Re: [time-nuts] DIY VNA design

[Orin Eman]

To 60MHz: http://n2pk.com; PCBs available here:
http://www.makarov.ca/vna.htm

To 500MHz, lower dynamic range to 1.3GHz:
http://sdr-kits.net/VNWA3_Description.html

OK, so the latter isn't build it yourself anymore.

I have version 2.6 of the latter and it works really well to about 575MHz.
Traces can get noisy after about 575MHz.

Remember these VNAs are only as good as the calibration kit you use with
them!

Orin.


On Sat, Aug 20, 2016 at 9:46 PM, Bob Albert via time-nuts <
time-nuts@febo.com> wrote:

> I was interested in this, but my needs are mostly below 100 MHz.  I wonder
> what could be done similarly for this lower range...
> Bob
>
>
> On Saturday, August 20, 2016 8:54 PM, Richard (Rick) Karlquist <
> rich...@karlquist.com> wrote:
>
>
>  Another great posting, Attila.
>
> When I was with Agilent, we looked at all kinds of
> simplified network analyzer architectures, and I
> would have to say the author is really well informed.
> One issue he doesn't seem to be aware of is that the
> ADL5801, when driven single ended, has some quirks
> below 100 MHz that I discovered experimentally.
> (The data sheet is silent on this).  IMHO, it
> would be worth 7 Euro's to use a balun, however,
> I would like to know the part number of this
> supposed component.  I am not so sure about MCL
> actually covering 30 MHz to 6 GHz in the same
> balun.  Sometimes their advertising is confusing,
> and when they say .03-6 GHz baluns, they mean
> that the range can be covered in several bands
> by several model numbers.
>
> Still, quite impressive work by an individual
> practitioner.
>
> Rick
>
> On 8/20/2016 7:19 PM, Attila Kinali wrote:
> > Moin,
> >
> > I stumbled over a new open hardware/source VNA design:
> > http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-
> network-analyzer.html
> >
> > Unlike other designs out there, this one is very well done and has very
> > little room for improvement, without increasing the price considerably.
> >
> > About the only things i would do different is to use two receiver
> > channels, one fix connected at the TX source to be able to do a
> > difference measurement between TX and the RX channels and thus
> > improving precision. And the other would be to use a dual ADC
> > with an FPGA for the data processing, again in order to increase
> > performance.
> >
> > But as I wrote, both changes would increase complexity and price.
> >
> > Other than being a well thought through design, the website also
> > explains all the big design choices and why this or that has been
> > done instead of one of the many alternatives. That alone makes it
> > worth reading, IMHO.
> >
> > Attila Kinali
> >
> >
> >
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Re: [time-nuts] DIY VNA design

[Bob Albert via time-nuts]

I was interested in this, but my needs are mostly below 100 MHz.  I wonder what 
could be done similarly for this lower range...
Bob
 

On Saturday, August 20, 2016 8:54 PM, Richard (Rick) Karlquist 
 wrote:
 

 Another great posting, Attila.

When I was with Agilent, we looked at all kinds of
simplified network analyzer architectures, and I
would have to say the author is really well informed.
One issue he doesn't seem to be aware of is that the
ADL5801, when driven single ended, has some quirks
below 100 MHz that I discovered experimentally.
(The data sheet is silent on this).  IMHO, it
would be worth 7 Euro's to use a balun, however,
I would like to know the part number of this
supposed component.  I am not so sure about MCL
actually covering 30 MHz to 6 GHz in the same
balun.  Sometimes their advertising is confusing,
and when they say .03-6 GHz baluns, they mean
that the range can be covered in several bands
by several model numbers.

Still, quite impressive work by an individual
practitioner.

Rick

On 8/20/2016 7:19 PM, Attila Kinali wrote:
> Moin,
>
> I stumbled over a new open hardware/source VNA design:
> http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html
>
> Unlike other designs out there, this one is very well done and has very
> little room for improvement, without increasing the price considerably.
>
> About the only things i would do different is to use two receiver
> channels, one fix connected at the TX source to be able to do a
> difference measurement between TX and the RX channels and thus
> improving precision. And the other would be to use a dual ADC
> with an FPGA for the data processing, again in order to increase
> performance.
>
> But as I wrote, both changes would increase complexity and price.
>
> Other than being a well thought through design, the website also
> explains all the big design choices and why this or that has been
> done instead of one of the many alternatives. That alone makes it
> worth reading, IMHO.
>
>             Attila Kinali
>
>
>
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Re: [time-nuts] DIY VNA design

[Richard (Rick) Karlquist]

Another great posting, Attila.

When I was with Agilent, we looked at all kinds of
simplified network analyzer architectures, and I
would have to say the author is really well informed.
One issue he doesn't seem to be aware of is that the
ADL5801, when driven single ended, has some quirks
below 100 MHz that I discovered experimentally.
(The data sheet is silent on this).  IMHO, it
would be worth 7 Euro's to use a balun, however,
I would like to know the part number of this
supposed component.  I am not so sure about MCL
actually covering 30 MHz to 6 GHz in the same
balun.  Sometimes their advertising is confusing,
and when they say .03-6 GHz baluns, they mean
that the range can be covered in several bands
by several model numbers.

