We have seen the future and for a glimpse of it, turn the page.
But in the world of GPS navigators, the future-at least one that you can buy-is still six months to a year away and if youre ready to upgrade now, with an eye toward buying something that wont be obsolete before the ink on your check dries, what to do?
Two companies-Garmin and IIMorrow-have stepped into the breach with GPS mapcoms specifically designed to fill the gap between the first round of IFR navigators and the soon-to-be WAAS boxes that will set us on course for the bold world of sole means satnav.
But get em while theyre hot. We see these mapcoms as interim products; theyll soon be overshadowed by glammed up, expensive WAAS receivers that will sport greater capabilities. (As we said, turn the page.)
We reviewed IIMorrows GX-series in the December 1997 issue of Aviation Consumer. In this report, we’ll examine Garmins new GNC 300XL mapcom.
Up front, we’ll say this: Garmin isn’t fooling around on price. At $4795 retail, the asking price is $200 cheaper than IIMorrows GX60 and $200 cheaper than Garmins venerable GPS 155, an older receiver with no map and no comm.
Add a Map
The world is full of surprises and IIMorrow sprung one late last year with its GX55/GX60 GPS mapcoms, considerably improved versions of its original 2001 NMS navigator. Although Garmin pledged a year ago that it wouldnt have any IFR-approved moving map receivers until WAAS arrived, it hurriedly reconsidered when the GX series began stirring things up.
Garmins response was the 155XL and GNC 300XL, respectively an approach-approved moving map navigator and a navigator plus a 760-channel comm. Except for the IFR approval, featurewise, these two new receivers are very similar to the 150XL/250XL receivers, the VFR-only units that Garmin introduced a year ago. And just in case youre not confused by this proliferation of models, don’t forget the GNC 250/300, both GPS navcoms without moving maps. The 250 is VFR-only, the 300 is IFR approved. (don’t worry, we have trouble keeping it straight, too.)
Except for the moving map, the GNC 300XL is outwardly similar to the VFR-only boxes with one important internal exception: It has Garmins new 12-channel GPS chip, not the older fast-multiplexing single-channel found in the original GPS 155 and in Garmins early handhelds. No doubt the 12-channel is the better performer but thats far more noticeable in the portables, where antenna placement is variable, than it is in panel mounts.
The overall size and shape of the GNC 300XL is identical to Garmins other panel mounts, yielding a display size of 3.5 X 1.187 inches, which is larger than the GX60s 2.5 X 1.25 inch display. However, Garmin uses some of that real estate for a nav display window, even when the map is selected, thus both map displays are almost identical in size.
The display itself is supertwist LCD black-on-green and very crisp, in our view. To reduce the distraction of nighttime overbrightness, the display can be set to revert to reverse video, either manually or automatically. Either mode is plainly visible in direct sunlight, which is more than can be said for the fluorescent display Garmin used in the GPS 155.
We found few compromises on what the map displays. In navigation mode, you have just two options: view the numerics-only screen with bearing, track, distance-to-go and so forth or you can flip over to the map page and read more limited nav numbers on the left and the map itself on the right, which consumes about three quarters of the display.
The map itself depicts airports, navaids, selected course (as a bold line) and special use airspace. As usual, the map can be scaled manually (down to .5 mile) or automatically and as with Garmins handhelds, you can selectively declutter the display by switching off various map features at any map scale you like.
Compared to other maps weve seen, the 300XLs display is probably the crispest and easiest to read, with the widest viewing angle. It isn’t quite up to Bendix/King KLN 90B standards-then again, it shows SUA, which the 90B doesnt-but is certainly far sharper than the KLN 89B and just edges out IIMorrows electroluminescent display, which washes out a bit in sunlight. Kudos to Garmin for the reverse video trick; it really is useful.
Operating Logic
When it rolled out the GPS 155, Garmin took a pasting for its complex operating logic. Interestingly, although the 300XL uses the same basic logic, we didnt find it at all difficult to load routes or fly approaches. In retrospect, the 155 simply wasnt so difficult to begin with.
Direct-to nav is simple; press the direct key from any page and the receiver drops into editing mode. Use the knobs to scroll in the airport, using the ICAO K for U.S. airport. Hit enter and youre on your way. Routes are entered by stepping into a dedicated route function, which is a standard design these days.
The 300XL can accommodate 20 routes with 31 waypoints each. (That may seem like overkill, but in a partnership airplane, every pilot may have a half-dozen favorites.) With a little head scratching, the routes can be altered and edited.
Approach set-up also happens in the route mode. With an airport as the active waypoint, punch the route key until the approach list comes up, then select the approach and the initial approach fix. All of the Garmin boxes use a resolver-type interface so the CDI/OBS has to be manually set to the appropriate course and the receivers switching box has to be set to either autosequencing or hold, as required. By comparison, the GX60 has a resolverless interface so the needle behaves like an ILS. Further, the GX60 has a semi-automated hold function so there’s a little less button mashing.
Comm Function
The 300XL has a first-rate 760-channel comm that required the addition of only a single button to the navigator only faceplate. From any display page, two frequencies appear prominently, the active and the standby. To exchange them, merely press the flip-flop key. To change a frequency, you activate the cursor button with a single push, then use the knobs to scroll the desired freq.
