[time-nuts] FRK specs.....

Brian, WA1ZMS wa1zms at att.net
Sun Aug 12 15:03:47 EDT 2012


Me too, please.


-Brian, WA1ZMS

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of dlewis6767 at austin.rr.com
Sent: Sunday, August 12, 2012 2:55 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] FRK specs.....


Bert:
Interesting.

I, too, have a couple of the HP 10811 oven-oscillators sitting on the shelf
for several years, ....waiting for a project. I want to 'discipline' them,
but really do not know how.

Could you kindly mark up the HP 10811 schematic and/or please tell me what
to cut, ... what to jumper???

Thanks a lot!

Don Lewis
Austin, TX



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---- EWKehren at aol.com wrote:
> In the commercial world a PRS10 is most likely the best but for time 
> nuts even at the surplus price in my opinion it is all hype and a 
> waste of money. Have you looked closely at the specification and the 
> design. Frequency accuracy can not be better than 1 E-12 since the 
> OCXO is driven strictly by a DAC and the A/V is for time nuts nothing 
> to write home about. Any digital loop controlling a Rb in tern with an 
> analog loop controlling a selected HP 10811 or for that matter a Morion
will outperform a PRS 10.
> I have a FRK-H controlling a HP 10811 that has an A/V below 1 E-12 
> from 1 to 100 seconds, I modified the FRK loop and the 10811. On the 
> 10811 it is easy to get to the bottom PCB and without un soldering any 
> component or further disassembly cutting two traces and two jumpers 
> you end up with a 2 to 12 Volt tuning voltage, perfect for a FRK or 
> M100.. A second option is to use a separate analog loop with a time
constant suitable for your OCXO.
> By the way the FRK-H is not lower noise but factor 2 lower aging with 
> the proper OCXO not an issue, since hopefully you discipline it with GPS.
> For 12 years I have used Shera in that application recently switching 
> the DAC to a LTC1655. Has served me well over the years.
> Other Rb's will do also a very credible job. On one extreme a FEI 5680 
> is waiting to be integrated with a MV180 on the other extreme a HP5065 
> RVFR assembly will be integrated with a M1000 OCXO along with state of 
> the art circuitry.
> Bert Kehren
>
>
>
> In a message dated 8/12/2012 8:09:54 A.M. Eastern Daylight Time, 
> wa1zms at att.net writes:
>
> Thanks Tom.
>
> I agree, the SRS seems to be the best
> overall Rb except maybe on old HP if one is willing to spend about the 
> same price on a 20 year old unit. The SRS units I bought for work were 
> only
> $2700 with chassis, rack ears and multiple outputs.
>
>
>
> -Brian, WA1ZMS
>
> On Aug 12, 2012, at 3:17 AM, Tom Knox <actast at hotmail.com> wrote:
>
> >
> > Hi Brian;
> > There are a few decent rubidium oscillators short term like the SRS 
> > but
> none are great, in my humble opinion you are much better off 
> disciplining a good quartz oscillator off your LPRO.
> > Best Wishes;
> > Thomas Knox
> >
> >
> >
> >> From: wa1zms at att.net
> >> Date: Sat, 11 Aug 2012 21:56:13 -0700
> >> To: time-nuts at febo.com
> >> Subject: [time-nuts] FRK specs.....
> >>
> >> I used to be of the opinion that the Efratom FRK-H was the best of 
> >> the
> models of FRK Rb standards for both short-term stability and overall 
> performance.
> >>
> >> Is that still true today?
> >>
> >> I know there are better solutions for short-term (BVA OCXO) and 
> >> long
> term
> >> (Cs & MASERS). But where to things stack up today?
> >>
> >> I'm looking to buy an Rb that's better than my LPROs and other models.
> >> But I do not own an FRK-H.
> >>
> >> Looking for comments, please.
> >>
> >> Thanks in advance,
> >> -Brian, WA1ZMS
> >> _______________________________________________
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> >
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