Re: [time-nuts] Tardis [WAS: Using the HP 58503a to correct your PC clock]

[Ron Ott]

That's encouraging!! I'm working on NTP and have no idea what's happening. The 
description says it takes over the PC clock, excluding other apps. I like the 
rate correction concept, but not if I lose my hair or have to wipe the drive.
Ron


  From: Charles Steinmetz 
 To: time-nuts@febo.com 
 Sent: Thursday, August 4, 2016 1:08 PM
 Subject: Re: [time-nuts] Tardis [WAS: Using the HP 58503a to correct your PC 
clock]
   
David wrote:

> I am not sure if Tardis works with Windows 7 and above though; I
> forget to test it on my Windows 7 test system when I had it.  It is a
> pretty old (but free) program.

About five years ago, after a lot of experience with Tardis under XP, I 
worked for several weeks trying to get it to work under Vista.  I never 
succeeded, and it fatally corrupted the system.  I had to wipe the boot 
drive and start over.

Best regards,

Charles


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Re: [time-nuts] Looking to find an antenna for a TrueTime XL-DC

[Hal Murray]

rick.jon...@hpe.com said:
> HalM was kind enough to come over the other day with some antennae which  we
> tried without success. 

I was going to suggest taking the cover off and looking inside but it fell 
off my to-do list.

GPS receivers are reasonably specialized.  I doubt it anybody makes one 
targeted at the down-converter market.

Is there an up-converter in there feeding a normal receiver?  If so, it might 
be possible/easy to bypass.

If it looks like a direct connection to a normal receiver, I'd guess it has 
special firmware.  It might be possible to replace it with one with normal 
firmware.


-- 
These are my opinions.  I hate spam.



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[time-nuts] NUT4NT: Four-channel All-frequency GNSS RF-to-Bits

[Daniel Mendes]

A new interesting toy soon to be crowdsourced:

https://www.crowdsupply.com/amungo-navigation/nut4nt

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Re: [time-nuts] GPS antenna selection

[Herbert Poetzl]

On Thu, Aug 04, 2016 at 06:26:28PM -0400, Bob Camp wrote:
> Hi

Hey Bob!

>> On Aug 4, 2016, at 5:29 PM, Herbert Poetzl  wrote:

>> Dear fellow time-nuts!

>> I'm currently investigating my options regarding 
>> GPS antennae (of course for time related purposes)
>> and I'm really confused by the variety they come
>> in ... (my apologies in advance for the long post).


>> Setting:

>> I'm living in a three storey house with a sloped
>> roof, a covered balcony and a larger garden with
>> huge trees on the Austrian countryside (Europe).

>> I've walked around with my smartphone (older one)
>> and I get a GPS position fix within 35s in the 
>> garden (nine satellites shown), within 100s on 
>> the balcony (also nine satellites), and not a
>> single satellite can be seen indoors.

>> The obvious choice would be to put the antenna on
>> top in the middle of the slanted roof for a perfect
>> sky view, but this brings a number of problems as
>> the roof is very hard to reach and quite high.

>> I have my 'lab' at the floor where the balcony is,
>> so I'm considering putting an antenna there and
>> run about 5-15m of coax cable to the GPS receiver.
>> The advantage there is that the antenna would be
>> somewhat protected (it still gets very hot during
>> summer and very cold during winter, but no rain
>> and no snow) and easy to reach for maintenance.

>> The third alternative would be to put the antenna
>> somewhere in the garden and have a rather long
>> cable running to the house and up to my lab.


>> Antennae:

>> Looking on eBay and Amazon shows a huge pricerange 
>> for active GPS antennae with and without cable. 

>> It seems to start at about 10 bucks with rather
>> small black boxes [1] designed for cars, probably 
>> containing a 25x25 ceramic GPS antenna and an 
>> amplifier, progresses over very interesting out-
>> door constructions for boats and whatnot [2] in 
>> the 20-100 bucks range and finally tops with high 
>> end devices [3] way above 100 bucks.

>> The information about the cheap devices is usually
>> very scarce, but typically boils down to:

>> 1575.42 +/- 5MHz 
>> 24-28dB LNA Gain with 10-25mA at (3-5V)

>> 7dB f0 +/- 20MHz
>> 20dB f0 +/- 50MHz
>> 30dB f0 +/- 100MHz

> That’s the spec on the interference rejection filter. 
> Tighter is better as long as it still passes the 
> desired signal(s). 

Understood!

>> They seem to use RG174 and come with SMA as well
>> as BNC connectors (and a number of others as well).

> The better ones will have a TNC connector on them

Hmm, I had to google TNC (Threaded Neill-Concelman).
Is it worth the trouble in the < 2GHz range?

>> The mid range devices seem to use larger antennae
>> with smaller tolerances (+/- 1MHz) and larger
>> voltage ranges for the amplifier (3-13V).


>> Questions:

>> - What are the key specifications which need to
>>   be verified before buying a GPS antenna?

> You want one that is designed for permanent outdoor 
> use. 

> That eliminates the $10 car mounts. 

Even under somewhat protected conditions like on the
covered balcony?


> These days, I’d get one that does both GPS and GLONASS

Makes sense.


>> - How can they be compared based on incomplete
>>   specifications?

> They can’t. It’s just luck. The ones you see for 
> about $40 and up that are designed for mast mounting 
> are usually pretty good.

Okay, thanks!

>> - Is a place on the roof or in the garden worth
>>   the trouble over the covered balcony?

> The real question is how much of a sky view you get. 

> Ideally you would like a clear view of the sky from 
> about NE clear around to NW (270 degrees). 

That would opt for the balcony, as it faces north
and extends the slanted roof, so basically clear
view from NE to NW down to the horizon.

> You also would like to be able to “see” down to within 
> 10 degrees of the horizon over that range. 

> The segment from E to W (180 degrees) is pretty
> important. 

