Re: [time-nuts] ANN: UK MSF 60 kHz interruption, 2012 June 14

[Tom Van Baak]

LF diurnal variations are considerable, in the many microseconds
range. Thus any claim of parts in 10^13 or 10^14 or 10^15 accuracy
is misleading.

Even one microsecond of atmospheric phase change over an hour
is equivalent to a 2.7e-10 apparent frequency offset. Cal labs that
still use LF signals average over an integral number of days to try
to reduce this effect. Or they upgrade to GPS where diurnal variations
are a hundred to a thousand times less.

/tvb



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Re: [time-nuts] ANN: UK MSF 60 kHz interruption, 2012 June 14

[David I. Emery]

On Sun, Jun 03, 2012 at 09:20:59AM -0700, J. Forster wrote:
> Is there any indication the carriers of WWVB and MSF are locked together?
> 
> -John
> 
> =

Given it's only 60 KHz and certainly somewhere north of parts in
10^13 and probably  down to 10^14 or 10^15 the distinction kinda escapes
one.

They may not be locked to each other, but are so close in
frequency that relative drift would be AWFULLY slow... especially if its
more like 10^15 from primary maser standards...

There are only 5.184 * 10^9 cycles of 60 KHz  in a day after
all... and it takes a while for a error of a few parts in 10^15 to
pile up to one whole cycle...



-- 
  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."


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[time-nuts] Fwd: GPS and Rubidium frequency standards and noise question (new...

[EWKehren]

 
I would not use a Thunderbolt. It dithers the OCXO frequency to correct  
the second pulse and that frequency change will be multiplied particularly in  
U wave applications.. I have never checked, but if LH has a hold function  
you could use it, but in that case I would also bring out the OCXO direct 
and  amplify external if you plan on using it 1 GHz and above, if so contact  
me off list
Bert Kehren 
 
 
In a message dated 6/3/2012 5:59:35 P.M. Eastern Daylight Time,  
ch...@chriswilson.tv writes:



> Hi

> For your immediate need, a  Thunderbolt sounds like the ideal
> solution. It will give you a very  accurate reference to sort out
> your test gear and likely "good  enough" phase noise for most of the
> rest of what you want to do.  Once you get into the microwave stuff,
> plan your PLL's properly and  all will be well there.

> Bob

OK, I'll go for a  Thunderbolt, is it allowed and acceptable etiquette to
show an Ebay ad to  check it's the later type, which I think it is?

You have all been a  great help, thank you very much indeed, I doubt I
will become as  obsessive with accuracy as some of you apparently are,
but it's good to  know that such a friendly and sharing group of
experts exists in one  locale!


03/06/2012 22:50



-- 
Best Regards,
Chris  Wilson.


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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (new...

[Bob Camp]

Hi

I think that if you switch to an averaging of a few seconds from "per pixel" 
the plot of frequency difference will look a bit different. The phase 
perturbations from DDS will still be there, and they are an issue. They just 
many not be as dramatic as that plot implies.

Bob

On Jun 3, 2012, at 8:14 PM, ewkeh...@aol.com wrote:

> The  FEI 5680A we recently discussed uses the DDS to generate  part of the 
> excitation to the filter. Fine stepping the excitation  frequency.  The 
> output is taken off the 60 MHz and divided by 6. I noticed  the changes when 
> doing my aging tests but some disagreed. The attached I think  it is from 
> John 
> Miles shows it very clearly and what is needed is a clean up  loop with some 
> thing like a MV89. I think the source is the control loop which  most 
> likely is digital. FRS and FRK are analog but will also improve with an  
> external 
> OCXO.
> Bert Kehren
>>> The FEI-5680A Rubidium that we discussed here  some time ago has a much
>>> worse phase noise plot of course, because  the 10MHz is generated 
> digitally
>>> through a DDS, not a 10MHz crystal  oscillator..
>>> 
>> There is a version that generates 10MHz  directly through DDS, but the 
> particular version we recently discussed a lot  about generates the 10MHz 
> signal from a 60MHz oscillator, and the DDS is used  for generating the 
> ~5.3125MHz signal for mixing with the 114th harmonic of the  60MHz to obtain 
> the Rb 
> resonance frequency.
>> 
>> I don't remember if  someone did a comparison in PN performance between 
> the two FE-5680A  flavours.
>> 
>> Regards,
>> 
>> Javier
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Bob Camp]

Hi

As long as it shows "rev E" or "rev D" it's likely a later version unit. The 
date code on the OCXO is the best indicator, but even that's not 100%. As long 
as it's one made after about 2002 you will have a good one. 

Bob
On Jun 3, 2012, at 5:58 PM, Chris Wilson wrote:

> 
> 
>> Hi
> 
>> For your immediate need, a Thunderbolt sounds like the ideal
>> solution. It will give you a very accurate reference to sort out
>> your test gear and likely "good enough" phase noise for most of the
>> rest of what you want to do. Once you get into the microwave stuff,
>> plan your PLL's properly and all will be well there.
> 
>> Bob
> 
> OK, I'll go for a Thunderbolt, is it allowed and acceptable etiquette to
> show an Ebay ad to check it's the later type, which I think it is?
> 
> You have all been a great help, thank you very much indeed, I doubt I
> will become as obsessive with accuracy as some of you apparently are,
> but it's good to know that such a friendly and sharing group of
> experts exists in one locale!
> 
> 
> 03/06/2012 22:50
> 
> 
> 
> -- 
>   Best Regards,
>   Chris Wilson.
> 
> 
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Chris Wilson]

> Hi

> For your immediate need, a Thunderbolt sounds like the ideal
> solution. It will give you a very accurate reference to sort out
> your test gear and likely "good enough" phase noise for most of the
> rest of what you want to do. Once you get into the microwave stuff,
> plan your PLL's properly and all will be well there.

> Bob

OK, I'll go for a Thunderbolt, is it allowed and acceptable etiquette to
show an Ebay ad to check it's the later type, which I think it is?

You have all been a great help, thank you very much indeed, I doubt I
will become as obsessive with accuracy as some of you apparently are,
but it's good to know that such a friendly and sharing group of
experts exists in one locale!


03/06/2012 22:50



-- 
   Best Regards,
   Chris Wilson.


