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Re: NEO series GPS modules

Eric Haskell <eric_haskell@...>
 

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Regards,
Eric Haskell
KC4YOE



To: ukmicrowaves@...
From: ukmicrowaves@...
Date: Tue, 26 Jul 2016 20:30:42 +0100
Subject: Re: [ukmicrowaves] NEO series GPS modules

 
The classic "Simple GPSDO" such as http://www.g4jnt.com/SimpleGPSDO.pdf   and  http://www.g4jnt.com/EvenSimplerSimplestGpsdoPossible.htm   generally run with a PLL time constant of a few tens of seconds; perhaps as much as a minute.  But this is not sufficient to smooth out the variations on the GPS timing signal itself, due to propagation anomalies.  

See  http://www.g4jnt.com/10MHz_Reference_Source_Stability.pdf   for a set of short term stability measurements I made on several reference types including various GPSDOs

To smooth out GPS's own frequency shift, which can amount to a couple of parts-per-billion easily,  you need to move to a time constant of tens of minutes to hours and that runs into a new problem altogether.

The simple short time constant approach allows a low cost TCXO to be used as the oscillator element since the loop is fast enough to track its drift and wobble due to thermal effects (no TCXO has perfect compensation, ~~1ppm is all they're specified to).   With a time constant of minutes, it is too easy for the TCXO to wobble faster than the loop can compensate and that ends up worse than a fast loop

So you now need an ovenned source that can maintain good performance over tens of minutes to hours - and once you've got that, you have something that's probably going to be good enough on its own, with a periodic calibration / check.  And then, of course, there is the lock up time.  If your GPSDO has a loop time constant, say, of 20 minutes, it could well take up 2 hours to lock from a cold switch on.  As a rule of thumb, 4 to 8 time constants are needed to reach fulll stability.  So unless you have an intelligent computer controlled PLL that can adaptively adjust bandwidth as lock is achieved any /P event will be well underway before it is locked.    So this sort of GPSDO should never be turned off, and in fact makes a very good fixed lab standard.

As really good lab standard, a GPS locked rubidium source can probably not be bettered for home use.  Rb gives you parts per trillion short term stability over hours, and GPS locking with a time constant of very many hours or days corrects Rb's inherent slight error.   Such a setup would probably hold its own against the older second hand Caesium source.

All of which brings in a third problem : how do you actually do a PLL with a time constant that long?   Analogue R/C is out of the question, and if you try to do it with D/A converters and / or DSP, there is the quantisation issue.  (One failing of the VE2ZAZ design)  The best D/A converters are only 16 bit, and you'll need a finer resolution than that or a very narrow adjustment range.  Pulse width mod couldy be made to work, but only with a PWM of very much higher resolution than the hardware ones provided on-board chips - which means doing it in software / firmware.  And that high a resolution means a fast clock.

It ain't simple, doing it properly!   But for practical purposes, you can get away with a lot less.

 Andy  G4JNT

On 26 July 2016 at 19:51, Neil neil@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 


Andy, when you say"very" narrow loop bandwidth, are we talking time constants of tens of seconds, or even longer? 

I'm with you totally on the Rubidium front, I now run an Efratom Rb source as the primary standard, and just use my G3RUH GPSDO for verification.  I also use a couple of Morions for /P, but I would like to lock them to GPS just for the sheer hell of it.  No real justification for doing it, perhaps I'm turning into a time-geek.

Neil G4DBN


On 26/07/2016 17:16, Andy Talbot andy.g4jnt@... [ukmicrowaves] wrote:
 
Instead of this rush for GPSDO based references with dubious short term stability, why not go for one of the several really good 10MHz OCXOs that have appeared recently or even a Rubidium source.   There are several Morion types out there, all capable of resetting to within a few parts per billion after a quite rapid warm up.

I have one in the 10GHz PortaBeacon that settles within a couple of tens of Hz (at 10GHz) within 5 minutes of switch on from cold - always.  And that module is an older generation OCXO  - later ones are better still.

Then use a basic GPS module with its 1 PPS output as the reference just for a frequency counter to confirm your calibration from time to time.

Best of all, get a Rubidium source - there are a few around on Ebay for £100 or so.   Not the cheapest option, but that will guarantee you sub PPB accuracy within less than 20 minutes of turn on.  

