[time-nuts] HP10811
Hello All, I have been sorting my photographs to pass the time and I came across two shots of a fault in some HP10811 oscillators. The varicap diode is connected to a bias resistor and the transistor via a joint on a ferule in a teflon bush. This has not been soldered correctly, the solder has not wet all the leads. Perhaps the operator had been told not to “cook” the joint by taking to long, but in at least two units out of the four that I own, the joint was not properly soldered, and in one case the EFC did not work. A couple of seconds with a soldering iron and it works perfectly. The units obviously worked on final test, but silver plated component leads can tarnish over 20 years and go OC. Even with a gold plated ferule. Cheers, Neville Michie ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz
I had to change from my "Marine Standard" 3 ft whip and preamp to a small loop antenna and high-gain preamp, but am getting the signal in a lot of noise and spherics in NH such that an Austron 2100F is locking. There is a big difference between 1MW from Nantucket and 75kW from New Jersey! David N1HAC On 8/14/20 5:52 PM, Dana Whitlow wrote: Thanks, Paul. Does this "standard marine preamp" have an integrated antenna of some kind? If not (or you're not using it), can you tell me about the antenna you *are* using? I've not "heard" so much as a peep here in south central Texas, but have only looked in the daytime. Is the station transmitting around the clock? I do suffer from an abysmally-high noise level here. But I'm trying to get a handle on whether it's even worth my trying further. Dana On Fri, Aug 14, 2020 at 4:23 PM paul swed wrote: Dana that was 11:29 am when you emailed me. Looking at the 3586 its -49 db now. To your second question I can't really know that. Its a standard marine preamp. Might guess 20-30 db. But its nothing special. Made by a company STS. Classic FET, filter , 2 X transistor design. It would be a bit of a math guess to use the 3586 reading and deduce the actual field strength. Regards Paul WB8TSL On Fri, Aug 14, 2020 at 4:08 PM Dana Whitlow wrote: Paul, What time of day did you measure that signal strength? And what are the characteristics of the "standard marine preamp"? Most importantly, what field strength corresponds to 1000 uV output from it? Thanks, Dana On Fri, Aug 14, 2020 at 12:17 PM paul swed wrote: Hello to the group. The signal is on the air. I have just discovered one of my favorite HP 3586 SLVM has an issue with sensitivity. For reference in Boston on a second 3586 the level is -51db avg. or 1000 uv using a standard marine preamp 6' off the ground. The signal should remain on until the 20th. I think this also points to the funny issue I was seeing yesterday with intermittent signal levels. Darn one more project to the list. Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.comdata=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7C61b6776a53e547d58a3108d8409cb4ed%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637330389083645065sdata=ew6q%2F6XZJ1Vwa0kaXm9kOjv32ZYr%2BcLO0r4mEi%2BM5Xw%3Dreserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz
Dana Its on the air now. Its a 4-8 foot whip that screws into the top of the preamp. Its just a marine boat loran c antenna they were $30-50. Seriously nothing exciting about them. Do a search on loran c antenna. When loran c was active they preamp and antenna could be had inexpensively. I will believe Texas is too far away to hear the transmitter. I know it reaches out to Indiana pretty well. Regards Paul On Fri, Aug 14, 2020 at 5:55 PM Dana Whitlow wrote: > Thanks, Paul. > > Does this "standard marine preamp" have an integrated antenna of some kind? > If not (or you're not using it), can you tell me about the antenna you > *are* using? > > I've not "heard" so much as a peep here in south central Texas, but have > only > looked in the daytime. Is the station transmitting around the clock? > > I do suffer from an abysmally-high noise level here. But I'm trying to get > a > handle on whether it's even worth my trying further. > > Dana > > > On Fri, Aug 14, 2020 at 4:23 PM paul swed wrote: > > > Dana that was 11:29 am when you emailed me. Looking at the 3586 its -49 > db > > now. > > To your second question I can't really know that. Its a standard marine > > preamp. Might guess 20-30 db. But its nothing special. Made by a company > > STS. Classic FET, filter , 2 X transistor design. It would be a bit of a > > math guess to use the 3586 reading and deduce the actual field strength. > > Regards > > Paul > > WB8TSL > > > > On Fri, Aug 14, 2020 at 4:08 PM Dana Whitlow > > wrote: > > > > > Paul, > > > > > > What time of day did you measure that signal strength? > > > > > > And what are the characteristics of the "standard marine preamp"? > > > Most importantly, what field strength corresponds to 1000 uV output > from > > > it? > > > > > > Thanks, > > > > > > Dana > > > > > > > > > On Fri, Aug 14, 2020 at 12:17 PM paul swed > wrote: > > > > > > > Hello to the group. > > > > The signal is on the air. > > > > I have just discovered one of my favorite HP 3586 SLVM has an issue > > with > > > > sensitivity. > > > > For reference in Boston on a second 3586 the level is -51db avg. or > > 1000 > > > uv > > > > using a standard marine preamp 6' off the ground. The signal should > > > remain > > > > on until the 20th. > > > > I think this also points to the funny issue I was seeing yesterday > with > > > > intermittent signal levels. Darn one more project to the list. > > > > Regards > > > > Paul > > > > WB8TSL > > > > ___ > > > > time-nuts mailing list -- time-nuts@lists.febo.com > > > > To unsubscribe, go to > > > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > > and follow the instructions there. > > > > > > > ___ > > > time-nuts mailing list -- time-nuts@lists.febo.com > > > To unsubscribe, go to > > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > and follow the instructions there. > > > > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz
Thanks, Paul. Does this "standard marine preamp" have an integrated antenna of some kind? If not (or you're not using it), can you tell me about the antenna you *are* using? I've not "heard" so much as a peep here in south central Texas, but have only looked in the daytime. Is the station transmitting around the clock? I do suffer from an abysmally-high noise level here. But I'm trying to get a handle on whether it's even worth my trying further. Dana On Fri, Aug 14, 2020 at 4:23 PM paul swed wrote: > Dana that was 11:29 am when you emailed me. Looking at the 3586 its -49 db > now. > To your second question I can't really know that. Its a standard marine > preamp. Might guess 20-30 db. But its nothing special. Made by a company > STS. Classic FET, filter , 2 X transistor design. It would be a bit of a > math guess to use the 3586 reading and deduce the actual field strength. > Regards > Paul > WB8TSL > > On Fri, Aug 14, 2020 at 4:08 PM Dana Whitlow > wrote: > > > Paul, > > > > What time of day did you measure that signal strength? > > > > And what are the characteristics of the "standard marine preamp"? > > Most importantly, what field strength corresponds to 1000 uV output from > > it? > > > > Thanks, > > > > Dana > > > > > > On Fri, Aug 14, 2020 at 12:17 PM paul swed wrote: > > > > > Hello to the group. > > > The signal is on the air. > > > I have just discovered one of my favorite HP 3586 SLVM has an issue > with > > > sensitivity. > > > For reference in Boston on a second 3586 the level is -51db avg. or > 1000 > > uv > > > using a standard marine preamp 6' off the ground. The signal should > > remain > > > on until the 20th. > > > I think this also points to the funny issue I was seeing yesterday with > > > intermittent signal levels. Darn one more project to the list. > > > Regards > > > Paul > > > WB8TSL > > > ___ > > > time-nuts mailing list -- time-nuts@lists.febo.com > > > To unsubscribe, go to > > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > > and follow the instructions there. > > > > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz
Dana that was 11:29 am when you emailed me. Looking at the 3586 its -49 db now. To your second question I can't really know that. Its a standard marine preamp. Might guess 20-30 db. But its nothing special. Made by a company STS. Classic FET, filter , 2 X transistor design. It would be a bit of a math guess to use the 3586 reading and deduce the actual field strength. Regards Paul WB8TSL On Fri, Aug 14, 2020 at 4:08 PM Dana Whitlow wrote: > Paul, > > What time of day did you measure that signal strength? > > And what are the characteristics of the "standard marine preamp"? > Most importantly, what field strength corresponds to 1000 uV output from > it? > > Thanks, > > Dana > > > On Fri, Aug 14, 2020 at 12:17 PM paul swed wrote: > > > Hello to the group. > > The signal is on the air. > > I have just discovered one of my favorite HP 3586 SLVM has an issue with > > sensitivity. > > For reference in Boston on a second 3586 the level is -51db avg. or 1000 > uv > > using a standard marine preamp 6' off the ground. The signal should > remain > > on until the 20th. > > I think this also points to the funny issue I was seeing yesterday with > > intermittent signal levels. Darn one more project to the list. > > Regards > > Paul > > WB8TSL > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN 99600 monitoring at 100 KHz
