[time-nuts] FA-2 questions

[djl]

I agree completely. A friend and I each had one of these and thought 
there was something wrong with each of them. The dither at 10 MHZ 
compared to a gpsdo is approximately 10 Hz. We spent many hours with the 
manual trying to find the cause of the fm to no avail. It's just a bad 
design. Unsuitable for any time-nuts use. Maybe OK for fixing pre-sdr 
ham radios. The attenuator section is pretty good. Otherwise in today's 
world a boat anchor.
Don

On 2019-10-14 16:57, Didier Juges wrote:
> HP8656 and spectral purity should not be used in the same sentence. I 
> had
> one and the best band is VHF where it may be usable for SSB or NBFM if 
> you
> are not too picky. It gets worse from there going up. The worst is the
> lower band (HF) because it is actually the high band mixed down.
> 
> http://www.ko4bb.com/getsimple/index.php?id=comparing-the-hp-8656a-hp-8657b-and-hp-3586a
> 
> 
> Didier KO4BB
> 
> On Sat, Oct 12, 2019 at 10:07 PM David <mcquate at sonic.net> wrote:
> 
>> The hp8656 spectral purity may be a problem.  Residual FM for output
>> frequencies above 494MHz is < 15 Hz rms ( 0.3 to 3 kHz BW ).  (The B
>> version is better by about a factor of 2)
>> Dave
>> 
>> Perry Sandeen via time-nuts <time-nuts at lists.febo.com> wrote:
>> 
>> >Yo Bubba Dudes!,
>> >First, does the internal OCXO run when the power is turned off?
>> >Wrote:
>> >We are presently experimenting using a ISC570B  multiplier at 100 MHz
>> >and get 13 digits seeattached but the data out of the back is only 12
>> >digits reliable.
>> >Looking it up I found out that the ISC570B is a teeny - tiny IC which
>> >for me would pose a problem to implement.
>> >
>> >So looking at alternatives that I already had I came up with two
>> >possible alternative multiplier ideas.
>> >The first was to put the 10 MHz DUT into the external reference of my
>> >(boat anchor) HP signal generator set the output frequency to 200 MHz
>> >and put the output into the channel 1 input to get extra resolution
>> >digits.
>> >Expanding upon that, I came with more complex but what may be a better
>> >error multiplier reading since I have both signal generators on hand.
>> >First I feed the 10 MHz DUT signal into my Fluke 6080 setting the
>> >output to 1 GHz.  I'd then feed the reference 10 MHz signal into the
>> >external reference of my HP 8656 and set the output to 990 MHz.
>> >Next I'd feed both outputs into a
>> >AD8342 LF to 3.8GHZ Active Mixer Down conversion Output withBalun
>> >Transformer
>> >
>> >board from ebay ($23) and then feed the multiplied signal into channel
>> >1. (I may need a simple low pass filter.)
>> >
>> >
>> >This should give me a 100X error multiplication.
>> >
>> >
>> >Am I on the right track or am I missing something?
>> >
>> >
>> >Regards,
>> >Perrier
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >_______________________________________________
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>> 
>> 
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-- 
Dr. Don Latham  AJ7LL
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304