Amateur radio, programming, electronics and other musings

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What is NTP?

Categories: Projects, Trimble Thunderbolt Monitor
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Network Time Protocol (NTP) is a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks developed back in 1985.

NTP provides Coordinated Universal Time (UTC) including scheduled leap second adjustments. No information about time zones or daylight saving time is transmitted; this information is outside its scope and must be obtained separately.

It is usually able to maintain time to within tens of milliseconds over the public Internet and can achieve 1 millisecond accuracy on local area networks under ideal conditions.

The current reference implementation is version 4 (NTPv4), which is a proposed standard as documented in RFC 5905. It succeeds version 3, specified in RFC 1305.

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Netduino Plus 2

Categories: Trimble Thunderbolt Monitor
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Last week I purchased the updated Netduino Plus 2 from Secret Labs.  This version has a network port on it which I have been playing with. It’s given me the nudge I needed to continue with the Trimble Monitor. I have been testing out code to act as a web server and I am currently looking at the spec for NTP (RFC1305). Read more

Report Packet 0x8F-AB Primary Timing Packet

Categories: Trimble Thunderbolt Monitor
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In an earlier post I posted a sample capture from my Trimble to demonstrate the kind of data packets which would need to be interpreted by the software.  I left it for a little while giving any readers the chance to dig into the documentation and decode it themselves.  I received an email from Sam in VKland who managed to do just that and send me the decoded output.  Not sure if Sam is a radio ham but he has already posted some ideas for the future of the project.

0x8F-AB is an automatic output packet which provides time information once per second if enabled with packet 0x8E-A5. GPS week number, GPS time-of-week (TOW), UTC integer offset, time flags, date and time-of-day (TOD) information is provided. This packet can be requested with packet 0x8E-AB.

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Point and shoot mods

Categories: High Altitude Balloon, Projects
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RCA added to trigger shutter externally

I have just modded a cheap point and shoot camera (9MP) to give it the facility to use an external battery pack (5v) or psu and the most important thing, external shutter trigger.

Both mods are needed before this poor camera leaves the Earth bound for space.

144MHz Linear Complete

Categories: 144Mhz Linear Amplifier, Projects
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This evening saw the completion of my 144MHz 500w linear amplifier. Could only get about 450 watts out of it even though the FET is rated at 600w. Pushed it a little to far on the input (5w) and caused it to break down. Ordered a new FET and now know the limits. Should be back on the air in a week or so.

Trimble Thunderbolt (RS232)

Categories: Projects, Trimble Thunderbolt Monitor
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If you are planning to connect your Trimble to a microcontroller as I am you will need to provide it appropriate levels as the RS-232 standard defines the voltage levels that correspond to logical one and logical zero levels for the data transmission and the control signal lines.  Read more


Categories: Projects, Trimble Thunderbolt Monitor
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I pulled out the PICAXE documentation, fired up the development environment and started to write some code.  It didn’t take too long before I worked out that the picaxe was just not up to the job of processing the serial traffic from the Thunderbolt.  It might just be my limited experience but I wasn’t prepared to spend any more time on it when I knew there were alternatives available.  I jumped onto the web and ordered a Netduino which is an open source electronics platform using the .NET Micro Framework.  Featuring a 32-bit microcontroller and a rich development environment it is perfect for me who is very comfortable with the C# programming environment.

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Trimble Thunderbolt Monitor Project (LCD)

Categories: Projects, Trimble Thunderbolt Monitor
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I decided I would like to start a new construction project for 2012. Having thought carefully I finalised on a 10MHz reference which can be used as a standard for test equipment, or to lock the master oscillator (TCXO) of a rig/transverter to a solid, accurate source. I did quite a bit of research over Christmas and concluded that the best bet would be to start with something commercial and add to it. It is possible to start from scratch but with the surplus market so cheap why not spend the time adding the sugar and actually using it.

My research eventually pointed me to the Trimble Thunderbolt which is a commercial GPS disciplined clock and readily available on eBay. This was to be the basis of the project. I ordered one and it arrived today.

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