Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
I've made a small Web page describing what happened when I changed the puck antenna on a Rapco 1804M for a more sensitive one. The Rapco 1804M expects a big outside antenna. http://www.satsignal.eu/ntp/Rapco-1804M-notes.html This page has now been updated to provide a comparison between three puck antennas - the Garmin GA 27 (BNC), a 3rd-party low-cost puck, and a Gilsson puck antenna. It seems that the even higher signal level from the Gilsson benefits the 1804M more than the other two. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
Assuming it's using a timing-optimized receiver, the lack of a clear view to the sky is probably the biggest problem. Once they have a valid almanac, they will normally select the satellites with the highest elevation angles - and if you have an obstructed view that might well include several that are not visible. Obviously, the less channels on the receiver, the bigger an issue this is - on top of this, the timing receivers tend to be engineered to favor selectivity over sensitivity (the idea being that the gain is in the antenna and you can select it to match the cable losses). I have no idea if the firmware in the Rapco will support the 8-channel UT+ - but the fact that the monitoring software seems to have spaces for up to 8 SVs gives me some hope it might (or possibly there is some later FW that does). This could be worth trying. Regards, Pete Bell On Wed, Nov 2, 2011 at 4:19 PM, David J Taylor david-tay...@blueyonder.co.uk wrote: I've made a small Web page describing what happened when I changed the puck antenna on a Rapco 1804M for a more sensitive one. The Rapco 1804M expects a big outside antenna. http://www.satsignal.eu/ntp/Rapco-1804M-notes.html This page has now been updated to provide a comparison between three puck antennas - the Garmin GA 27 (BNC), a 3rd-party low-cost puck, and a Gilsson puck antenna. It seems that the even higher signal level from the Gilsson benefits the 1804M more than the other two. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
Assuming it's using a timing-optimized receiver, the lack of a clear view to the sky is probably the biggest problem. Once they have a valid almanac, they will normally select the satellites with the highest elevation angles - and if you have an obstructed view that might well include several that are not visible. Obviously, the less channels on the receiver, the bigger an issue this is - on top of this, the timing receivers tend to be engineered to favor selectivity over sensitivity (the idea being that the gain is in the antenna and you can select it to match the cable losses). Yes, that in consistent with what I'm seeing, Pete, thanks. I am told that the actual receiver is a Trimble SVeeSix, so why I occasionally see eight reports from the Rapco firmware I don't understand. I have no idea if the firmware in the Rapco will support the 8-channel UT+ - but the fact that the monitoring software seems to have spaces for up to 8 SVs gives me some hope it might (or possibly there is some later FW that does). This could be worth trying. Regards, Pete Bell As the unit is only required for frequency, I am not intending to modify it. It has OCXO with quite good specifications, so it will more than meet my needs. It would likely meet my needs five minutes after being switched on! Thanks for your comments. I've updated the Web page about the 6/8 channels, and added a couple of pointers for those who might want to try the antennas. An outside one with a clear sky view would like be better than any of these puck antennas. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] VIGO time interval devices
Jose Camara-Berkeley Nucleonics has them, Keithley has them, they all must come from the same Chinese OEM. Maybe the quality is good, maybe the specs are honest and apples to apples. Or maybe not. --- Interesting to note that the Picotest/Array U6200A and the BNC 1105 use exactly the same photos in their ads. The major difference seems to be the asking price. http://www.picotest.com.tw/product02.html http://www.array.sh/yq-u6200ae.htm http://www.berkeleynucleonics.com/products/model_1105.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] VIGO time interval devices
A couple more :) http://www.acquitek.com/u6200a/counter-test-measurement.html http://www.ptsyst.com/U6200A-B.pdf (even with 20GHz input option) Similar thing I found some time ago when looking for an electronic load. Same thing with several different branding, price ranging for 1 to 2. Regards, Javier El 02/11/2011 12:19, Arthur Dent escribió: Jose Camara-Berkeley Nucleonics has them, Keithley has them, they all must come from the same Chinese OEM. Maybe the quality is good, maybe the specs are honest and apples to apples. Or maybe not. --- Interesting to note that the Picotest/Array U6200A and the BNC 1105 use exactly the same photos in their ads. The major difference seems to be the asking price. http://www.picotest.com.tw/product02.html http://www.array.sh/yq-u6200ae.htm http://www.berkeleynucleonics.com/products/model_1105.html ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
