The Treehouse Blog

Tag: gps

Device Convergence: GPS

by on Jun.01, 2010, under Technology

Are cell phones yet to the point where they can replace a hand-held hiking GPS?  Up until recently, I’ve been quick to dismiss this notion.  The announcement of Garmin’s latest hand-helds that appear to be moving closer to their cell phone brethren has me wondering.  Reports of the new touch-screen interface are about as bad as one would expect.

So, what are the issues?  I tried my G1 running OruxMaps on a 3.5hr / 10 mile hike in the mountains on Monday to get a better perspective.

Battery Life. It barely survived.  I would probably expect twice the battery life from my Garmin GPSMap 76S with a constantly running display.  Can the battery life issues be solved with an external AA-based battery pack to keep the cell phone charged?  I have no experience with these things.  Reviews indicate that ones without regulators aren’t worth much.  I might have to try one.

GPS Hardware. Cell phones may have GPS receivers, but it is not their primary function.  Most Android phones I’ve looked at seem to use the Qualcomm gpsOne chipset instead of a dedicated chipset such as the oft-mentioned SiRFstar III.  This is a cause for concern, since gpsOne currently seems to lack support for WAAS and likely is not as sensitive as the SiRFstar.  The upside of gpsOne is that AGPS will provide a faster lock when within range of the cell network.

Usability. Another major hurdle is the availability of high quality GPS software for the phone.  I’ve tried Maverick Lite, OruxMaps, and My Tracks and found them all to be lacking the necessary features of a hand-held GPS.  My Tracks is the Google-sponsored outdoor activity tracking app that was very recently open-sourced.  Maverick and Orux both provide offline map access (another must), but they seem to accomplish this with saved graphic tiles and not vector data as would be desired.  Any new GPS solution I get should have high-resolution topo maps included.

Durability. Hand-held GPS receivers tend to be waterproof and a bit rugged.  I’ve dropped my GPSmap 76s a number of times – and it once fell off my bike at 15+ mph.  There’s no way any phone I’ve owned would be happy with that kind of treatment.

Bottom line?  Not sure yet.  I do think the concept of a hand-held GPS is already starting to fade.  I’m not ready just yet to give mine up in favor of the cell phone.  I hope the newly open-sourced My Tracks starts gaining some useful hand-held features.

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TM-D710A vs FTM-350R

by on Feb.23, 2010, under Radio

I’ve been checking into some mobile amateur radio rigs recently.  I had for awhile been intending to get the Kenwood TM-D710A, but a new contender has recently entered the market, namely the Yaesu FTM-350R.  I don’t presently own either rig, but as there is a lack of direct comparisons between them currently posted online, I wanted to share my research.  If you find any errors, please let me know so I can correct them.  If someone who actually owns or has used both rigs eventually posts a comparison, I’d like to link to it as well.

RF Capabilities

Both rigs provide 50W power on the 2-meter and 70-cm ham bands.  The 350R additionally can transmit 1W on the 1.25-meter band.  The extended receive ranges are also divergent, with notable differences being the lack of 13cm/1.3GHz band (and possibly the 33cm/902MHz band per a footnote) coverage on the 350R .  There are published mods to provide extended transmit capabilities for both units.  Both radios have a cross-band repeater capability.

Kenwood TM-D710A Yaesu FTM-350R
Transmit 2M – 50W
70cm – 50W
2M – 50W
1.25M – 1W
70cm – 50W
Extended Transmit Range 136-174 MHz
400-470 MHz

Link

136-174 MHz
420-470 MHz

Link

Receive Range Band A: 118 – 524 MHz
Band B: 136 – 524 MHz
Band B: 800 – 1300 MHz (excluding cellular)
0.5 – 1.8 MHz (AM Radio)
76 – 108 MHz (FM Radio)
108 – 250 MHz
300 – 1000 MHz (excluding cellular)

APRS

APRS is the feature that places these two radios in their own category.

GPS

One aspect of APRS is the use of a GPS for automated position reporting.  In the D710A, an external third-party GPS receiver (such as the GPS-710) needs to be connected to the control head.  For the 350R, Yaesu sells their own FGPS-1 module which installs in the back of the control head.  Documentation indicates it is possible to use the FGPS-2 module, which is the GPS receiver used on the VX-8R, but the required CT-133 cable could not be located from various retailers websites.  It does not seem to be readily possible to use a non-Yaesu GPS receiver.  Personally, I think having a GPS connection available from the radio body would make sense.  My intended control head mounting location is not likely to have the best view of the sky.

Digipeater Functions

The D710A appears to have a robust set of digipeater functions.  This feature would primarily be useful in situations where a temporary digipeater was needed to serve an area not covered by a permanent digipeater.  The 350R appears to not have this feature.

Other APRS Features

The D710A supports QSY information, weather station attachment, and a Kenwood GPS format for tactical display integration with AvMap G5.  Both radios are equipped with the SmartBeaconing feature which bases position update intervals on the speed of travel and direction changes.  The 350R has some navigation enhancements providing direction indication to other stations.

TNC

The built-in TNC on the D710A can be used by a PC or other external device, and supports KISS.  The 350R supports a “modem” mode for both 1200 and 9600, which hopefully means it can be used as a TNC as well, but I’ve not found anything explicitly confirming success with this.

Software / Firmware

These modern radios, like most recent electronics, have some computer-ness to them.  Programming software and firmware updates for the D710A are freely available from Kenwood.  These updates have added new features to existing products at no additional cost.  So far, there is no indication of any software available for the 350R[Update 2010-04-24: KC7HP pointed out that software is now available.] The repair for the navigation issue discussed below involved mailing the unit in for repair – for what should be a firmware update.  Given the newness of the product, it is possible that the rolling out of consumer firmware updating is forthcoming, but the situation with the VX-8R upgrade to VX-8DR doesn’t make this prospect seem likely.

Bluetooth

It’s only fair to mention that the 350R has an optional Bluetooth module.  The only Bluetooth capability provided is audio, such as the use of a Bluetooth headset for using the radio.  I’d be much more interested in this if Bluetooth data capability of some sort were provided.

Quirks

The 350R is a really new radio, and that means there is not much information available, and that it has a few bugs and quirks.  Already there are reports that APRS navigation feature leads you in the wrong direction.  There are also reports that the radio will hang, requiring power to be physically removed to reset the unit.

Conclusion

While the 350R does introduce some new capabilities (222 MHz, Bluetooth, integrated GPS, navigation feature), there are still features of the D710 that it seems to lack (digipeating, tactical GPS protocol).  The free firmware/software of the D710 is hard to beat.  Given the quirkiness of the new hardware, and feeling that the features unique to the D710 have more potential use than those unique to the 350R, my inclination would be to get the tried and true D710 if purchasing a unit today.

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