[time-nuts] GPS antenna??
Dennis Czelusniak
czelusniakd at yahoo.com
Tue Apr 9 08:14:58 EDT 2013
I dont know? Maybe the obvious solution is to go well in advance, and see if the GPS works in the building. It would be much easier to resolve your problem if you knew if you actually have one.
Dennis
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Today's Topics:
1. Re: GPS antenna?? (Grant Hodgson)
2. Re: GPS antenna?? (Azelio Boriani)
3. Re: GPS antenna?? (Bob Camp)
4. Re: GPS antenna?? (Bob Camp)
5. Re: Trimble SVeeSix -- was DATUM 9390-52054 Grief again...
(Rob Kimberley)
6. Re: GPS antenna?? (Rob Kimberley)
----------------------------------------------------------------------
Message: 1
Date: Tue, 09 Apr 2013 09:27:38 +0100
From: Grant Hodgson <grant at ghengineering.co.uk>
To: time-nuts at febo.com, time-nuts-request at febo.com
Subject: Re: [time-nuts] GPS antenna??
Message-ID:
<20130409092738.94222kn3697iyozk at webmail.ghengineering.co.uk>
Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes";
format="flowed"
Alan
As has already been stated by others, if the purpose of the GPS signal
is for a GPSDO, then putting an active patch next to a SW facing
window should work fine. No need to re-radiate. You only need to
receive 1 satellite in order to get a timing signal - more satellites
will give better (lower) jitter/ADEV, but if you just want an accurate
frequency source for a counter or signal generator then the setup you
describe should be fine.
If that's the case, then it might be worth taking a Rubidium source as
a higher-performance back-up than the GPSDO in holdover, although some
GPSDOs are more equal than others in holdover performance.
regards
Grant
Quoting time-nuts-request at febo.com:
>
> Hi all an interesting problem you may have encountered, I want to use a GPS
> frequency standard inside a building with no opening windows (opening
> windows are known as air conditioning in the UK :-)) )
> This is part of a two day amateur microwave conference so we should have the
> expertise.
>
> I intend to try and pass the signal through a a double glazed glass window
> unit (hopefully not metalised) using a couple of patch antennas. The outer
> GPS antenna is active so will need a 5v supply via an inserter. Inner patch
> active, outer patch passive to avoid problems of feedback. Main antenna can
> be shielded from the "coupling" either physically or with a slab of
> absorber.
>
> Has anyone tried this?.... does it work?.....any gotchas?
>
> Thanks
> Alan
> G3NYK
>
>
>
------------------------------
Message: 2
Date: Tue, 9 Apr 2013 11:56:42 +0200
From: Azelio Boriani <azelio.boriani at screen.it>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] GPS antenna??
Message-ID:
<CAL8XPmMto=O4j=A=eEB8YGR7uTaWHe1FLZi10pehu0Y1YHQFWA at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
One satellite, OK, but before a GPSDO can use 1 satellite it must have the
normal satellite visibility to complete the autosurvey (usually 10K seconds
long). You can enter the exact lat/lon, if available, and start the 1
satellite operation (known as position hold mode) at once but, usually,
surveyed coordinates of a new antenna installation are not available.
On Tue, Apr 9, 2013 at 10:27 AM, Grant Hodgson <grant at ghengineering.co.uk>wrote:
> Alan
>
> As has already been stated by others, if the purpose of the GPS signal is
> for a GPSDO, then putting an active patch next to a SW facing window should
> work fine. No need to re-radiate. You only need to receive 1 satellite in
> order to get a timing signal - more satellites will give better (lower)
> jitter/ADEV, but if you just want an accurate frequency source for a
> counter or signal generator then the setup you describe should be fine.
>
> If that's the case, then it might be worth taking a Rubidium source as a
> higher-performance back-up than the GPSDO in holdover, although some GPSDOs
> are more equal than others in holdover performance.