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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Bob Camp]

Hi

For your immediate need, a Thunderbolt sounds like the ideal solution. It will 
give you a very accurate reference to sort out your test gear and likely "good 
enough" phase noise for most of the rest of what you want to do. Once you get 
into the microwave stuff, plan your PLL's properly and all will be well there.

Bob

On Jun 3, 2012, at 2:19 PM, Chris Wilson wrote:

> 
> 
> 
> 
> 03/06/2012 19:09
> 
> Thanks for the great replies! My immediate need is to check some used
> test equipment I have bought, a Racal dana 9908 counter and a Marconi
> 2019A signal generator. They don't agree with one another! I was going
> to get a Thunderbolt unit and PS, but my friend mentioning noise got
> me worried. I may have a play with some SDR gear and I know they can
> be locked to a standard i you have one. Longer term my aim is to have
> a play with microwaves, which is what this friend is into, and maybe
> he has a particular issue with noise with sort of multiplication he is
> using? The fact that a GPS reference can be always on and locked to a
> reference that someone else maintains, if I understand things correctly,
> if simplistically, appeals. I am happy to be guided though, and I
> suppose I could always get a different type later if the specific need
> arose, although I am not made of money ;)
> 
> Thanks!
> 
> 
> 
> -- 
>   Best Regards,
>   Chris Wilson.
> 
> 
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Re: [time-nuts] Rapco 1804m

[Paul Flinders]

On 03/06/12 21:41, gandal...@aol.com wrote:

  I have several of these, all work well, all take some time to settle down 
after the control LED comes up. I can't remember now if any of mine have shown 
fine either but have compared all with a trio of Thundebolts and all work well 
as I say.
There's a manual for the Rb version available from at least two of the UK Ebay 
suppliers so worth asking if you bought from there. All you need is in the 
manual and the Rb command set is very similar to the OCXO version but I can let 
you have a pdf copy of the proper OCXO version manual next week if you don't 
get one before then.
I'm away from home right now and internet is very hit and miss here but will be 
back Wednesday.
regards
Nigel
GM8PZR
With many thanks to David and Björn (both of whom can claim the beverage 
of their choice if we ever meet) I have a couple of copies of the manual 
which I'm now reading.


I did contact the vendor - twice - although to be fair the second time 
was only this morning. However, as yet, I haven't had a reply. There 
seems to be only one seller on ebay at present - pre sales and delivery 
10/10- but after sales is falling into the "6/10 could do better" category.


My current plan is a better antenna with a better position.

Thanks once again to all.

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Re: [time-nuts] Rapco 1804m

[gandalfg8]

 I have several of these, all work well, all take some time to settle down 
after the control LED comes up. I can't remember now if any of mine have shown 
fine either but have compared all with a trio of Thundebolts and all work well 
as I say.
There's a manual for the Rb version available from at least two of the UK Ebay 
suppliers so worth asking if you bought from there. All you need is in the 
manual and the Rb command set is very similar to the OCXO version but I can let 
you have a pdf copy of the proper OCXO version manual next week if you don't 
get one before then.
I'm away from home right now and internet is very hit and miss here but will be 
back Wednesday.
regards
Nigel
GM8PZR


Hi

Just joined the list - recently acquired a Rapco 1804m, mainly to use as 
a frequency standard, especially to have something to check the FE-5680A 
that I have.

The unit itself seems to work OK - connected to a cheapie puck style GPS 
antenna I got a 2D fix, occasionally 3D which corresponded pretty well 
with my actual location and "Coarse" oscillator lock, but never "Fine". 
It's the version with an OXCO rather than local Rubidium oscillator.

I've read David Taylor's notes and had a hunt through the list archives 
- I suspect I need a slightly better antenna, or a better position for 
the one I already have. It had a decent enough view southwards/southwest 
but somewhat obstructed to the north and north-east and comparing the 
visible satellites on my 'phone it was certainly the 
northerly/north-eastern ones that had low or no signal strength.

However I could really do with a copy of the manual, at least to 
understand the difference between "Coarse" and "Fine" locks on the 
oscillator - does anyone have an electronic copy that they would be 
willing to let me have? Or a physical copy - I'm happy to pay a 
reasonable sum.

Also is the serial protocol for these documented anywhere?

 

 

 

-Original Message-
From: Paul Flinders 
To: time-nuts 
Sent: Sun, 3 Jun 2012 11:16
Subject: [time-nuts] Rapco 1804m


Hi

Just joined the list - recently acquired a Rapco 1804m, mainly to use as 
a frequency standard, especially to have something to check the FE-5680A 
that I have.

The unit itself seems to work OK - connected to a cheapie puck style GPS 
antenna I got a 2D fix, occasionally 3D which corresponded pretty well 
with my actual location and "Coarse" oscillator lock, but never "Fine". 
It's the version with an OXCO rather than local Rubidium oscillator.

I've read David Taylor's notes and had a hunt through the list archives 
- I suspect I need a slightly better antenna, or a better position for 
the one I already have. It had a decent enough view southwards/southwest 
but somewhat obstructed to the north and north-east and comparing the 
visible satellites on my 'phone it was certainly the 
northerly/north-eastern ones that had low or no signal strength.

However I could really do with a copy of the manual, at least to 
understand the difference between "Coarse" and "Fine" locks on the 
oscillator - does anyone have an electronic copy that they would be 
willing to let me have? Or a physical copy - I'm happy to pay a 
reasonable sum.

Also is the serial protocol for these documented anywhere?

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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Chris Albertson]

On Sun, Jun 3, 2012 at 11:19 AM, Chris Wilson  wrote:

>
>
>
>
> 03/06/2012 19:09
>
> ...My immediate need is to check some used
> test equipment I have bought, a Racal dana 9908 counter and a Marconi
> 2019A signal generator. They don't agree with one another! I was going
> to get a Thunderbolt unit and PS, but my friend mentioning noise got
> me worried.
>
>
A Thunderbolt is pretty much a turn-key solution for you.  Just add an
atenna and power supply.  On thing is you can both of those to be good.
 The PS should be a "clean" and the antenna needs to have a full view of
the entire sky for best result.

Here is some real date on the Thunderbolt.  You can decide if it is noisy
or not (noisy being a relative term.)http://www.ke5fx.com/tbolt.htm





-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Stan, W1LE]

Hello Chris,

You are on the right track.