GPSDOs may be cheap, and although I've never tried these GPS modules being talked bout here, do get an uncomfortable feeling that unless used with a very narrow loop bandwidth locking up a reference, they won't be all that nice when multiplied up to the higher uave bands.

Unless someone knows better, and has done so ?

Andy  G4JNT


Virus-free. www.avast.com



Re: NEO series GPS modules

Eric Haskell <eric_haskell@...>
 

FYI,

The topics are covered frequently in the Time-nuts Yahoo group.  I have learned a lot by reading there.

Regards,
Eric Haskell
KC4YOE
Keller, TX USA



To: ukmicrowaves@...
From: ukmicrowaves@...
Date: Tue, 26 Jul 2016 20:30:42 +0100
Subject: Re: [ukmicrowaves] NEO series GPS modules

 
The classic "Simple GPSDO" such as http://www.g4jnt.com/SimpleGPSDO.pdf   and  http://www.g4jnt.com/EvenSimplerSimplestGpsdoPossible.htm   generally run with a PLL time constant of a few tens of seconds; perhaps as much as a minute.  But this is not sufficient to smooth out the variations on the GPS timing signal itself, due to propagation anomalies.  

See  http://www.g4jnt.com/10MHz_Reference_Source_Stability.pdf   for a set of short term stability measurements I made on several reference types including various GPSDOs

To smooth out GPS's own frequency shift, which can amount to a couple of parts-per-billion easily,  you need to move to a time constant of tens of minutes to hours and that runs into a new problem altogether.

The simple short time constant approach allows a low cost TCXO to be used as the oscillator element since the loop is fast enough to track its drift and wobble due to thermal effects (no TCXO has perfect compensation, ~~1ppm is all they're specified to).   With a time constant of minutes, it is too easy for the TCXO to wobble faster than the loop can compensate and that ends up worse than a fast loop

So you now need an ovenned source that can maintain good performance over tens of minutes to hours - and once you've got that, you have something that's probably going to be good enough on its own, with a periodic calibration / check.  And then, of course, there is the lock up time.  If your GPSDO has a loop time constant, say, of 20 minutes, it could well take up 2 hours to lock from a cold switch on.  As a rule of thumb, 4 to 8 time constants are needed to reach fulll stability.  So unless you have an intelligent computer controlled PLL that can adaptively adjust bandwidth as lock is achieved any /P event will be well underway before it is locked.    So this sort of GPSDO should never be turned off, and in fact makes a very good fixed lab standard.

As really good lab standard, a GPS locked rubidium source can probably not be bettered for home use.  Rb gives you parts per trillion short term stability over hours, and GPS locking with a time constant of very many hours or days corrects Rb's inherent slight error.   Such a setup would probably hold its own against the older second hand Caesium source.

All of which brings in a third problem : how do you actually do a PLL with a time constant that long?   Analogue R/C is out of the question, and if you try to do it with D/A converters and / or DSP, there is the quantisation issue.  (One failing of the VE2ZAZ design)  The best D/A converters are only 16 bit, and you'll need a finer resolution than that or a very narrow adjustment range.  Pulse width mod couldy be made to work, but only with a PWM of very much higher resolution than the hardware ones provided on-board chips - which means doing it in software / firmware.  And that high a resolution means a fast clock.

It ain't simple, doing it properly!   But for practical purposes, you can get away with a lot less.

 Andy  G4JNT

On 26 July 2016 at 19:51, Neil neil@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 


Andy, when you say"very" narrow loop bandwidth, are we talking time constants of tens of seconds, or even longer? 

I'm with you totally on the Rubidium front, I now run an Efratom Rb source as the primary standard, and just use my G3RUH GPSDO for verification.  I also use a couple of Morions for /P, but I would like to lock them to GPS just for the sheer hell of it.  No real justification for doing it, perhaps I'm turning into a time-geek.

Neil G4DBN


On 26/07/2016 17:16, Andy Talbot andy.g4jnt@... [ukmicrowaves] wrote:
 
Instead of this rush for GPSDO based references with dubious short term stability, why not go for one of the several really good 10MHz OCXOs that have appeared recently or even a Rubidium source.   There are several Morion types out there, all capable of resetting to within a few parts per billion after a quite rapid warm up.

