Re: [time-nuts] ZCD Article

[Tom Van Baak]

If you don't like to click on encoded URL's or don't trust box.com,

The original source of the PTTI paper:

Zero-Crossing Detector with Sub-Microsecond Jitter and Crosstalk
https://tycho.usno.navy.mil/ptti/1990papers/Vol%2022_20.pdf

Another trusted source:

Zero-Crossing Detector with Sub-Microsecond Jitter and Crosstalk
https://apps.dtic.mil/dtic/tr/fulltext/u2/a515384.pdf

/tvb


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

[time-nuts] ZCD Article

[AC0XU (Jim)]

TNs - Bob Martin asked me to post this article reference about designing ZCD 
systems.

https://app.box.com/s/b7d45z2cpq0x5ilz4jtn7a424btzjdhm

Jim


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

[time-nuts] A comparison of the TAPR-TICC and BG7TBL FA1

[Mark Sims]

FA1 noise test was shown here:
http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2019-August/097445.html

TAPR TICC noise test was shown here:
https://www.eevblog.com/forum/metrology/comparing-the-performance-of-17-different-gpsdos/?action=dlattach;attach=591979;image

Tom ran my TICC data through Timelab to get pretty plots:
http://leapsecond.com/u/sims/gpsdo17/


-

>   however I think it is interesting to have the noise floor of the test set 
> because it is a reference absolute value.

___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

[rfnuts]

Paul,

the Adret 4110 is great for frequency difference measurements and
adjustments.

For serious ADEV measurements, it's just too noisy on low tau's and has
too much temperature drift / long term phase instability on high tau's.

See the attched noise floor test.

I have a 4110 with a paper op and service manual. parts of it are in
French only.

Regards Adrian


Am 06.09.2019 um 20:08 schrieb Paul Bicknell:
> 
> Dear all
> 
> Could any one let me have there experience with using the 
> ADRAT 4110 Frequency difference multiplier
> 
> It dues the same as the  TRACOR 527 except it works 
> On any of the following frequencies  1 , 2 , 2.5 , 5 , & 10 Mhz
> 
> Making it a very useful item in the Lab / work shop 
> 
> Also looking for a PDF of the Service manual 
> 
> Regards Paul  South Coast UK
> 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
> 
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

[ew via time-nuts]

As to availability the only ones II know, will ask Juerg if he knows of any 
others.  


In a message dated 9/7/2019 8:03:07 AM Eastern Standard Time, 
p...@bicknells.f2s.com writes:

Hi Bert
Thank you for you post 
Looking for a service manual in PDF format for the ADRAT 4110 if you ever
come across one 

Am I correct that Tracor 527 & ADRAT 4110 are the only Frequency difference
units available  ?

PS there is one of each available on  Ebay

Regards Paul 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of ew
via time-nuts
Sent: 06 September 2019 20:10
To: time-nuts@lists.febo.com
Cc: ew
Subject: Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

Juerg has two I have one love it also have Tracor 527 each. Same performance
Tracor also works at 10 MHz and has a meter, comes in handy.
Bert Kehren


In a message dated 9/6/2019 2:12:04 PM Eastern Standard Time,
p...@bicknells.f2s.com writes:

Dear all

Could any one let me have there experience with using the 
ADRAT 4110 Frequency difference multiplier

It dues the same as the  TRACOR 527 except it works 
On any of the following frequencies  1 , 2 , 2.5 , 5 , & 10 Mhz

Making it a very useful item in the Lab / work shop 

Also looking for a PDF of the Service manual 

Regards Paul  South Coast UK


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

[ew via time-nuts]

PaulYes ere is a 527 on ebay at one time they where more than 10K the 4110 
acording to Juerg was close to 20K Franken he had one in his Lab when he worked 
for a living probably 20 years ago.We will look if we have somewhere some 
info.We use these dayle, the fastest way to do do precise high resolution 
testing. I will check with Juerg I think we have AV data on both units that 
Juerg did.Bert
In a message dated 9/7/2019 8:03:07 AM Eastern Standard Time, 
p...@bicknells.f2s.com writes:

Hi Bert
Thank you for you post 
Looking for a service manual in PDF format for the ADRAT 4110 if you ever
come across one 

Am I correct that Tracor 527 & ADRAT 4110 are the only Frequency difference
units available  ?

