[time-nuts] HP-5065a advise and purchase decision

[Edgardo Molina]

Dear Chris,

Thank you for your advise. Yes I have seen the Ebay units below a  
hundred dollars. I have been attracted by those units, but I have been  
unable to find a USA seller. Most of them are being offered by chinese  
ebayers. I haven't ordered anything from China through Ebay yet. Still  
I can order anything from the USA.

I have seen frequency adjustable units. 1Hz to 20Mhz. I am still in  
diapers in this field of time and frequency experimentation. I am  
building a couple of nixie clocks and plan to do some disciplining  
using Rubidium, GPS and WWVB. Among all those second hand rubidium  
modules, could you please share some advise on brands & models? There  
are so many variations. I am aware most of them are in their end of  
life cycle. I have learned some can be restored by using focalized  
heat on the Rb cells. Still I haven't made a decision. I have a decent  
electronics lab at home and could build or test those units to find  
their best abilities. Interesting how nowadays those frequency  
standards are so readily available.

Your kind comments are always welcome. Thank you all for taking the  
time to share ideas and advise with me. I promise to keep the thread  
up to the expected standards.

Regards,



Edgardo Molina
XE1XUS



On Jun 30, 2012, at 2:58 AM, Chris Albertson wrote:

> Have you checked the price of comparable units in eBay.  Many of us  
> bought
> some quite usable Rb oscillators for $40 each but I think the price  
> might
> be up to $60 by now.
>
> On Fri, Jun 29, 2012 at 11:27 PM, Edgardo Molina <xe1xus at amsat.org>  
> wrote:
>
>> Dear Group,
>>
>> Good morning. I wish you well. This is my first post to the Time-Nuts
>> group. Please be gentle with the newbie ;)
>>
>> I have been offered an HP 5065a Rubidium Frequency Standard  
>> recently in
>> what I feel, a bad operational condition. I need a reliable rubidium
>> standard for my time/frequency experiments, still I am in doubt to  
>> invest
>> in buying such and old beast. The general situation of the  
>> instrument (for
>> what I have been able to see from the first inspection) is:
>>
>> 100 Khz output: Not working, noise coming out of it.
>>
>> 1Mhz output: Working, sine wave clean and not distorted, a couple of
>> frequency meters showing 1.0000030 Mhz in frequency, the  
>> oscilloscope shows
>> a transient pulse on top of the sine wave signal and affecting the
>> frequency readout instantly and then returning to the value  
>> previously
>> mentioned. Last digits vary sporadically.
>>
>> 5Mhz output: Working. sine wave clean but a little bit distorted when
>> ramping up. A couple of frequency counters showing 5.0000014 Mhz in
>> frequency. No transient pulses or other glitches around the output  
>> signal.
>> Last digits vary sporadically.
>>
>> No lights coming up when the instrument turned on. No physical  
>> damage of
>> abuse on case or internal components. No options installed . A  
>> couple of
>> electrolytic caps replaced on some boards, no trace of burnt PCB  
>> traces or
>> visible damage to electronic components or physics package. Haven't  
>> got the
>> manual until today and was unable to check on the front panel  
>> voltages to
>> check on general health. As turning the voltage test selector knob,  
>> voltage
>> is shown for most positions, except of course battery and the 100 Khz
>> oscillator output. Some voltage test positions get the instrument  
>> needle to
>> go full scale and out of range, other appear to be within scale.
>>
>> I can perform a second visual and operational inspection today,  
>> this time
>> with a copy of the instrument manual. I will take my own trusted  
>> frequency
>> counter and portable digital storage oscilloscope. Would really  
>> appreciate
>> if I could receive comments from you experts to evaluate if such a  
>> unit
>> could be worth buying. The asking price is $1K USD. Should I  
>> consider it an
>> instrument that can be repaired and serviced to show some decent
>> performance? Or should I look somewhere else to get a decent rubidium
>> frequency standard.
>>
>> Thank you beforehand for all your kind and expert comments.
>>
>>
>> Respectfully,
>>
>>
>>
>> Edgardo Molina
>> Mexico City, Mexico
>>
>>
>>
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>
>
> -- 
>
> Chris Albertson
> Redondo Beach, California
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