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  #1  
Old 05-04-2014, 12:54 PM
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bruceh bruceh is offline
 
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Location: Ramona, CA
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Default APRS drops off

I've got the MicroTrak ready to go model on my RV-9A in the wingtip, running a J-pole antenna. The settings are in line with the recommendations in this forum. As you can see on my last couple of flights, the tracker is putting out good packets in the beginning of the flight, then it goes MIA.

I did a dozen laps around the field and only got this:


Yesterday I flew out east from the airport for over an hour and only got this:


Any ideas on why this APRS tracker poops out after a few minutes of flight?
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RV-9A N5771H flown over 500 hours!
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  #2  
Old 05-04-2014, 01:20 PM
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Plugging my Call Sign, N79599, into the APRS.fi window and comparing the info to yours indicates to me that you and I apparently have different configurations. I can't tell you all the settings off the top of my head, but I'm very sure I configured my MicroTrak based on the recommendations of Sam Buchanan.
Check his postings and make sure you are set up per his recommendations. Maybe someone else can post more detailed help for you.
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RV-7 Wings
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N79599/APRS Automatic Position Reporting System

“Certainly, travel is more than the seeing of sights;
it is a change that goes on, deep and permanent, in the ideas of living." Miriam Beard


"It should be added that the sublime beauty of the facture brings within the realm of discourse the substructure of critical thinking. " -using Doug's Art Critique jargon link and my birthday, I get this!

Last edited by rv7boy : 05-04-2014 at 01:25 PM.
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  #3  
Old 05-04-2014, 02:27 PM
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I can't tell your configuration from the raw data but I do see t least on (and perhaps two) misbehaving iGates (or digipeaters) in your area that is messing up your messages. It's probably not the only issue but is is part of the problem.
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  #4  
Old 05-04-2014, 09:00 PM
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Did another flight today and here is the same result. The APRS just stops transmitting (or the iGates stop receiving).

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RV-9A N5771H flown over 500 hours!
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  #5  
Old 05-04-2014, 09:16 PM
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Sam Buchanan Sam Buchanan is offline
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Couple of thoughts:

I always suspect equipment or connection faults when a tracker performs poorly. A GPS that is dropping out after it gets hot would cause this problem. Also check to make sure the center pin in the coax connector is making good contact. It may be the tracker signal is being degraded by a bad connection to the point that it can't be recieved when flying away from iGates. Looks like you are flying in some mountainous terrain.

As Glen pointed out, there are some flaky digipeaters in your area. Afraid there isn't much you can do about that except:

You might do a little reprogramming of the tracker. Remove MIC-E encoding so you can activate the "timestamp HMS" feature. This might help the bad digis and aprs.fi play nice if there is a time stamp in your beacons. More info here:

http://www.vansairforce.com/communit...672#post566672

Once you get everything sorted out try removing the WIDE1-1 sentence so your beacons won't get bounced as many times and contribute to congestion.

Keep working at it. APRS is too good to not use if you have the license and equipment.
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Last edited by Sam Buchanan : 05-04-2014 at 09:24 PM.
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  #6  
Old 05-05-2014, 07:44 AM
VHS VHS is offline
 
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Default Odd pattern

Very strange. If you have a 2 meter portable with the squelch set high, you should be able to determine if your transmitter is actually transmitting. There are not a lot of apparent receiving stations in your area ( If only we knew someone who knew something about setting up I-Gates....) Just from a quick glance, it looks like you are hitting an I-gate from one side of your ship, so my first guess would be Wing-shielding ( Creating a one-side favored transmission lobe as a result of having the antenna on one wing tip, and blocking transmissions with the fuselage in the other direction(s))
This is pretty much a known complication of cross polarization in a one sided installation, but generally the power margin is enough to overcome absorption and cross polarization losses. In your area, it may not be sufficient. Can you check your antenna connection and orientation? ( How about installing a belly whip and bypassing the problem altogether?)