> Being able to see to within 30 degrees of the horizon 
> is also pretty important.


>> - Are there any typical pit-falls or general
>>   tips and tricks regarding mounting and cable
>>   connection to the receiver?

> Some receivers put out +12V, most antennas don’t like 
> +12 and want +5. 

> Some modern antennas will only handle +3.3V.

> If you have a long run to the antenna, feed line loss 
> is what matters. 

> To some degree you can cope with this by buying an
> antenna that has a higher gain amp in it. 

> They range from about 21 db to about 50 db. 

> You also don’t want to over drive your receiver so 
> just getting the 50 db version is not a perfect
> solution.

Understood! Is there some rule of thumb at what
cable lengths which amplifier gain is best suited?

> Grounding the antenna is always a good idea. 

> A surge suppressor in the line could save you some 
> real cost if there is a lightning strike. 

I did a quick search for SMA/BNC/TNC based surge
protectors and not much did come up, any suggestions
what to 

Re: [time-nuts] GPS antenna selection

[Bob Camp]

Hi

> On Aug 4, 2016, at 7:26 PM, Herbert Poetzl  wrote:
> 
> On Thu, Aug 04, 2016 at 06:26:28PM -0400, Bob Camp wrote:
>> Hi
> 
> Hey Bob!
> 
>>> On Aug 4, 2016, at 5:29 PM, Herbert Poetzl  wrote:
> 
>>> Dear fellow time-nuts!
> 
>>> I'm currently investigating my options regarding 
>>> GPS antennae (of course for time related purposes)
>>> and I'm really confused by the variety they come
>>> in ... (my apologies in advance for the long post).
> 
> 
>>> Setting:
> 
>>> I'm living in a three storey house with a sloped
>>> roof, a covered balcony and a larger garden with
>>> huge trees on the Austrian countryside (Europe).
> 
>>> I've walked around with my smartphone (older one)
>>> and I get a GPS position fix within 35s in the 
>>> garden (nine satellites shown), within 100s on 
>>> the balcony (also nine satellites), and not a
>>> single satellite can be seen indoors.
> 
>>> The obvious choice would be to put the antenna on
>>> top in the middle of the slanted roof for a perfect
>>> sky view, but this brings a number of problems as
>>> the roof is very hard to reach and quite high.
> 
>>> I have my 'lab' at the floor where the balcony is,
>>> so I'm considering putting an antenna there and
>>> run about 5-15m of coax cable to the GPS receiver.
>>> The advantage there is that the antenna would be
>>> somewhat protected (it still gets very hot during
>>> summer and very cold during winter, but no rain
>>> and no snow) and easy to reach for maintenance.
> 
>>> The third alternative would be to put the antenna
>>> somewhere in the garden and have a rather long
>>> cable running to the house and up to my lab.
> 
> 
>>> Antennae:
> 
>>> Looking on eBay and Amazon shows a huge pricerange 
>>> for active GPS antennae with and without cable. 
> 
>>> It seems to start at about 10 bucks with rather
>>> small black boxes [1] designed for cars, probably 
>>> containing a 25x25 ceramic GPS antenna and an 
>>> amplifier, progresses over very interesting out-
>>> door constructions for boats and whatnot [2] in 
>>> the 20-100 bucks range and finally tops with high 
>>> end devices [3] way above 100 bucks.
> 
>>> The information about the cheap devices is usually
>>> very scarce, but typically boils down to:
> 
>>> 1575.42 +/- 5MHz 
>>> 24-28dB LNA Gain with 10-25mA at (3-5V)
> 
>>> 7dB f0 +/- 20MHz
>>> 20dB f0 +/- 50MHz
>>> 30dB f0 +/- 100MHz
> 
>> That’s the spec on the interference rejection filter. 
>> Tighter is better as long as it still passes the 
>> desired signal(s). 
> 
> Understood!
> 
>>> They seem to use RG174 and come with SMA as well
>>> as BNC connectors (and a number of others as well).
> 
>> The better ones will have a TNC connector on them
> 
> Hmm, I had to google TNC (Threaded Neill-Concelman).
> Is it worth the trouble in the < 2GHz range?

It threads on rather than latches on like a BNC. That makes it 
more water tight in the outdoor environment. 

> 
>>> The mid range devices seem to use larger antennae
>>> with smaller tolerances (+/- 1MHz) and larger
>>> voltage ranges for the amplifier (3-13V).
> 
> 
>>> Questions:
> 
>>> - What are the key specifications which need to
>>>  be verified before buying a GPS antenna?
> 
>> You want one that is designed for permanent outdoor 
>> use. 
> 
>> That eliminates the $10 car mounts. 
> 
> Even under somewhat protected conditions like on the
> covered balcony?

You still have fog / condensation / humidity and the other sources
of moisture. So not quite so important, but we rule out the balcony below. 

> 
> 
>> These days, I’d get one that does both GPS and GLONASS
> 
> Makes sense.
> 
> 
>>> - How can they be compared based on incomplete
>>>  specifications?
> 
>> They can’t. It’s just luck. The ones you see for 
>> about $40 and up that are designed for mast mounting 
>> are usually pretty good.
> 
> Okay, thanks!
> 
>>> - Is a place on the roof or in the garden worth
>>>  the trouble over the covered balcony?
> 
>> The real question is how much of a sky view you get. 
> 
>> Ideally you would like a clear view of the sky from 
>> about NE clear around to NW (270 degrees). 
> 
> That would opt for the balcony, as it faces north
> and extends the slanted roof, so basically clear
> view from NE to NW down to the horizon.

It needs to face south and have a clear view over a 270 degree arc. 
If it faces north …. not going to work very well at all. 

