New User - Aerial Problems

[Easy Cruising]

I just got my PAW. Works in Skydemon and EasyVFR nicely. Very good job . It comes with 2 aerials : A thin one on a long lead, and a thick one that screws-in.

1. On the cable of the 'thin' aerial I have to forcibly hold the end of the cable in to the dongle if I am to get traffic reception. As soon as I stop pushing the cable, the traffic disappears. I think the end of the long lead on the thin aerial is a bit broken because I can see some exposed wire. So, where can I get a replacement 'thin' aerial or cable ? (Would be better to have no cable at all for me .. just have a thin aerial sticking out of the dongle directly would be best)

2. I think the thin aerial picks up the traffic, so do I need the 'thick' aerial at all ? I am in Switzerland/Germany area so very few PAW users here and the thick aerial gets in the way because its too long. Can I leave it off ?

Any help appreciated since I'm not an electronics person. I notice that the thin aerial unscrews from its base. Would be great to get a small L-piece and attach the lightweight aerial to the dongle direct.

[Paul_Sengupta]

Don't leave off the thick antenna, you could damage the unit. That's connected to a transceiver, so it will transmit the P3i through that. Best to keep it on as it'll help once the unit gains popularity there. There are smaller 868MHz antennae available but they won't be as good at picking up traffic or sending traffic to others. There may be remote antennae available where you can mount them somewhere more appropriate.

As for mounting a different antenna directly onto the ADS-B dongle, yes, you can get an MCX to SMA adaptor and then use any sort of SMA antenna for this. But the mechanical strength of the MCX connector to the dongle isn't that great and you'll find it rotates, so will need to secure it with some blue tack or hot glue or something!

This is the adaptor:

http://www.ebay.co.uk/itm/252163211287?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

This antenna works really well for me:

http://www.ebay.co.uk/itm/GSM-900MHZ-Omnidirectional-99-UK-Module-Antenna-SMA-Head-5DBI-19cm-/171802354206?hash=item280037e21e:g:DtsAAOSwofxUjo-j

Or just do a search for "GSM antenna SMA", you can get smaller ones but will need to set your signal strength for Mode S reception accordingly.

[Easy Cruising]

Hi Paul. I really appreciate the response so soon. Concerning the broken 'thin' aerial it might be easier if I just get another one and try to be more careful. Do you have a link to that one, or an alternative 'thin' one that will fit in the existing dongle and work ok ?

[Vic]

If you did want to leave the PAW antenna disconnected then you must terminate the output from the bridge with something like this..

http://www.ebay.co.uk/itm/1pcs-SMA-Plug-RF-Coaxial-Termination-Dummy-Loads-1-2-W-0-5-watt-DC-2-5GHz-50-Ohm-/322065885392?hash=item4afc9f68d0:g:4z0AAOSwQJhUbwtx

[Easy Cruising]

Thanks Vic. Was just thinking the same.

[Paul_Sengupta]

This is the sort of antenna which comes with the unit:

http://www.ebay.co.uk/itm/FG-5dBi-Freeview-DVB-T-Digital-Booster-Antenna-For-TV-HDTV-MCX-Male-Connector-ST-/162094796196

Something that other people have done is to use a 15cm MCX to SMA "tail" and then feed it through the case. You can then attach an SMA antenna on the other side, with the P3i antenna. However during testing with the old RF module, it was shown that having the two antennae on the same side of the PAW wasn't the optimum positioning as the ADS-B antenna changed the propagation characteristics for the P3i. Maybe worth experimenting with though.

A fairly small antenna should be sufficient for Mode S/ADS-B as the signal strengths involved are quite high. I have a smaller antenna which I've tried and rather than bring in contacts from 200nm away, it only brings them in from about 50nm, which is adequate for traffic purposes I guess!

