>> After getting to the bottom I found a locked 10 Mhz signal on U206
>> pin 1
>>>>>> somewhat of a sine wave but compressed top and bottom at 5 V and pin
>> 2 a
>>>>>> squared up version. Pin 1 goes off to several transistors. Also I have
>>>> not
>>>>>> looked at the rest of u206.
>>>>>> So good or bad a tracking 10 Mhz exists. Not so easy to get to
>> frankly.
>>>>>> Regards
>>>>>> Paul
>>>>>> WB8TSL
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