> 
>> You also would like to be able to “see” down to within 
>> 10 degrees of the horizon over that range. 
> 
>> The segment from E to W (180 degrees) is pretty
>> important. 
> 
>> Being able to see to within 30 degrees of the horizon 
>> is also pretty important.
> 
> 
>>> - Are there any typical pit-falls or general
>>>  tips and tricks regarding mounting and cable
>>>  connection to the receiver?
> 
>> Some receivers put out +12V, most antennas don’t like 
>> +12 and want +5. 
> 
>> Some modern antennas will only handle +3.3V.
> 
>> If you have a long run to the 

Re: [time-nuts] GPS antenna selection

[Tom Miller]

Do you have a picture of the balcony?


- Original Message - 
From: "Herbert Poetzl" 

To: 
Sent: Thursday, August 04, 2016 5:29 PM
Subject: [time-nuts] GPS antenna selection




Dear fellow time-nuts!

I'm currently investigating my options regarding
GPS antennae (of course for time related purposes)
and I'm really confused by the variety they come
in ... (my apologies in advance for the long post).


Setting:

I'm living in a three storey house with a sloped
roof, a covered balcony and a larger garden with
huge trees on the Austrian countryside (Europe).

I've walked around with my smartphone (older one)
and I get a GPS position fix within 35s in the
garden (nine satellites shown), within 100s on
the balcony (also nine satellites), and not a
single satellite can be seen indoors.

The obvious choice would be to put the antenna on
top in the middle of the slanted roof for a perfect
sky view, but this brings a number of problems as
the roof is very hard to reach and quite high.

I have my 'lab' at the floor where the balcony is,
so I'm considering putting an antenna there and
run about 5-15m of coax cable to the GPS receiver.
The advantage there is that the antenna would be
somewhat protected (it still gets very hot during
summer and very cold during winter, but no rain
and no snow) and easy to reach for maintenance.

The third alternative would be to put the antenna
somewhere in the garden and have a rather long
cable running to the house and up to my lab.


Antennae:

Looking on eBay and Amazon shows a huge pricerange
for active GPS antennae with and without cable.

It seems to start at about 10 bucks with rather
small black boxes [1] designed for cars, probably
containing a 25x25 ceramic GPS antenna and an
amplifier, progresses over very interesting out-
door constructions for boats and whatnot [2] in
the 20-100 bucks range and finally tops with high
end devices [3] way above 100 bucks.

The information about the cheap devices is usually
very scarce, but typically boils down to:

1575.42 +/- 5MHz
24-28dB LNA Gain with 10-25mA at (3-5V)

7dB f0 +/- 20MHz
20dB f0 +/- 50MHz
30dB f0 +/- 100MHz

They seem to use RG174 and come with SMA as well
as BNC connectors (and a number of others as well).

The mid range devices seem to use larger antennae
with smaller tolerances (+/- 1MHz) and larger
voltage ranges for the amplifier (3-13V).


Questions:

- What are the key specifications which need to
  be verified before buying a GPS antenna?

- How can they be compared based on incomplete
  specifications?

- Is a place on the roof or in the garden worth
  the trouble over the covered balcony?

- Are there any typical pit-falls or general
  tips and tricks regarding mounting and cable
  connection to the receiver?

Many thanks in advance and my apologies again for
the rather lengthy post. Please feel free to point
me to previous discussion regarding this topic.

All the best,
Herbert


[1] 
http://www.ebay.com/itm/99-Good-GPS-Antenna-SMA-Screw-Needle-10m-Super-Signal-Navigation-DVD-Antenna-/171802461614


https://www.amazon.com/Waterproof-Active-Antenna-28dB-Gain/dp/B00LXRQY9A

[2] 
http://www.ebay.com/itm/Standard-Horizon-XUCMP0014-GPS-Antenna-f-CP150-CP160-CP170/331364914004


https://www.amazon.com/Garmin-010-12017-00-GPS-GLONASS-Antenna/dp/B00EVT2HSE

https://www.amazon.com/SUNDELY®-External-Marine-Antenna-connector/dp/B00D8WAVTC

[3] 
http://www.ebay.com/itm/NEW-FURUNO-GPA018-Gps-dgps-Antenna-/182223355414

   https://www.amazon.com/Garmin-nmea-2000-orders-over/dp/B0089DU96A

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[time-nuts] Looking to find an antenna for a TrueTime XL-DC

[Rick Jones]

I have been bequeathed a TrueTime XL-DC, Model 151-601-1, serial number 
1671 per a sticker on the side.  On the back, on the right as one faces 
the back, is a small sticker that says "Down Conv. Req'd"


Unsurprisingly, it has arrived without an antenna.  If the original 
antenna still exists, it is on a building roof in Ft. Collins Colorado 
and is likely effectively lost.  (I'm in Sunnyvale, CA)


HalM was kind enough to come over the other day with some antennae which 
we tried without success.  Since then I've done a bit of web searching 
and come across:


http://www.prostudioconnection.com/Symmetricom-TrueTime-GPS-Antenna-140-615-Downconve-p/282092173717.htm

It seems to be a part that was (also) included in a larger down/up 
conversion product, the 140-6150.  I was wondering if the naive 
assumption that "TrueTime down conversion is TrueTime down conversion" 
and the sticker on the back of the DC-XL might mean the 140-615 antenna 
would work with the DC-XL?


thanks muchly,

rick jones
intrigued member of the peanut gallery
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Re: [time-nuts] GPS antenna selection

[Bob Camp]

