and the decision was....

the Magellan 310. I trotted down to J&R in lower Manhattan, and paid $108 for it after tax.

Initial impressions: does what it says on the tin. Had to walk over to East River to get an initial satellite fix, but after that, it's been working in NYC very nicely.

It will be used for real when I go on a long cross country next weekend to Gettysburg. That's a distance of.. let me see now... 152 NM from KCDW acording to my route :), which took about 5 mins to code the 5 waypoints into it.

I will be happy to report back on the outcome.

Thanks all for helping me with this

KCDW

Database Accuracy
 

No doubt there are things that I don't understand well enough about how the database works, that define some of the problems and which Datum is which, which could affect it. The software is V2.12, the land database V2.0 and the last update was Nov 2002 - so I think it's as current as it reasonably can be - due for an aviation update soon (CAA chart + 6 mnths = August).

I flew over Portsmouth this morning, (Fairoaks - Sandown and back) and whilst the ground features are not spot on (and I am sure the comment about Jeppesen's interest in this is pretty accurate and the main reason for what I observe) for a less than £400 piece of kit, it is good enough for secondary naviational use and (what I used it for this morning - in conjunction with a map and a calculated VFR plan) accurate track keeping whilst dodging round the showers and in and out of bits of low clag. It also agreed with the aeroplanes VOR/DME kit as to where MID was and EGHN was totally accurate, my landing and take-off were straight down the little line of the symbol.

Interestingly the A3M / M27 junction wasn't too accurately represented - by 1/2 mile or so) and I put an extra waypoint in for Ryde from the Pooley's GPS companion which missed the "Ryde" in the Jepp database by about 0.4 mile and the "Pooley's" Ryde brought me nearer the pier than the Jepp one.

All in all my view is that it is just inaccuracies in the land database as it is not uniformly out of kilter and the EPE doesn't affect it much with varying satelite coverage either.

Jeppeson/Garmin ....... 8/10 - could try harder.