I have had the Trimble Thunderbolts (3 each) for about 5 years now.
Just to be sure everything compares favorably
I use Lady Heather PC software to monitor their performance (de KE5FX 
website)


Stay tuned to this reflector, lotsa interesting discussions.

For me, it all started when I needed better than 1 Hz accuracy to  monitor
the 137 KHz band for local experimental activity.

the 10 MHz from the GPS/DO was the external reference to the HP-3336B 
synthesizer
as a RF test signal to calibrate my RX (IC-706MK2 and a IC-703+) and PC 
soundcard.
Spectrum Lab PC software has a provision to calibrate the PC soundcard, 
for greater accuracy,

but you have to have a very accurate signal source.

Then there are the FMT-Nuts, frequency measuring contest nuts, who are 
getting better than 1 milliHz
frequency measurement accuracies on intercontinental (US) HF 
communications !!


I was also doing LORAN-C receiving and could achieve Cesium accuracy,
at least 2 orders of magnitude greater accuracy than a GPS/DO.
But US/Canadian  based LORAN went off the air, but it is still available 
in Europe.

I do not know where you are located, so maybe LORAN has potential for you.

AUSTRON made a variety of LORAN-C receivers, 2100F, 2100(R), 2000, etc
Stanford Research Systems (SRS) also made the FS-700
Because they are useless in the US, pricing on Ebay has dropped.

Stan, W1LECape Cod   FN41sr



On 6/3/2012 2:19 PM, Chris Wilson wrote:




03/06/2012 19:09

Thanks for the great replies! My immediate need is to check some used
test equipment I have bought, a Racal dana 9908 counter and a Marconi
2019A signal generator. They don't agree with one another! I was going
to get a Thunderbolt unit and PS, but my friend mentioning noise got
me worried. I may have a play with some SDR gear and I know they can
be locked to a standard i you have one. Longer term my aim is to have
a play with microwaves, which is what this friend is into, and maybe
he has a particular issue with noise with sort of multiplication he is
using? The fact that a GPS reference can be always on and locked to a
reference that someone else maintains, if I understand things correctly,
if simplistically, appeals. I am happy to be guided though, and I
suppose I could always get a different type later if the specific need
arose, although I am not made of money ;)

Thanks!






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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (new...

[Javier Herrero]

Hi, Said,

I think that all of the last cheap ebay lot are of the second variety 
(60MHz osc + 5.3125MHz DDS, very narrow tuning range through serial port 
message). I remember your phase noise and adev plots on them. But I 
don't know if the first variety (the ones with a 55MHz or so crystal 
oscillator and 10MHz DDS-derived output, with wide range of frequency 
settability through the serial port) are better or worse in the phase 
noise, spurious and adev sections compared with the second one.


Regards,

Javier

El 03/06/2012 21:35, Said Jackson escribió:

Hello Javier,

I have a couple from that last Ebay lot , and the phase noise/spurs are so bad 
on these that I figured the 10MHz must have been generated by a DDS. I posted 
the phase noise and ADEV plots of this unit to this list earlier this year.

bye,
Said

Sent From iPhone

On Jun 3, 2012, at 2:19, Javier Herrero  wrote:


Hello,

El 03/06/2012 10:46, saidj...@aol.com escribió:


The FEI-5680A Rubidium that we discussed here some time ago has a much
worse phase noise plot of course, because the 10MHz is generated digitally
through a DDS, not a 10MHz crystal oscillator..


There is a version that generates 10MHz directly through DDS, but the 
particular version we recently discussed a lot about generates the 10MHz signal 
from a 60MHz oscillator, and the DDS is used for generating the ~5.3125MHz 
signal for mixing with the 114th harmonic of the 60MHz to obtain the Rb 
resonance frequency.

I don't remember if someone did a comparison in PN performance between the two 
FE-5680A flavours.

Regards,

Javier



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--

Javier Herrero
Chief Technology Officer  EMAIL: jherr...@hvsistemas.com
HV Sistemas S.L.  PHONE: +34 949 336 806
Los Charcones, 17 FAX:   +34 949 336 792
19170 El Casar - Guadalajara - Spain  WEB: http://www.hvsistemas.com


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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Mark Spencer]

Sorry for the waste of bandwidth with my prior blank email.

Mea Culpa.

Chris, I went thru this process several years ago and ended up purchasing the 
G3RUH GPSDO.  For amateur radio usage (vs time nuts usage) it seemed like a 
good choice to me.   I also liked not having to roll the dice on an auction 
site purchase for a piece of surplus gear.   I've since acquired a number of 
other units that are more time nuts oriented.   Be warned acquiring a GPSDO can 
be the first step in long journey to determine how good your GSPDO actually is. 
 Over the last few years I've spent far more time and money on time nuts 
pursuits than on amateur radio.


Regards
Mark Spencer
VE7AFZ

--- On Sun, 6/3/12, Mark Spencer  wrote:

> From: Mark Spencer 
> Subject: Re: [time-nuts] GPS and Rubidium frequency standards and noise 
> question (newbie).
> To: "Chris Wilson" , "Discussion of precise time and 
> frequency measurement" 
> Received: Sunday, June 3, 2012, 3:27 PM
> 
> 
> Sent from my iPod
> 
> On 2012-06-03, at 2:19 PM, Chris Wilson 
> wrote:
> 
> > 
> > 
> > 
> > 
> > 03/06/2012 19:09
> > 
> > Thanks for the great replies! My immediate need is to
> check some used
> > test equipment I have bought, a Racal dana 9908 counter
> and a Marconi
> > 2019A signal generator. They don't agree with one
> another! I was going
> > to get a Thunderbolt unit and PS, but my friend
> mentioning noise got
> > me worried. I may have a play with some SDR gear and I
> know they can
> > be locked to a standard i you have one. Longer term my
> aim is to have
> > a play with microwaves, which is what this friend is
> into, and maybe
> > he has a particular issue with noise with sort of
> multiplication he is
> > using? The fact that a GPS reference can be always on
> and locked to a
> > reference that someone else maintains, if I understand
> things correctly,
> > if simplistically, appeals. I am happy to be guided
> though, and I
> > suppose I could always get a different type later if
> the specific need
> > arose, although I am not made of money ;)
> > 
> > Thanks!
> > 
> > 
> > 
> > -- 
> >       Best Regards,
> >               
>    Chris Wilson.
> > 
> > 
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to 
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (new...

