[time-nuts] modification Lucent RFTG

[Jörg Logemann]

Paul,
thanks for your reply. I did not cut any trace on the pc board. The
separation from the 15MHz signal is done by removing the 10nF capacitor.
Yes, the short line leeding to the cap is still there but this little
"stub" has no effect. Of course the line can be cut, but I like to "keep
all doors open" if I want to remove the modification one day, hi. With
the video amp you will have more power compared to my solution, also a
good way... I will build a distribution box with 9 outputs for the 10MHz
signal (4 powersplitter 1to3) and thus will need another amplifier.
Perhaps you could make it passive because of more gain.

73
Joerg
DL2NI

Am 13.12.2015 um 16:21 schrieb paul swed:
> Joerg
> Yes this looks like a nice simple mod.
> Its difficult to tell from the pictures but in order to use the sma it
> looks like you cut the trace over by the cap.
> I ran into the same thing. The lead goes into the board and its end point
> is unclear.
> When I released a solution about 9 months ago I used a video op-amp. This
> gave gain and drive. But with more complexity.
> It is a bit of a challenge to slip the boards in and out.
> Thanks
> Paul
> WB8TSL
>
> On Sun, Dec 13, 2015 at 6:00 AM, Rex <rexa at sonic.net> wrote:
>
>> Joerg,
>>
>> This looks like a very useful mod on a unit that many of us have. I'm not
>> aware of any schematics available for these, so I guess you have
>> reverse-engineered the "black"  part of the schematic that you provided. --
>> Nice work!
>>
>> Having said that, may I offer some minor criticism (constructive and
>> positive, I hope) of your document?
>>
>> The schematic you provided shows the key transistors as Q1 and Q2. In the
>> text you refer to Q208 and Q209 (which I think are marked on the board).
>> From the description, I think Q1 = Q208 and Q2 = Q209. It would be nice if
>> the schematic had the Q-numbers changed, or at least, you mentioned the
>> equivalence in your text.
>>
>> (Trivial) Aren't you using an existing SMA connector for your output? So,
>> maybe it should be black in the schematic.
>>
>> Your picture of the board rework is pretty low resolution; even zooming
>> into it just gives bigger blurry image. You have added some annotations but
>> they are in red over the green board color. Combined with the low
>> resolution they are very hard to read. I'm pretty sure they remain in
>> German in the English version too.
>>
>> My suggestions:
>>     - Edit the schematic to change the Q-numbers to match the board and
>> text, or at least give the equivalence in the text.
>>     - Use a higher resolution picture and make the annotations more
>> readable with different color or background shading.
>>     - The picture you provide is "after". It would be nice to also have
>> "before". If you don't have a before picture, I or some other member could
>> probably take one.
>>     - Consider having picture annotations in English for the English
>> version.
>>
>> I think what you have done is great. I just think the sharing document
>> could be improved to make it easier for others to duplicate.
>>
>> If you like, I could possibly help make a more readable annotated picture
>> if you can provide me a higher res picture of the board. Just an offer to
>> help if you would consider my suggestions. I think you will see my email in
>> my post.
>>
>> -Rex   KK6MK
>>
>>
>>
>> On 12/12/2015 4:39 PM, Jörg Logemann wrote:
>>
>>> Hi,
>>> I worked out a modification of the Lucent GPSDO to get 10MHz out of it
>>> which I offer to the community. The article is available in english and
>>> german (attached).
>>>
>>> best 73
>>> Joerg, DL2NI
>>>
>>>
>>>
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-- 
Dipl.Ing.(FH) Jörg Logemann 
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D-89150 Laichingen 
Germany 
Tel. +49 7333 922506 
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mail: joerg.logemann at t-online.de