About a week and a half ago, we sent our RV-8?s GNS 430 in to Garmin to have it upgraded to a 430W. It has done fine in its ?primitive? state for well over five years, but the fact that we are building the RV-3 with a 430W argued for commonality, so we figured it was time to take the plunge. In the meantime, since the -8 is flying and the -3 is not, I slid ?junior?s? 430W into the Valkyrie?s rack to see how it would do. All the connections match right up, so naturally, it did just fine ? except for the GPS?s performance.
I knew that a new antenna was coming with the upgrade, but being otherwise occupied, I figured that I would wait to make the swap until the new unit came back. In the meantime, I was curious how the WAAS unit would work with the old antenna. The answer is ? not very well. It was pretty obvious from the start that yes, indeed, there is magic behind the antenna swap when you go to the WAAS model. Initial solution times were abysmal by today?s standards ? usually, with a newer GPS, you are locked up before you can get the airplane in motion. The new GPS/Old Antenna combination was lucky to find itself by the run-up pad. In flight, it took very little maneuvering to make the unit lose lock ? a quick roll and it was ?Dead reckoning? (Garmin?s spelling, BTW?.).
With an unexpected trip across the country looming in a couple of days, I decided I should go ahead and install the new antenna to make sure we had full capability. It took longer to take the top cowl off and put it back on than it did to swap antennas (I did use a BNC/TNC adapter for now, rather than stringing in a new cable), and I was off for a test flight. Note that I did NOT add additional cable length to satisfy the installation criteria ? I will do that before we consider it ?IFR capable?. But the upgrade in performance was remarkable. It locked on quicker than the old unit ever did, and I never lost lock through a series of loops, rolls, Cubans and clover leafs ? pretty nice.
So there you have it ? one data point, one observation ? the antenna DOES seem to make a difference!
Paul
I knew that a new antenna was coming with the upgrade, but being otherwise occupied, I figured that I would wait to make the swap until the new unit came back. In the meantime, I was curious how the WAAS unit would work with the old antenna. The answer is ? not very well. It was pretty obvious from the start that yes, indeed, there is magic behind the antenna swap when you go to the WAAS model. Initial solution times were abysmal by today?s standards ? usually, with a newer GPS, you are locked up before you can get the airplane in motion. The new GPS/Old Antenna combination was lucky to find itself by the run-up pad. In flight, it took very little maneuvering to make the unit lose lock ? a quick roll and it was ?Dead reckoning? (Garmin?s spelling, BTW?.).
With an unexpected trip across the country looming in a couple of days, I decided I should go ahead and install the new antenna to make sure we had full capability. It took longer to take the top cowl off and put it back on than it did to swap antennas (I did use a BNC/TNC adapter for now, rather than stringing in a new cable), and I was off for a test flight. Note that I did NOT add additional cable length to satisfy the installation criteria ? I will do that before we consider it ?IFR capable?. But the upgrade in performance was remarkable. It locked on quicker than the old unit ever did, and I never lost lock through a series of loops, rolls, Cubans and clover leafs ? pretty nice.
So there you have it ? one data point, one observation ? the antenna DOES seem to make a difference!
Paul