[Said Jackson]

Hello Javier,

I have a couple from that last Ebay lot , and the phase noise/spurs are so bad 
on these that I figured the 10MHz must have been generated by a DDS. I posted 
the phase noise and ADEV plots of this unit to this list earlier this year.

bye,
Said

Sent From iPhone

On Jun 3, 2012, at 2:19, Javier Herrero  wrote:

> Hello,
> 
> El 03/06/2012 10:46, saidj...@aol.com escribió:
>> 
>> The FEI-5680A Rubidium that we discussed here some time ago has a much
>> worse phase noise plot of course, because the 10MHz is generated digitally
>> through a DDS, not a 10MHz crystal oscillator..
>> 
> There is a version that generates 10MHz directly through DDS, but the 
> particular version we recently discussed a lot about generates the 10MHz 
> signal from a 60MHz oscillator, and the DDS is used for generating the 
> ~5.3125MHz signal for mixing with the 114th harmonic of the 60MHz to obtain 
> the Rb resonance frequency.
> 
> I don't remember if someone did a comparison in PN performance between the 
> two FE-5680A flavours.
> 
> Regards,
> 
> Javier
> 
> 
> 
> ___
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (new...

[Said Jackson]

hello Rex,

from what I have seen the lowest noise is available on the Z3801 with 10811. I 
also have a Z3815 with E1938A oscillator, but the 3801 is much less noisy and 
more stable. Don't have a 3816 or 3805 to test against.

Keep in mind that there is  a large performance variation from unit to unit as 
can be seen in TVB's Z3801A performance plots..

there are a good number of Z3801As modified to be 58503As on Ebay now. Got one 
from Yinxh some time ago, and that unit took over one year to fully settle 
down! Now I am consistently getting xE-013 ADEV from 0.1s to a couple 100s out 
of it. PN is excellent on that unit too.

bye,
Said

Sent From iPhone

On Jun 3, 2012, at 2:21, Rex  wrote:

> Said,
> 
> Thanks for the info and congrats on the stats from the Jackson Labs stuff.
> 
> You mentioned the older HP Z3801. I wonder if you (or others) happen to have 
> comparison numbers on the Z3816A with the MTI 260 oscillator or the Z3805 
> with (I think) the same oscillator. I thought I heard the MTI 260 might be 
> slightly better than the 10811 but can't recall if anyone here actually made 
> measurements,
> 
> Not to say that any of the HP Z stuff is seen for sale often these days. 
> But I have one of each of the above mentioned.
> 
> Guess it may be close to the *time* where I should take the *time* to build 
> or set up a system where I could get trustworthy measurements of these 
> *timing* quality things myself. I keep reading but never seem to find the 
> time to actually do it.
> 
> -Rex
> 
> 
> On 6/3/2012 1:46 AM, saidj...@aol.com wrote:
>> Jerry, Chris,
>> 
>> it's all relative, while the Lpro may be a good Rb standard, it's phase
>> noise is not that good really. You list:
>> 
>>-96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets
>> 
>> For the Lpro. The new Jackson Labs Technologies LN CSAC GPSDO with SC-cut
>> phase noise and ADEV filter achieves the following:
>> 
>>-138dBc/Hz @ 10Hz, -148dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets.
>> 
>> At 1Hz offset we see -105dBc/Hz and better on that unit.
>> 
>> The FEI-5680A Rubidium that we discussed here some time ago has a much
>> worse phase noise plot of course, because the 10MHz is generated digitally
>> through a DDS, not a 10MHz crystal oscillator..
>> 
>> It all depends on your requirements, and your budget.. I think the Z3801A
>> (or it's brother the 58503A) is still one of the lowest phase noise and
>> best ADEV GPSDO on the surplus market if you get a typical unit, and if you 
>> can
>>  locate one.
>> 
>> bye,
>> Said
>> 
>> From: Jerry Mulchin<_jmulchin@cox.net_ (mailto:jmulc...@cox.net)>
>> Date: June 2,  2012 16:44:14 PDT
>> To: Discussion of precise time and frequency  measurement
>> <_time-nuts@febo.com_ (mailto:time-nuts@febo.com)>
>> Subject:  Re: [time-nuts] GPS and Rubidium frequency standards and noise
>> question  (newbie).
>> Reply-To: Discussion of precise time and frequency  measurement
>> <_time-nuts@febo.com_ (mailto:time-nuts@febo.com)>
>> 
>> 
>> 
>> 
>> 
>> Chris,
>> 
>> To answer your question  regarding using a Rubidium standard as a frequency
>>  reference
>> for your  Transverters.
>> 
>> GPS really has nothing to do  the main requirement regarding Phase Noise
>> and  your
>> Transceivers. But the 10MHz oscillator inside the  Rubidium standard is the
>> item
>> that will be the Phase Noise  problem if you get the wrong Rubidium
>> standard. There
>> are  cheap Rubidiums and there are good Rubidium standards to  consider.
>> 
>> An LPRO-101 is actually a very  good Rubidium standard, and exhibits Phase
>> Noise
>> values of  -96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets
>> from carrier. This is what I use for my 10GHz  Transverter reference, but I
>> don't lock it
>> to GPS when in  the field. LPRO-101's can be gotten pretty  reasonably.
>> 
>> Locking the LPRO-101 to a GPS  will require more support circuitry, and
>> most of the
>> folks  on this list can help you with that.
>> 
>> Also,  Thunderbolt GPS disciplined units are nice, but I do not know the
>> Phase  Noise
>> numbers of a typical Thunderbolt unit. Others here  probably know the
>> answer to that.
>> 
>> The  important thing to remember is you don't what to use 10MHz oscillators
>> that  have
>> poor Phase Noise performance as it will effect your  weak signal capability
>> if you use
>> a poor Phase Noise  oscillator.
>> 
>> Jerry
>> 
>> At  03:05 PM 6/2/2012, you wrote:
>> 
>> If you want a frequency reference.  There is nothing better than GPS.  In
>> 
>> 
>> fact it you bought a Rubidium you would  still need the GPS so you could
>> 
>> 
>> calibrate its  frequency.
>> 
>> 
>> 
>> 
>> 
>> Some GPSes might be noisy but then you can  lock a good double oven crystal
>> 
>> 
>> oscillator to it and have what they call a  "GPS disciplined crystal
>> 
>> 
>> oscillator or "GPSDO".
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> On Sat, Jun 2, 2012 at 2:57 PM, Chris Wilson<_chris@chriswilson.tv_
>> (mailto:ch...@chr

Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Mark Spencer]

Sent from my iPod

On 2012-06-03, at 2:19 PM, Chris Wilson  wrote:

> 
> 
> 
> 
> 03/06/2012 19:09
> 
> Thanks for the great replies! My immediate need is to check some used
> test equipment I have bought, a Racal dana 9908 counter and a Marconi
> 2019A signal generator. They don't agree with one another! I was going
> to get a Thunderbolt unit and PS, but my friend mentioning noise got
> me worried. I may have a play with some SDR gear and I know they can
> be locked to a standard i you have one. Longer term my aim is to have
> a play with microwaves, which is what this friend is into, and maybe
> he has a particular issue with noise with sort of multiplication he is
> using? The fact that a GPS reference can be always on and locked to a
> reference that someone else maintains, if I understand things correctly,
> if simplistically, appeals. I am happy to be guided though, and I
> suppose I could always get a different type later if the specific need
> arose, although I am not made of money ;)
> 
> Thanks!
> 
> 
> 
> -- 
>   Best Regards,
>   Chris Wilson.
> 
> 
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Re: [time-nuts] ANN: UK MSF 60 kHz interruption, 2012 June 14

[paul swed]

Not obvious from here at least. Though they could be closely matched and
propagations playing games.

On Sun, Jun 3, 2012 at 12:20 PM, J. Forster  wrote:

> Is there any indication the carriers of WWVB and MSF are locked together?
>
> -John
>
> =
>
>
>
> > I do
> >
> > On Sun, Jun 3, 2012 at 5:48 AM, Magnus Danielson
> >  >> wrote:
> >
> >> On 01/06/12 17:24, paul swed wrote:
> >>
> >>> David
> >>> Thanks
> >>> With the changes to wwvb in the states I may need to turn the antennas
> >>> towards MSF so my equipment keeps running.
> >>> Its funny as I was working on the d-psk-r the rcvrs were locking to
> >>> MSF.
> >>> That was a chuckle to see.
> >>> Lets see, a 10 ft loop towards England and a big screen to mask WWVB.
> >>>
> >>> Hey is your frequency english or metric? ;-)
> >>> Regards
> >>> Paul
> >>> WB8TSL
> >>>
> >>
> >> Surely you mean, english or metric (from england)? :)
> >>
> >> Cheers,
> >> Magnus - A not to far drive away from WWVB as being in Boulder.
> >>
> >> __**_
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> >> mailman/listinfo/time-nuts<
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
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> >>
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Chris Wilson]

03/06/2012 19:09

Thanks for the great replies! My immediate need is to check some used
test equipment I have bought, a Racal dana 9908 counter and a Marconi
2019A signal generator. They don't agree with one another! I was going
to get a Thunderbolt unit and PS, but my friend mentioning noise got
me worried. I may have a play with some SDR gear and I know they can
be locked to a standard i you have one. Longer term my aim is to have
a play with microwaves, which is what this friend is into, and maybe
he has a particular issue with noise with sort of multiplication he is
using? The fact that a GPS reference can be always on and locked to a
reference that someone else maintains, if I understand things correctly,
if simplistically, appeals. I am happy to be guided though, and I
suppose I could always get a different type later if the specific need
arose, although I am not made of money ;)

Thanks!



-- 
   Best Regards,
   Chris Wilson.


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Re: [time-nuts] Rapco 1804m

[David J Taylor]

But I was really hoping to cadge a copy of the manual.


Sent offline.

David GM8ARV
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk 


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Re: [time-nuts] Rapco 1804m

[Paul Flinders]

On 03/06/2012 16:59, paul swed wrote:

Sounds like a better antenna and location might be the trick. You don't say
how high what coax length and type...
Since you do not have a manual you sat mask angles may also be causing an
issue by eliminating possible sats.
But weak signals will do exactly what you see 2 d fixes and an occasional 3.
Thas a pretty good clue.
Regards

Yes - I'm not too worried about that part in the sense that it's obvious 
I need a better signal


Antenna is this one 
http://www.ebay.co.uk/itm/BNC-GPS-Antenna-5M-GARMIN-Streetpilot-GPSCOM-GPSMAP-/250687616146?pt=UK_CE_GPS_Accessories_Software_ET&hash=item3a5e257492 
which is mentioned in David Taylor's article with the supplied 5M length 
of rather thin coax.


Position was along the roofline of the garage - about 2M up but the 
garage roof obscures the view to the north and northeast, as I said.


I'm going to look for a properly weatherproof antenna and put it on the 
garage apex - that's about 3.5M up and will have a much better view at 
the expense of needing 10-12M of cable run.


But I was really hoping to cadge a copy of the manual.



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Re: [time-nuts] ANN: UK MSF 60 kHz interruption, 2012 June 14

[J. Forster]

Is there any indication the carriers of WWVB and MSF are locked together?

-John

=



> I do
>
> On Sun, Jun 3, 2012 at 5:48 AM, Magnus Danielson
> > wrote:
>
>> On 01/06/12 17:24, paul swed wrote:
>>
>>> David
>>> Thanks
>>> With the changes to wwvb in the states I may need to turn the antennas
>>> towards MSF so my equipment keeps running.
>>> Its funny as I was working on the d-psk-r the rcvrs were locking to
>>> MSF.
>>> That was a chuckle to see.
>>> Lets see, a 10 ft loop towards England and a big screen to mask WWVB.
>>>
>>> Hey is your frequency english or metric? ;-)
>>> Regards
>>> Paul
>>> WB8TSL
>>>
>>
>> Surely you mean, english or metric (from england)? :)
>>
>> Cheers,
>> Magnus - A not to far drive away from WWVB as being in Boulder.
>>
>> __**_
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>> and follow the instructions there.
>>
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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (newbie).

[Bob Camp]

Hi

If you are trying to do microwave work, phase noise is going to be an issue no 
matter how you do it.  A lot of the design effort always goes into a low noise 
oscillator chain in that sort of gear. For HF gear, phase noise may not be 
quite as big an issue. A lot of rigs pretty much ignore the phase noise of 
their reference. 

