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Stratus and External Antenna

n5lp

fugio ergo sum
I was a very early adopter of XM satellite weather. What a heady time that was. Near real time weather, including doppler radar, right there in my little homemade airplane. It was a good run.

Recently I became extremely motivated to eliminate all my Sirius XM subscriptions, and new technology has made that very feasible. I have 10s of thousand of songs on my phone that I like, and that are easy to play in the cars. Ok, well what about the airplane weather.

Normally my desolate area is the last to get any new technology, but that isn't so with ADS-B, we are well covered now.

After a bit of study I decided that the the Stratus ADS-B weather receiver would work well for me as I have already adopted iPad charts using ForeFlight and since I always carry the cell phone, that makes a good backup.

Anybody who has researched the Stratus receiver knows that there is an overheating issue and because of my climate I knew that would be a problem for me so I ordered the external antenna from the git go.

I made a couple of flights with the Stratus today, first without the external antenna I moved the receiver around the cockpit to get a feel for the reception. It worked quite well sitting on the glare shield, but I knew that wouldn't work long term.

Next I connected the external antenna and moved it around. Placement made a a big difference. It didn't work well in any horizontal orientation and didn't work at all when placed next to my GPS puck antenna. What I decided on was a location behind the left seat next to the side skin and rear canopy. This was a good spot and was also convenient because I had already made a little bracket for mounting the XM antenna there. Conveniently, the XM antenna has just been retired. From here the cable runs easily under the arm rest to the receiver and nothing has to flex or move with canopy opening and closing.

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As can be seen, it is a quick and dirty mounting system using a cable tie over the supplied mounting suction cup. That quick and dirty system will probably still be in use 15 years from now. It appears that the antenna would be too shaded by the side skins, but it doesn't seem to be an issue.

The receiver is mounted with velcro, on edge, on the forward end of the arm rest. That is a well shaded spot and it is convenient to reach the on/off switch and see the indicator light.

I made another flight with the equipment mounted as indicated. I received the first station at about 200 AGL after takeoff. This station is in Artesia about 37 statute miles north (toward the tail of the airplane on the departure) over pretty flat terrain. At about 5,000 AGL I was receiving six stations, five of them very strongly.

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At that altitude I was receiving no stations to the west (the direction of the mountains), not that that matters. I'm sure if I fly over that way I will soon receive different stations.

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There is a slight hassle factor having to take the Stratus receiver home and keep it charged, but I need to do that anyway with the iPad. There are no products unique to XM that I will miss. Some people think that XM shows real time winds aloft, but it does not. The doppler weather is not animated but does have movement prediction tracks. In theory the TFR information on XM is one of the best features. In practice I have found it to be pretty useless because of unreliability. At least five times in the last couple of years I have had incidents such as the TFR depicted in the wrong place and/or the wrong size and the TFR showing as current long after it has been cancelled. I don't know if this will be better with ADS-B or not; I sure hope so.

I think this is the start of a beautiful friendship and ..... no more monthly fees.
 
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Where did you find the map of ADS-B antenna locations?

Stan Blanton

Stan, I made the map that I posted using the locations that show on foreFlight when you are receiving data from the transmitters. I have searched long and hard to find the location data nationwide and am not able to find that. There is a very rough and imprecise map available here. You need to click "Click to Begin" then click "ADS-B" at left. I thought I knew some of the locations using this but was mostly wrong.
 
I am glad you are giving this a try Larry, and Hope that you can do a few cross-countries across the west to let us know how the coverage works out. I have frequently said that i prefer my weather data to come to me from "overhead" so that I KNOW I can get it anywhere, rather than from ground transmitter sites that I may or may not be able to see. That statement is, however, based on direct knowledge of XM, and uneducated speculation on ADSB...so I am keeping an open mind as early adopters (like you) explore the envelope.

Keep us informed!

Paul
 
I have searched long and hard to find the location data nationwide and am not able to find that.

The FAA considers the locations of the ADS-B sites to be somewhat secret information, so you won't find a list. We've asked, and even as a manufacturer of equipment, they will only give us one or two near us to help us test.

The irony is, as you have seen, every tower broadcasts its location, so once you have a working ADS-B receiver, you know exactly where the ones near you are.

Ultimately, the low resolution coverage map is pretty accurate though, and does match our experience for coverage pretty well.

--Ian Jordan
Dynon Avionics
 
I like the new technology and I am glad you took the time to report. I currently use XM and YES, it is pricey. From a cost perspective I can justify it though, sort of.

The stratus requires an initial purchase AND an iPad. The use of fore flight requires periodic subscription fees. So with all that...it is currently a wash. At least for a couple years until the pain of the purchase price of the stratus wears off. I predict there may be bigger and better equipment by then but who knows.

In any event, it sure is nice to have options! I hope that XM will be forced to lower the price to compete. They really could be avoiding this recent innovation if the prices were more reasonable.
 
...as you have seen, every tower broadcasts its location...

Sort of. The resolution is not very good. Since I am built that way I tried to find the nearest location to me. My understanding is that they will normally be on cell towers. The not-precise location would have been in the middle of a street. I drove there and found two cell towers in the general area; one closer than the other. Then I looked at that tower trying to find something that wasn't on the other, and I couldn't find anything. I need more information.

Hope this doesn't put me even more on the FAA radar after all the calls I have gotten over the Secret Salt Flat Airport.
 
I know this is an old thread but I recently picked up a used Stratus-1 and was not too impressed with the internal antenna reception. But, I did not want to pay 60+shipping for the external antenna. After all, how hard can it be to roll your own?

Easy, except for that little jack the Stratus uses. It's a Hirose MS-151NB jack and its VERY particular about what plug you use as the jack selects between internal and external antennas based on the plug rim. The plug to use is a MS-151-CLP and I found it at Mouser for $15. Buy two because your odds of ruining the first one is pretty good. It's fussy to solder.

Jumping to the conclusion: Just buy the commercial one unless you're obsessed. For about $60+shipping I finally bought enough of the wrong and right parts to build two 1/4 wave antennas and saw a UAT equipped plane at 13,000ft 112NM from my house.

(I have no idea why TinyPic inverted my image)
o7kmtk.jpg
 
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