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Stratus wanna-be (Stratux)

Scrabo said:
There is a new image just posted a few hours ago.

http://imgur.com/HAoNwiV

http://imgur.com/HAoNwiV
Click to expand...

I installed this image and took it out to the hanger and fired up my panel mounted G3X+GDL39 and compared the traffic to the Stratus and Foreflight. The Stratux was picking up a couple extra targets that the GDL-39 wasn't seeing. Granted, the GDL-39 antenna is on the bottom of the plane. I also saw targets as far as 100nm away (@FL390). Overall, I'm fairly impressed with the range just using it on the ground.

The display in Foreflight is much improved over the last Stratux image. N-numbers and relative altitudes are displaying correctly.
 
GTWreck said:
I installed this image and took it out to the hanger and fired up my panel mounted G3X+GDL39 and compared the traffic to the Stratus and Foreflight. The Stratux was picking up a couple extra targets that the GDL-39 wasn't seeing. Granted, the GDL-39 antenna is on the bottom of the plane. I also saw targets as far as 100nm away (@FL390). Overall, I'm fairly impressed with the range just using it on the ground.

The display in Foreflight is much improved over the last Stratux image. N-numbers and relative altitudes are displaying correctly.
Click to expand...

Agree, it seems better overall and being able to disable the u and e prefixes on traffic cleans the screen up.
 
It's pretty impressive and it hasn't even hit its 1.0 release yet!

One of the big improvements will be the "read-only" SD card work. It will insure long term stability of the unit over many many flights.

If this sounds confusing, just remember that disconnecting the battery at the end of your flight is like turning off you home computer by pulling the plug out of the wall. :eek:

I'll definitely plan an update and flight this weekend!
 
For your consideration

Hi Everybody,

Already having an ADS-B solution (NavWorx and AFS-4500), it didn't seem to make sense to duplicate the work that the NavWorx was doing (receiving and decoding ADS-B messages). So I took the StraTux project and substituted the NavWorx for the SDR and gen_gdl90 program. I wrote a simple Python script that essentially listens on the NavWorx's RS-232 TX line and re-broadcasts the ADS-B messages via WiFi so that ForeFlight Mobile (FFM) could take it in.

Things that don't seem to work just quite right:
- GPS Altitude. As noted in the bottom left corner of the FFM pictures as '-------'.
- Traffic positions appear delayed. Comparing the AFS-4500's display with what I saw out the window with what I saw on FFM, the AFS-4500 and actual won hands down. On one occasion, a jet landing into Austin was way off my left wingtip and several thousand feet higher. The AFS display had it spot on. FFM had it way behind and to my left.
- Traffic altitudes were off compared to the AFS-4500 display. At most they seemed about 1000 ft off. This may coincide with the lack of 'GPS Altitude' mentioned earlier.
- Course was delayed. Prior to reaching KSOA, I made a U-Turn. It took FFM maybe 30-60 seconds before it showed the correct course.

What seems to work but has not been confirmed as accurate:
- SIGMETs and AIRMETs
- WX RADAR and looping
- Surface Winds

As this was my first foray into FFM and ADS-B, I may have other info available that I don't know how to access/display properly. For example, at times I was receiving data from three ADS-B antennas but I don't know how to display their location.

Some screen shots I got today:

http://caura.homenet.org/gallery/d/28935-2/IMG_0060.PNG

http://caura.homenet.org/gallery/d/28939-2/IMG_0061.PNG

http://caura.homenet.org/gallery/d/28942-2/IMG_0062.PNG

To make this work, I used:
- A copy of StraTux - mainly for the WiFI Access Point work.
- RPi Model B
- RS-232 / USB Dongle
- Cigarette Lighter to USB Power Adaptor to power the RPi
- Some wire, connectors, and a DB-9 that plugs into the above RS-232 / USB Dongle

During development, I used a USB / RS-232 dongle that plugs into the RPi's GPIO pins.
Bear in mind that this is highly alpha level stuff and nothing about it is guaranteed. If you are interested in helping out, drop me a line and I'll share the source code and any notes.

Today's test flight was about 1.5 hours. I am planning on going to the Bad Lands fly-in , WX permitting, and I intend on taking this contraption and seeing how it does for the long haul (about 6.5 hours).

Question to the folks using StraTux: Have you compared FFM's ADS-B display with a known good ADS-B display solution?