Still, quite impressive work by an individual
practitioner.

Rick

On 8/20/2016 7:19 PM, Attila Kinali wrote:

Moin,

I stumbled over a new open hardware/source VNA design:
http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html

Unlike other designs out there, this one is very well done and has very
little room for improvement, without increasing the price considerably.

About the only things i would do different is to use two receiver
channels, one fix connected at the TX source to be able to do a
difference measurement between TX and the RX channels and thus
improving precision. And the other would be to use a dual ADC
with an FPGA for the data processing, again in order to increase
performance.

But as I wrote, both changes would increase complexity and price.

Other than being a well thought through design, the website also
explains all the big design choices and why this or that has been
done instead of one of the many alternatives. That alone makes it
worth reading, IMHO.

Attila Kinali




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[time-nuts] DIY VNA design

[Attila Kinali]

Moin,

I stumbled over a new open hardware/source VNA design:
http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html

Unlike other designs out there, this one is very well done and has very
little room for improvement, without increasing the price considerably.

About the only things i would do different is to use two receiver
channels, one fix connected at the TX source to be able to do a
difference measurement between TX and the RX channels and thus
improving precision. And the other would be to use a dual ADC
with an FPGA for the data processing, again in order to increase
performance.

But as I wrote, both changes would increase complexity and price.

Other than being a well thought through design, the website also
explains all the big design choices and why this or that has been
done instead of one of the many alternatives. That alone makes it
worth reading, IMHO.

Attila Kinali



-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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[time-nuts] Austron Phase Stepper Manual needed

[g4gjl]

Has anyone here got a copy of the manual for the Austron 2055 Phase stepper 
that I could borrow, beg, rent etc?
Reasonable price paid.
PeteG4GJL
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Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

[Bob kb8tq]

Hi

At the most basic level, ADEV is a standard deviation. When people read an 
instrument they usually want a "max error" sort of number. ADEV operates on 
delta between readings so a simple "three sigma" mental math conversion is not 
all you need. It *is* the right measure. It can take a bit of work to convert 
it to useful units .

Bob


> On Aug 20, 2016, at 7:38 AM, Charles Steinmetz  wrote:
> 
> Bryan wrote:
> 
>> With a GPSDO as a general rule is there much variation of the 0.005 to 0.02 
>> ppb range. Would there me much if only 2 satellites were visible but the 
>> unit was no in holdover vs say 6 satellites. I assume there is probably a 
>> lot of variables such as quality of GPSDO and OCXO, multi path interference, 
>> antenna location, etc, but worse case what would a user expect assuming the 
>> unit isn't in holdover.
> 
> There are lots of ADEV plots of GPSDOs on the web, if you search for them.  
> Tom has the attached plot posted on his web site -- it includes one decent 
> (but not stellar) GPSDO, the HP Z3801.  That is about what you can expect 
> without heroic tuning efforts (on a GPSDO that supports user fiddling, such 
> as the Trimble Thunderbolt).
> 
> Since many counters gate for one second (or gate faster, then average), the 
> ADEV at tau=1 second is a reasonable estimate of the real-world performance 
> of a good counter driven by a GPSDO.  Note that, since the ADEV at 1 second 
> depends largely on the OCXO, the heroic tuning efforts mentioned above won't 
> change the ADEV at tau=1 second hardly at all. That is attributable strictly 
> to the OCXO (unless the GPSDO is very poorly designed).  Building a GPSDO 
> using the best OCXO available can improve things.  For example, look at the 
> "BVA" plot -- at 1 second, its ADEV is nearly a full decade better than the 
> Z3801, better even than the hydrogen masers.  (While I referred to the 3801 
> above as "decent but not stellar," that is based on its performance at tau 
> from 100-100k seconds.  Its OCXO -- and, thus, its ADEV -- is better than 
> most others at 1 second.)
> 
> Best regards,
> 
> Charles
> 
> 
> 
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Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

[Bob kb8tq]

Hi

If your time base is doing < 5 ppb per year, that is an unusual 10811. I
suspect it does not spend a lot of time powered off. 

Bob

Sent from my iPad

> On Aug 19, 2016, at 10:10 PM, Hal Murray  wrote:
> 
> 
> kb...@n1k.org said:
>> Ok let's toss some numbers into the mix.
>> The counter time base one day after calibration is in the 0.5 to 1.5 ppb
>> range.
> 
> I have two 5334Bs wih opt 010.  It's been many years since either was near a 
> calibration lab.
> 
> One is 30 ppb fast, the other is 75 ppb fast.  (I might have the sign 
> backwards.)
> 
> One swings roughly 0.15 ppb over 10F.
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

[Charles Steinmetz]

Bryan wrote:


With a GPSDO as a general rule is there much variation of the 0.005 to 0.02 ppb 
range. Would there me much if only 2 satellites were visible but the unit was 
no in holdover vs say 6 satellites. I assume there is probably a lot of 
variables such as quality of GPSDO and OCXO, multi path interference, antenna 
location, etc, but worse case what would a user expect assuming the unit isn't 
in holdover.


