[time-nuts] Looking for datasheet for Oscilloquartz 8602

Bob Camp lists at rtty.us
Tue May 28 12:29:14 EDT 2013


The cost of a BVA oscillator is primarily a function of the cost of the
blank used and secondarily a function of the resonator processing. You see
numbers in the $200 to $400 range tossed around for the blank (vs < $10 for
a good SC blank). The packaged resonator starts looking like $600 to $900
once you have that sort of blank in it (vs < $20 for a similar SC). BVA's
are never going to be cheap or plentiful. 

I think you will find a number of people selling 5 MHz OCXO's in the -110 to
-120 dbc/Hz at 1 Hz range. That's not really where the BVA is needed. It's
benefit is more in the 0.1 or 0.01Hz phase noise. Put another way, ADEV is
the better tool to rate a BVA. 

If you really want to get any resonator (or even an atomic standard) to look
good on ADEV at 1 to 10,000 seconds, it needs to be temperature stable.
Either it needs a really good oven, or you need a lab that doesn't change
temperature. For good ADEV in a normal environment, that means a "hockey
puck" style single oven, or a good double oven. Again, a cost adder /
greater scarcity thing. 

Given all that, a BVA that gives you < 1x10^-13 from 1 to >1,000 seconds in
a normal lab is a very rare item. What ever the cost, it's going to be
pretty steep.  


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Tom Knox
Sent: Tuesday, May 28, 2013 11:55 AM
To: Time-Nuts
Subject: Re: [time-nuts] Looking for datasheet for Oscilloquartz 8602

I think that used BVA pricing is difficult since prices of really good
quartz is to me exponential. What the BVA offers is exceptional close in
phase noise. And because of their reputation any BVA listed on eBay will get
some serious bids. I would find it interesting to see what a couple nice
8607 would sell for on eBay. I know I would pay dearly, and I doubt I would
be up with the highest bidders. But today companies like Wenzel offers
exceptional performance at much more reasonable prices.  So based on Phase
Noise alone an older 8600 could  be much less. The other big thing is find a
BVA for sale. They rarely become available used and I would say it is a
seller market.  That said none of us time nuts have jumped on the chance to
buy the one currently on eBay at $4500, so everyone seems to agree that is
to expensive. But if you are lucky enough to own a BVA what would you sell
yours for? I imagine that in view of what you would sell for the guys $4500
price looks a bit more 
 le.  I guess my question is what would you pay and what have you paid for a
5MHz oscillator with -120dB @1Hz? what about  -130dB @1Hz? what about -135dB
at 1Hz?

Tom Knox
> Date: Tue, 28 May 2013 09:27:55 +0200
> From: magnus at rubidium.dyndns.org
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] Looking for datasheet for Oscilloquartz 8602
> On 05/28/2013 06:57 AM, Attila Kinali wrote:
> > Moin,
> >
> > On Sun, 26 May 2013 18:15:22 +0200
> > Magnus Danielson<magnus at rubidium.dyndns.org>  wrote:
> >
> >> The OSA 8602 is a variant of the OSA 8600 and 8601. These variants is
> >> mainly on the connection on the "front".
> >>
> >> I don't have a 8602 datasheet as such, but I have some 8602 related
> >> specs as found in the extended OSA 3000 manual.
> >>
> >> It is essentially the same AT-cut oscillator that you can expect from
> >> the 8600 base.
> >
> > Hmm.. IIRC AT cut oscillators have the "problem" of frequency jumps
> > on slight temperature changes. Using an AT cut oscillator thus kind
> > of defeats the effort of doing a BVA.
> Frequency jumps isn't a particular feature of AT cut, but rather to 
> cleanness of the crystal and mechanical stresses. The BVA strategy aims 
> to reduce systematic shift, it is then baked out to remove residues that 
> is known to cause issues. There is a good article on it amongst the PTTI 
> papers. Also, it's an oven within a dewar flask, so temperature 
> conditions is pretty stable. The AT-cut BVA is far from the same thing 
> that a typical TTL-can AT-cut is. There seems to be an overbeleif in the 
> cut and not look at all the other things that needs to come together to 
> make a great oscillator.
> >> What information are you really seeking?
> >
> > What such an oscillator would be worth :-)
> > You might be aware that there is one 8602 on sale on ebay for 4500USD.
> > I asked Oscilloquartz about that and from what i gathered, it's
> > not worth that money. For slightly more you can get a new 8607 already.
> > The 8602 worth is probably around 150 to 200USD.
> That is overpriced. An OSA 8602 should have about the same price as OSA 
> 8600, whatever the going price of that is.
> Cheers.
> Magnus
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