If your radios are not already set up to use a 10 MHz reference, you will need 
to do some frequency conversion to feed them what they want / need. If that's 
the case, clean up the phase noise in the conversion process. Normally it's as 
basic as a crystal oscillator locked up with a narrow band PLL. No need for any 
fancy OCXO or TCXO, just a home made voltage tunable XO. It's not really even a 
VCXO, since the tune range can be very narrow. 

Lots of options…

Bob

On Jun 2, 2012, at 5:57 PM, Chris Wilson wrote:

> 
> 
>  I am looking to get a frequency standard for my amateur radio shack,
>  initially for verifying test gear readings, but later as a standard
>  to lock receiver and transmitter oscillators to. I was going to buy
>  a GPS frequency standard but a friend warned me these may have noise
>  issues when I come to use it with an oscillator in RX / TX
>  applications. It's not something I had considered, so what's the
>  score here please? Should I not buy a GPS standard? Thanks. Any
>  links to known safe suitable purchase sources from personal
>  experience welcome, either here or by PM or e-mail. I am in the UK.
> 
> -- 
> Best regards,
> Chris Wilson  mailto:ch...@chriswilson.tv
> 
> 
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Re: [time-nuts] ANN: UK MSF 60 kHz interruption, 2012 June 14

[paul swed]

I do

On Sun, Jun 3, 2012 at 5:48 AM, Magnus Danielson  wrote:

> On 01/06/12 17:24, paul swed wrote:
>
>> David
>> Thanks
>> With the changes to wwvb in the states I may need to turn the antennas
>> towards MSF so my equipment keeps running.
>> Its funny as I was working on the d-psk-r the rcvrs were locking to MSF.
>> That was a chuckle to see.
>> Lets see, a 10 ft loop towards England and a big screen to mask WWVB.
>>
>> Hey is your frequency english or metric? ;-)
>> Regards
>> Paul
>> WB8TSL
>>
>
> Surely you mean, english or metric (from england)? :)
>
> Cheers,
> Magnus - A not to far drive away from WWVB as being in Boulder.
>
> __**_
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Re: [time-nuts] Rapco 1804m

[paul swed]

Sounds like a better antenna and location might be the trick. You don't say
how high what coax length and type...
Since you do not have a manual you sat mask angles may also be causing an
issue by eliminating possible sats.
But weak signals will do exactly what you see 2 d fixes and an occasional 3.
Thas a pretty good clue.
Regards
Paul.

On Sun, Jun 3, 2012 at 6:16 AM, Paul Flinders  wrote:

> Hi
>
> Just joined the list - recently acquired a Rapco 1804m, mainly to use as a
> frequency standard, especially to have something to check the FE-5680A that
> I have.
>
> The unit itself seems to work OK - connected to a cheapie puck style GPS
> antenna I got a 2D fix, occasionally 3D which corresponded pretty well with
> my actual location and "Coarse" oscillator lock, but never "Fine". It's the
> version with an OXCO rather than local Rubidium oscillator.
>
> I've read David Taylor's notes and had a hunt through the list archives -
> I suspect I need a slightly better antenna, or a better position for the
> one I already have. It had a decent enough view southwards/southwest but
> somewhat obstructed to the north and north-east and comparing the visible
> satellites on my 'phone it was certainly the northerly/north-eastern ones
> that had low or no signal strength.
>
> However I could really do with a copy of the manual, at least to
> understand the difference between "Coarse" and "Fine" locks on the
> oscillator - does anyone have an electronic copy that they would be willing
> to let me have? Or a physical copy - I'm happy to pay a reasonable sum.
>
> Also is the serial protocol for these documented anywhere?
>
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Re: [time-nuts] NTP latency monitoring

[Magnus Danielson]

On 03/06/12 12:34, Magnus Danielson wrote:

On 28/05/12 19:48, Hal Murray wrote:


ei6iz.bren...@gmail.com said:


Anyone tinkered with measuring GPSd, NTPd and network delay tomography?



No, but as the network admin for a reasonably large network, much of it
wireless I'd like to explore this


If you turn on rawstats in ntp.conf, it will collect the data for you.

After the classic client-server exchange, you have 4 timestamps. That
turns
into one line in rawstats.

ntpd assumes the network propagation is symmetric and computes the clock
offset. If you assume the clocks are correct, you can compute the network
transit times in each direction.

If you collect a bunch of data and graph it, and poke around for a while,
it's pretty easy to get a feel for what's going on. I split things up
by IP
Address, then show "similar" targets on the same graph.

Samples with low round trip time are the ones that didn't hit any
(significant) queuing delays. If your routing really is symmetric and the
clocks are accurate, the transit times should match. If they don't match,
you can probably figure out what's going on by looking at the graph.
Asymmetric delays change in jumps in one direction. Clock drift turns
into a
drift in one transit time and same drift with the sign reversed in the
other
transit time.

I'll put together a few samples if anybody is interested.


If you can dig up some, it would be good.

What would be of particular interrest would be to plot the RTT and
asymmetry of the delay over time. Another plot would be to plot
asymmetry vs RTT. Naturally would one-way delays in both directions be
interesting to plot vs time.

I expect that delays vary over time, and that the delay during rush-hour
is both higher and of higher asymmetry. Such patterns will
phase-modulate your time. The slopes will cause frequency errors naturally.

I don't trust packet delays to be symmetric, unless it's a clean pipe
and a good design.


Forgot to add. Anyone interested in packet timing should look up the 
ITU-T G.8260 and G.8261 standards. There is more in the same effort, but 
it may be a good reading.


Cheers,
Magnus

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Re: [time-nuts] Z3801A Power Connector

[Magnus Danielson]

On 27/04/12 05:12, Larry McDavid wrote:

I unexpectedly came into a small supply of the 3-pin "Universal"
Mate-N-Lock connectors that plug into the power connector on the rear
panel of the HP Z3801A GPSDO. If you need one of these and can't readily
find it locally, contact me off-list.



I really should get one.

Cheers,
Magnus

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Re: [time-nuts] NTP latency monitoring

[Magnus Danielson]

On 28/05/12 19:48, Hal Murray wrote:


ei6iz.bren...@gmail.com said:


Anyone tinkered with measuring GPSd, NTPd and network delay tomography?



No, but as the network admin for a reasonably large network, much of it
wireless I'd like to explore this


If you turn on rawstats in ntp.conf, it will collect the data for you.