PS there is one of each available on  Ebay

Regards Paul 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of ew
via time-nuts
Sent: 06 September 2019 20:10
To: time-nuts@lists.febo.com
Cc: ew
Subject: Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

Juerg has two I have one love it also have Tracor 527 each. Same performance
Tracor also works at 10 MHz and has a meter, comes in handy.
Bert Kehren


In a message dated 9/6/2019 2:12:04 PM Eastern Standard Time,
p...@bicknells.f2s.com writes:

Dear all

Could any one let me have there experience with using the 
ADRAT 4110 Frequency difference multiplier

It dues the same as the  TRACOR 527 except it works 
On any of the following frequencies  1 , 2 , 2.5 , 5 , & 10 Mhz

Making it a very useful item in the Lab / work shop 

Also looking for a PDF of the Service manual 

Regards Paul  South Coast UK


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

[Paul Bicknell]

Hi Bert
Thank you for you post 
Looking for a service manual in PDF format for the ADRAT 4110 if you ever
come across one 

Am I correct that Tracor 527 & ADRAT 4110 are the only Frequency difference
units available  ?

PS there is one of each available on  Ebay

Regards Paul 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of ew
via time-nuts
Sent: 06 September 2019 20:10
To: time-nuts@lists.febo.com
Cc: ew
Subject: Re: [time-nuts] ADRAT 4110 Frequency difference multiplier

Juerg has two I have one love it also have Tracor 527 each. Same performance
Tracor also works at 10 MHz and has a meter, comes in handy.
Bert Kehren


In a message dated 9/6/2019 2:12:04 PM Eastern Standard Time,
p...@bicknells.f2s.com writes:

Dear all

Could any one let me have there experience with using the 
ADRAT 4110 Frequency difference multiplier

It dues the same as the  TRACOR 527 except it works 
On any of the following frequencies  1 , 2 , 2.5 , 5 , & 10 Mhz

Making it a very useful item in the Lab / work shop 

Also looking for a PDF of the Service manual 

Regards Paul  South Coast UK


___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] GPS Antennas

[John C. Westmoreland, P.E.]

To the OP, Dan,

Just curious - do you use something like this:
https://endruntechnologies.com/products/antennas-accessories/lightning-arrestor


Good luck with the new antenna.

73's,
John
AJ6BC


On Sat, Sep 7, 2019 at 3:17 AM Björn  wrote:

> https://www.ngs.noaa.gov/ANTCAL/#
>
> Look at say an old Ashtech ASH700936D_M which you can find calibrations
> for both SCIS and “Snow” radomes and without radome for the same antenna.
>
> I have seen more recent radomes that are hemisphere-shaped. However these
> are more prone to be favored bird view points.
>
> Radomes, like the Aeroantenna SPKE with a plastic “spike” to discourage
> birds are less ideal for super high accuracy applications due to its non
> uniform signal delay impact.
>
> See also clear acrylic domes OSOD/OSOS
>
> http://www.euref.eu/symposia/2015Leipzig/p-02-01-Ohlsson.pdf
>
> https://kb.unavco.org/kb/article/unavco-resources-radomes-520.html
>
> /Björn
>
> Sent from my iPhone
>
> > On 7 Sep 2019, at 02:54, Bob kb8tq  wrote:
> >
> > Hi
> >
> > Based on the papers I have seen, there is no “magic” shape that can be
> ignored.
> > Part of the issue is that the cover is going to be in the near field of
> the antenna.
> > As noted in another post, the impact is more complex than a simple
> delay. ( consider
> > that signals bounce off the cover material …. ).
> >
> > Also consider that if I’m going to 3D print the device, I have a limited
> number of
> > materials available. Teflon isn’t going to run through a 3D printer.
> Unless you paint
> > the gizmo it will not be water tight so humidity will get into the act
> as well.
> >
> > =
> >
> > A “good” GPS antenna should have roughly the same phase center
> regardless of
> > the angle to the sat it’s receiving. Indeed GPS antennas in general get
> this right.
> > There is a modest variation with angle, but it’s not all that great.
> Units of mm are not
> > uncommon. It will be greater on a multi band design. The impact of your
> cover also
> > will be greater on a multi band device. All the various delay /. loss /
> reflection parameters
> > are frequency dependent…..
> >
> > Bob
> >
> >> On Sep 6, 2019, at 5:57 PM, Hal Murray  wrote:
> >>
> >>
> >> kb...@n1k.org said:
> >>> The gotcha with putting anything on top of a GPS antenna is that it
> impacts
> >>> the phase  shift from the sat’s. How important that is gets quickly
> into just
> >>> how picky you happen to be.
> >>
> >> How picky do I have to be before that is significant?  How geeky would
> I have
> >> to be to measure it?
> >>
> >> Would a hemispherical cover provide equal delays at all elevations?  I
> think
> >> the solidly mounted USGS fault/volcano monitoring setups have a round
> top.
> >> https://www.usgs.gov/media/images/gps-tracks-ground-deformation
> >>
> >> Do any antenna manufacturers advertise uniform phase delay?
> >> Do any software vendors advertise that their software works better with
> >> specific antennas?
> >>
> >>
> >>
> >> --
> >> These are my opinions.  I hate spam.
> >>
> >>
> >>
> >>
> >> ___
> >> time-nuts mailing list -- time-nuts@lists.febo.com
> >> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> >> and follow the instructions there.
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> > and follow the instructions there.
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] Looking for Symmetricom system info: 105542-002A

