I did a few more experiments on changing the initial date, hoping to get
it to accept more recent values, and still give correct date reports. It
seems like there's an absolute limit somewhere in 2007. 01 Jan 2007
seems to work, and during startup, it momentarily forces 28 Dec 2006,
but still g
e...@telight.com said:
> I can't figure out why the 01 Jan 2006 initial date allows it to apparently
> work. I've looked at rollover info online, and ballparked some numbers -
> nothing makes sense to me to explain it numerically
It's simple after you see it.
You get a date/time from GPS. The
I just did another experiment with the new deal. I shut it down for
about an hour, to get fairly close to a fully cold start. Here's
approximately the sequence of events and timing:
T=0, power on
SatStat establishes com
GPS time 04:00:00 and counting
Date 01 Jan 2006
"OCXO warmup"
T+2 min
I think I finally fixed the date issue on the Z3801A, by some fooling
around with settings using SatStat, combined with experiments and lots
of power ups and downs.
The GPS RX unit now thinks it was installed 1 Jan 2006, and everything
starts tracking, and reports the right date within about t
On 2/24/22 11:31 PM, Larry McDavid wrote:
I give up! Where is this $5 USB-to-RS422 Adapter to be found?
Amazon has such a DTECH adapter for $22.
Indeed the price has gone up substantially - $15
https://www.amazon.com/DSD-TECH-SH-U10-Converter-Compatible/dp/B078X5H8H7
I am using a RS422-to
I give up! Where is this $5 USB-to-RS422 Adapter to be found?
Amazon has such a DTECH adapter for $22.
I am using a RS422-to-RS232 adapter and it has been totally reliable for
many years. I am not trying to use the pps output via the serial link so
any delay in the USB adapter would be irrelev
j...@luxfamily.com said:
> These days, since PCs don't have serial ports, you can buy a RS422 USB
> adapter for $5. If I were doing it now, I wouldn't bother reconfiguring.
USB is ugly for timing. I can get RS-232 PCI cards cheap enough.
Has anybody found a good RS-422 card? The ones I just
Some information on the Motorola Oncore VP used in the HP Z3801A
http://www.ko4bb.com/getsimple/index.php?id=download&file=02_GPS_Timing/Motorola_Oncore/Oncore_Interface_Brian_Kirby.pdf
http://www.realhamradio.com/tac32-interface.htm
http://www.realhamradio.com/GPS_Frequency_Standard.htm
_
On 2/24/22 7:25 PM, ed breya wrote:
Paul and Hal, I think there may be some confusion here. I modified the
Z3801A to RS-232 way back when I first got it. My recent post was just
discussing some of what's in this demo/testing unit thing. It's just a
translator for TTL/RS-232 for when the GPS RX
Paul and Hal, I think there may be some confusion here. I modified the
Z3801A to RS-232 way back when I first got it. My recent post was just
discussing some of what's in this demo/testing unit thing. It's just a
translator for TTL/RS-232 for when the GPS RX board (TTL serial) is used
by itself
paulsw...@gmail.com said:
> Internally there was a mod that allowed the 3801 to output true rs 232.
> Numbers of jumpers as I recall. Like 8 or 10.
Jeff Mock wrote up a nice description of how to do it, with good pictures.
https://support.ntp.org/bin/view/Support/Z3801AReceiverModifications
Hi Ed
I have used satstat also but favor ladyheather. So nice.
Internally there was a mod that allowed the 3801 to output true rs 232.
Numbers of jumpers as I recall. Like 8 or 10.
If your using satstat then it doesn't remember anything.
As suggested in the points if the almanac is gone it can take
Paul,I'm using the old HP SatStat program. It's plenty good enough for
my simple needs. I also found I have a bunch of old stuff from over ten
years ago, while organizing the older PCs and consolidating backup
files. The original Motorola WinOncore program is included. This can
talk to the RXs
Ed what tool are you using to monitor the 3801.
LadyHeather remembers these bits of good stuff.
Regards
Paul.
WB8TSL
On Thu, Feb 24, 2022 at 2:46 PM ed breya wrote:
> Last night I told it to do a survey, and let it slog through it
> overnight. This morning it seemed to be working fine, and appar
Aha, thanks John. I just saw your message after sending my previous reply.