Regards,
 
Received my hardware today.
Using a MacBookPro, I didn't have any luck installing the OS with the stratux image. Multiple issues with the SD write protect tab(had to apply tape), then formatting issues, then pi filler not able to find SD even though it was present. Will start over tomorrow from scratch.

Oh & I also got taboola adware from the downloads that keeps popping up a tab in Safari. :mad:
 
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roadrunner20 said:
Received my hardware today.
Using a MacBookPro, I didn't have any luck installing the OS with the stratux image. Multiple issues with the SD write protect tab(had to apply tape), then formatting issues, then pi filler not able to find SD even though it was present. Will start over tomorrow from scratch.

Oh & I also got taboola adware from the downloads that keeps popping up a tab in Safari. :mad:
Click to expand...

I had a similar problem using Pi Filler on MacOS. I fell back to using the terminal and the 'dd' program to write the image out.

Information here should help you out. If you're not comfortable figuring out which disk of the SD card, then you may not want to do this, as writing to the wrong disk device can potentially corrupt your hard disk.
https://www.raspberrypi.org/documentation/installation/installing-images/mac.md
 
Burned the new image this morning and took it out for a 2.5 cross-country. Attached the stock antenna to the canopy strut. Solid signal and information, better than my XGPS170 in the other plane performs. Had to restart twice airborne, but that was a function of the flaky, way too long power cord I was using. Need to find a nice short cord with 90* connections on each end.
 
okei said:
Pi Filler works great for me. I found that the trick was to not insert the SD card until it gets to the point where it says "Looking for SD card..." Otherwise it won't find it on my MacBook Air.
Click to expand...

Thank you Okei.
That did the trick. It found the SD card and the image has been loaded.
I'll try the bootup later on tonight.

I really appreciate your help on this. :)
 
Stratux goes up North

Quick lunch trip to Superior gave me a chance to try out the Gizmo. Pretty impressive..... some captioned pics in the link

The Gizmo and IFlyGPS.............
IMG_20150907_114440441_HDR.jpg


Traffic!
Screenshot_2015-09-07-11-53-29.jpg


Good Reception - 6 Towers...........
Screenshot_2015-09-07-11-55-22.jpg
 
petehowell said:
Quick lunch trip to Superior gave me a chance to try out the Gizmo. Pretty impressive..... some captioned pics in the link

The Gizmo and IFlyGPS.............
IMG_20150907_114440441_HDR.jpg


Traffic!
Screenshot_2015-09-07-11-53-29.jpg


Good Reception - 6 Towers...........
Screenshot_2015-09-07-11-55-22.jpg
Click to expand...


So you are the iFlyGPS user....:D. But serious surprised you have to extend the antenna that much to get good UAT data rates, mine is not extended at all and surprised me with the rates
 
Scrabo said:
So you are the iFlyGPS user....:D. But serious surprised you have to extend the antenna that much to get good UAT data rates, mine is not extended at all and surprised me with the rates
Click to expand...

I flew mine from South St. Paul MN to Hutchinson KS and back on Friday, and extending the antenna at all had negative consequences on the reception. My antenna is stuck to the side of the slider frame, antenna vertical.

I bought a dedicated 978MHz antenna, and as a quarter wave antenna it is quite a bit shorter than the collapsed "stock" antenna is. Will try that next, but the existing antenna was quite usable - always at least three towers visible on the trip I mentioned above, with usually five or six and as many as nine at times.
 
Hi everyone,

I'm contributing to the Stratux project for the WebUI. I'd love your input on what you want in the web interface (and a brief detail of why). The VAF site is not the forum for that work. So ...

I'd like to have as many of you who wish, post over on the reddit subgroup for Stratux. I've already defined a few VAFers. Thanks! The developers and a broad range of users are active in that corner of the Internet.

If you have ideas, suggestions, or even issues, please share on the reddit subgroup.

Over the next 2-3 weeks, we hope for stability as well as some big additions. I (we) look forward to your input.

Thanks!
 
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978 antenna

I have some mcx connectors coming in the mail to allow me to make a properly sized antenna. I was surprised at the extension as well, but it was repeatable in the plane and on my back porch.

I was always able to meet or better the reception of my GDL39.
 
petehowell said:
I have some mcx connectors coming in the mail to allow me to make a properly sized antenna. I was surprised at the extension as well, but it was repeatable in the plane and on my back porch.

I was always able to meet or better the reception of my GDL39.
Click to expand...