In case I am not being clear, VHF is a Vertical antenna world. You have a horizontal antenna, Which immediately eats up most of your signal. This may not be a deal-killer, but the antenna rotates 360 degrees ( in level flight) in respect to any other ground based antenna as your ship changes bearing. The horizontal antenna has radiation "lobes" (Maximum power) radiating at right angles to the antenna, and radiation "nulls" (minimal or no power) from the antenna ends. Your ship can act as a reflector for radio waves, absorb them, or reflect back power out of phase, cancelling out the transmission by making the receiver see it as two separate transmissions, and failing to achieve the FM "capture" that is required for data transmission. With packet, its all or nothing; Either the receiver sees a perfect packet or it ignores the cross noise and the signal.


73,

Allen
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  #7  
Old 05-17-2014, 10:18 PM
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Finally back home after 2 weeks on the road. I had time today to pull off the wingtip, connect up the old laptop and see what the settings were that might be causing the problem.



I did as suggested and turned off the Mic-E enable setting, then wrote the new setting out to the microtrak box.

I don't see any Timestamp HMS setting on this screen.

I hope to get in the air tomorrow and see if things change.
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Bruce Hill
RV-9A N5771H flown over 500 hours!
http://www.overthehills.com/RV-9A-Project
APRS Tracking for KJ6YRP and New Flying Blog
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  #8  
Old 05-18-2014, 07:24 AM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by bruceh View Post
Finally back home after 2 weeks on the road. I had time today to pull off the wingtip, connect up the old laptop and see what the settings were that might be causing the problem.



I did as suggested and turned off the Mic-E enable setting, then wrote the new setting out to the microtrak box.

I don't see any Timestamp HMS setting on this screen.

I hope to get in the air tomorrow and see if things change.
Bruce, I see a major problem.

Your screen shot is of the Secondary settings. You have to set the tracker for Secondary via a hardwire connection. If you don't have this connection (pretty sure you don't) then your tracker is actually using Primary settings. Hit the Primary tab at the top of the screen to see the settings the tracker is now using. The Secondary settings won't have any effect regardless of what you do with them unless you force the tracker into Secondary mode.

You will not see Timestamp options until you disable MIC-E. Then the Timestamp box will be active and you can select that option. Also, disable TX Twist and Send DOA, they don't apply to our application.

Reading the doc file in the software download will be helpful:

http://www.byonics.com/tinytrak/tinytrak3plus.zip
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Last edited by Sam Buchanan : 05-18-2014 at 07:30 AM.
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  #9  
Old 05-18-2014, 11:32 AM
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bruceh bruceh is offline
 
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Default Secondary is enabled

Sam,

I installed a switch on the tracker box so I can use both profiles. The first one is for the car and the second one is for the airplane. I have the switch set to #2.

I will turn off the TX Twist and Send DAO and enable the Timestamp setting.

Thanks!
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Bruce Hill
RV-9A N5771H flown over 500 hours!
http://www.overthehills.com/RV-9A-Project
APRS Tracking for KJ6YRP and New Flying Blog
2017 VAF donator
EAA Tech Counselor
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  #10  
Old 05-18-2014, 11:35 AM
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bruceh bruceh is offline
 
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Location: Ramona, CA
Posts: 2,017
Default Secondary is enabled

Sam,

I installed a switch on the tracker box so I can use both profiles. The first one is for the car and the second one is for the airplane. I have the switch set to #2.

I will turn off the TX Twist and Send DAO and enable the Timestamp setting.

Here is the screen shot after turning off Mic-E, and I can see now that the Timestamp window is enabled. I didn't see that before!



Thanks!
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Bruce Hill
RV-9A N5771H flown over 500 hours!
http://www.overthehills.com/RV-9A-Project
APRS Tracking for KJ6YRP and New Flying Blog
2017 VAF donator
EAA Tech Counselor
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