I have one in the 10GHz PortaBeacon that settles within a couple of tens of Hz (at 10GHz) within 5 minutes of switch on from cold - always.  And that module is an older generation OCXO  - later ones are better still.

Then use a basic GPS module with its 1 PPS output as the reference just for a frequency counter to confirm your calibration from time to time.

Best of all, get a Rubidium source - there are a few around on Ebay for £100 or so.   Not the cheapest option, but that will guarantee you sub PPB accuracy within less than 20 minutes of turn on.  

GPSDOs may be cheap, and although I've never tried these GPS modules being talked bout here, do get an uncomfortable feeling that unless used with a very narrow loop bandwidth locking up a reference, they won't be all that nice when multiplied up to the higher uave bands.

Unless someone knows better, and has done so ?

Andy  G4JNT


Virus-free. www.avast.com



GB3USK 1296.870

Peter G3SMT
 

Hi Graham,

Still audible in IO82KV with some fading down to the noise.

Many thanks for your efforts.

73

Peter

G3SMT


On 26-Jul-16 4:13 PM, Graham Kimbell g3tct@... [ukmicrowaves] wrote:

Hi all
I've just put GB3USK on today - 1296.870, IO81VC73. Runs 0600 to 2200z subject to enough solar / wind power.
Reception reports are appreciated, please use www.beaconspot.eu
Copy me on an initial report and for any faults.

73
Graham


Re: NEO series GPS modules

Andy G4JNT
 

The classic "Simple GPSDO" such as http://www.g4jnt.com/SimpleGPSDO.pdf   and  http://www.g4jnt.com/EvenSimplerSimplestGpsdoPossible.htm   generally run with a PLL time constant of a few tens of seconds; perhaps as much as a minute.  But this is not sufficient to smooth out the variations on the GPS timing signal itself, due to propagation anomalies.  

See  http://www.g4jnt.com/10MHz_Reference_Source_Stability.pdf   for a set of short term stability measurements I made on several reference types including various GPSDOs

To smooth out GPS's own frequency shift, which can amount to a couple of parts-per-billion easily,  you need to move to a time constant of tens of minutes to hours and that runs into a new problem altogether.

The simple short time constant approach allows a low cost TCXO to be used as the oscillator element since the loop is fast enough to track its drift and wobble due to thermal effects (no TCXO has perfect compensation, ~~1ppm is all they're specified to).   With a time constant of minutes, it is too easy for the TCXO to wobble faster than the loop can compensate and that ends up worse than a fast loop

So you now need an ovenned source that can maintain good performance over tens of minutes to hours - and once you've got that, you have something that's probably going to be good enough on its own, with a periodic calibration / check.  And then, of course, there is the lock up time.  If your GPSDO has a loop time constant, say, of 20 minutes, it could well take up 2 hours to lock from a cold switch on.  As a rule of thumb, 4 to 8 time constants are needed to reach fulll stability.  So unless you have an intelligent computer controlled PLL that can adaptively adjust bandwidth as lock is achieved any /P event will be well underway before it is locked.    So this sort of GPSDO should never be turned off, and in fact makes a very good fixed lab standard.

As really good lab standard, a GPS locked rubidium source can probably not be bettered for home use.  Rb gives you parts per trillion short term stability over hours, and GPS locking with a time constant of very many hours or days corrects Rb's inherent slight error.   Such a setup would probably hold its own against the older second hand Caesium source.

All of which brings in a third problem : how do you actually do a PLL with a time constant that long?   Analogue R/C is out of the question, and if you try to do it with D/A converters and / or DSP, there is the quantisation issue.  (One failing of the VE2ZAZ design)  The best D/A converters are only 16 bit, and you'll need a finer resolution than that or a very narrow adjustment range.  Pulse width mod couldy be made to work, but only with a PWM of very much higher resolution than the hardware ones provided on-board chips - which means doing it in software / firmware.  And that high a resolution means a fast clock.

It ain't simple, doing it properly!   But for practical purposes, you can get away with a lot less.

 Andy  G4JNT

On 26 July 2016 at 19:51, Neil neil@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

Andy, when you say"very" narrow loop bandwidth, are we talking time constants of tens of seconds, or even longer? 