Hi

> On Aug 4, 2016, at 5:29 PM, Herbert Poetzl  wrote:
> 
> 
> Dear fellow time-nuts!
> 
> I'm currently investigating my options regarding 
> GPS antennae (of course for time related purposes)
> and I'm really confused by the variety they come
> in ... (my apologies in advance for the long post).
> 
> 
> Setting:
> 
> I'm living in a three storey house with a sloped
> roof, a covered balcony and a larger garden with
> huge trees on the Austrian countryside (Europe).
> 
> I've walked around with my smartphone (older one)
> and I get a GPS position fix within 35s in the 
> garden (nine satellites shown), within 100s on 
> the balcony (also nine satellites), and not a
> single satellite can be seen indoors.
> 
> The obvious choice would be to put the antenna on
> top in the middle of the slanted roof for a perfect
> sky view, but this brings a number of problems as
> the roof is very hard to reach and quite high.
> 
> I have my 'lab' at the floor where the balcony is,
> so I'm considering putting an antenna there and
> run about 5-15m of coax cable to the GPS receiver.
> The advantage there is that the antenna would be
> somewhat protected (it still gets very hot during
> summer and very cold during winter, but no rain
> and no snow) and easy to reach for maintenance.
> 
> The third alternative would be to put the antenna
> somewhere in the garden and have a rather long
> cable running to the house and up to my lab.
> 
> 
> Antennae:
> 
> Looking on eBay and Amazon shows a huge pricerange 
> for active GPS antennae with and without cable. 
> 
> It seems to start at about 10 bucks with rather
> small black boxes [1] designed for cars, probably 
> containing a 25x25 ceramic GPS antenna and an 
> amplifier, progresses over very interesting out-
> door constructions for boats and whatnot [2] in 
> the 20-100 bucks range and finally tops with high 
> end devices [3] way above 100 bucks.
> 
> The information about the cheap devices is usually
> very scarce, but typically boils down to:
> 
> 1575.42 +/- 5MHz 
> 24-28dB LNA Gain with 10-25mA at (3-5V)
> 
> 7dB f0 +/- 20MHz
> 20dB f0 +/- 50MHz
> 30dB f0 +/- 100MHz

That’s the spec on the interference  rejection filter. Tighter is better 
as long as it still passes the desired signal(s). 

> 
> They seem to use RG174 and come with SMA as well
> as BNC connectors (and a number of others as well).

The better ones will have a TNC connector on them

> 
> The mid range devices seem to use larger antennae
> with smaller tolerances (+/- 1MHz) and larger
> voltage ranges for the amplifier (3-13V).
> 
> 
> Questions:
> 
> - What are the key specifications which need to
>   be verified before buying a GPS antenna?

You want one that is designed for permanent outdoor use. That eliminates the 
$10 
car mounts. These days, I’d get one that does both GPS and GLONASS

> 
> - How can they be compared based on incomplete
>   specifications?

They can’t. It’s just luck. The ones you see for about $40 and up that are 
designed
for mast mounting are usually pretty good. 

> 
> - Is a place on the roof or in the garden worth
>   the trouble over the covered balcony?

The real question is how much of a sky view you get. Ideally you would like a 
clear view
of the sky from about NE clear around to NW (270 degrees). You also would like 
to be
able to “see” down to within 10 degrees of the horizon over that range. The 
segment from 
E to W (180 degrees) is pretty important. Being able to see to within 30 
degrees of the 
horizon is also pretty important. 

> 
> - Are there any typical pit-falls or general
>   tips and tricks regarding mounting and cable
>   connection to the receiver?

Some receivers put out +12V, most antennas don’t like +12 and want +5. Some 
modern
antennas will only handle +3.3V. 

If you have a long run to the antenna, feed line loss is what matters. To some 
degree
you can cope with this by buying an antenna that has a higher gain amp in it. 
They 
range from about 21 db to about 50 db. You also don’t want to over drive your 
receiver
so just getting the 50 db version is not a perfect solution. 

Grounding the antenna is always a good idea. A surge suppressor  in the line 
could save
you some real cost if there is a lightning strike. I don’t know about Austria, 
but here in 
the US, both are required. 

Bob

> 
> Many thanks in advance and my apologies again for
> the rather lengthy post. Please feel free to point
> me to previous discussion regarding this topic.
> 
> All the best,
> Herbert
> 
> 
> [1] 
> http://www.ebay.com/itm/99-Good-GPS-Antenna-SMA-Screw-Needle-10m-Super-Signal-Navigation-DVD-Antenna-/171802461614
>https://www.amazon.com/Waterproof-Active-Antenna-28dB-Gain/dp/B00LXRQY9A
> 
> [2] 
> http://www.ebay.com/itm/Standard-Horizon-XUCMP0014-GPS-Antenna-f-CP150-CP160-CP170/331364914004
>
> https://www.amazon.com/Garmin-010-12017-00-GPS-GLONASS-Antenna/dp/B00EVT2HSE
>
> 

Re: [time-nuts] GPS antenna selection

[Alex Pummer]

Hi Herbert,

just look the loss of the cable at 1500 MHz, and you will start to cry 
at 1500MHz tha cable will have cca 30dB for a 30meter long 
piecebasically that RG174 looks very nice with that small antenna 
but that is the only positive aspect. Meinberg in Germany has one 
up/down converting system, which makes it possible to go more than 50 meter.
On the other hand if you could stay on the balcony and use the cable 
which came with the antenna, 2m  to 3 meter,  you could have a good 
working system, but with 15m RG174  is asking to much. For 1500 MHz BNC 
is not the best solution,

73
KJ6UHN
Alex
P.S.: wo ist diese "Austrian countryside"

On 8/4/2016 2:29 PM, Herbert Poetzl wrote:

Dear fellow time-nuts!

I'm currently investigating my options regarding
GPS antennae (of course for time related purposes)
and I'm really confused by the variety they come
in ... (my apologies in advance for the long post).


Setting:

I'm living in a three storey house with a sloped
roof, a covered balcony and a larger garden with
huge trees on the Austrian countryside (Europe).

I've walked around with my smartphone (older one)
and I get a GPS position fix within 35s in the
garden (nine satellites shown), within 100s on
the balcony (also nine satellites), and not a
single satellite can be seen indoors.

