Re: [time-nuts] C-Max Receiver Experiment

2011-11-02 Thread Justin Pinnix
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/upload

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Peter Bell
> 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 o

Re: [time-nuts] 10811 thermal fuses

2011-11-02 Thread J. L. Trantham
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

Re: [time-nuts] 10811 thermal fuses

2011-11-02 Thread Dan Rae
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, a

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changesaffect the unit

2011-11-02 Thread Alan Melia
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 - Fro

Re: [time-nuts] 10811 thermal fuses

2011-11-02 Thread J. L. Trantham
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'

[time-nuts] 10811 thermal fuses

2011-11-02 Thread Dan Rae
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 _

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changesaffect the unit

2011-11-02 Thread Alan Melia
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 recol

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Joe Leikhim
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- Fro

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Robin Kimberley
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] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Joe Leikhim
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

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Dave Martindale
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

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread David J Taylor
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

Re: [time-nuts] VIGO time interval devices

2011-11-02 Thread Mark Spencer
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.

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Peter Bell
> 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 a

Re: [time-nuts] VIGO time interval devices

2011-11-02 Thread Javier Herrero
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. Regard

[time-nuts] VIGO time interval devices

2011-11-02 Thread Arthur Dent
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/Arr

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread David J Taylor
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 tha

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread Peter Bell
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

Re: [time-nuts] Monitoring the Rapco 1804M - how antenna changes affect the unit

2011-11-02 Thread David J Taylor
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 thr