There are lots of ADEV plots of GPSDOs on the web, if you search for 
them.  Tom has the attached plot posted on his web site -- it includes 
one decent (but not stellar) GPSDO, the HP Z3801.  That is about what 
you can expect without heroic tuning efforts (on a GPSDO that supports 
user fiddling, such as the Trimble Thunderbolt).


Since many counters gate for one second (or gate faster, then average), 
the ADEV at tau=1 second is a reasonable estimate of the real-world 
performance of a good counter driven by a GPSDO.  Note that, since the 
ADEV at 1 second depends largely on the OCXO, the heroic tuning efforts 
mentioned above won't change the ADEV at tau=1 second hardly at all. 
That is attributable strictly to the OCXO (unless the GPSDO is very 
poorly designed).  Building a GPSDO using the best OCXO available can 
improve things.  For example, look at the "BVA" plot -- at 1 second, its 
ADEV is nearly a full decade better than the Z3801, better even than the 
hydrogen masers.  (While I referred to the 3801 above as "decent but not 
stellar," that is based on its performance at tau from 100-100k seconds. 
 Its OCXO -- and, thus, its ADEV -- is better than most others at 1 
second.)


Best regards,

Charles


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Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

[Bob kb8tq]

Hi

I do not know of any commercial GPSDO's that do not have a holdover 
feature. There are a lot of variables. With a large package OCXO and a couple 
days 
operation, the numbers I gave should be good 90 to 99% of the time.(99 seconds 
out
of 100).

If the unit has such a poor antenna location that (unlike the original post) it 
never
completes survey, then all bets are off... The basic assumption is "locked to > 
4 sats 
at all times. That generally translates to 6 or more most of the time.

Bob

Sent from my iPad

> On Aug 20, 2016, at 5:43 AM, Bryan _  wrote:
> 
> Bob:
> With a GPSDO as a general rule is there much variation of the 0.005 to 0.02 
> ppb range. Would there me much if only 2 satellites were visible but the unit 
> was no in holdover vs say 6 satellites. I assume there is probably a lot of 
> variables such as quality of GPSDO and OCXO, multi path interference, antenna 
> location, etc, but worse case what would a user expect assuming the unit 
> isn't in holdover.
> 
> -=Bryan=-
> 
>> From: kb...@n1k.org
>> Date: Fri, 19 Aug 2016 20:03:59 -0400
>> To: time-nuts@febo.com
>> Subject: Re: [time-nuts] Expected 10 MHz offset from a GPSDO?
>> 
>> Hi
>> 
>> Ok let's toss some numbers into the mix.
>> 
>> The counter time base one day after calibration is in the 0.5 to 1.5 ppb 
>> range.
>> 
>> The LPRO ten years after it left the factory is in the 0.5 to 1.5 ppb range.
>> 
>> The GPSDO when running properly should be in the 0.005 to 0.02 ppb range at 
>> one second.
>> 
>> One ppb at 10 MHz is 0.01 Hz. It also is a the resolution limit on a 5335 at 
>> 1 second.
>> 
>> Bob
>> 
>> 
>> 
>>> On Aug 19, 2016, at 5:29 PM, Mark Sims  wrote:
>>> 
>>> Try driving your counter frequency reference input with the LPRO or 
>>> comparing the LPRO with the GPSDO.  The LPRO is (most likely) much more 
>>> accurate the counters' internal timebase.
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Re: [time-nuts] Expected 10 MHz offset from a GPSDO?

[Bryan _]

Bob:
With a GPSDO as a general rule is there much variation of the 0.005 to 0.02 ppb 
range. Would there me much if only 2 satellites were visible but the unit was 
no in holdover vs say 6 satellites. I assume there is probably a lot of 
variables such as quality of GPSDO and OCXO, multi path interference, antenna 
location, etc, but worse case what would a user expect assuming the unit isn't 
in holdover.

-=Bryan=-

> From: kb...@n1k.org
> Date: Fri, 19 Aug 2016 20:03:59 -0400
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Expected 10 MHz offset from a GPSDO?
> 
> Hi
> 
> Ok let's toss some numbers into the mix.
> 
> The counter time base one day after calibration is in the 0.5 to 1.5 ppb 
> range.
> 
> The LPRO ten years after it left the factory is in the 0.5 to 1.5 ppb range.
> 
> The GPSDO when running properly should be in the 0.005 to 0.02 ppb range at 
> one second.
> 
> One ppb at 10 MHz is 0.01 Hz. It also is a the resolution limit on a 5335 at 
> 1 second.
> 
> Bob
> 
> 
> 
> > On Aug 19, 2016, at 5:29 PM, Mark Sims  wrote:
> > 
> > Try driving your counter frequency reference input with the LPRO or 
> > comparing the LPRO with the GPSDO.  The LPRO is (most likely) much more 
> > accurate the counters' internal timebase.
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