In Australia, we have a national grid. It's big.
National meaning all but a few isolated towns like Darwin, Perth. Perth
might be connected via a 1800 km HVDC line in the future... which is a
different story DC interconnectors
So, I gather someone with their MASER in Adelaide
Hello Time-Nuts,
I'm trying to lighten the load some and this HP instrument has risen
to the surface. I acquired it with the intention of compensating the
1pps output of a GPS receiver for sawtooth correction. The intention
was to take the serial output of the receiver and outputting a GPIB
Hi Rob
Thanks for the post. wow. OK thanks for the notes.
No expense spared anywhere on the quality of those parts used.
mine are Rev Bs
EEPROM. might need to read out that info while it is good.
Probably important parameters
what goes wrong with these babies ? or should I consult
Hi
The whole “phase here vs phase there” thing was at the heart of the papers the
power guys started presenting back in the late 1980’s …. At least back then the
data
was between points a lot further spread out than both sides of a valley.
Bob
> On Jul 7, 2019, at 5:39 PM, jimlux wrote:
>
>
On 7/7/19 11:48 AM, Bill Hawkins wrote:
Group,
We've discussed this before, but maybe it needs to be said again.
Line frequency is not constant.
I think the research is more about understanding the frequency and time
shifts across the network, referred to a more accurate and stable
> So no, you can't compare data from different regions, unless you want to know
> which way DC power is flowing.
How does knowing data about two regions tell me anything about how much power
is flowing and which direction?
--
These are my opinions. I hate spam.
When I first got my TAPR-TICC one of the first tests that I did with it was to
put a coil of RG-58 in the freezer then measured the prop delay as it warmed
up. I posted a plot on the list. I didn't have a temp sensor in the coil,
though.
Group,
We've discussed this before, but maybe it needs to be said again.
Line frequency is not constant. There is no master PLL. Approximate
frequency is maintained by a central power dispatching office in each of the
four (?) regions tied together by their power distribution grid. The
Leo Bodnar writes:
> Correction on all Ublox receivers including F9P is done at navigation
> rate which can be set as high as 20Hz.
If you are thinking of the sawtooth correction, then I think you'll find
that this is only available for the full second. There is some mumbling
in the manual that
Hi
As far as the coax goes, termination is a good idea. As far as the signal goes
… maybe not so much ….
Using 5V logic as an example:
If you build up a driver that has a 50 ohm source impedance, you have a (so
far) do-able project. The
output delivered into a light load could be the same as
On 7/6/19 8:34 PM, Glen English VK1XX wrote:
Hal, Good point.
and I have never seen a spec for phase stability for Cat-7 cable !
for RG58, OR OTHER polyethylene, might be up to 150ppm /deg C. maybe as
good as 10 ppm/deg C for some LMR.
With 1000 feet of cable might be an issue for fine
Being a Ham and experienced 10base-2, I'm rather careful with termination but
thanks for the reminder. I've decided to use coax relay 18GHz that I have a
lot of, and purchased cheaply. That way, there is no question.
---
(Mr.) Taka Kamiya
KB4EMF / ex
Hi
They go absolutely crazy updating nav….. but they only come up with the timing
correction once a second.
From the latest version of the F9T Manual UBX-19005590 - R02 on page 43:
The recommended configuration when using the UBX-TIM-TP message is to set both
the measurement rate
Correction on all Ublox receivers including F9P is done at navigation rate
which can be set as high as 20Hz.
Leo
> From: Bob kb8tq
> Frequency of any GNSS output on the F9P is limited by the accuracy of the
> time pulse.
> Correction is only done once a second.
Gerhard, does not sound right, Tom did an extensive evaluation, steps in 6.6
E-15 at 15 MHz. Our best GPSDO.Am out of town back Tuesday have extensive info
on my PC need to get off listBertSent from my Galaxy Tab® A
Original message From: Gerhard Hoffmann Date:
7/6/19 11:58
Hi Taka,
I made an 1:8 multiplexer with TE HF3 relays. They are specified up to 3
GHz, but the 'tree'-design has log2(8) = 3 levels - i.e. the signal always
passes through three relays.
in practice I got around 1 GHz -3dB bandwidth, which I think is OK for 1PPS
Hi Bob, and Achim . thanks for the comments. I've change the subject
line to fit more in line we the morphed discussion.
Good discussion, and like Bob said, there will be lots of common mode on
the GPSs. The diurnal GPS derived clock errors due to the ionosphere are
well described . Bob
Glen English VK1XX writes:
> My intention is to use the average of multiple stationary mode GPS
> 1PPS signals to drive a single OCXO, the idea to be a better 1pps
> estimate. I'll upsample the inputs to get the control sample rate up.
I'd expect a lot of correlation among multiple GPS receivers,
Hi,
On 2019-07-06 20:39, Poul-Henning Kamp wrote:
>
> In message
> ,
> "D. Resor" writes:
>
>>> From another list I was directed to this link for those who do not have a
>> shortwave radio.
>>
>> http://websdr.ewi.utwente.nl:8901/
>>
>> I entered the frequency of 60Khz and am curious
Hi,
On 2019-07-06 20:39, Poul-Henning Kamp wrote:
>
> In message
> ,
> "D. Resor" writes:
>
>> >From another list I was directed to this link for those who do not have a
>> shortwave radio.
>>
>> http://websdr.ewi.utwente.nl:8901/
>>
>> I entered the frequency of 60Khz and am curious
In that case, my suggestion is think of them all as transmission lines
in coax. terminate as needed.
Others here will also have points I have missed I am sure, or
alternative equally valid suggestions.
beign critical (maybe I am being over critical) :
watch out also for reflections from
I should have mentioned this clearly earlier, but all converting and switching,
then measuring happens in ONE 2U rack case. Length of each cable is minimal.
I thought mention of TICC would make it sort of clear but it didn't.
I have LOTS of coax relays. I'll use them. It's a gross overkill
---
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
On Sunday, July 7, 2019, 12:00:52 AM EDT, Glen English VK1XX
wrote:
Hal, Good point.
and I have never seen a spec for phase stability for Cat-7 cable !
for RG58, OR OTHER polyethylene, might be up to
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