The obvious choice would be to put the antenna on
top in the middle of the slanted roof for a perfect
sky view, but this brings a number of problems as
the roof is very hard to reach and quite high.

I have my 'lab' at the floor where the balcony is,
so I'm considering putting an antenna there and
run about 5-15m of coax cable to the GPS receiver.
The advantage there is that the antenna would be
somewhat protected (it still gets very hot during
summer and very cold during winter, but no rain
and no snow) and easy to reach for maintenance.

The third alternative would be to put the antenna
somewhere in the garden and have a rather long
cable running to the house and up to my lab.


Antennae:

Looking on eBay and Amazon shows a huge pricerange
for active GPS antennae with and without cable.

It seems to start at about 10 bucks with rather
small black boxes [1] designed for cars, probably
containing a 25x25 ceramic GPS antenna and an
amplifier, progresses over very interesting out-
door constructions for boats and whatnot [2] in
the 20-100 bucks range and finally tops with high
end devices [3] way above 100 bucks.

The information about the cheap devices is usually
very scarce, but typically boils down to:

  1575.42 +/- 5MHz
  24-28dB LNA Gain with 10-25mA at (3-5V)

  7dB f0 +/- 20MHz
  20dB f0 +/- 50MHz
  30dB f0 +/- 100MHz

They seem to use RG174 and come with SMA as well
as BNC connectors (and a number of others as well).

The mid range devices seem to use larger antennae
with smaller tolerances (+/- 1MHz) and larger
voltage ranges for the amplifier (3-13V).


Questions:

  - What are the key specifications which need to
be verified before buying a GPS antenna?

  - How can they be compared based on incomplete
specifications?

  - Is a place on the roof or in the garden worth
the trouble over the covered balcony?

  - Are there any typical pit-falls or general
tips and tricks regarding mounting and cable
connection to the receiver?

Many thanks in advance and my apologies again for
the rather lengthy post. Please feel free to point
me to previous discussion regarding this topic.

All the best,
Herbert


[1] 
http://www.ebay.com/itm/99-Good-GPS-Antenna-SMA-Screw-Needle-10m-Super-Signal-Navigation-DVD-Antenna-/171802461614
 https://www.amazon.com/Waterproof-Active-Antenna-28dB-Gain/dp/B00LXRQY9A

[2] 
http://www.ebay.com/itm/Standard-Horizon-XUCMP0014-GPS-Antenna-f-CP150-CP160-CP170/331364914004
 
https://www.amazon.com/Garmin-010-12017-00-GPS-GLONASS-Antenna/dp/B00EVT2HSE
 
https://www.amazon.com/SUNDELY®-External-Marine-Antenna-connector/dp/B00D8WAVTC

[3] http://www.ebay.com/itm/NEW-FURUNO-GPA018-Gps-dgps-Antenna-/182223355414
 https://www.amazon.com/Garmin-nmea-2000-orders-over/dp/B0089DU96A
 
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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7690 / Virus Database: 4627/12745 - Release Date: 08/04/16


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Re: [time-nuts] Tardis [WAS: Using the HP 58503a to correct your PC clock]

[Charles Steinmetz]

David wrote:


I am not sure if Tardis works with Windows 7 and above though; I
forget to test it on my Windows 7 test system when I had it.  It is a
pretty old (but free) program.


About five years ago, after a lot of experience with Tardis under XP, I 
worked for several weeks trying to get it to work under Vista.  I never 
succeeded, and it fatally corrupted the system.  I had to wipe the boot 
drive and start over.


Best regards,

Charles


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[time-nuts] GPS antenna selection

[Herbert Poetzl]

Dear fellow time-nuts!

I'm currently investigating my options regarding 
GPS antennae (of course for time related purposes)
and I'm really confused by the variety they come
in ... (my apologies in advance for the long post).


Setting:

I'm living in a three storey house with a sloped
roof, a covered balcony and a larger garden with
huge trees on the Austrian countryside (Europe).

I've walked around with my smartphone (older one)
and I get a GPS position fix within 35s in the 
garden (nine satellites shown), within 100s on 
the balcony (also nine satellites), and not a
single satellite can be seen indoors.

The obvious choice would be to put the antenna on
top in the middle of the slanted roof for a perfect
sky view, but this brings a number of problems as
the roof is very hard to reach and quite high.

I have my 'lab' at the floor where the balcony is,
so I'm considering putting an antenna there and
run about 5-15m of coax cable to the GPS receiver.
The advantage there is that the antenna would be
somewhat protected (it still gets very hot during
summer and very cold during winter, but no rain
and no snow) and easy to reach for maintenance.

The third alternative would be to put the antenna
somewhere in the garden and have a rather long
cable running to the house and up to my lab.


Antennae:

Looking on eBay and Amazon shows a huge pricerange 
for active GPS antennae with and without cable. 

It seems to start at about 10 bucks with rather
small black boxes [1] designed for cars, probably 
containing a 25x25 ceramic GPS antenna and an 
amplifier, progresses over very interesting out-
door constructions for boats and whatnot [2] in 
the 20-100 bucks range and finally tops with high 
end devices [3] way above 100 bucks.

The information about the cheap devices is usually
very scarce, but typically boils down to:

 1575.42 +/- 5MHz 
 24-28dB LNA Gain with 10-25mA at (3-5V)

 7dB f0 +/- 20MHz
 20dB f0 +/- 50MHz
 30dB f0 +/- 100MHz

They seem to use RG174 and come with SMA as well
as BNC connectors (and a number of others as well).

The mid range devices seem to use larger antennae
with smaller tolerances (+/- 1MHz) and larger
voltage ranges for the amplifier (3-13V).


Questions:

 - What are the key specifications which need to
   be verified before buying a GPS antenna?

 - How can they be compared based on incomplete
   specifications?

 - Is a place on the roof or in the garden worth
   the trouble over the covered balcony?