[Paul_Sengupta]

This 868MHz (P3i) antenna is a little bit smaller. No idea how good it is.

http://www.ebay.co.uk/itm/ANT-900MR-Antenna-Whip-90Deg-868Mhz-EASY-RADIO-/200993627774

Are you, yourself, broadcasting ADS-B?

[Easy Cruising]

The DVB-T antenna was broken anyway so I cut the cable and the metal antenna off, and soldered the metal part of the antenna directly on to the connector that pushes into the ADSB dongle. Seems to work well. It's a bodge but lets me use the PAW until a replacement antenna arrives.

Went flying today with this setup, with Skydemon on a Samsung Galaxy S5 and Easy VFR on a Sony Z3 Tablet Compact connected simultaneously (Z3 tablet is a good tip because the screen is 600 nits and visible even in bright sunlight). PAW is powered from lighter socket which also powers/charges the Galaxy S5.  Here's what I did and what I noticed :

Started in southern Germany with PAW sitting on top of my rucksack in the passenger seat of my 2 seater. Could immediately see airline traffic around Zurich (30nm south of me). Also could see a light jet departing from my home field as soon as it left the ground.

Headed over black forest to Basle. Could see a couple of airliners inbound on SD. Checked to see how hot the PAW is getting in direct sunlight (bubble canopy) on a very sunny day. Not too bad. Certainly much less hot than an iPad gets.

Saw a twin landing at Bremgarten so shadowed it in. No ADSB but such an aircraft in Germany certainly has Mode-S so wanted to test SkyDemon 'show bearingless targets'. Never saw any indication on SD or Easy VFR (no little white airplane in SD). Was quite close to the aircraft but not silly-close.

Headed home and on the way back picked up a light aircraft transmitting ADSB, 200 feet below. Looked for it where Easy VFR showed it, and spotted it bang in the exact place indicated. Good stuff. Note that at one point I lost the signal for that aircraft for a couple of seconds, even though it was only a couple of miles away. Dont know why .. maybe my bodged aerial was the problem.

Made a second flight. Easy VFR immediately showed an inbound aircraft in the circuit, depicted in red presumably due to close proximity to me. Very good. Headed over lake constance to Friedrichshafen. Spotted a Zeppelin over the lake. These always have a squawk. This time switched into Firefox to look at the PAW 'traffic' output. The Zeppelin showed up 1500 feet below, but I never saw it as a bearingless target on SD or Easy VFR even though I was reasonably close and my mode-s setting was on 'long range'.

Noticed that my own aircraft , squawk and tail number showed up on the PAW, marked as altitude -60 feet or so.

Headed for home. Noticed that the Ublox showed '7' satellites on the PAW 'home page'. Doesnt seem very impressive given that it had clear skies above in the bubble canopy and should get Glonass as well as gps. Somehow I expected more.

I'm impressed. Generally PAW worked right away, booted quickly, had no power outs and didnt get too hot. Multiple devices could connect and all connections seemed to be reliable. The one aspect I couldnt fathom was Mode-S targets. It looked like the PAW was picking them up (no position but squawk code and altitude were there on the PAW 'web page'), but they never showed in SD or Easy VFR. Should they ? .. and how close does one have to be ? Should it work out of the box or some special PAW config needed ?

[Paul_Sengupta]

There's a pull down box for altitude separation as well for Mode S, did you have that set for a larger altitude range?

As for seeing your own aeroplane, if you enter your hex code into the PAW this shouldn't happen.

Oh, and you may get more satellites on the GPS if you put it on a short extension lead to take it further from the other dongles. How do you have the USB devices plugged in? I have top left GPS, bottom left DVB-T, bottom right WiFi.

[Admin]

Hi Easy Cruising,

Great feedback!

Couple of comments :-

Saw a twin landing at Bremgarten so shadowed it in. No ADSB but such an aircraft in Germany certainly has Mode-S so wanted to test SkyDemon 'show bearingless targets'. Never saw any indication on SD or Easy VFR (no little white airplane in SD). Was quite close to the aircraft but not silly-close.