[Andy Gardner via time-nuts]

Haven't been able to find anything so far. Can you post a hi-res pic of the 
front of the system please?

On 7/09/19 10:17 am, Walter Shawlee 2 wrote:

I recently got a rack shelf filled with Symmetricom black modules (PMM 
controller w/LCD display, GPS, PRS-RB Rb oscillator and PRS-XO ovenized crystal 
oscillator). the whole rack has an assembly number 105542-0002A, but searching 
by any of the module or assembly numbers doesn't reveal much. I had similar bad 
luck trying to find info on my Ball-Efratorm rack.




___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] GPS Antennas

[Björn]

https://www.ngs.noaa.gov/ANTCAL/#

Look at say an old Ashtech ASH700936D_M which you can find calibrations for 
both SCIS and “Snow” radomes and without radome for the same antenna.

I have seen more recent radomes that are hemisphere-shaped. However these are 
more prone to be favored bird view points.

Radomes, like the Aeroantenna SPKE with a plastic “spike” to discourage birds 
are less ideal for super high accuracy applications due to its non uniform 
signal delay impact.

See also clear acrylic domes OSOD/OSOS

http://www.euref.eu/symposia/2015Leipzig/p-02-01-Ohlsson.pdf

https://kb.unavco.org/kb/article/unavco-resources-radomes-520.html

/Björn 

Sent from my iPhone

> On 7 Sep 2019, at 02:54, Bob kb8tq  wrote:
> 
> Hi
> 
> Based on the papers I have seen, there is no “magic” shape that can be 
> ignored. 
> Part of the issue is that the cover is going to be in the near field of the 
> antenna.
> As noted in another post, the impact is more complex than a simple delay. ( 
> consider 
> that signals bounce off the cover material …. ).
> 
> Also consider that if I’m going to 3D print the device, I have a limited 
> number of 
> materials available. Teflon isn’t going to run through a 3D printer. Unless 
> you paint
> the gizmo it will not be water tight so humidity will get into the act as 
> well. 
> 
> =
> 
> A “good” GPS antenna should have roughly the same phase center regardless of
> the angle to the sat it’s receiving. Indeed GPS antennas in general get this 
> right.
> There is a modest variation with angle, but it’s not all that great. Units of 
> mm are not 
> uncommon. It will be greater on a multi band design. The impact of your cover 
> also 
> will be greater on a multi band device. All the various delay /. loss / 
> reflection parameters
> are frequency dependent…..
> 
> Bob
> 
>> On Sep 6, 2019, at 5:57 PM, Hal Murray  wrote:
>> 
>> 
>> kb...@n1k.org said:
>>> The gotcha with putting anything on top of a GPS antenna is that it impacts
>>> the phase  shift from the sat’s. How important that is gets quickly into 
>>> just
>>> how picky you happen to be. 
>> 
>> How picky do I have to be before that is significant?  How geeky would I 
>> have 
>> to be to measure it?
>> 
>> Would a hemispherical cover provide equal delays at all elevations?  I think 
>> the solidly mounted USGS fault/volcano monitoring setups have a round top.
>> https://www.usgs.gov/media/images/gps-tracks-ground-deformation
>> 
>> Do any antenna manufacturers advertise uniform phase delay?
>> Do any software vendors advertise that their software works better with 
>> specific antennas?
>> 
>> 
>> 
>> -- 
>> These are my opinions.  I hate spam.
>> 
>> 
>> 
>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to 
>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Re: [time-nuts] GPS Antennas