Stuff like this is why I think RF engineers are akin to voodoo witchdoctors. Anything related to RF seems to me to be black magic of the darkest kind :)
 
Funny you should mentions RF engineers. I have a dear friend who is a voodoo doer.

We talked at length about the antennas and I concluded that a half-wave was the way to go since we are "receive only" and there is no need for a ground plane on a receive-only antenna.

A half wave antenna for 978Mhz is close enough to 5-7/8" as we want it to be.

Those voodoo doers are a precious commodity.
 
humptybump said:
Hi everyone,

I'm contributing to the Stratux project for the WebUI. I'd love your input on what you want in the web interface (and a brief detail of why). The VAF site is not the forum for that work. So ...

I'd like to have as many of you who wish, post over on the reddit subgroup for Stratux. I've already defined a few VAFers. Thanks! The developers and a broad range of users are active in that corner of the Internet.

If you have ideas, suggestions, or even issues, please share on the reddit subgroup.

Over the next 2-3 weeks, we hope for stability as well as some big additions. I (we) look forward to your input.

Thanks!
Click to expand...

As the project uses dump1090 - is it possible to turn the dump1090 web server on so when not in the plane using foreflight, I can use it to display traffic ?
 
Voodoo....

I took a quick and dirty sample of 978 UAT data tonight using the IFLY data rate dialog. One tower only from the comfort of my back porch. The data seems to support what I saw in the plane today - that a longer antenna with length of ~7.75-8.25 inches from transition of plastic base to metal antenna provides a better data transfer rate.

Methodology - Antenna length was set and then data taken at 10 sec intervals for 4 intervals.

I'll try it again later - not intuitive at all...happy to be proven wrong

Stratux%252520Data%252520Rate.jpg


Stratux%252520Data%252520Rate%252520Graph.jpg
 
Stratux user report w Foreflight, 11 hrs X-country

Quick Labor Day weekend x-country, Houston to Ft. Benning and back. 11 hours flight time including VFR weather deviations.

At altitudes above 500', every time I checked FFlight indicated at least 1 tower, most frequently 3 or more. Also used flight following on every leg. Cruise altitudes were 1000', 2.5K, 3.5K, 4.5K, and 5.5K.

I taped the Stratux antenna to the top of the passenger seat seatback, behind her left shoulder, with antenna un-extended, and battery/R Pi sat on the baggage compartment floor.

In eleven hours I only saw traffic in my vicinity twice, in the Houston area, and a single plane I was overtaking while enroute at 3.5K near Montgomery AL. Maybe cumulative view of traffic for 20 minutes time in 11 hours of towers in view. Did see distant weather at least a few of the hours.

I still see value in keeping/buying XM Wx on my 496, and look forward to more ADSB-out aircraft "pinging" the ground stations so traffic appears more consistently.

Pleased to have another tool to increase Situational Awareness, and it does indeed provide traffic and weather information to Foreflight on a 64 gB iPad2 for a one-time cost of around $120. My GPS position comes from the BadElf chip plugged into the iPad2 charging/data connector. Since the Pad 2 battery has weakened I supplement power with USB "recharger" packs.

It would really be nice if FFlight would audio announce that ADSB identified traffic is within a certain range of your position. That annunciation could draw your attention to the display.

Carl
 
petehowell said:
I took a quick and dirty sample of 978 UAT data tonight using the IFLY data rate dialog. One tower only from the comfort of my back porch. The data seems to support what I saw in the plane today - that a longer antenna with length of ~7.75-8.25 inches from transition of plastic base to metal antenna provides a better data transfer rate.

Methodology - Antenna length was set and then data taken at 10 sec intervals for 4 intervals.

I'll try it again later - not intuitive at all...happy to be proven wrong
Click to expand...


Must reports I have seen have it the antenna at 5.5 to 5.75 inches
 
Anyone have it working on FlyQ V2.0 ? I know you have to change the SSID to "Stratus12345" for it to recognize it but the app loses traffic after about 30 seconds.

Rock solid on WingX the complete time.
 
Pete it looks like you've rediscovered the 5/8 wave antenna. You should be able to increase your efficiency some with an impedance matching network. I'm curious to see how it performs in the air. The sensitivity directly above and below you will probably suffer (I'm guessing TIS-B traffic is broadcast from the nearest ground station). You could get some data on the ground by tilting the antenna towards or away from the ground station to look at the gain at various elevation angles.