After the classic client-server exchange, you have 4 timestamps.  That turns
into one line in rawstats.

ntpd assumes the network propagation is symmetric and computes the clock
offset.  If you assume the clocks are correct, you can compute the network
transit times in each direction.

If you collect a bunch of data and graph it, and poke around for a while,
it's pretty easy to get a feel for what's going on.  I split things up by IP
Address, then show "similar" targets on the same graph.

Samples with low round trip time are the ones that didn't hit any
(significant) queuing delays.  If your routing really is symmetric and the
clocks are accurate, the transit times should match.  If they don't match,
you can probably figure out what's going on by looking at the graph.
Asymmetric delays change in jumps in one direction.  Clock drift turns into a
drift in one transit time and same drift with the sign reversed in the other
transit time.

I'll put together a few samples if anybody is interested.


If you can dig up some, it would be good.

What would be of particular interrest would be to plot the RTT and 
asymmetry of the delay over time. Another plot would be to plot 
asymmetry vs RTT. Naturally would one-way delays in both directions be 
interesting to plot vs time.


I expect that delays vary over time, and that the delay during rush-hour 
is both higher and of higher asymmetry. Such patterns will 
phase-modulate your time. The slopes will cause frequency errors naturally.


I don't trust packet delays to be symmetric, unless it's a clean pipe 
and a good design.


Cheers,
Magnus

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[time-nuts] Rapco 1804m

[Paul Flinders]

Hi

Just joined the list - recently acquired a Rapco 1804m, mainly to use as 
a frequency standard, especially to have something to check the FE-5680A 
that I have.


The unit itself seems to work OK - connected to a cheapie puck style GPS 
antenna I got a 2D fix, occasionally 3D which corresponded pretty well 
with my actual location and "Coarse" oscillator lock, but never "Fine". 
It's the version with an OXCO rather than local Rubidium oscillator.


I've read David Taylor's notes and had a hunt through the list archives 
- I suspect I need a slightly better antenna, or a better position for 
the one I already have. It had a decent enough view southwards/southwest 
but somewhat obstructed to the north and north-east and comparing the 
visible satellites on my 'phone it was certainly the 
northerly/north-eastern ones that had low or no signal strength.


However I could really do with a copy of the manual, at least to 
understand the difference between "Coarse" and "Fine" locks on the 
oscillator - does anyone have an electronic copy that they would be 
willing to let me have? Or a physical copy - I'm happy to pay a 
reasonable sum.


Also is the serial protocol for these documented anywhere?

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Re: [time-nuts] ANN: UK MSF 60 kHz interruption, 2012 June 14

[Magnus Danielson]

On 01/06/12 17:24, paul swed wrote:

David
Thanks
With the changes to wwvb in the states I may need to turn the antennas
towards MSF so my equipment keeps running.
Its funny as I was working on the d-psk-r the rcvrs were locking to MSF.
That was a chuckle to see.
Lets see, a 10 ft loop towards England and a big screen to mask WWVB.

Hey is your frequency english or metric? ;-)
Regards
Paul
WB8TSL


Surely you mean, english or metric (from england)? :)

Cheers,
Magnus - A not to far drive away from WWVB as being in Boulder.

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Re: [time-nuts] GPS and Rubidium frequency standards and noise question (new...

[Rex]

Said,

Thanks for the info and congrats on the stats from the Jackson Labs stuff.

You mentioned the older HP Z3801. I wonder if you (or others) happen to 
have comparison numbers on the Z3816A with the MTI 260 oscillator or the 
Z3805 with (I think) the same oscillator. I thought I heard the MTI 260 
might be slightly better than the 10811 but can't recall if anyone here 
actually made measurements,


Not to say that any of the HP Z stuff is seen for sale often these 
days. But I have one of each of the above mentioned.


Guess it may be close to the *time* where I should take the *time* to 
build or set up a system where I could get trustworthy measurements of 
these *timing* quality things myself. I keep reading but never seem to 
find the time to actually do it.


-Rex


On 6/3/2012 1:46 AM, saidj...@aol.com wrote:

Jerry, Chris,

it's all relative, while the Lpro may be a good Rb standard, it's phase
noise is not that good really. You list:

-96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets

For the Lpro. The new Jackson Labs Technologies LN CSAC GPSDO with SC-cut
phase noise and ADEV filter achieves the following:

-138dBc/Hz @ 10Hz, -148dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets.

At 1Hz offset we see -105dBc/Hz and better on that unit.

The FEI-5680A Rubidium that we discussed here some time ago has a much
worse phase noise plot of course, because the 10MHz is generated digitally
through a DDS, not a 10MHz crystal oscillator..

It all depends on your requirements, and your budget.. I think the Z3801A
(or it's brother the 58503A) is still one of the lowest phase noise and
best ADEV GPSDO on the surplus market if you get a typical unit, and if you can
  locate one.

bye,
Said

From: Jerry Mulchin<_jmulchin@cox.net_ (mailto:jmulc...@cox.net)>
Date: June 2,  2012 16:44:14 PDT
To: Discussion of precise time and frequency  measurement
<_time-nuts@febo.com_ (mailto:time-nuts@febo.com)>
Subject:  Re: [time-nuts] GPS and Rubidium frequency standards and noise
question  (newbie).
Reply-To: Discussion of precise time and frequency  measurement
<_time-nuts@febo.com_ (mailto:time-nuts@febo.com)>





Chris,

To answer your question  regarding using a Rubidium standard as a frequency
  reference
for your  Transverters.

GPS really has nothing to do  the main requirement regarding Phase Noise
and  your
Transceivers. But the 10MHz oscillator inside the  Rubidium standard is the
item
that will be the Phase Noise  problem if you get the wrong Rubidium
standard. There
are  cheap Rubidiums and there are good Rubidium standards to  consider.

An LPRO-101 is actually a very  good Rubidium standard, and exhibits Phase
Noise
values of  -96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets
from carrier. This is what I use for my 10GHz  Transverter reference, but I
don't lock it
to GPS when in  the field. LPRO-101's can be gotten pretty  reasonably.

Locking the LPRO-101 to a GPS  will require more support circuitry, and
most of the
folks  on this list can help you with that.

Also,  Thunderbolt GPS disciplined units are nice, but I do not know the
Phase  Noise
numbers of a typical Thunderbolt unit. Others here  probably know the
answer to that.