 - Are there any typical pit-falls or general
   tips and tricks regarding mounting and cable
   connection to the receiver?

Many thanks in advance and my apologies again for
the rather lengthy post. Please feel free to point
me to previous discussion regarding this topic.

All the best,
Herbert


[1] 
http://www.ebay.com/itm/99-Good-GPS-Antenna-SMA-Screw-Needle-10m-Super-Signal-Navigation-DVD-Antenna-/171802461614
https://www.amazon.com/Waterproof-Active-Antenna-28dB-Gain/dp/B00LXRQY9A

[2] 
http://www.ebay.com/itm/Standard-Horizon-XUCMP0014-GPS-Antenna-f-CP150-CP160-CP170/331364914004
https://www.amazon.com/Garmin-010-12017-00-GPS-GLONASS-Antenna/dp/B00EVT2HSE

https://www.amazon.com/SUNDELY®-External-Marine-Antenna-connector/dp/B00D8WAVTC

[3] http://www.ebay.com/itm/NEW-FURUNO-GPA018-Gps-dgps-Antenna-/182223355414
https://www.amazon.com/Garmin-nmea-2000-orders-over/dp/B0089DU96A

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Re: [time-nuts] Using the HP 58503a to correct your PC clock

[David]

On Thu, 4 Aug 2016 19:05:13 + (UTC), you wrote:

>My granddaughter would love to know I have a Tardis program. (-;>  Lots of 
>things to try here, just to get a more accurate clock. No wonder there's a 
>time-nutz group!

The Tardis log shows that accessing external NTP servers is a problem
for me so I was going to setup a local server using a Garmin 18x but
during tests, a squirrel chewed the cable through and stole it.

http://www.mingham-smith.com/tardis.htm

2016/08/04 08:06:29.58
Correction of 0.071 seconds used to adjust clock frequency
2016/08/04 09:18:29.97
Correction of -0.102 seconds used to adjust clock frequency
2016/08/04 10:28:29.78
Correction of 0.220 seconds used to adjust clock frequency
2016/08/04 11:34:31.95
The time has been corrected by 1.431 seconds (Clock stepped)
2016/08/04 12:32:32.08
The time has been corrected by -2.206 seconds (Clock stepped)
2016/08/04 13:14:32.22
The time has been corrected by -1.588 seconds (Clock stepped)
2016/08/04 13:24:32.73
Correction of -0.377 seconds used to adjust clock frequency
2016/08/04 13:34:32.82
Correction of -0.374 seconds used to adjust clock frequency
2016/08/04 13:44:32.78
Correction of -0.225 seconds used to adjust clock frequency

https://s31.postimg.org/515gxfo4r/Tardis2000.gif
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Re: [time-nuts] Using the HP 58503a to correct your PC clock

[cfo]

On Thu, 04 Aug 2016 17:24:31 +, Mark Sims wrote:

> Probably the best way for most people to keep their clock accurate is to
> use something like NTP 
Doesn't Meinberg have a Win7 version of ntp on their homepage ?

Why not use that

CFO

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Re: [time-nuts] Using the HP 58503a to correct your PC clock

[Ron Ott]

My granddaughter would love to know I have a Tardis program. (-;>  Lots of 
things to try here, just to get a more accurate clock. No wonder there's a 
time-nutz group!


  From: David 
 To: Discussion of precise time and frequency measurement  
 Sent: Thursday, August 4, 2016 11:47 AM
 Subject: Re: [time-nuts] Using the HP 58503a to correct your PC clock
   
The old Tardis program for Windows (Tardis2000 now) handles it
correctly by altering the rate and only jamming the time if it is
outside of a specified window but I do not think its GPS mode supports
the 1 PPS signal.

I am not sure if Tardis works with Windows 7 and above though; I
forget to test it on my Windows 7 test system when I had it.  It is a
pretty old (but free) program.

On Tue, 2 Aug 2016 23:28:06 -0700, you wrote:

>The WRONG way to adjust a PC clock is to set the TIME periodically from
>some standard.  When you do this then the time on the PC is not running at
>a constant rate.  The correct way to do this is to adjust the PC's clocks
>RATE.  You make it runs slightly faster if you notice it is getting behind
>and slightly slower if it is running fast.
>
>Think about what you would do to a real physical clock.  You would not set
>it every few minutes, you'd adjust the rate and wait a little while to see
>if the adjustment needs refinement or not.
>
>...
>
>Most operating systems in use today run NTP to keep their clocks in order.
>Well most OSes except for Windows.  Microsoft uses a vey much simplified
>version of this that does the wrong thing and periodically sets the PC's
>clock.  You could enable this and likely, maybe reach your +/- 100ms goal.
>  Not the "real" NTP is a free program and not hard to set up so you can
>have 1ms level accuracy without much effort and better with some work.
>
>On Tue, Aug 2, 2016 at 8:13 PM, Ron Ott  wrote:
>
>> This has probably been covered in the past, but is there a way correct or
>> control a PC (Windows 7) clock with the HP 58503A GPS receiver? I just
>> bought one (on the way now) and have a copy of satstats50 on hand. I've
>> been using Dimension 4 and I'm surprised at the size of correction every
>> couple minutes to my PC clock.  I'd be happy if my PC clock were accurate
>> to plus/minus 100ms.
>> Ron
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Re: [time-nuts] Using the HP 58503a to correct your PC clock

[David]

The old Tardis program for Windows (Tardis2000 now) handles it
correctly by altering the rate and only jamming the time if it is
outside of a specified window but I do not think its GPS mode supports
the 1 PPS signal.

I am not sure if Tardis works with Windows 7 and above though; I
forget to test it on my Windows 7 test system when I had it.  It is a
pretty old (but free) program.