That would explain a couple of things - first, that the TCXO needs a
workout, and may have been the entire cause all along, and second, that
those Flash parts (or is it something else?) are used for storing data
during
Last night I told it to do a survey, and let it slog through it
overnight. This morning it seemed to be working fine, and apparently in
position hold mode.
Then I shut it down for about 45 min to let things cool down to nearly a
fresh cold-start condition. On power up, it went through the usua
I recently fired up my old Z3801As and ran across a similar problem.
Art Sepin helpfully reminded me that the old Motorola receivers'
on-board oscillators drift with time and after a long power off the
oscillator may drift so far that it can't lock. The receiver stores
calibration data in eepr
Hi
If the unit has been off long enough ( could be decades ….. ) there is a lot
about the GPS system that it really has no way of knowing. It will have to
grab a full almanac and the ephemeris data from whatever it might happen
to be able to download it from. Since the data rate on GPS is mind bo
Ed these older units do indeed take hours to potentially sync. Powerup and
let go for 24 hours if its been off a long time. Normally doesn't take
anything like 24 hours. But if that much time goes by thats a really bad
indicator.
I actually add in the battery backup to the gps receivers. 2 X AA mou
Ed,
I don't have any first-hand knowledge with the Oncore, but with 'other'
GPSDO's that haven't been turned on for some time (weeks/months or longer)
or almost always from a significant change in (antenna) location, there
maybe a significant time lag before the (a) oscillator gets up to
temperatu
I found a spare Oncore VP GPS RX unit in the parts department last week,
and tried it out in the Z3801A. It would not track, even after quite
some time in use. The original would pop right up almost immediately,
after warm up.This one had some slight differences from the original,
around the an
Hi
> On Feb 8, 2022, at 11:16 PM, ed breya wrote:
>
> Sorry I haven't been proactive on this. My main PC crapped out last week in a
> big way. I've been doing almost a total rebuild on it. Just got internet and
> email working this morning, followed by printer problems.
>
> Regarding the Z38
Ed,
Even with 1024 week rollover error the time should be correct.
The easiest way to get correct day and date is look at it with LadyHeather.
She will add appropriate number of 1024 weeks to get it right.
Bill
On Tue, 8 Feb 2022 20:16:32 -0800, ed breya wrote:
>Regarding the Z3801A date/rollo
Sorry I haven't been proactive on this. My main PC crapped out last week
in a big way. I've been doing almost a total rebuild on it. Just got
internet and email working this morning, followed by printer problems.
Regarding the Z3801A date/rollover issue, it looks like there's no easy
fix, so I
j...@febo.com said:
> Of course, many of the old units still work fine except for the rollover
> providing a bogus date, and external software can easily correct that.
If you tell it the date, it will do the right thing.
T220220205235450339
>From the status page:
GPS 23:55:19
The Z3801As that I have seen have the Motorola Oncore VP 6-channel
receiver which I think predates the UT+, and all have had the rollover
issue.
The problem with swapping in another unit is that unless it sufficiently
imitates the VP at startup, the Z3801A will throw an error and never get
to
I do not know what Z3801 uses for GPS.
I have several Motorola UT+ GPS modules running.
Older ones with V2 firmware suffer 1024 week rollover failure.
My units with V3.2 and V3.1 do 1024 week rollover correctly.
If you are able to communicate with your device using Lady Heather
she will correct an
I think the problem with the Z3801 is that it expects to see specific
handshake things at startup, in Motorola binary protocol. Dropping in a
random GPS will result in a "No GPS" error.
John
On 2/5/22 12:44 PM, Keelan Lightfoot wrote:
Depending on who’s GPS chipset is being used, a fix
>
> You can also fix your software to add 1024 weeks until the date is past a
> magic constant. If your tools support it, you can get that date as the
> build
> date from when you compiled your software.
>
Then there's US patent 5,923,618: "Leap-second cure for 1999 GPS rollover
problem"
The aut
Depending on who’s GPS chipset is being used, a fix might be possible. I’ve
poked around inside the firmware of a number of Trimble receivers (so far three
generations of the 4000 series, and the Placer series). Because the first week
rollover occurred in 1999, any receiver made close to that da
Hi
Any time you relocate things (even by 10m) it’s a really good idea to
do a resurvey. The same is true if the GPS module gets replaced. Yes
this is a “Timenut” talking :). Clicking on the resurvey button isn’t
all that big a deal.