Paige
 
Hi Paige,

I'm not an RF guy. I always look for experts when this stuff comes up. I tried to do some reading and came up dry.

Everything I read about impedance matching focuses on transmit efficiency. Can you point me to a book or document or internet page that goes into the specific influence of impedance matching on a receive-only system?

Thanks.
 
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Data looks reasonable.

Pete,

Your data makes sense for 1/2, 5/8, & 3/4 wavelength antenna lengths.
These are the lengths I calculate for 978MHz:

Speed of light 299792458
Frequency 978000000

Antenna length in inches.
Full wave: 12.06820977
3/4 wave: 9.051157327
5/8 wave: 7.542631106
1/2 wave: 6.034104885
1/4 wave: 3.017052442

Looks like 1/2 wave and above really helps.

Not an antenna expert just following a basic calculation.
Dave
 
humptybump said:
Hi Paige,

I'm not an RF guy. I always look for experts when this stuff comes up. I tried to do some reading and came up dry.

Everything I read about impedance matching focuses on transmit efficiency. Can you point me to a book or document or internet page that goes into the specific influence of impedance matching on a receive-only system?

Thanks.
Click to expand...

Impedance matching works both ways. You are attempting to couple maximum power from one device to another. Bad things happen to transmitters with a poor match, but performance is also lost when a receiver has a bad match.

Noise also enters into the equation in receive systems, so sometimes the best signal to noise ratio is achieved when the receiver's internal matching network is adjusted for best noise performance instead of maximum power transfer, but that's the radio designer's problem. You can basically treat the receiver as a black box that expects to see an antenna of a specific impedance (usually 50, sometimes 75 ohms).

The best you can do is match the antenna to the transmission line (coax) to the receiver. If you don't, you lose power and increase noise.

Here's a pretty extreme example from google books:https://books.google.com/books?id=6-tZBAAAQBAJ&pg=PA123&lpg=PA123&dq=impedance+matching+receive+noise+figure&source=bl&ots=RVfcK8gVXx&sig=a6kTWf2Gh9-PQP9Ok-A_4q4dP60&hl=en&sa=X&ved=0CCkQ6AEwAzgKahUKEwiT1bfIvOjHAhWQD5IKHW3GAB8#v=onepage&q=impedance%20matching%20receive%20noise%20figure&f=false
 
I finally got back to booting up the latest image installed from pi_filler macbook pro.
On bootup, I select option 1, for using the remainder of the sd card as writeable.
Then, I was prompted for the userid & password.
I remember the uid = pi, and pwd=null.
no go on the null password.
Can someone chime in?
 
Thread drift

So how long before someone comes up with an ADSB out solution like this? GPS layers are all over for Rasberry. I would transmit, so maybe that is the problem, just not legal? Just wondered if anyone had heard anything. It surely would never meet the mandate, but if it was cheap, it might give you better situational awareness.

cheers

Geoff
 
mchargmg said:
So how long before someone comes up with an ADSB out solution like this? GPS layers are all over for Rasberry. I would transmit, so maybe that is the problem, just not legal? Just wondered if anyone had heard anything. It surely would never meet the mandate, but if it was cheap, it might give you better situational awareness.
Click to expand...

Technically, it's very feasible - it's been done already, in fact. Doing so would run afoul of both FAA and FCC rules.

As an aside, that it is in fact so easy to do demonstrates the lack of security inherent in the current ADS-B system and why primary radar will continue to have a place in the ATC system in a post-9/11 world.
 
roadrunner20 said:
I finally got back to booting up the latest image installed from pi_filler macbook pro.
On bootup, I select option 1, for using the remainder of the sd card as writeable.
Then, I was prompted for the userid & password.
I remember the uid = pi, and pwd=null.
no go on the null password.
Can someone chime in?
Click to expand...

Default Raspberry Pi password is raspberry
 
roadrunner20 said:
I finally got back to booting up the latest image installed from pi_filler macbook pro.
On bootup, I select option 1, for using the remainder of the sd card as writeable.
Then, I was prompted for the userid & password.
I remember the uid = pi, and pwd=null.
no go on the null password.
Can someone chime in?
Click to expand...


Username: pi, password: raspberry. The blue screen comes up but you really don't need to interact with the device at that point, it's already reading from the tuner and has created the wifi network.
 
New update available

I just checked the site and saw there is a new update available. I have not downloaded it yet but will try tomorrow.