I'm with you totally on the Rubidium front, I now run an Efratom Rb source as the primary standard, and just use my G3RUH GPSDO for verification.  I also use a couple of Morions for /P, but I would like to lock them to GPS just for the sheer hell of it.  No real justification for doing it, perhaps I'm turning into a time-geek.

Neil G4DBN


On 26/07/2016 17:16, Andy Talbot andy.g4jnt@... [ukmicrowaves] wrote:
 
Instead of this rush for GPSDO based references with dubious short term stability, why not go for one of the several really good 10MHz OCXOs that have appeared recently or even a Rubidium source.   There are several Morion types out there, all capable of resetting to within a few parts per billion after a quite rapid warm up.

I have one in the 10GHz PortaBeacon that settles within a couple of tens of Hz (at 10GHz) within 5 minutes of switch on from cold - always.  And that module is an older generation OCXO  - later ones are better still.

Then use a basic GPS module with its 1 PPS output as the reference just for a frequency counter to confirm your calibration from time to time.

Best of all, get a Rubidium source - there are a few around on Ebay for £100 or so.   Not the cheapest option, but that will guarantee you sub PPB accuracy within less than 20 minutes of turn on.  

GPSDOs may be cheap, and although I've never tried these GPS modules being talked bout here, do get an uncomfortable feeling that unless used with a very narrow loop bandwidth locking up a reference, they won't be all that nice when multiplied up to the higher uave bands.

Unless someone knows better, and has done so ?

Andy  G4JNT


Virus-free. www.avast.com



Re: GB3USK 1296.870

Tony G4NBS
 

I concur it is HF (maybe 400Hz?).

Back to +6dB but for a while it dropped into the noise shortly after I first spotted it. Other beacons also showed similar drop – not sure what effect the birds roosting on the mast had………

 

73

Tony G4NBS

 

From: ukmicrowaves@... [mailto:ukmicrowaves@...]
Sent: Tuesday, July 26, 2016 19:17
To: uk microwaves
Subject: [ukmicrowaves] Re: GB3USK 1296.870

 

 

 

Well done Graham - pleased to hear it again and at an increased level .

599 here in Dorset IO80XS77JR .Some good AS products viewable .

By my measurement its 362Hz high of nominal - no problem for basic FSK.

V 73

John

G0API


Re: NEO series GPS modules

Neil Smith G4DBN
 

Andy, when you say"very" narrow loop bandwidth, are we talking time constants of tens of seconds, or even longer? 

I'm with you totally on the Rubidium front, I now run an Efratom Rb source as the primary standard, and just use my G3RUH GPSDO for verification.  I also use a couple of Morions for /P, but I would like to lock them to GPS just for the sheer hell of it.  No real justification for doing it, perhaps I'm turning into a time-geek.

Neil G4DBN


On 26/07/2016 17:16, Andy Talbot andy.g4jnt@... [ukmicrowaves] wrote:
 
Instead of this rush for GPSDO based references with dubious short term stability, why not go for one of the several really good 10MHz OCXOs that have appeared recently or even a Rubidium source.   There are several Morion types out there, all capable of resetting to within a few parts per billion after a quite rapid warm up.

I have one in the 10GHz PortaBeacon that settles within a couple of tens of Hz (at 10GHz) within 5 minutes of switch on from cold - always.  And that module is an older generation OCXO  - later ones are better still.

Then use a basic GPS module with its 1 PPS output as the reference just for a frequency counter to confirm your calibration from time to time.

Best of all, get a Rubidium source - there are a few around on Ebay for £100 or so.   Not the cheapest option, but that will guarantee you sub PPB accuracy within less than 20 minutes of turn on.  

GPSDOs may be cheap, and although I've never tried these GPS modules being talked bout here, do get an uncomfortable feeling that unless used with a very narrow loop bandwidth locking up a reference, they won't be all that nice when multiplied up to the higher uWave bands.

Unless someone knows better, and has done so ?

Andy  G4JNT


Virus-free. www.avast.com


Re: GB3USK 1296.870

John Fell
 



Well done Graham - pleased to hear it again and at an increased level .
599 here in Dorset IO80XS77JR .Some good AS products viewable .
By my measurement its 362Hz high of nominal - no problem for basic FSK.
V 73
John
G0API


Re: GB3USK 1296.870

Tony G4NBS
 

Hi Graham

 

Thanks for your efforts in getting this back on air.