>
> regards
> Grant
>
> Quoting time-nuts-request at febo.com:
>
>>
>> Hi all an interesting problem you may have encountered, I want to use a
>> GPS
>> frequency standard inside a building with no opening windows (opening
>> windows are known as air conditioning in the UK :-)) )
>> This is part of a two day amateur microwave conference so we should have
>> the
>> expertise.
>>
>> I intend to try and pass the signal through a a double glazed glass window
>> unit (hopefully not metalised) using a couple of patch antennas. The outer
>> GPS antenna is active so will need a 5v supply via an inserter. Inner
>> patch
>> active, outer patch passive to avoid problems of feedback. Main antenna
>> can
>> be shielded from the "coupling" either physically or with a slab of
>> absorber.
>>
>> Has anyone tried this?.... does it work?.....any gotchas?
>>
>> Thanks
>> Alan
>> G3NYK
>>
>>
>>
>>
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> time-nuts mailing list -- time-nuts at febo.com
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------------------------------
Message: 3
Date: Tue, 9 Apr 2013 06:47:32 -0400
From: Bob Camp <lists at rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] GPS antenna??
Message-ID: <B7EFF990-AD44-4A71-B7ED-BAE67E2C9A54 at rtty.us>
Content-Type: text/plain; charset=us-ascii
Hi
If this is a modern building, there may be some pretty good GPS location data associated with it. If you can find that data and if you can find the building plans you might be able to come up with a pretty good location for the window.
Yes that's a lot of if's and a lot of work.
Bob
On Apr 9, 2013, at 5:56 AM, Azelio Boriani <azelio.boriani at screen.it> wrote:
> One satellite, OK, but before a GPSDO can use 1 satellite it must have the
> normal satellite visibility to complete the autosurvey (usually 10K seconds
> long). You can enter the exact lat/lon, if available, and start the 1
> satellite operation (known as position hold mode) at once but, usually,
> surveyed coordinates of a new antenna installation are not available.
>
> On Tue, Apr 9, 2013 at 10:27 AM, Grant Hodgson <grant at ghengineering.co.uk>wrote:
>
>> Alan
>>
>> As has already been stated by others, if the purpose of the GPS signal is
>> for a GPSDO, then putting an active patch next to a SW facing window should
>> work fine. No need to re-radiate. You only need to receive 1 satellite in
>> order to get a timing signal - more satellites will give better (lower)
>> jitter/ADEV, but if you just want an accurate frequency source for a
>> counter or signal generator then the setup you describe should be fine.
>>
>> If that's the case, then it might be worth taking a Rubidium source as a
>> higher-performance back-up than the GPSDO in holdover, although some GPSDOs
>> are more equal than others in holdover performance.
>>
>> regards
>> Grant
>>
>> Quoting time-nuts-request at febo.com:
>>
>>>
>>> Hi all an interesting problem you may have encountered, I want to use a
>>> GPS
>>> frequency standard inside a building with no opening windows (opening
>>> windows are known as air conditioning in the UK :-)) )
>>> This is part of a two day amateur microwave conference so we should have
>>> the
>>> expertise.
>>>
>>> I intend to try and pass the signal through a a double glazed glass window
>>> unit (hopefully not metalised) using a couple of patch antennas. The outer
>>> GPS antenna is active so will need a 5v supply via an inserter. Inner
>>> patch
>>> active, outer patch passive to avoid problems of feedback. Main antenna
>>> can
>>> be shielded from the "coupling" either physically or with a slab of
>>> absorber.
>>>
>>> Has anyone tried this?.... does it work?.....any gotchas?
>>>
>>> Thanks
>>> Alan
>>> G3NYK
>>>
>>>
>>>
>>>
>> ______________________________**_________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/**
>> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts>
>> and follow the instructions there.
>>
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> time-nuts mailing list -- time-nuts at febo.com
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------------------------------
Message: 4
Date: Tue, 9 Apr 2013 07:25:02 -0400
From: Bob Camp <lists at rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] GPS antenna??
Message-ID: <877E660D-8352-40E1-930A-6E70F90753B1 at rtty.us>
Content-Type: text/plain; charset=us-ascii
Hi
One other possibility is that we are talking about "illuminating" a fleet of devices.