Paul, What time of day did you measure that signal strength? And what are the characteristics of the "standard marine preamp"? Most importantly, what field strength corresponds to 1000 uV output from it? Thanks, Dana On Fri, Aug 14, 2020 at 12:17 PM paul swed wrote: > Hello to the group. > The signal is on the air. > I have just discovered one of my favorite HP 3586 SLVM has an issue with > sensitivity. > For reference in Boston on a second 3586 the level is -51db avg. or 1000 uv > using a standard marine preamp 6' off the ground. The signal should remain > on until the 20th. > I think this also points to the funny issue I was seeing yesterday with > intermittent signal levels. Darn one more project to the list. > Regards > Paul > WB8TSL > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Isolated +20V for lamp supply
I will guess to minimize radiated noise. Regards Paul On Fri, Aug 14, 2020 at 4:34 AM wrote: > >Corby, > >so why did HP use a coaxial cable for the lamp power? it seems nonsense. > >Luciano > >Luciano P. S. Paramithiotti >tim...@timeok.it >www.timeok.it > >Da "time-nuts" time-nuts-boun...@lists.febo.com >A time-nuts@lists.febo.com >Cc >Data Thu, 13 Aug 2020 10:46:01 -0700 >Oggetto [time-nuts] Isolated +20V for lamp supply >Luciano, > >You should "Ohm out" the lamp connector shield to the chassis with >nothing connected to the connector. >Depending on how your optical unit is mounted there is a good chance the >lamp assy is grounded to the chassis through the threaded stud! >Especially so if the optical is the newer unpainted one. >If so isolating it as you detailed does not change anything! > >Cheers, >Corby > > >___ >time-nuts mailing list -- time-nuts@lists.febo.com >To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] eLORAN 99600 monitoring at 100 KHz
Hello to the group. The signal is on the air. I have just discovered one of my favorite HP 3586 SLVM has an issue with sensitivity. For reference in Boston on a second 3586 the level is -51db avg. or 1000 uv using a standard marine preamp 6' off the ground. The signal should remain on until the 20th. I think this also points to the funny issue I was seeing yesterday with intermittent signal levels. Darn one more project to the list. Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Eloran signal level
Its been on since last week and should be on till teh 20th. I did see something odd yesterday at 3pm east or so teh signal appeared like it was breaking up. Dropping some 10 db. But then it settled back down to its typical -71 DB on a HP3586 SLVM. So who knows? Regards Paul WB8TSL On Fri, Aug 14, 2020 at 6:58 AM Rodger via time-nuts < time-nuts@lists.febo.com> wrote: > What type of antenna are you using to receive Wildwood Loran? > > > -Original Message- > From: time-nuts On Behalf Of rputz > Sent: Thursday, August 13, 2020 11:30 PM > To: time-nuts@lists.febo.com > Subject: [time-nuts] Eloran signal level > > Hi all, > > Quick check reveals that is Wildwood receivable here in Indiana on > communications receiver, signal was on the ragged edge with atmosph(f)erics > but easily found. > > Rich > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Isolated +20V for lamp supply
Hi, On 2020-08-14 11:31, Poul-Henning Kamp wrote: > > tim...@timeok.it writes: >>Corby, >> >>so why did HP use a coaxial cable for the lamp power? it seems nonsense. > Because it generates a LOT of noise, being in essense a VHF/UHF generator. > Recall it is about 100 MHz and 5 W or thereabouts. So, you have the DC current and you have the 100 MHz AC current. Both can cause interference. The total isolation approach really only work for DC, at 100 MHz you jump gaps through capacitive or magnetic coupling, which exists because of voltage difference or current flow respectively. The best way to handle both of these is to provide a low impedance path on the preferred way, as that will dominated the current flow. For DC, this means adding a low resistive path for the current. For AC it is all about keeping a low-inductive path and keep the loop area low, which is also about low-inductance. The chassi path for ground should be a very low-resistive and low-inductive path, but the +20 V does not match that. The AC-return path can be made shorter