On Tue, 2 Aug 2016 23:28:06 -0700, you wrote:

>The WRONG way to adjust a PC clock is to set the TIME periodically from
>some standard.  When you do this then the time on the PC is not running at
>a constant rate.  The correct way to do this is to adjust the PC's clocks
>RATE.  You make it runs slightly faster if you notice it is getting behind
>and slightly slower if it is running fast.
>
>Think about what you would do to a real physical clock.  You would not set
>it every few minutes, you'd adjust the rate and wait a little while to see
>if the adjustment needs refinement or not.
>
>...
>
>Most operating systems in use today run NTP to keep their clocks in order.
>Well most OSes except for Windows.  Microsoft uses a vey much simplified
>version of this that does the wrong thing and periodically sets the PC's
>clock.   You could enable this and likely, maybe reach your +/- 100ms goal.
>  Not the "real" NTP is a free program and not hard to set up so you can
>have 1ms level accuracy without much effort and better with some work.
>
>On Tue, Aug 2, 2016 at 8:13 PM, Ron Ott  wrote:
>
>> This has probably been covered in the past, but is there a way correct or
>> control a PC (Windows 7) clock with the HP 58503A GPS receiver? I just
>> bought one (on the way now) and have a copy of satstats50 on hand. I've
>> been using Dimension 4 and I'm surprised at the size of correction every
>> couple minutes to my PC clock.  I'd be happy if my PC clock were accurate
>> to plus/minus 100ms.
>> Ron
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Re: [time-nuts] standard fusion for accuracy and redundancy

[Attila Kinali]

On Thu, 4 Aug 2016 11:08:52 -0400
Ruslan Nabioullin  wrote:

> Hi, I'm in the process of setting up a public stratum 1 NTP server which 
> will have at least one standard as a fallback to GPS (and possibly WWV 
> and CHU), in addition to its primary purpose as a timebase for a 
> microwave active SETI transmitter.  So far I have an aging = 1E-11 
> rubidium standard (which has expired calibration documentation), and I'm 
> interested in adding more standards in the future, specifically 
> high-quality OCXO(s) and additional rubidium standard(s) (I'm 
> uninterested in cesium standards due to their definite and short 
> lifespan, and masers are, in almost all certainty, insanely expensive).

I am not sure whether you want to build an ensemble for your ntp server
or you want to build an ensemble for your microwave transmitter.

The former is relatively easy to do, as us level of precision/accuracy
is more than enough. The latter is more involved and requires proper
elecronic design to achieve short term stability improvements over
a single frequency standard.


> Based on attempts of understanding the NTP documentation and answers 
> from NTP fora, NTP doesn't perform PPS fusion for accuracy, but rather 
> merely for redundancy (correct me if I'm wrong).  Therefore, this 
> complicates things to an extreme degree, for it means that the RF 
> outputs (typically 100 kHz, 1 MHz, 5 Mhz, and/or 10 MHz), or PPS outputs 
> have to be combined using some sort of a weighted fusion method (or 
> simply unweighted, if the aging figures are similar across all the 
> standards).  The only commercial piece of equipment to perform this, 
> manufactured by some Russian corporation, is obscure and just by the 
> look of it prohibitively-expensive.

Mostly because this kind of equpiment is (semi-)custom build, these days.

Generally, there is a DMTD based phase comparator in combination
with a phase microstepper (or a DDS solution) together with a PC or similar
for the control software.

>  So that leaves custom fabrication; 
> the best information I could find regarding this is the paper ``A 
> Digital Technique for Combining Frequency Standards'', by Lynn Hawkey, 
> published in '69, which outlines nonnovel approaches and a novel 
> approach to fusion.  The method that's attractive to myself is the old 
> RF mixing one, wherein double-balanced mixer(s) are used to sum RF 
> signals from standards of similar aging figures, the resulting output(s) 
> filtered, and the output finally sent to a frequency divider to generate 
> the desired final RF signal (like 1 MHz for typical time code 
> generators).  Any ideas?

The easiest idea, if you are only looking for a NTP class solution,
would be to use some microcontroller, with a sufficient number of
timer (aka capture/compare) units and measure the individual PPS
arrival times, without any ciruitry inbetween (beside level adjustment).
This gives you a precision in the order of 10-50ns. You can generate
the output PPS from the uC with the same precision.

The nice thing about this solution is, that everything is done in
software (and quite simple software at that) and you dont have to
mess with any hardware (beside the level adjustments). And you still
get much better stability of the PPS than NTP can ever hope to make use of. 

You can improve on this by using interpolators at the input to get
below 1ns resolution and using a OCXO as clock source for the uC
so you can shift the phase of the uC in small steps.

If you want to use the ensemble for your microwave transmitter,
then it becomes a question on what kind of performance levels you
want to reach, as the complexity increases very fast when you try
to improve stability and phase noise.


BTW: if you want to improve stability _and_ get redundancy,
then things become algorithmically complicated. Do not underestimate
the complexity you get into, if you add/remove frequency standards
from your weighting algorithm. How to achieve sufficent level of
redundancy while getting the maximum of stability from an ensemble
is an open research question.


Attila Kinali
-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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[time-nuts] Using the HP 58503a to correct your PC clock

[Mark Sims]

Probably the best way for most people to keep their clock accurate is to use 
something like NTP with a local GPS receiver  that provides a 1PPS signal that 
you can get into your computer (not always an easy thing to do and get working 
properly).  Done properly, this can get you into the micro-second area.


The next best way is something like NTP with only an internet connection...  
this gets asymmetric network path timing errors into play.  This can get you 
into the millisecond area.


Finally, if you have no net connection or 1PPS signal into your computer or 
your device can't run NTP,  you have to resort to poor man kludges like using 
Lady Heather to periodically sync your system clock.   This gets you into the 
10's of millisecond area...  plus your system clock probably won't be 
monotonically increasing.