Solid copy in JO02AF, minimum +6dB at the moment.

Hope it remains windy enough to provide signals after dark!

 

73

Tony G4NBS

 

From: ukmicrowaves@... [mailto:ukmicrowaves@...]
Sent: Tuesday, July 26, 2016 16:14
To: ukmicrowaves@...; uk_beacons@...
Subject: [ukmicrowaves] GB3USK 1296.870

 

 

Hi all
I've just put GB3USK on today - 1296.870, IO81VC73.  Runs 0600 to 2200z subject to enough solar / wind power.
Reception reports are appreciated, please use www.beaconspot.eu
Copy me on an initial report and for any faults.

73
Graham


Re: GB3USK 1296.870

Dave <g4rqi@...>
 

Hello Graham

Is it omni ?

David


On 26-Jul-16 4:13 PM, Graham Kimbell g3tct@... [ukmicrowaves] wrote:

Hi all
I've just put GB3USK on today - 1296.870, IO81VC73. Runs 0600 to 2200z subject to enough solar / wind power.
Reception reports are appreciated, please use www.beaconspot.eu
Copy me on an initial report and for any faults.

73
Graham


Re: NEO series GPS modules

Andy G4JNT
 

Instead of this rush for GPSDO based references with dubious short term stability, why not go for one of the several really good 10MHz OCXOs that have appeared recently or even a Rubidium source.   There are several Morion types out there, all capable of resetting to within a few parts per billion after a quite rapid warm up.

I have one in the 10GHz PortaBeacon that settles within a couple of tens of Hz (at 10GHz) within 5 minutes of switch on from cold - always.  And that module is an older generation OCXO  - later ones are better still.

Then use a basic GPS module with its 1 PPS output as the reference just for a frequency counter to confirm your calibration from time to time.

Best of all, get a Rubidium source - there are a few around on Ebay for £100 or so.   Not the cheapest option, but that will guarantee you sub PPB accuracy within less than 20 minutes of turn on.  

GPSDOs may be cheap, and although I've never tried these GPS modules being talked bout here, do get an uncomfortable feeling that unless used with a very narrow loop bandwidth locking up a reference, they won't be all that nice when multiplied up to the higher uWave bands.

Unless someone knows better, and has done so ?

Andy  G4JNT

On 26 July 2016 at 15:04, usuallyqrt@... [ukmicrowaves] <ukmicrowaves@...> wrote:
 

I think users will find with the basic NEO types of GPS modules if you look at the output with the scope referenced against a truly stable source, not another GPS,  that the output signal has a number of discrete phases so is unlikely to be useful directly but might be ok with further integration.  I have not looked at the timing version which ought to have this issue fixed ?

This is much like the phase shifting of Droitwich locked references which many seemed not to be aware of in simple designs.

Good investigation is required before implementation.  The scope must be externally locked or its trace will simply follow the meander.

73 John G8ACE



GB3USK 1296.870

Graham G3TCT
 

Hi all
I've just put GB3USK on today - 1296.870, IO81VC73.  Runs 0600 to 2200z subject to enough solar / wind power.
Reception reports are appreciated, please use www.beaconspot.eu
Copy me on an initial report and for any faults.

73
Graham


NEO series GPS modules

usuallyqrt@...
 

I think users will find with the basic NEO types of GPS modules if you look at the output with the scope referenced against a truly stable source, not another GPS,  that the output signal has a number of discrete phases so is unlikely to be useful directly but might be ok with further integration.  I have not looked at the timing version which ought to have this issue fixed ?

This is much like the phase shifting of Droitwich locked references which many seemed not to be aware of in simple designs.

Good investigation is required before implementation.  The scope must be externally locked or its trace will simply follow the meander.

73 John G8ACE


hupRF website update - new DG8 Masthead preamp versions.

dave powis <g4hup@...>
 

Good day folks,

Excuse the bandwidth, but wanted to let you know that I've just updated the website to cover the new masthead pre-amp versions for 4m and 6m, based on the original DG8 for 2m by Ian, GM3SEK.  These are identified as the DG8-4 and DG8-6 (not surprisingly!).


