[time-nuts] HP3325B as LO for a transceiver or receiver? Phase noise?

[Jeff Blaine]

Take a look at the plots at the bottom of this page.

http://hpmemoryproject.org/technics/bench/3048/hp_sources_02.htm

Note the 8642b vs the 3325B.  The '42b has much lower ultimate noise far 
out but see how decent the 3325B is in comparison.  HP really made great 
stuff back in the day!!!

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com

On 01-Jan-19 5:32 PM, Jeff Blaine wrote:
> I was doing some DR3 testing of receivers fitted with additional 
> crystal filtering and at the time wanted to find a sig gen that was as 
> clean as the pair of xtal oscillators which were the baseline.  Of 
> course I never found anything that clean (at least not without 
> spending a fortune) but do remember the 3325B was exceptionally clean 
> close in.  The tradeoff of that as a source is that the noise floor 
> does not roll off nearly as fast as something like an 8657b.  It lacks 
> spurs close to the fundamental which are found in all the HP stuff of 
> the age at least until you get to the 864x stuff.
>
> The answer, as others mentioned, depends on what you are really trying 
> to do with that rig though.  If you want a quick LO source then I 
> would bet you will have a hard time showing the that rig's performance 
> is suffering with the 3325B as the LO.  At least not without some 
> pretty specific test criteria setup (e.g. DR3 testing vs. a pure xtal 
> source).
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
> On 01-Jan-19 3:33 PM, Artek Manuals wrote:
>> The question that remains begging here from the original post (maybe 
>> off topic ?) is how low a phase noise does he really NEED in this 
>> application? We here at time-nuts tend to think in the 10e-12 minutia 
>> area, but In this application ( a HF Communications receiver) the 
>> 3325B  may be "good enough" that PN wont really be an issue as a 
>> practical matter. Don't see who the original poster is from this 
>> snippet but a possible better place to get a "practical" answer might 
>> be over on the EEVBlog?
>>
>> Dave
>> manuals at artekmanuals.com
>>
>>
>> On 1/1/2019 3:38 PM, Brooke Clarke wrote:
>>> Hi Chris:
>>>
>>> The HP 8648 Signal Generator was developed to have low phase noise 
>>> that was needed for testing pagers.
>>> See second table of SSB Phase Noise at:
>>> https://prc68.com/I/HP8648.shtml
>>>
>>> -- 
>>> Have Fun,
>>>
>>> Brooke Clarke
>>> https://www.PRC68.com
>>> http://www.end2partygovernment.com/2012Issues.html
>>> axioms:
>>> 1. The extent to which you can fix or improve something will be 
>>> limited by how well you understand how it works.
>>> 2. Everybody, with no exceptions, holds false beliefs.
>>>
>>> -------- Original Message --------
>>>>
>>>>    01/01/2019 14:22
>>>>
>>>> Could I use my HP3325B locked to a Trimble Thunderbolt GPS disciplined
>>>> 10MHz oscillator as the master LO of my Kenwood TS-590S transceiver
>>>> that has a LO at 15.6 MHz, or is the phase noise too great? My VK3HZ
>>>> gps disciplened LO replacement died recently, I may be able to repair
>>>> it but as they are no longer available I am looking at alternatives to
>>>> achieve a very stable frequency. Thanks
>>>>
>>>> https://www.febo.com/pages/hp3325b/
>>>>
>>>> http://www.vk3hz.net/XRef/XRef_Home.html
>>>>
>>
>
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