Yes, that in consistent with what I'm seeing, Pete, thanks. I am told that the actual receiver is a Trimble SVeeSix, so why I occasionally see eight reports from the Rapco firmware I don't understand. Ah, I didn't realize this was based on the Trimble board - I was having a mental seizure and thinking it was using a Motorola OnCore, as so many of the others did. Are you really sure it is an SV6? Trimble also made an SV8 timing that was in the same form factor and if it was using that it would certainly explain why you sometimes see more than 6 satellites - although I have a vague memory that if you talk to it as if it was a 6-channel board it starts pretending to be one for reasons of backwards compatibility, so even if you do have the SV8 in there it likely won't do you much good. As the unit is only required for frequency, I am not intending to modify it. It has OCXO with quite good specifications, so it will more than meet my needs. It would likely meet my needs five minutes after being switched on! True, but this is time-nuts. The pursuit of more accuracy than you need is the whole purpose of the list :) Regards, Pete ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] VIGO time interval devices
If anyone was ever to review such a device the actual power consumption would be usefull to know. The likely savings in electricty costs could provide some justification for replacing one of my HP5370B's (: Devices that could also easily run from a DC power source could have merit as well. --- On Tue, 11/1/11, Jose Camara camar...@quantacorp.com wrote: From: Jose Camara camar...@quantacorp.com Subject: Re: [time-nuts] VIGO time interval devices To: 'Arthur Dent' golgarfrinc...@yahoo.com, 'Discussion of precise time and frequency measurement' time-nuts@febo.com Received: Tuesday, November 1, 2011, 11:50 PM There seems to be a deluge of these OEM counters, mimicking the 53132 operation, with a bit better specs and built-in 3rd channel. Berkeley Nucleonics has them, Keithley has them, they all must come from the same Chinese OEM. Maybe the quality is good, maybe the specs are honest and apples to apples. Or maybe not. The only experience I had was with another Agilent knock-off, the BNC-branded arb generator model 645, which was cheaper than the Agilent, with a higher frequency capability (50MHz compared to 20MHz) and SCPI compatible. Didn't check side by side on a spectrum analyzer, but for the application I had it worked fine. As a plus, it had also digital output on the back (16 bits) so it doubled as a cheap word generator. It would be nice for a real time nutter to get one (BNC often offered 1 month loaners) and measure the actual performance. One thing we will only know 10 years from now is if they last as long as the HPs - or if the manufacturer will still exist. BNC has a comparison to Agilent and Pendulum on their site. Caveat Emptor. http://www.berkeleynucleonics.com/Comp/1105/1105_comp_chart.htm Jose -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Arthur Dent Sent: Monday, October 31, 2011 2:25 PM To: time-nuts@febo.com Subject: [time-nuts] VIGO time interval devices Has anyone looked into the Picotest (also sold as Array) U6200A TIC? Looks like DC-6Ghz with 12 digits/sec and 40ps resolution. Check the specs at: http://www.picotest.com.tw/product02.html One seller on the popular auction site has them for $1270 (with shipping). http://www.ebay.com/itm/New-Universal-Frequency-Counter-meter-ARRAY-U6200A-/ 270788500453 -Arthur ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
Ah, I didn't realize this was based on the Trimble board - I was having a mental seizure and thinking it was using a Motorola OnCore, as so many of the others did. Are you really sure it is an SV6? Trimble also made an SV8 timing that was in the same form factor and if it was using that it would certainly explain why you sometimes see more than 6 satellites - although I have a vague memory that if you talk to it as if it was a 6-channel board it starts pretending to be one for reasons of backwards compatibility, so even if you do have the SV8 in there it likely won't do you much good. Next time I have the unit open I will take a look. Are there obvious markings to distinguish the boards (it's a board and not a box), as I recall looking but no seeing any. As the unit is only required for frequency, I am not intending to modify it. It has OCXO with quite good specifications, so it will more than meet my needs. It would likely meet my needs five minutes after being switched on! True, but this is time-nuts. The pursuit of more accuracy than you need is the whole purpose of the list :) Regards, Pete Yes, I know! Sad, but 10 Hz at 150 MHz and PCs to within a few microseconds will do me nicely! Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