---


I'm working with NTP right now, using Dimension 4, after having discovered D4's 
history info.
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[time-nuts] standard fusion for accuracy and redundancy

[Ruslan Nabioullin]

Hi, I'm in the process of setting up a public stratum 1 NTP server which 
will have at least one standard as a fallback to GPS (and possibly WWV 
and CHU), in addition to its primary purpose as a timebase for a 
microwave active SETI transmitter.  So far I have an aging = 1E-11 
rubidium standard (which has expired calibration documentation), and I'm 
interested in adding more standards in the future, specifically 
high-quality OCXO(s) and additional rubidium standard(s) (I'm 
uninterested in cesium standards due to their definite and short 
lifespan, and masers are, in almost all certainty, insanely expensive).


Based on attempts of understanding the NTP documentation and answers 
from NTP fora, NTP doesn't perform PPS fusion for accuracy, but rather 
merely for redundancy (correct me if I'm wrong).  Therefore, this 
complicates things to an extreme degree, for it means that the RF 
outputs (typically 100 kHz, 1 MHz, 5 Mhz, and/or 10 MHz), or PPS outputs 
have to be combined using some sort of a weighted fusion method (or 
simply unweighted, if the aging figures are similar across all the 
standards).  The only commercial piece of equipment to perform this, 
manufactured by some Russian corporation, is obscure and just by the 
look of it prohibitively-expensive.  So that leaves custom fabrication; 
the best information I could find regarding this is the paper ``A 
Digital Technique for Combining Frequency Standards'', by Lynn Hawkey, 
published in '69, which outlines nonnovel approaches and a novel 
approach to fusion.  The method that's attractive to myself is the old 
RF mixing one, wherein double-balanced mixer(s) are used to sum RF 
signals from standards of similar aging figures, the resulting output(s) 
filtered, and the output finally sent to a frequency divider to generate 
the desired final RF signal (like 1 MHz for typical time code 
generators).  Any ideas?


Thanks in advance,
Ruslan
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Re: [time-nuts] Using the HP 58503a to correct your PC clock

[Ron Ott]

Thanks. Although I'm brand new here, I've seen some posts talking about Lady 
Heather (some with amusing suggestions) and will look into it. Might just be 
what I need. I'm working with NTP right now, using Dimension 4, after having 
discovered D4's history info.
Thanks again, Ron


  From: Mark Sims 
 To: "time-nuts@febo.com"  
 Sent: Wednesday, August 3, 2016 8:50 PM
 Subject: [time-nuts] Using the HP 58503a to correct your PC clock
   
Lady Heather has the ability to set the system clock from any just about any 
GPS receiver.  It can set the clock every day, hour, minute, or when system 
time and receiver time diverge by more than "x" milliseconds.  Most stock 
Windows  systems have a clock granularity of +/- 15.6 milliseconds,  so the 
default "time set anytime" divergence threshold is  40 milliseconds.


Lady Heather now talks to SCPI devices and has support for the HP5 devices, 
but I don't have one and have not verified that the program works with them or 
analyzed their time stamp message arrival time offset.  You can get something 
like a cheap Ublox GPS module for less than $20 and they work really well.


--


> This has probably been covered in the past, but is there a way correct or 
> control a PC (Windows 7) clock with the HP 58503A GPS receiver?
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Re: [time-nuts] Using the HP 58503a to correct your PC clock

[Chris Albertson]

The WRONG way to adjust a PC clock is to set the TIME periodically from
some standard.  When you do this then the time on the PC is not running at
a constant rate.  The correct way to do this is to adjust the PC's clocks
RATE.  You make it runs slightly faster if you notice it is getting behind
and slightly slower if it is running fast.

Think about what you would do to a real physical clock.  You would not set
it every few minutes, you'd adjust the rate and wait a little while to see
if the adjustment needs refinement or not.

Most computers can run "NTP" what does this.  In fact, using NTP you don't
need a GPS receiver to keep the clock to within a few milliseconds of UTC
as NTP will synchronize with other NTPs running on servers on the
Internet.  Yes you can pull millisecond level time over the Internet.   But
using a GPS receiver NTP can keep your PC's internal clock accurate at the
hundreds of microseconds level.

NTP is an interesting piece of software.  With the very long delays over
the Internet you'd think you'd never be able to accurately transfer time
but you can get millisecond level accuracy even over a communications path
that has a 100 millisecond delay.  The trick is to think about what you
would do if you lived in the 1700's (before the telegraph) and owned a
grandfather clock that was to big to carry and where given the task of
setting it to match a clock that was a ten minute walk away in a different
house.   You best plan would be to first walk the round trip between the
two houses many times and measure the time it takes then add /2 the round
trip delay.Later you find that other neighbor own clocks so you start
making round trips to their houses too and keeping good notes on the trip
times between all the clocks.  You could set everyone's clock based on the
consensus of other nearby clocks.   Next you'd notice that some clocks are
just poorly made and you'd ignore these when building the consensus.   This
is exactly what NTP does

Most operating systems in use today run NTP to keep their clocks in order.
Well most OSes except for Windows.  Microsoft uses a vey much simplified
version of this that does the wrong thing and periodically sets the PC's
clock.   You could enable this and likely, maybe reach your +/- 100ms goal.
  Not the "real" NTP is a free program and not hard to set up so you can
have 1ms level accuracy without much effort and better with some work.

On Tue, Aug 2, 2016 at 8:13 PM, Ron Ott  wrote:

> This has probably been covered in the past, but is there a way correct or
> control a PC (Windows 7) clock with the HP 58503A GPS receiver? I just
> bought one (on the way now) and have a copy of satstats50 on hand. I've
> been using Dimension 4 and I'm surprised at the size of correction every
> couple minutes to my PC clock.  I'd be happy if my PC clock were accurate
> to plus/minus 100ms.
> Ron
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>



-- 

Chris Albertson
Redondo Beach, California
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