Bob
> On Feb 4, 2022, at 8:11 AM, Hal Murray wrote:
>
>
> e
e...@telight.com said:
> The location seems right on. I found some of my notes from way back, when I
> had it hooked to a decent outdoor antenna - the coordinates are exactly the
> same. This setup is about 5-10 m away from the original location.
They are exactly the same. The results from
> The date issue is a 1024 week rollover failure in the GPS receiver. A fix is
> to replace the GPS receiver with one that does not have this problem.
You can also fix your software to add 1024 weeks until the date is past a
magic constant. If your tools support it, you can get that date as t
On Thu, 3 Feb 2022 18:44:54 -0800, ed breya wrote:
>It seems to all be working OK, except the reported date is slightly off
>- by about twenty years. It says it's 20 Jun 2002. The setup isn't
>optimal - it's just a little GPS antenna propped up against the office
>door glass. It only sees abo
I've been wrapping up the last major sheet metal parts, and found I had
no ground tie in for the box that holds the Z3801A's power supply. This
is the part that holds the PS board cantilevered up over the main board,
in its proper position that's necessarily different from original. The
whole t
Tom Holmes wrote:
"I am curious about one part of the warmup process. At around 7 minutes,
the power jumps up radically, which you attribute to
the outer oven kicking in. It has often been stated on this list that
the outer oven was intended for use during really cold
starts, which I would expec
t; -Original Message-
> From: Ed Palmer
> Sent: Saturday, January 29, 2022 11:07 AM
> To: time-nuts@lists.febo.com
> Subject: [time-nuts] Re: HP Z3801A project update
>
> On 2022-01-29 2:30 AM, "Tom Holmes" wrote:
>> Ed...
>>
>> Very good data!
#x27;t heating fast enough?
Tom Holmes, N8ZM
-Original Message-
From: Ed Palmer
Sent: Saturday, January 29, 2022 11:07 AM
To: time-nuts@lists.febo.com
Subject: [time-nuts] Re: HP Z3801A project update
On 2022-01-29 2:30 AM, "Tom Holmes" wrote:
> Ed...
>
> Very good
On 2022-01-29 2:30 AM, "Tom Holmes" wrote:
Ed...
Very good data!
I am curious about one part of the warmup process. At around 7 minutes, the
power jumps up radically, which you attribute to
the outer oven kicking in. It has often been stated on this list that the outer
oven was intended for
lmes, N8ZM
-Original Message-
From: ed breya
Sent: Friday, January 28, 2022 9:50 PM
To: time-nuts@lists.febo.com
Subject: [time-nuts] Re: HP Z3801A project update
I've been doing some more cold start testing, and thought I'd share this
info, for any Z3801A owners who may be curious abou
I've been doing some more cold start testing, and thought I'd share this
info, for any Z3801A owners who may be curious about the behavior. Some
aspects are probably well known since long ago. I've seen it all since
first starting work on this some 10-12 years ago, so I know
approximately what
The new boost converter is working great for external DC power input.
Yesterday I put the Z3801A guts back into the carcass, after being out
of commission since October when I started the latest round of additions
and changes. The bench supply I've been using doesn't have enough oomph
to do col
The battery control system uses relays to ultimately control the
connect/disconnect operations. The front panel battery control switch
selects the external, off, or internal battery mode, mutually exclusive
(although they don't necessarily have to be).
The internal battery operation will be fu
Hi
Stacking switchers is generally not a good idea. Even stacking them with
non-switchers is not a recommended way to go. Can it be done? Sure, if
you know a lot about exactly what’s inside the switcher ….
Best approach:
Convert all the this and that to some voltage > 20 V and then do the “vot
Ed thats quite a story and good to read.
But a bit hard to follow to actually answer your question that appears not
to need a answer now.
The diode switch makes sense. But I think you need another diode to stop
the converter from seeing the large filter cap. A thought at least.
Switching converters
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