Which brings to mind one minor editing quirk. When editing flightplans or selecting approaches, you have to remember to punch the cursor key twice to skip past the comm selection function, otherwise you’ll be scrolling through frequencies, not approach waypoints.
As did IIMorrow, Garmin knitted the nav and comm functions together, providing limited autotuning. For example, on the navcom page, the 300XL lists all the frequencies (in order of use) for the departure and the arrival airport. Very handy. Jab the nearest airport key and load it as an active fix and the receiver fetches the frequencies you’ll need.
Holding the flip-flop key for two seconds automatically tunes the 121.5 MHz emergency frequency. Beyond that, the 300XL doesnt have the comm tricks found in IIMorrows GX60, which stores the last used frequencies and allows monitoring of the standby frequency with an automatic override for active radio traffic. Furthermore, the GX60 has its own built-in intercom, a nice feature if you don’t already have one.
Construction
Garmin has distinguished itself for producing high-quality boxes and the 300XL continues that tradition. Marrying GPS and VHF comm is a bit like mixing oil and water; they don’t like each other much. Garmin has taken care to make sure the relationship lasts.
The 300XL is built using surface-mount technology and the main component boards fold out for easy access. Should repair be required, we suspect it wont be done in the field but at the Garmin factory, perhaps with the exception of the power supply. To its credit, Garmin has been consistently quick in returning repairs and even takes the trouble to log squawks into a computer database to track trends. Other manufacturers would do we’ll to emulate this practice, in our view.
We found the Garmin installation kit and related support material to be complete and detailed with the kind of additional information that makes the installers job easier and ultimately reduces the customers cost. Garmin paid especially close attention to comm interference issues, which can be chronic and difficult to solve in GPS installations. The amplified antenna provided with the kit installs without any external screws showing, a nice corrosion fighting touch.
The 300XL (and 155XL) operate only on 14-volts, so 28-volt systems will require Garmins optional voltage converter. Speaking of options, one that Garmin has traditionally offered is a remote NiCad emergency battery back-up pack to run the navigator long enough to find an airport in an emergency. Frankly, were not fans of this option. It has proven technically fussy and unreliable and we suspect it will soon be discontinued. If the battery is going to be offered, it should be inside the unit but there’s no room for it in the 300XL.
One thing we don’t like about the 300XL is heat build up. Although it runs cooler than the fluorescent displays used in the 155, the 300XL gets noticeably warm to the touch and is much toastier than the IIMorrow models. While this isn’t a showstopper, we would rather have cooler than warmer and although Garmin doesnt require a cooling fan, we would recommend one.
Other installation notes: The tray is built like the George Washington Bridge and has new and improved pin connectors, which should improve reliability. During diagnostics, we noted that the GNC 300XLs system software ran slower than do the other Garmin units. We suspect the moving map is pushing the processors resources to the limit. In operation, this is noticeable in the form of slower refresh rate but its hardly intolerable.
The 300XL interfaces nicely with other indicators including the ARINC 429 for glass cockpits. That may seem obvious these days, but not all boxes will do it without some technical handwringing. For that reason, we wouldnt be surprised to find the 300XL in bizjet cockpits.
Conclusions
Should you buy a panel-mount GPS now or wait just a little longer?
If you were counting on one of these products to clarify the purchase decision for you, were sorry to disappoint. In reality, the introduction of the 155XL and GNC 300XL serve only to muddy the market with more choices and at price points that cant fail to get your attention.
Lets see if we can sort through the confusion. As we go to press, the FAAs WAAS TSO is still not published but is expected to be this summer or fall at the latest.
Once it has appeared, the manufacturers can then say with some assurance if any of the current C129 navigators will be upgradeable to WAAS status. (Doubtful, in our view, but anything is possible.)
With its GNC 430-see sidebar-Garmin has already declared the shape of things to come so if youre waiting for WAAS, a 430-type box is the sort of thing thats in the works. Waiting will cost more but you’ll also get more for your money. If youre ready to buy now, heres our recommendation:
Consider either of the two receivers mentioned in this report ahead of any GPS-only navigator, either the Garmin 300XL or the IIMorrow GX60. Of the two, we give the GX60 a razor thin edge, primarily because IIMorrow so improved the approach-loading logic and the GX60s integration of comm functions is a bit better. But we think an owner would be satisfied with either.
The advantage of buying a GPS navcom (with a map) now is that regardless of whether WAAS is deployed on time (or ever), it will remain a usable box for the foreseeable future. When WAAS units arrive en mass, theyre very likely to contain all navcomm functions in a single box, meaning the need for a number 2 nav will be greatly diminished.
Our thinking is that if you buy now figuring on sliding the navigator into the number 2 slot later, it ought to have a comm option. Since you can buy it for essentially the same price as a standalone GPS navigator, it makes little sense to pass up the radio.
One other possibility is the Northstar M-3, an approach-approved navigator that wins the simplicity-of-operation sweepstakes handsdown. The M-3 has a SmartComm option that ties the navigator to a remote-mounted Becker VHF comm. However, the two together cost $8100, substantially more than either the Garmin or IIMorrow navcoms. And the M-3 has only a single-line display, no moving map. (Of course, if you hate moving maps, the Northstar may be just the thing.)
Also With This Article
Click here to view the Garmin 300XL Checklist.
Click here to view “Garmin Ups the Ante.”
-by Larry Anglisano
Larry Anglisano is a principal in Exxel Avionics in Hartford, Connecticut.