Bob
On Apr 8, 2013, at 11:18 PM, Mark Spencer <mspencer12345 at yahoo.ca> wrote:
> I'll be curious to hear more details from Alan (the original poster.) I agree it's not a slam dunk that the device in question is a GPSDO that supports hold over.
>
> I also agree with Bill that we may be missing some details regarding this matter.
>
>
> Re: [time-nuts] GPS antenna??
> Bob Camp Mon, 08 Apr 2013 15:57:11 -0700
>
> Hi
>
> I'm not sure that the "real" application here is a GPSDO. If it is, then
> holdover may well be the easy answer.
> Bob
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
------------------------------
Message: 5
Date: Tue, 9 Apr 2013 12:44:22 +0100
From: "Rob Kimberley" <robkimberley at btinternet.com>
To: "'Discussion of precise time and frequency measurement'"
<time-nuts at febo.com>
Subject: Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief
again...
Message-ID: <000401ce3517$96e6a160$c4b3e420$@btinternet.com>
Content-Type: text/plain; charset="us-ascii"
You need to be careful as Nigel says as Datum had special SVeeSix units from
Trimble in the early days which were specifically modified for timing.
Rob Kimberley
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of GandalfG8 at aol.com
Sent: 07 April 2013 18:37
To: time-nuts at febo.com
Subject: Re: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief
again...
Hi Robert,
You need to be careful on this one.
I've never owned a Placer 400, so can't be 100% sure, but whilst I have
seen it suggested that it contained an SVeeSix I've have also seen at least
one quite emphatic comment, from a not very happy user, stating that it's
definitely not an SVeeSix, but that there was a firmware upgrade available
for the Placer 400 at one time to make it SVeeSix compatible, whatever that
might imply.
What I can confirm is that the version that's more generally available on
Ebay, the Placer 450, consists of a single board inside the housing that
integrates a GPS receiver with the control section.
I discovered this the hard way after I bought a couple, and expecting them
to contain one of the usual Trimble GPS modules with a separate PCB for the
control section, silly me:-)
Quite what the GPS section of that board might be derived from I don't know,
but it would seem very unlikely that it's going to be a drop in replacement
for a standard module.
Nigel
GM8PZR
In a message dated 07/04/2013 17:47:40 GMT Daylight Time,
robert8rpi at yahoo.co.uk writes:
Hi,
IIRC the early Trimble Placer vehicle tracking GPS receivers used the
SVee6 and SVee8. I think the Placer 400 used the SVee6. These units turn
up on ebay etc at very low cost.
Robert G8RPI.
________________________________
From: "GandalfG8 at aol.com" <GandalfG8 at aol.com>
To: time-nuts at febo.com
Sent: Sunday, 7 April 2013, 8:53
Subject: [time-nuts] Trimble SVeeSix -- was DATUM 9390-52054 Grief again...
The Trimble TNL 22880-B was indeed the original SV6, or SVeeSix as Trimble
chose to call it, I have just confirmed this from a photo I took some time
ago, and of which I can supply a copy if required.
The SVeeSix manual from 1992 is here.....
http://rapidshare.com/files/446743737/Trimble_SveeSix.pdf
and a much smaller, optimised version, here......
http://rapidshare.com/files/446744995/Trimble_SveeSix_Optimised.pdf
Thanks for these should be directed to Rob Kimberley on the list who
provided the original printed copy.
This original SVeeSix was approx 4 x 3.5 inches and was eventually
replaced by the SVeeEight of similar appearance and again the same size.
The SVeeSix Plus and SVeeEight Plus were the same modules mounted in metal
boxes.
The SVeeEight Plus manual from 2000 is available on the Trimble ftp site.
I know of at least one application where an SVeeEight PCB module has been
used as a drop in replacement for an SVeeSix, the Rapco 1804M GPS frequency
standard, albeit using the opposite serial port, but don't know if this was
an "out of the box" drop in or whether the port needed to be configured
first.