Just wanted to pass it on.
 
okei said:
Username: pi, password: raspberry. The blue screen comes up but you really don't need to interact with the device at that point, it's already reading from the tuner and has created the wifi network.
Click to expand...

The boot cycle throws some errors & the wifi network is not active.
 
humptybump said:
Funny you should mentions RF engineers. I have a dear friend who is a voodoo doer.

We talked at length about the antennas and I concluded that a half-wave was the way to go since we are "receive only" and there is no need for a ground plane on a receive-only antenna.

A half wave antenna for 978Mhz is close enough to 5-7/8" as we want it to be.

Those voodoo doers are a precious commodity.
Click to expand...

My EFHW experience, while extensive, is all at 7, 10 and 14 MHz. UHF is a different animal when it comes to practical design and construction.

I'm going to sit back and watch the stripline and waveguide guys figure out proper matching for your receive antennas, which is important for Rx just as it is in Tx, except you don't blow finals with your mismatch in a receiver ;)

Enjoying this very geeky thread.

-Stormy
 
I've been using AvNav EFB for a while now and like it. Relatively inexpensive too at $4.99 a month after the 30 day free trial.

I sent the developer an e-mail tipping him off about the Stratux project and let him know it might be a good move to support the device. I don't really want to change at this point as I'm used to it.

Anyway, I got this reply today. Just thought ya'all might like to know of this option.


"Jesse, this is a very exciting development. We will certainly support it. As soon as next week's release. Thanks for the heads up. Sanjay"
 
Got it working! Stratux is enabled & available.
On the ground I'm seeing weather. No traffic, but as others have said, you gotta be flyin' :D

I'll be test flying it tomorrow as my last flight prior to a panel upgrade.

I just received my GRT 8.4 Sport SX EFIS with synthetic vision. I'll use the old Dynon10A as a backup. It was state of the art when I installed it back in 2006.
 
Received my pi on Friday,, waiting for the SDRadio stick next week.

I'm planning to add a USB serial out to the go code to feed my Odyssey's ADSB in...looking forward to integrating this.

Once done, I will share it.

Chris
 
Any ideas

I have bought my Stratux and love it so far. I was wondering what people are using as a case and other options for the antennas. I was hoping to find a way to clean it up and keep the wires contained and maybe some type of quick disconnect for the antenna.

The main reason I am asking is because I went on my trip to ATL and had to fly back on the airlines due to weather and my wife made me dissemble it, split up the pieces and put in in several different bags. She didn’t want to have the TSA holding me for several hours trying to get it through security…LOL. Also I was at work before I left for the trip and had it was sitting on my desk and a K9 deputy (friend of mine) came in the hanger and he thought he might have to go get his dog to do a sweep of the device to make sure it was safe.….He was joking :D:D:D:D.

Also is there a need for the dual attennas?

So any photos would be nice. Thanks.
 
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Flew today with it again, didnt take long for it to shutdown on the glare screen, but sitting on the backseat it was fine.
 
Anybody know how well this stub antenna would work with the Raspberry Pi setup? The return loss graph in the datasheet makes it look like it should work ok. It is much better than the graph for the antenna used by the Skyguard TWX setup.
 
emuyshondt said:
Anybody know how well this stub antenna would work with the Raspberry Pi setup? The return loss graph in the datasheet makes it look like it should work ok. It is much better than the graph for the antenna used by the Skyguard TWX setup.
Click to expand...

I'm not sure what skyguard is using, but a 4dB return loss isn't good. The higher the return loss number, the better (lower) the SWR is.

Simply stripping the shield off a piece of the coax, leaving 2 7/8" of insulated center conductor exposed would probably work better. For best performance use a $20 transponder antenna on your belly and connect it to the SDR dongle.

Paige
 
PaigeHoffart said:
I'm not sure what skyguard is using, but a 4dB return loss isn't good. The higher the return loss number, the better (lower) the SWR is.

Simply stripping the shield off a piece of the coax, leaving 2 7/8" of insulated center conductor exposed would probably work better. For best performance use a $20 transponder antenna on your belly and connect it to the SDR dongle.

Paige
Click to expand...

Skyguard uses these and this is their supplier.. I use these myself.

http://www.digikey.com/product-detail/en/ANT-916-CW-HWR-SMA/ANT-916-CW-HWR-SMA-ND/1139580
 
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