Archive for the ‘Reviews’ Category

Review: Opticron Trailfinder II Monocular. Small is beautiful.

October 16, 2009 5 comments

I’ve been using the Opticron Trailfinder II Monocular for a few months now, and it’s really impressed me.

OpticronWhen out and about, walking, I was finding my compact binoculars were just too heavy — they’d often get left at home and forgotten. Hence my search for something lightweight, water proof and cheap, that I could sling in my pocket. I immediately disregarded the ultra-cheap binoculars, I’ve used a really cheap pair and, frankly, you could hardly see through them.

A bit of searching on the internet, and I stumbled upon a recommendation for buying one of these monoculars — I didn’t even know they existed. The advantage of a monocular is it immediately cuts half the weight of a comparable binocular. The disadvantage is a narrower field of view, but I can easily live with that for the sheer convenience.

I bought a 10×25 unit from Sherwoods Photo, for £30 (free delivery is always a selling feature!) Neither too cheap, or too expensive. The monocular arrived in a couple of days.  Once the extra tie-on end cap and strap were fitted, you’re ready to go.

Weighing in at a featherweight 125 grams, with a rubberised case, the build feels solid, and should resist knocks and water. They’re supplied with a case, but it’s frankly a pain to get them in and out of, and rather defeats the ‘grabbable’ purpose. The lens caps fit tightly, defending them from dust and splashes.

Optically, the unit is pretty impressive, with good clarity. Focus is a bit tricky, as it’s by means of a lever arrangement, rather than a wheel. This tends to stick if you haven’t used it for a while, stopping you focussing with one finger. A tiny bit more force, with two fingers, frees it up and then it works very well. The technique I use is to put both middle fingers either side of the lever, allowing a fine degree of control. Focus can still be tricky, but you soon get used to it.

The monocular has a twisting eyepiece, to accommodate spectacle wearers, and this must be twisted out for non-spectacle use. It helps to have fixed the ‘drop-down’ lens caps at the right rotation (see top photo), so that they both hand down when the unit is untwisted.

The neck strap is adequately long, and adjustable. It’s a bit thin, but perfectly usable. The monocular slips nicely into your shirt pocked, with the strap around your neck, for convenient access.

In all, very good value for money and very easy to take out on walks to provide that bit of extra magnification.

Overall, 8/10. Definitely recommended.

iBlue 747A+ GPS Data Logger (with Bluetooth) Review

August 20, 2009 Leave a comment

iBlue 747A+ GPS Data LoggerJust bought an iBlue 747A+ GPS Data Logger (with Bluetooth) on Ebay for UKP 35 + P&P (it’s probably possible to get it cheaper by careful bidding, this was a buy-it-now price, and I’m impatient).

The device logs data to internal memory, as well as providing Bluetooth connectivity for external devices. There is a single button on the front which logs a waypoint, and a dual mode switch for Bluetooth only / Bluetooth + logging.

The software supplied with the device isn’t great, but does allow basic communication with the device, and the ability to upload AGPS (Assisted GPS) data, which allows the device to obtain a satellite fix in about 5 seconds (you have to upload a new copy every 6 days, but it’s well worth it for the quick fixes obtained).

External Software:

A quick internet search revealed the excellent (and free) BT747 software. As the software runs in Java, it can run on Windows 32, 64 bit, Mac OS and Linux. A J2ME version is available for mobile phones and devices that support it. I’ve tested it on my Sony Ericsson K800i, and it runs perfectly, allowing you to check how many satellites can be seen, and how full the log is, when on the go. I’ve yet to experiment with the mobile ‘log download’ function which should allow me to collect several days worth of data, if away from a PC for a while, by downloading it to the mobile phone’s data card.

BT747 software allows you to tailor the device’s logging, to record either just the basic Latitude, Longitude and time (this results in the maximum number of data points being recordable), to adding the recording of HDOP, heading, height, satellites fixes, speed, etc. Turning these on, however, would result in fewer data points being recordable.

I’m only interested in latitude and longitude, not elevation, speed, etc, and I’m logging HDOP (Horizontal Dilution of Precision — basically, accuracy), which can be displayed in the OpenStreetMap editor, JOSM. BT747 will also extract the raw data from the device, and convert it into a variety of formats, including .GPX files, which can be read by JOSM and used for tracing map data.

Other Applications:

Together with another Ebay  special — an HP Ipaq 5550 bought for the bargin price of 30 quid, I can now use OSMTracker to record data (including audio). Not bad for very little outlay.

I’ve been experimenting with using it in tandem with my Etrex Venture Cx, which being the older, lower sensitivity receiver, I’ve been having to take multiple readings for many paths. Dual GPS receivers should help with getting more accurate readings and save a bit of flogging up and down.

All in all, the is a very cheap way of logging reasonable quality data – the addition of Bluetooth allows external monitoring and configuration, and you can extract the data later on a PC (or even on the go from the mobile).

I’ve been using it for a couple of weeks now, and it’s been performing perfectly. Good, accurate readings, acquires a GPS fix in seconds (largely thanks to the AGPS download facility). Bluetooth syncs perfectly, and the battery life appears fine, although I’ve not run it for more than a few hours at a time.

Complete Specifications, Windows USB Drivers and Software:

The manufacturer has an obscure website, with the details for the iBlue 747A+, including downloadable software, manuals, etc, as well as its complete specification.

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