[Björn]

Run the plastic in a microwave oven, with a glass of water. Don’t use it if the 
plastic gets warm.

/Björn 

Sent from my iPhone

> On 6 Sep 2019, at 21:45, David G. McGaw  wrote:
> 
> Also, as I have found, some plastics don't just delay but actually 
> absorb the signal.
> 
> David N1HAC
> 
>> On 9/6/19 2:28 PM, Bob kb8tq wrote:
>> Hi
>> 
>> The gotcha with putting anything on top of a GPS antenna is that it impacts 
>> the phase
>> shift from the sat’s. How important that is gets quickly into just how picky 
>> you happen to be.
>> 
>> Bob
>> 
>>> On Sep 6, 2019, at 11:07 AM, Nick Sayer via time-nuts 
>>>  wrote:
>>> 
>>> I’m late to the party, but my go-to antenna is the Gilsson marine antenna. 
>>> If it has a downside, it’s that it has a flat top instead of a cone. I’ve 
>>> got one mounted outside at our vacation home near Lake Tahoe, so we’ll see 
>>> whether snow loading becomes a problem shortly. The fix would presumably 
>>> just be a 3D printed plastic gnome’s cap, though even that might not be 
>>> useful if we get snow like we did last year.
>>> 
>>> It has a standard 14 tpi 1” standard thread, though I’ve managed to make do 
>>> on more than one occasion with 3/4” NPT.
>>> 
>>> Under normal circumstances, I routinely get 8 or more satellites with the 
>>> top SNRs in the 50s.
>>> 
>>> I designed a 3D printed mount for mounting it on a flat surface (which I 
>>> needed to do here): 
>>> https://nam05.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.thingiverse.com%2Fthing%3A3664978data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cf3faa3a2e9ed46ead3fb08d732fc9785%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637033932771963548sdata=IHu%2Fco9fp3KRNuoi0NNUBqR8dyWAw6rKl8Bpr8m0Gl8%3Dreserved=0
>>>  
>>> .
>>> 
>>> 
>>> 
 On Aug 30, 2019, at 11:35 AM, Denny Page via time-nuts 
  wrote:
 
 Could be. They sell a aluminum mounting rod for use with a magnetic base 
 which mates with the unit perfectly, so I sorta assumed it was 
 intentional. Tapering helps prevents over tightening / over extension 
 which could damage the casing.
 
 Denny
 
 
> On Aug 30, 2019, at 10:49, Bryan _  wrote:
> 
> Or a mfg. defect and thus why on the surplus market.
> 
> -=Bryan=-
> 
> 
> From: time-nuts  on behalf of Denny 
> Page via time-nuts 
> Sent: August 29, 2019 7:39 PM
> To: Discussion of precise time and frequency measurement 
> 
> Cc: Denny Page 
> Subject: Re: [time-nuts] GPS Antennas
> 
> I think several people have run into that issue, including myself. It 
> seems designed for a slightly tapered rod. Easy to fix with the right 
> tool.
> 
> Denny
> 
>> On Aug 29, 2019, at 16:41, Ben Hall  wrote:
>> 
>> Only issue with mine was that the thread wasn't fully cut, so I modified 
>> an old taper tap to be a bottoming tap with the bench grinder and 
>> finished tapping the hole to the bottom.
 