The  important thing to remember is you don't what to use 10MHz oscillators
that  have
poor Phase Noise performance as it will effect your  weak signal capability
if you use
a poor Phase Noise  oscillator.

Jerry

At  03:05 PM 6/2/2012, you wrote:

If you want a frequency reference.  There is nothing better than GPS.  In


fact it you bought a Rubidium you would  still need the GPS so you could


calibrate its  frequency.





Some GPSes might be noisy but then you can  lock a good double oven crystal


oscillator to it and have what they call a  "GPS disciplined crystal


oscillator or "GPSDO".











On Sat, Jun 2, 2012 at 2:57 PM, Chris Wilson<_chris@chriswilson.tv_
(mailto:ch...@chriswilson.tv)>   wrote:
















I am looking to get a frequency standard  for my amateur radio shack,




initially for verifying test gear  readings, but later as a standard




to lock receiver and transmitter  oscillators to. I was going to buy




a GPS frequency standard but a friend  warned me these may have noise




issues when I come to use it with an  oscillator in RX / TX




applications. It's not something I had  considered, so what's the




score here please? Should I not buy a GPS  standard? Thanks. Any




links to known safe suitable purchase  sources from personal




experience welcome, either here or by PM  or e-mail. I am in the UK.









--




Best  regards,




Chris Wilson  _mailto:chris@chriswilson.tv_ (mailto:ch...@chriswilson.tv)














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and

Re: [time-nuts] GPS and Rubidium frequency standards and noise question (new...

[Javier Herrero]

Hello,

El 03/06/2012 10:46, saidj...@aol.com escribió:


The FEI-5680A Rubidium that we discussed here some time ago has a much
worse phase noise plot of course, because the 10MHz is generated digitally
through a DDS, not a 10MHz crystal oscillator..

There is a version that generates 10MHz directly through DDS, but the 
particular version we recently discussed a lot about generates the 10MHz 
signal from a 60MHz oscillator, and the DDS is used for generating the 
~5.3125MHz signal for mixing with the 114th harmonic of the 60MHz to 
obtain the Rb resonance frequency.


I don't remember if someone did a comparison in PN performance between 
the two FE-5680A flavours.


Regards,

Javier



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[time-nuts] GPS and Rubidium frequency standards and noise question (new...

[SAIDJACK]

Jerry, Chris,
 
it's all relative, while the Lpro may be a good Rb standard, it's phase  
noise is not that good really. You list:
 
   -96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets
 
For the Lpro. The new Jackson Labs Technologies LN CSAC GPSDO with SC-cut  
phase noise and ADEV filter achieves the following:
 
   -138dBc/Hz @ 10Hz, -148dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets.
 
At 1Hz offset we see -105dBc/Hz and better on that unit.
 
The FEI-5680A Rubidium that we discussed here some time ago has a much  
worse phase noise plot of course, because the 10MHz is generated digitally  
through a DDS, not a 10MHz crystal oscillator..
 
It all depends on your requirements, and your budget.. I think the Z3801A  
(or it's brother the 58503A) is still one of the lowest phase noise and  
best ADEV GPSDO on the surplus market if you get a typical unit, and if you can 
 locate one.
 
bye,
Said
 
From: Jerry Mulchin <_jmulchin@cox.net_ (mailto:jmulc...@cox.net) >
Date: June 2,  2012 16:44:14 PDT
To: Discussion of precise time and frequency  measurement 
<_time-nuts@febo.com_ (mailto:time-nuts@febo.com) >
Subject:  Re: [time-nuts] GPS and Rubidium frequency standards and noise 
question  (newbie).
Reply-To: Discussion of precise time and frequency  measurement 
<_time-nuts@febo.com_ (mailto:time-nuts@febo.com) >





Chris,

To answer your question  regarding using a Rubidium standard as a frequency 
 reference
for your  Transverters.

GPS really has nothing to do  the main requirement regarding Phase Noise 
and  your
Transceivers. But the 10MHz oscillator inside the  Rubidium standard is the 
item
that will be the Phase Noise  problem if you get the wrong Rubidium 
standard. There
are  cheap Rubidiums and there are good Rubidium standards to  consider.

An LPRO-101 is actually a very  good Rubidium standard, and exhibits Phase 
Noise
values of  -96dBc/Hz @ 10Hz, -138dBc/Hz @ 100Hz, -152dBc/Hz @ 1KHz  offsets
from carrier. This is what I use for my 10GHz  Transverter reference, but I 
don't lock it
to GPS when in  the field. LPRO-101's can be gotten pretty  reasonably.

Locking the LPRO-101 to a GPS  will require more support circuitry, and 
most of the
folks  on this list can help you with that.

Also,  Thunderbolt GPS disciplined units are nice, but I do not know the 
Phase  Noise
numbers of a typical Thunderbolt unit. Others here  probably know the 
answer to that.

The  important thing to remember is you don't what to use 10MHz oscillators 
that  have
poor Phase Noise performance as it will effect your  weak signal capability 
if you use
a poor Phase Noise  oscillator.

Jerry

At  03:05 PM 6/2/2012, you wrote:

If you want a frequency reference.  There is nothing better than GPS.  In


fact it you bought a Rubidium you would  still need the GPS so you could


calibrate its  frequency.





Some GPSes might be noisy but then you can  lock a good double oven crystal


oscillator to it and have what they call a  "GPS disciplined crystal


oscillator or "GPSDO".











On Sat, Jun 2, 2012 at 2:57 PM, Chris Wilson  <_chris@chriswilson.tv_ 
(mailto:ch...@chriswilson.tv) >  wrote:
















I am looking to get a frequency standard  for my amateur radio shack,




initially for verifying test gear  readings, but later as a standard




to lock receiver and transmitter  oscillators to. I was going to buy




a GPS frequency standard but a friend  warned me these may have noise




issues when I come to use it with an  oscillator in RX / TX




applications. It's not something I had  considered, so what's the




score here please? Should I not buy a GPS  standard? Thanks. Any




links to known safe suitable purchase  sources from personal




experience welcome, either here or by PM  or e-mail. I am in the UK.









--




Best  regards,




Chris Wilson  _mailto:chris@chriswilson.tv_ (mailto:ch...@chriswilson.tv) 














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-- 





Chris Albertson


Redondo Beach,  California


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Jerry  Mulchin



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