Ordered a Garmin eTrex Vista HCx for aviation use
Join Date: Nov 2006
Location: Direct REVTU
Age: 45
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Regarding GPS jamming:
Last year I was flying with another pilot near Lossiemouth. We had three GPSs that day and were navigating primarily with GPS. (We had a current, marked up chart and plog before anybody asks!)
A Garmin Pilot III, A Garmin Etrex Ventrue and a Windows CE sat-nav unit running SkyDemon. When I called Lossie Radar the Etrex and Pilot III both lost signals, but the box running SkyDemon continued as expected.
So was this GPS jamming? Nope!
The cause? The chap I was flying with also mentioned he's seen this happen near Coventry with the Pilot III. Our VHF Com set when tuned to Lossie was on 119.35, and I understand Coventry is 119.25. It seems there's an intermediate frequency in the radio that interferes with either the GPS signal itself, or another IF in the Garmin GPS chipset.
Ground testing identified that moving the GPS a metre or so from the Com radio fixed the issue.
Just another potential issue to be aware of if you're using a handheld/portable GPS without an airframe mounted antenna.
-j34-
Last year I was flying with another pilot near Lossiemouth. We had three GPSs that day and were navigating primarily with GPS. (We had a current, marked up chart and plog before anybody asks!)
A Garmin Pilot III, A Garmin Etrex Ventrue and a Windows CE sat-nav unit running SkyDemon. When I called Lossie Radar the Etrex and Pilot III both lost signals, but the box running SkyDemon continued as expected.
So was this GPS jamming? Nope!
The cause? The chap I was flying with also mentioned he's seen this happen near Coventry with the Pilot III. Our VHF Com set when tuned to Lossie was on 119.35, and I understand Coventry is 119.25. It seems there's an intermediate frequency in the radio that interferes with either the GPS signal itself, or another IF in the Garmin GPS chipset.
Ground testing identified that moving the GPS a metre or so from the Com radio fixed the issue.
Just another potential issue to be aware of if you're using a handheld/portable GPS without an airframe mounted antenna.
-j34-
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Join Date: Jan 2011
Location: Pennsylvania, USA
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Regarding GPS jamming:
Last year I was flying with another pilot near Lossiemouth. We had three GPSs that day and were navigating primarily with GPS. (We had a current, marked up chart and plog before anybody asks!)
A Garmin Pilot III, A Garmin Etrex Ventrue and a Windows CE sat-nav unit running SkyDemon. When I called Lossie Radar the Etrex and Pilot III both lost signals, but the box running SkyDemon continued as expected.
So was this GPS jamming? Nope!
The cause? The chap I was flying with also mentioned he's seen this happen near Coventry with the Pilot III. Our VHF Com set when tuned to Lossie was on 119.35, and I understand Coventry is 119.25. It seems there's an intermediate frequency in the radio that interferes with either the GPS signal itself, or another IF in the Garmin GPS chipset.
Ground testing identified that moving the GPS a metre or so from the Com radio fixed the issue.
Just another potential issue to be aware of if you're using a handheld/portable GPS without an airframe mounted antenna.
-j34-
Join Date: Apr 2011
Location: UK
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GPX support ? Nav calculations, etc
Does it support route import/export via open standard GPX format ? If so, send a blank email to [email protected] to see how we've solved the problem of nav calcs and planning for use with GPS units.
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It can be done! (and even with old monochrome version!!)
As the airplane I picked up had no installed GPS (yes, there still are a few), I took two handhelds along. The photo was simply for my own future amusement, that I had a C 182 going 179 MPH at 12,700 feet (it had actually peaked at 181, but I missed it).
When used in harmony with a chart, it was completely satisfactory, and far superior to the dead reconing, with perhaps one VOR, of my earlier days of flying.
It was interesting later in that flight though, as I crossed the rather featureless expanses of central Saskatchewan, that neither GPS would obtain a useable signal for nearly an hour. With no VOR's within reception range, I did have to revert to very basic (and much less precise) navigation for a while. I am convinced that even a panel mounted GPS would have suffered too, as both of the handhelds showed unuseable constellations for that period. This was not the only time this had happened to me, though is was the longest period.
Even a modest GPS, operated appropriately, is a wonderful supplement to a chart, and safe navigation.