Mode-S is disabled by default.
Did you enable on the configuration page ?
If you have enabled, can you tell me what settings you have selected ?

Noticed that my own aircraft , squawk and tail number showed up on the PAW, marked as altitude -60 feet or so.

Have you entered your own ICAO code into PilotAware ?
This is used to filter your own Mode-S returns

The one aspect I couldnt fathom was Mode-S targets. It looked like the PAW was picking them up (no position but squawk code and altitude were there on the PAW 'web page'), but they never showed in SD or Easy VFR. Should they ? .. and how close does one have to be ? Should it work out of the box or some special PAW config needed ?

When you looked at the Mode-S contacts on the traffic page, were they highlighted in any color, eg green, amber, red ?
The color indicates the threat level that is passed to the navigation device, so again depends on the settings in the Configure page, and also, you mention an issue with the ADS-B antenna, I am wondering if this antenna issue could be attenuating the signal strength which ultimately resolves to the threat level.

Thx
Lee

[Ian Melville]

SkyDemon also needs to be set to show bearing less targets.

[Easy Cruising]

Thanks for the various tips. Yes, in SD I had it set to show bearingless targets. I have filled-in the flight ID to be my tail number (no hyphen) but it still showed-up in paw, although there was a red 'blob' or box somewhere in the entry. Maybe the 'hyphen' is important ? I dont know.

Concerning Hex-code : I guess I need to enter it. I guess thats my Mode-S hex code from somewhere. I've got a GTX330. Not sure how to get the hex code out of it. Will research.

For Mode-S settings I have these as defaults :

Display Traffic Info: Alternate
Mode-S Seperation: Disabled       (I dont understand this. Does this mean I cant get Mode-S, or just that some kind of seperation setting is disabled?)
Mode-S Detect: Medium Range

-- when I looked at the mode-s returns, only my own one had a red fill/blob, all the rest were white.

Concerning USB plug-ins I have same as Paul except Ublox is top right (above wifi unit). I think that's the standard as per quick start guide.


I didnt change the mode-s settings from the default so I think I have to do something to make it work.

Will test again when I get the new aerial.

One other thing : anyone know how to limit the altitude diff at which Easy VFR shows traffic ... I really dont care about an airliner thats 30K+ feet above me. Is easy to set on SD.

[Paul_Sengupta]

Aha. Right, yes, the Mode S thing set to disabled has to be set to the altitude difference you want to display alerts within. For testing set it to+/- 30000ft. Set it more sensibly for traffic purposes.

As for your hex code, put your reg into G-INFO and it'll tell you.

http://publicapps.caa.co.uk/modalapplication.aspx?appid=1

The flight ID will just be what is displayed on the screens of those who receive you, so type anything you want to appear. I'd recommend the hyphen, most people have it. :-)

Move the GPS to top left so it's not immediately in line with the Wi-Fi dongle.

Oh and don't worry too much about the antenna, what you've done sounds fine for the time being. Maybe set the Mode S to long range for the moment.

[AlanG]

Hi Easy Cruising

In EVFR altitude separation setting is in the flarm settings.
In PAW the Mode S separation needs to be set to one of the settings other than "disabled" to send this info to your nav software.  Medium detection range will give you a reasonable starting point but having been involved in the testing and determining of these settings I use the Short range which for GA xpdrs is giving amber alert at approx 7km and red alert at 4km. Obviously commercial traffic will be at greater distances but that's the nature of the beast when relying on signal strength from different outputs.
I would suggest both of the above altitude settings should be the same but that's a matter of choice.
In the UK our Hex code is available on the CAA GINFO website but I don't know if you have an equivalent in Germany.

Regards
Alan

[Paul_Sengupta]

Ah, Germany... In which case ignore the G-INFO advice! 

You can see your hex code on the PAW if you go into the traffic page on the web interface while it's receiving your own transponder.