Best 73,

Dave, G4HUP 

http://hupRF.com
http://g4hup.com
twitter  @hupRF


Re: Réf. : Re: replacement GPS module

R Hopkins
 

Thanks Francois for the info.

The outputs from the Ublox rx don't look very good on an oscilloscope. The 10MHz output looks awful
on a spectrum analyser as far as I remember. It's a couple of years since I played with it.
That's why I asked if anybody had tried it. I'll probably do it the same way as your friend.

Cheers

Roger GW4NOS

On Mon, 25 Jul 2016 14:59:27 +0200 (Paris, Madrid (heure d'été)), you wrote:

Nice job Mister GW4NOS !



A friend of mine told me that we must remember that the internal oscillator

in te NE0- or 07 is 48 MHZ

and to avoid Jitter we must use a FULL division ratio

please have a look on a test

https://www.youtube.com/watch?v=tYWuMe9v98k



it seems that DF9NP is using 800Hz from a NEO-6M on this nice PLL stuff.



Francois F1CHF





-------Message original-------



De : R Hopkins gw4nos@btinternet.com [ukmicrowaves]

Date : 07/25/16 14:21:30

A : ukmicrowaves@yahoogroups.com

Sujet : Re: [ukmicrowaves] replacement GPS module





I've got a Ublox GPS. I think it's the same as the NEO6. It will output a
vast range of frequencies

if you send the correct strings to it. In the files you'll find 'GW4NOS GPS
Programmes.zip'. There

is a list of strings there for 1,2,4,5,10MHz that you can send from a
terminal program or the

programme 'GPS Utility.exe'. I'd be interested to know how well this GPS
works in a frequency

standard. It's much more sensitive receiver than the Jupiter GPS's.



Roger GW4NOS



On 25 Jul 2016 03:17:04 -0700, you wrote:



Hi,
I am currently in the process of rebuilding my GPSDO and thought It might
be a good time to replace/update the Jupiter-T receiver. Can anyone
recommend a suitable modern replacement that still has the 10Khz output?

thanks,
Mike G6TRM







Re: replacement GPS module

R Hopkins
 

I've got a Ublox GPS. I think it's the same as the NEO6. It will output a vast range of frequencies
if you send the correct strings to it. In the files you'll find 'GW4NOS GPS Programmes.zip'. There
is a list of strings there for 1,2,4,5,10MHz that you can send from a terminal program or the
programme 'GPS Utility.exe'. I'd be interested to know how well this GPS works in a frequency
standard. It's much more sensitive receiver than the Jupiter GPS's.

Roger GW4NOS

On 25 Jul 2016 03:17:04 -0700, you wrote:

Hi,
I am currently in the process of rebuilding my GPSDO and thought It might be a good time to replace/update the Jupiter-T receiver. Can anyone recommend a suitable modern replacement that still has the 10Khz output?

thanks,

Mike G6TRM


Réf. : Re: replacement GPS module

F1CHF
 

Nice job Mister GW4NOS !
 
A friend of mine told me that we must remember that the internal oscillator
in te NE0- or 07 is 48 MHZ 
and to avoid Jitter we must use a FULL division ratio
please have a look on a test
 
it seems that DF9NP is using 800Hz from a NEO-6M on this nice PLL stuff.
 
Francois F1CHF
 
 
-------Message original-------
 
Date : 07/25/16 14:21:30
Sujet : Re: [ukmicrowaves] replacement GPS module
 
 

I've got a Ublox GPS. I think it's the same as the NEO6. It will output a vast range of frequencies
if you send the correct strings to it. In the files you'll find 'GW4NOS GPS Programmes.zip'. There
is a list of strings there for 1,2,4,5,10MHz that you can send from a terminal program or the
programme 'GPS Utility.exe'. I'd be interested to know how well this GPS works in a frequency
standard. It's much more sensitive receiver than the Jupiter GPS's.