by providing a capacitive path back, with inductance on the 20 V feed. Care should be made to ensure inductance can handle the current through it, as you do not want the core to be saturated. If one wants to separate coupling, one can do "star-ground" feed, but for the 5065 it's mostly the +20V and not the ground that needs it because of significant difference in conductance area between wires and chassi, so reasonable to assume wired to provide higher resistance and thus higher problem with common path. So sure, pulling a separate wire for the +20V from the PSU to the lamp would help. Less so for the ground, but you can do that too if you want to, but that is on the diminishing returns effort list. In the end, adding more wires in parallel to existing conductions paths will lower the resistance, and thus lower the cross-coupling. You have a number of different ways around it. However, for RF-signals you always want an AC return-path for that current very close to the signal, and if that happens to bridge between two different DC points you will lower the voltage difference between these, if that current is high, add a parallel thick wire. This is also true for AC-power at 50-60 Hz. Many attempts to break the connection for DC or 50/60 Hz tends to cause severe isolation problems for the signal, so instead shunting with a thick wire to connect things tighter together ends up making sense. So, isolation can maybe be a local strategy, but it doesn't work as one builds larger things in a box or even a system of boxes. As soon as you start interconnect you get into issues. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Eloran signal level
What type of antenna are you using to receive Wildwood Loran? -Original Message- From: time-nuts On Behalf Of rputz Sent: Thursday, August 13, 2020 11:30 PM To: time-nuts@lists.febo.com Subject: [time-nuts] Eloran signal level Hi all, Quick check reveals that is Wildwood receivable here in Indiana on communications receiver, signal was on the ragged edge with atmosph(f)erics but easily found. Rich ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Isolated +20V for lamp supply
tim...@timeok.it writes: > >Corby, > >so why did HP use a coaxial cable for the lamp power? it seems nonsense. Because it generates a LOT of noise, being in essense a VHF/UHF generator. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 58503A GPS receiver not locking to GPS
This Motorola Service Bulletin astonished users in the timing community who kept their VP Oncore timing products operating 24/7/365 - Most everyone! https://synergy-gps.com/wp-content/uploads/2019/06/VP_SERVICE_NOTE.pdf All of the PVT6, 6 and 8 channel Basic Oncore and 6 and 8 channel VP Oncore OEM GPS receiver boards incorporated a Pendulum Oscillator that was recalibrated every time the boards were power cycled. If the receivers were powered-on for long periods, no calibration occurred so it was possible for the oscillator to drift beyond a point where a board could easily acquire satellites; even if powered off for a short period. Randy Warner (RIP) authored an App-Note "Startup Times for VP Oncore Receivers" that discusses the details (our web site was hacked and we're still in the process of replenishing content that was deleted. The text of Randy's App-Note is below). A condition not mentioned in either one of these App-Notes was brought to our attention by our friend, Doug Baker (then at Datum Corp.) sometime in the late nineties. Long term, always on, operation in CDMA cell sites would also suffer from this oscillator drift problem. Anyone with 6 and 8 channel VP Oncore based timing instruments may have noticed this phenomenon too: The longer these VP receivers remained in a powered-on state, the more the oscillator drifted due to no recalibration occurring. The oscillator drift caused the receiver to take longer to acquire satellites as they rose up from the horizon. An attendant effect of not re-calibrating the oscillator was that the longer the receivers were powered on, they appeared to become less sensitive. For example, a receiver installed at a new site that was continuously locking on to 5 to 8 satellites would only be able to see something like 2 to 5 satellites if powered on continuously for more than a year, or so. That's why Motorola generated the VP Oncore Service Note recommending periodic power cycling. BTW - The 1024 Week Roll-Over for a VP Oncore with v8.8 firmware was 3/22/2016; With v10.0 firmware was 8/13/2017 and with v10.1 firmware was 7/11/2018. These receivers will continue to operate