The smaller, 1.8 x 3.3 inches, version of the SVeeSix is the SVeeSix-CM3
embedded module, and the 1997 manual for that is also on the Trimble ftp
site in the manuals/CM3 folder.
It's possible that an SVeeSix-CM3 could be configured as an SVeeSix
replacement but I've not investigated this, both the SVeeSix and SVeeEight
came fitted with 1 or 2 standard serial ports on DB9 connectors, the
SVeeSix-CM3
used an 8 pin header with I/O at TTL levels.
Regards
Nigel
GM8PZR
In a message dated 06/04/2013 23:10:28 GMT Daylight Time, biwa at att.net
writes:
(Note: additional information about the receiver module has been added.)
Burt
Gang,
You will remember several months ago I had some stranges that I thought
were related to a defective Vectron oscillator in one of my DATUM
9390-52054. That turned out to be a the internal switching
power supply so I replaced it with an external Cisco unit. I've done
this in three units, two are mine and one belongs to Stu, K6YAZ.
Well, I now have a different grief in one of my units. It had been
cooking along swell with no problem ever since I replaced the power
supply. This morning I notice that one of my units had the lock and
tracking lights out. The display said that the signal level was low and
there were no usable satellites. The 10 MHz output is also about
20 or more dB low. I assumed the power supply is all right because the
display was working and it said it was 9-E9, not so good, but working -
sorta. I swapped antennas and the good Datum was happy so I know the
antenna is ok. when I got inside I checked the power supply rails and
they're within .05 Volts of where they should be. There is 5 Volts on the
GPS module and there is 4.96 Volts on the antenna Type-N connector
(measured with the antenna line
disconnected.) Power cycling the DATUM did not resolve the problem.
Does anyone know if the symptoms above will occur if the 10 MHz oscillator
is defective? I can understand it not tracking or not locked, but could
this cause the receiver to not see or indicate any satellites? Since I
only have two of these units on line, I'm very reluctant to start swapping
modules because I would be without any working reference, so I need to keep
one up and running. Both of my units are on a UPS, and according to the
clocks in the kitchen, the bedroom, and the old VCR, we've not had a power
interruption.
I do not recognize the GPS receiver module, but it has the following
number on it: TNL 22880-B. I have the schematics for the overall
DATUM 9390-25054, but the GPS module in just a block. By the way,
the GPS block on the DATUM overall schematic is marked, "SV6 / (TANS)". I
suspect this means something noteworthy.
Any guidance would be appreciated.
Thanks,
Burt
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
biwa at att.net
www.biwa.cc
K6OQK
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Message: 6
Date: Tue, 9 Apr 2013 12:47:00 +0100
From: "Rob Kimberley" <robkimberley at btinternet.com>
To: "'Discussion of precise time and frequency measurement'"
<time-nuts at febo.com>
Subject: Re: [time-nuts] GPS antenna??
Message-ID: <000501ce3517$f25ffd20$d71ff760$@btinternet.com>
Content-Type: text/plain; charset="us-ascii"
Alan,
I used to do a lot of my Datum demos with customers with antennae up against
a window as outside access wasn't available.
Usually worked OK, unless as you say, the glass is metalised.
Rob
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Alan Melia
Sent: 08 April 2013 18:00
To: time-nuts measurement
Subject: [time-nuts] GPS antenna??
Hi all an interesting problem you may have encountered, I want to use a GPS
frequency standard inside a building with no opening windows (opening
windows are known as air conditioning in the UK :-)) ) This is part of a
two day amateur microwave conference so we should have the expertise.
I intend to try and pass the signal through a a double glazed glass window
unit (hopefully not metalised) using a couple of patch antennas. The outer
GPS antenna is active so will need a 5v supply via an inserter. Inner patch
active, outer patch passive to avoid problems of feedback. Main antenna can
be shielded from the "coupling" either physically or with a slab of
absorber.
Has anyone tried this?.... does it work?.....any gotchas?
Thanks
Alan
G3NYK
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