By the way, this doesn't mean that the GA-27 is a poor antenna design, it's just not the best antenna choice for this situation. The GA-27 is intended as an external antenna for Garmin's handheld receivers, which normally operate with passive patch or helix antennas. So the receiver itself needs to be sensitive enough to work well when an unamplified antenna is connected directly to the receiver, and the GA-27 preamp only needs to provide enough gain to overcome the losses in the cable plus a bit more. Additional gain could be detrimental in some circumstances (e.g. when placed near transmitting antennas on a vehicle), so the GA-27 might well be the best antenna for the Garmin handheld receivers. But a GPS board module is intended to be built into some piece of equipment, and probably expected to always be fed from a remote amplified antenna, never a local passive antenna. In those circumstances, it makes sense to put all the necessary gain at the antenna preamp and let the receiver be less sensitive. The manufacturer will recommend some antenna for use with the receiver, and though you don't usually have to use that particular antenna, it's probably a good idea for your antenna/cable/splitter setup to provide roughly the same signal level at the receiver. - Dave On Wed, Nov 2, 2011 at 01:19, David J Taylor david-tay...@blueyonder.co.uk wrote: I've made a small Web page describing what happened when I changed the puck antenna on a Rapco 1804M for a more sensitive one. The Rapco 1804M expects a big outside antenna. http://www.satsignal.eu/ntp/Rapco-1804M-notes.html This page has now been updated to provide a comparison between three puck antennas - the Garmin GA 27 (BNC), a 3rd-party low-cost puck, and a Gilsson puck antenna. It seems that the even higher signal level from the Gilsson benefits the 1804M more than the other two. Cheers, David -- ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
I tried a similar Garmin antenna with my Datum ET6000 and the lock times were really long, even with the antenna on a 14 foot pole above the roof. I attribute a lot of this to the long 8 ft RG174 style coax pigtail. I have to wonder if the gain of the preamp as published actually includes the inherent cable loss, and even if so the preamp must be screaming in gain to make up for the loss. I intend to get a proper antenna. Here is a comparison of specs of these type antennas: http://gpsinformation.net/main/gpsantrev1.htm -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
The ET6000 used Trimble Bullet antennae when I was selling them in the UK. I seem to remember about 35db of gain in that antenna. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim Sent: 02 November 2011 18:52 To: time-nuts@febo.com Subject: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit I tried a similar Garmin antenna with my Datum ET6000 and the lock times were really long, even with the antenna on a 14 foot pole above the roof. I attribute a lot of this to the long 8 ft RG174 style coax pigtail. I have to wonder if the gain of the preamp as published actually includes the inherent cable loss, and even if so the preamp must be screaming in gain to make up for the loss. I intend to get a proper antenna. Here is a comparison of specs of these type antennas: http://gpsinformation.net/main/gpsantrev1.htm -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
So easily a 20 dB shortfall. I will look out for a similar antenna. Thanks On 11/2/2011 5:01 PM, Robin Kimberley wrote: The ET6000 used Trimble Bullet antennae when I was selling them in the UK. I seem to remember about 35db of gain in that antenna. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim Sent: 02 November 2011 18:52 To: time-nuts@febo.com Subject: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit I tried a similar Garmin antenna with my Datum ET6000 and the lock times were really long, even with the antenna on a 14 foot pole above the roof. I attribute a lot of this to the long 8 ft RG174 style coax pigtail. I have to wonder if the gain of the preamp as published actually includes the inherent cable loss, and even if so the preamp must be screaming in gain to make up for the loss. I intend to get a proper antenna. Here is a comparison of specs of these type antennas: http://gpsinformation.net/main/gpsantrev1.htm -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.1834 / Virus Database: 2092/4591 - Release Date: 11/02/11 -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changesaffect the unit