Roger GW4NOS


On 25 Jul 2016 03:17:04 -0700, you wrote:

>Hi,
>I am currently in the process of rebuilding my GPSDO and thought It might be a good time to replace/update the Jupiter-T receiver. Can anyone recommend a suitable modern replacement that still has the 10Khz output?
>
>thanks,
>
>Mike G6TRM
>

 


Re: replacement GPS module

mike G6TRM
 


Hi,
Thanks for the replies so far, perhaps I should expand on what I'm trying to do. As I have already mentioned I have a Jupiter-T module that I have connected to a G3RUH PLL. I manually check the lock voltage with a voltmeter, to know when it stabilizes.( PITA but it works) When I first built the unit I wanted to include some sort of a  lock monitor (led) and maybe a 16x2 line type display for time/position but gave up as the Jupiter module required a pic program to swap between Motorola/nmea every time it was powered up, and despite trying different software, I never got it to work, so left it as a basic unit.
Present day, I needed to add a G4HUP 4 way distribution amplifier and I assumed by now, there must be better/updated gps modules that might have all the extra I needed which might be easier to implement without having to redo what I  had...
 
thanks
 
Mike G6TRM
 
 

----- Original Message -----
Sent: Monday, July 25, 2016 12:02 PM
Subject: Re: [ukmicrowaves] replacement GPS module

 

Have a look at the Ublox 6T or 8T devices/modules, they are optimised for timing applications and can be configured to give a secondary output up to 1MHz (or more).

Stephen Tompsett


On 25 Jul 2016 11:17, "mb.golfmad@... [ukmicrowaves]" <ukmicrowaves@...> wrote:
 

Hi,
I am currently in the process of rebuilding my GPSDO and thought It might be a good time to replace/update the Jupiter-T receiver. Can anyone recommend a suitable modern replacement that still has the 10Khz output?

thanks,

Mike G6TRM



Re: replacement GPS module

Stephen Tompsett
 

Have a look at the Ublox 6T or 8T devices/modules, they are optimised for timing applications and can be configured to give a secondary output up to 1MHz (or more).

Stephen Tompsett


On 25 Jul 2016 11:17, "mb.golfmad@... [ukmicrowaves]" <ukmicrowaves@...> wrote:
 

Hi,
I am currently in the process of rebuilding my GPSDO and thought It might be a good time to replace/update the Jupiter-T receiver. Can anyone recommend a suitable modern replacement that still has the 10Khz output?

thanks,

Mike G6TRM



Re: replacement GPS module

Mark GM4ISM
 

Mike,
I have not tried it yet but the Neo6M I have  is able to output  10KHz in lieu of 1PPS ( actually it seems to produce 100kHz ok too)
the Neo7M can produce 10MHz, but this version  has to have a battery backup of parameters, the Neo6M can write them to onboard EPROM
 
I have not yet tried to substitute  my Neo6M for the Jupiter,  but I believe that this has been done successfully.
 
I would also note that I have added a lock detector, GPS antenna currrent check etc.   to the Jupiter based RUH GPSDO, partly in hardware, partly within an Arduino (which happens to be there providing a maidenhead locator display from the nmea data)
 
The lock indicator shows when the 10 KHz signals are locked, determines if the GPS is suitably locked ( important on the Jupiter) and adds a  settling time delay before indicating that 10MHz is stable.
Some of the functionality may not be needed with the neo GPS engine, as you can stop it outputting 10KHz when there is no GPS lock and i don’t think it has the same  settling time issues as the Jupiter
 
Regards
Mark GM4ISM
 
 
 

Sent: Monday, July 25, 2016 11:17 AM
Subject: [ukmicrowaves] replacement GPS module
 
 

Hi,
I am currently in the process of rebuilding my GPSDO and thought It might be a good time to replace/update the Jupiter-T receiver. Can anyone recommend a suitable modern replacement that still has the 10Khz output?

thanks,

Mike G6TRM


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Re: replacement GPS module

geoffrey pike
 

Hi MIke,
Not necessarily a replacement but i use a NEO-6 and a G3RUH PLL multiplier to 10 MHz.
You need to programme the NEO-6 to get 10 KHz however.
regards
Geoff


On Monday, 25 July 2016, 11:17, "mb.golfmad@... [ukmicrowaves]" wrote:


 
Hi,
I am currently in the process of rebuilding my GPSDO and thought It might be a good time to replace/update the Jupiter-T receiver. Can anyone recommend a suitable modern replacement that still has the 10Khz output?

thanks,

Mike G6TRM