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

W4wj at aol.com W4wj at aol.com
Tue Nov 18 11:29:49 EST 2014

Hello all...
Just getting up to speed on the KS-24361...
My stupid question (s)...
Where does the GPS antenna connect??
Does the GPS antenna port power the antenna?
Need a replacement for my dead HP Z3816A...   ;-(

In a message dated 11/18/2014 3:26:52 A.M. Central Standard Time,  
mark at alignedsolutions.com writes:

One of  my Z3805's (with the double oven 10811 ocxo iirc) also performs 
similarly at  times to the 58503A mentioned by Said.   From an adev perspective 
 it's close to my BVA at some tau's (around a hundred seconds or so  iirc.) 
 At times though the output seems to "jump" in  frequency.   My other Z3805 
from the same source doesn't work as  well.

None of the 10811's in my various pieces of test gear (some of  which I 
basically purchased to get the 10811's) worked all that well from an  Adev 
perspective.  I used to buy HP5328 counters on the usual auction  site with 
10811's and the 500MHz C channel for quite low prices.     At least I still have 
a nice collection of frequency counters.

Sent  from my iPad

On 2014-11-17, at 1:23 PM, Said Jackson via time-nuts  <time-nuts at febo.com> 

> Correct on all counts  Bob.
> My two 58503A units from China are great for both ADEV  and PN 
measurements, better than anything else I have as a combo (I have  Wenzel ULNs for 
even lower PN testing but they don't have any usable  ADEV).  I also have a 
costly BVA and it can't compete against the HP  unit.
> Those 10811s just rule.
> In fact my  only complaint about the 58503A are the 60Hz related small 
spurs you can see  in the plots...
> Bye,
> Said
> Sent From  iPhone
>> On Nov 17, 2014, at 12:28, Bob Camp  <kb8tq at n1k.org> wrote:
>> Hi
>> The 58503 is a Z3801 with a pretty instrument style package put  around 
it - right?
>> If so, it might / should   have a 10811 in it rather than an MTI OCXO. 
The 10811 is rated for -155 dbc at  100 Hz. That is much better than the 
noise floor that the MTI’s seem to  produce at 100 Hz. About the only other 
GPSDO OCXO that gets to that level is  the one in the original TBolts . There 
you very much have to deal with spurs.  That make the noise floor of limited 
use in a practical system. 
>> Bob
>>> On Nov 17, 2014, at 2:26 PM,  SAIDJACK at aol.com wrote:
>>> Hi  Bob,
>>> yes, the 10MHz plot is rotten, no doubt.  The 15MHz plot is quite good 
till about 40Hz offset, then it becomes pretty  rotten too.
>>> Here is one of my 58503A units  (using the 10811 OCXO) as a 
comparison.. measured against our DROR-IIA (this  plot was actually done to show the 
DROR-IIA PN, but since that unit actually  has less noise and spurs than the 
58503A we can simply use it as the reference  for this purpose).
>>> The good news is that  getting the close-in phase noise to be good is 
very hard to do and the unit  delivers that out-of-the box already. Filtering 
out the noise and spurs above  40Hz offset is pretty easy to do. It should 
be fairly straight forward to  cobble up a small PN filter for those units 
to get rid of the noise and spurs  above 40Hz offset.
>>> bye,
>>>  Said
>>> In a message dated 11/17/2014 09:31:46  Pacific Standard Time, 
kb8tq at n1k.org writes:
>>>  Hi
>>> Here’s the phase noise on the 15 MHz.  There are a few spurs, and an 
very real hump out at the likely frequency of  the Lucent switcher.  The 15 
MHz is pretty clean compared to most /all of  the other units I’ve seen on the 
surplus market. 
>>> I would not multiply this up to 40 GHz with a broadband  multiplier. I 
would be quite happy to run it into a PLL with a rational  bandwidth. You 
will beat the noise on the output with a fairly simple VHF VCXO  past 100 Hz. 
No reason to have a bandwidth outside the 20 to 80 Hz range.  
>>> Math:
>>> 15  MHz to 150 MHz -> 20 log (N) -> 20 db.
>>>  -140 dbc / Hz shown below at 100 Hz offset -> -120 dbc/Hz
>>> You can get numbers better than -120 dbc/Hz at 100 Hz offset  out of a 
number of pretty simple VHF VCXO circuits. Bert has one that seems to  work 
fine for him. 
>>> Bob
>>> <DROR-IIA_Phase_Noise.png>
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