 ___
 time-nuts mailing list -- time-nuts@lists.febo.com
 To unsubscribe, go to 
 https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cf3faa3a2e9ed46ead3fb08d732fc9785%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637033932771973545sdata=yFIp1EQIDNQfOuqkyUAIY2QjSq4yNYMmrt6wi%2Bdu21M%3Dreserved=0
 and follow the instructions there.
>>> ___
>>> time-nuts mailing list -- time-nuts@lists.febo.com
>>> To unsubscribe, go to 
>>> https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cf3faa3a2e9ed46ead3fb08d732fc9785%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637033932771973545sdata=yFIp1EQIDNQfOuqkyUAIY2QjSq4yNYMmrt6wi%2Bdu21M%3Dreserved=0
>>> and follow the instructions there.
>> 
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
>> To unsubscribe, go to 
>> https://nam05.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cf3faa3a2e9ed46ead3fb08d732fc9785%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637033932771973545sdata=yFIp1EQIDNQfOuqkyUAIY2QjSq4yNYMmrt6wi%2Bdu21M%3Dreserved=0
>> and follow the instructions there.
> 
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To 

Re: [time-nuts] A comparison of the TAPR-TICC and BG7TBL FA1

[tim...@timeok.it]

   Hi Mark,

   the tests you did are between two different sources, so it is not a test 
that can determine the noise floor of the instruments under test.
   I understand that it is still a comparison on the field between the two 
measuring instruments,
   however I think it is interesting to have the noise floor of the test set 
because it is a reference absolute value.

   I enclose a plot I made about the n.f. of the TICC to which I inserted a 
10MHz in the reference channel and in the measurement channel the same signal,

   divided up to 1PPS in the measurement channel.

   I believe that this is the only way to measure the noise floor.

   best regards,

   Luciano


   Da "time-nuts" time-nuts-boun...@lists.febo.com
   A "time-nuts@lists.febo.com" time-nuts@lists.febo.com
   Cc
   Data Fri, 6 Sep 2019 20:05:57 +
   Oggetto [time-nuts] A comparison of the TAPR-TICC and BG7TBL FA1
   I did a comparison of the performance of the TAPR-TICC/TADD2-Mini divider 
and the BG7TBL FA1 frequency analyzer performance. The reference clock for both 
devices was a 5071A cesium. The device being tested was a Nortel NTPX GPSDO 10 
MHz output. Attached are screen dumps of the two Lady Heather runs.

   The noisy orange plot in the TICC run is the measured frequency offset from 
10 MHz. The noisy blue plot in the FA1 run is the measured frequency offset 
from 10 MHz. (Note the scale factor differences) Looking at the SPAN value (the 
difference between the max and min frequency measurements) shows that the FA1 
noise level is around 4 times higher than the TICC. The FA1 ADEV measurements 
are around 3 time higher. The FA1 may be better than the TICC at lower (<50 
second) tau, but I have no way to verify that. The FA1 screen dump includes a 
histogram of the frequency measurements.

   issue with the FA1 is that it seems to have an inherent frequency 
measurement bias of around -0.0002 Hz. See the "avg#" value in the lower left 
corner of the plot. I get nearly the same bias values when measuring 1, 5, and 
10 MHz signals. (I added a setting in Lady Heather to specify a measurment bias 
correction value). It is interesting that the same -0.0002 Hz bias was present 
in the original BG7TBL GPSDO.

   TAPR TICC pros:
   high performance
   lots of measurement and configuration options
   open source design

   TAPR TICC cons:
   more expensive
   requires external dividers to measure frequency (and a second power supply)
   no case

   FA1 pros:
   inexpensive (around $100), decent bang for the buck
   no frequency divider needed, 1 .. 80 MHz range
   very simple operation (no configuration needed)
   nice small unit with an extruded metal case.

   FA1 cons:
   measures frequency (no way to test 1PPS signals)
   around 3X-4x less performance than the TAPR TICC.
   closed source "black box"
   inherent minor frequency measurement offset

   Lately BG7TBL has released the FA2. This appears to be similar to the FA1, 
but it has some VERY nice features including a basic 1 Hz .. 200 MHz range plus 
a 30:1 pre-scaler allowing measurements to 6 GHz. It as an LCD display, an 
internal (adjustable) OCXO and external freq ref input, reference output, 
selectable 0.1/1/10 second timebase. Costs around $120 (with power supply) If 
the FA2 measurement performance matches the FA1, it would be greatly preferable 
over the FA1. I have an FA2 the way.
___
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to 
http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.