but with incorrect dates. We know of no resource for information about VP Oncore behavior with future Week Roll-Overs, Leap Second, etc. Apologies for the long-winded explanation! Art Sepin START UP TIMES FOR VP RECEIVERS At first glance, it probably seems a little strange for me to be writing an application note for the Motorola VP OncoreTM series of GPS receivers fully six months after they were phased out due to parts procurement problems, but I am getting enough calls, emails, and receivers returned due to extended Time To First Fix (TTFF) to warrant a quick note. HISTORY - One result of the impending phase out is that Synergy Systems purchased quantities of VP receivers from other Motorola distributors world-wide in order to support our customers for as long as possible. These receivers included 6 channel B1's and 6/8 channel B3's and B8's. Some of these receivers have been in distributor stock for up to five years after the original date of manufacture. The receivers themselves are in perfect condition, but what can cause problems with many of them is aging of the oscillator components. Unlike the newer GT+, UT+, and M12 receivers, the VP used a "pendulum oscillator" that was much more complicated to stabilize than the newer units. During the board manufacturing process the oscillator on every board is characterized, and the appropriate oscillator characteristics are stored in EEPROM. The next time the board is powered on (usually by you) the oscillator characteristics are downloaded from EEPROM during initialization and used to set the oscillator output frequency. THE REAL WORLD - OK, that sounds great. What's the problem? Well, normally this all works fine, but what can slow things down is if the receiver has been sitting around for a while in an un -powered state. In this case, when the receiver is powered up, the stored oscillator characteristics are all wrong, the receiver runs off frequency, and as a result it cannot acquire satellites. [Art - also see Motorola VP Oncore Service Note] This will continue for some time (an hour or more in some cases) as the receiver tries to lock onto satellite carriers: searching for SVs, adjusting oscillator frequency, etc. Finally, the receiver hits on the right combination and BANG, things ret urn to normal. This is best illustrated with the following graph. This graph shows the start-up progression of an old 6 channel VP that has been sitting in a box since 1995. The receiver was initialized using our SynTAC control program, which initialized the receiver and loaded in correct time and position at time "0". Note that the receiver variously tracks 0, 1, 2, or 3 SVs for approximately 5000 seconds (over an hour and twenty minutes!) without ever
Re: [time-nuts] Isolated +20V for lamp supply
Corby, so why did HP use a coaxial cable for the lamp power? it seems nonsense. Luciano Luciano P. S. Paramithiotti tim...@timeok.it www.timeok.it Da "time-nuts" time-nuts-boun...@lists.febo.com A time-nuts@lists.febo.com Cc Data Thu, 13 Aug 2020 10:46:01 -0700 Oggetto [time-nuts] Isolated +20V for lamp supply Luciano, You should "Ohm out" the lamp connector shield to the chassis with nothing connected to the connector. Depending on how your optical unit is mounted there is a good chance the lamp assy is grounded to the chassis through the threaded stud! Especially so if the optical is the newer unpainted one. If so isolating it as you detailed does not change anything! Cheers, Corby ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 58503A GPS receiver not locking to GPS
On Fri, 14 Aug 2020 at 02:55, Eric Garner wrote: > Have you manually set the date/time yet? > > Last time I powered mine up. I had to update the current time and date and > it locked right up. > > -Eric Yes, I have set time, date, location and antenna height. When I first switched it on a few days ago I didn’t. It gave no information about any satellites at all. Then I set the date and location, and it appears that it is seeing some satellites, in that it’s trying to lock to a few. It has just crossed my mind that I set the time to GPS time, not UTC, although I doubt an 18 s error is going to be significant, but I can reset the time to UTC. Dave. -- Dr. David Kirkby, Kirkby Microwave Ltd, drkir...@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Eloran signal level
Hi all, Quick check reveals that is Wildwood receivable here in Indiana on communications receiver, signal was on the ragged edge with atmosph(f)erics but easily found. Rich ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