Hi Rob I picked up a couple of mushroom shaped (white flat top rounded edges prob 70mm diam.) antennas with a small right-angle bracket and a TNC connector (5v supply) no nameplate but they seem to work fine on 20 feet of RG-58. The manual for the 1804M says its an 8-channel receiver and I recollect it being a Trimble. Alan G3NYK - Original Message - From: Robin Kimberley robkimber...@btinternet.com To: jleik...@leikhim.com; 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Wednesday, November 02, 2011 9:01 PM Subject: Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changesaffect the unit The ET6000 used Trimble Bullet antennae when I was selling them in the UK. I seem to remember about 35db of gain in that antenna. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim Sent: 02 November 2011 18:52 To: time-nuts@febo.com Subject: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit I tried a similar Garmin antenna with my Datum ET6000 and the lock times were really long, even with the antenna on a 14 foot pole above the roof. I attribute a lot of this to the long 8 ft RG174 style coax pigtail. I have to wonder if the gain of the preamp as published actually includes the inherent cable loss, and even if so the preamp must be screaming in gain to make up for the loss. I intend to get a proper antenna. Here is a comparison of specs of these type antennas: http://gpsinformation.net/main/gpsantrev1.htm -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 10811 thermal fuses
While looking for something else I stumbled on an eBay seller in Hong Kong offering five 113°C thermal fuses for $6 including shipping, which seems like a reasonable deal... Item number:130579771801 Usual disclaimers apply, and before anyone complains, yes, it's a generic photo. Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10811 thermal fuses
These look like the ones I got from Mouser or whom ever. They look different from what I got from Agilent. The ones from Agilent are smaller, about the size of a 1/4 watt resistor, short leads, pre-bent, to allow them to 'plug' into the PC board of the 10811. Cutting the leads and 'pre-bending' probably explain the higher price from Agilent. Or it could be the computerized tracking expense. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]On Behalf Of Dan Rae Sent: Wednesday, November 02, 2011 4:30 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] 10811 thermal fuses While looking for something else I stumbled on an eBay seller in Hong Kong offering five 113°C thermal fuses for $6 including shipping, which seems like a reasonable deal... Item number:130579771801 Usual disclaimers apply, and before anyone complains, yes, it's a generic photo. Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changesaffect the unit
re my last, suggesting it was an 8ch GPS.. I have just realised I was looking at the Rb version manual not the OCXO version which does have a 6ch receiver. (at least on the manual version I have ) apologies ...put brain in gear before etc. Alan G3NYK - Original Message - From: Robin Kimberley robkimber...@btinternet.com To: jleik...@leikhim.com; 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Wednesday, November 02, 2011 9:01 PM Subject: Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changesaffect the unit The ET6000 used Trimble Bullet antennae when I was selling them in the UK. I seem to remember about 35db of gain in that antenna. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim Sent: 02 November 2011 18:52 To: time-nuts@febo.com Subject: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit I tried a similar Garmin antenna with my Datum ET6000 and the lock times were really long, even with the antenna on a 14 foot pole above the roof. I attribute a lot of this to the long 8 ft RG174 style coax pigtail. I have to wonder if the gain of the preamp as published actually includes the inherent cable loss, and even if so the preamp must be screaming in gain to make up for the loss. I intend to get a proper antenna. Here is a comparison of specs of these type antennas: http://gpsinformation.net/main/gpsantrev1.htm -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida www.Leikhim.com jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10811 thermal fuses
Joe, I had forgotten that it is a tight squeeze in there, so yes, they may be too big to fit easily! Dan On 11/2/2011 2:59 PM, J. L. Trantham wrote: These look like the ones I got from Mouser or whom ever. They look different from what I got from Agilent. The ones from Agilent are smaller, about the size of a 1/4 watt resistor, short leads, pre-bent, to allow them to 'plug' into the PC board of the 10811. Cutting the leads and 'pre-bending' probably explain the higher price from Agilent. Or it could be the computerized tracking expense. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]On Behalf Of Dan Rae Sent: Wednesday, November 02, 2011 4:30 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] 10811 thermal fuses While looking for something else I stumbled on an eBay seller in Hong Kong offering five 113°C thermal fuses for $6 including shipping, which seems like a reasonable deal... Item number:130579771801 Usual disclaimers apply, and before anyone complains, yes, it's a generic photo. Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 10811 thermal fuses
OK. I am now in my shop and I have the items in my hand. I got the replacements from Allied. They are marked '141 degrees C D139ZPXL'. I think they were NTE. They are 4 mm dia., 13 mm long, and the leads are 1 mm dia. The HP/Agilent parts are marked 'UMI 1A 250V 115 degrees C'. They are 2 mm dia., about 9.5 mm long, and the leads are 0.52 mm dia. Therefore, the lead diameter would appear to be the rate limiting step in this approach. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Dan Rae Sent: Wednesday, November 02, 2011 6:40 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 10811 thermal fuses Joe, I had forgotten that it is a tight squeeze in there, so yes, they may be too big to fit easily! Dan On 11/2/2011 2:59 PM, J. L. Trantham wrote: These look like the ones I got from Mouser or whom ever. They look different from what I got from Agilent. The ones from Agilent are smaller, about the size of a 1/4 watt resistor, short leads, pre-bent, to allow them to 'plug' into the PC board of the 10811. Cutting the leads and 'pre-bending' probably explain the higher price from Agilent. Or it could be the computerized tracking expense. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]On Behalf Of Dan Rae Sent: Wednesday, November 02, 2011 4:30 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] 10811 thermal fuses While looking for something else I stumbled on an eBay seller in Hong Kong offering five 113°C thermal fuses for $6 including shipping, which seems like a reasonable deal... Item number:130579771801 Usual disclaimers apply, and before anyone complains, yes, it's a generic photo. Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit
Next time I have the unit open I will take a look. Are there obvious markings to distinguish the boards (it's a board and not a box), as I recall looking but no seeing any. It's been a while, but from what I remember the boards look almost identical - the standard configuration has a part of 9-pin D-Types, an SMB connector for the antenna and a 3-pin header for the power. Probably the best thing to do is to look for the P/N and google it. Those older units seem to have fallen into the memory hole at Trimble, though - they don't quite deny ever making them, but seem to have almost no info on them now. I have had a look on my external hard drive that's got all the old crap backed up on it, but came up blank - that doesn't mean it's not there, just that my filing system has failed :) Regards, Pete ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] C-Max Receiver Experiment
Update - I attempted to look at the analog signal. I looked at the output of the crystal. With the scope's low-pass filter turned on I was able to see a very weak sine wave with a period of roughly 15us. It was too weak for any analysis. http://www.fuzzythinking.com/wordpress/wp-content/uploads/2011/11/60khz.png I also looked at the demodulator out. This is a much larger amplitude signal, though it has already been rectified. However, I was able to see good correlation between it (blue) and the TCON output (yellow) http://www.fuzzythinking.com/wordpress/wp-content/uploads/2011/11/dem_out.png Most importantly, I've been reading up on the subject and have adjusted my expectations. I didn't realize that frequency measurements (like those done by the HP117 and Fluke 207) don't actually use the timecode part of the signal. Page 11 of http://tf.nist.gov/general/pdf/1383.pdf tells me that WWVB is 3-4 orders of magnitude better than WWV for frequency measurements, but that the two services' time uncertainties overlap and WWVB is at best 1 order better. As a matter of fact, my measurements of the C-MAX line up with the top end of that estimate (and Tom's :-)). I'm still planning on capturing a long set of timings, but I need to do some hardware mods first. Thanks, -Justin On Mon, Oct 31, 2011 at 1:04 PM, David J Taylor david-tay...@blueyonder.co.uk wrote: Hi David, Thanks for pointing out the problem with the figures in my webpage. I have fixed it. I'm going to attempt to capture the analog signal by probing the QOut pin. The updated images make the effects clearer. It will be interesting to see the image capture. Good point about precision - it's all relative. This is an extension of a previous project of mine - a clock I built around an LPro. Setting it to the Thunderbolt is a bit of a pain and I was hoping to build in the C-Max to make it more fire and forget. I was hoping for a time signal within several microseconds of UTC without the need of an outdoor antenna. Like most of my projects, the journey is more interesting than the destination, so even if I don't accomplish that goal I'm still having fun. Embedding a consumer GPS is probably the more practical solution. Thanks, -Justin Microseconds, no. Milliseconds perhaps. But sometimes nothing at all depending on the time of day and season of the year etc. etc. Let's hear more about the project as it progresses. Cheers, David -- SatSignal software - quality software written to your requirements Web: http://www.satsignal.eu Email: david-tay...@blueyonder.co.uk __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
