The place for technical discussions about GA and flying.
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By PaulB
#1534875
I wish I understood all this! I've no idea what a ground plane is and don't know whether a balun is something technical or a typo!
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By GrahamB
FLYER Club Member  FLYER Club Member
#1534878
ChrisRowland wrote:I've only been following this thread and it hadn't occurred to me that PAW doesn't come with optimised antennae.

A half wave dipole may be better because it doesn't need a ground plane, it does need a balun though.

The reality is it doesn't matter. I pick up ADSB traffic over 50 miles away with the standard antenna. The PAW P3i antenna works well as well, I've seen traffic I've known to be P3i only over 10 miles away; I may well have seen others as well much further away but haven't bothered to look at the traffic display to check.

There are other antenna options available from the PAW website.
By PaulB
#1534880
Indeed, when I was testing a PAW unit on the ground I could see CAT (admittedly high level) over the Solent and over the Mersey with the standard antenna placed at ground level in Coventry.
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By Paul_Sengupta
FLYER Club Member  FLYER Club Member
#1534915
The P3i antenna which comes with the unit is an end fed dipole.

For the transponder antenna, it really doesn't matter that much. It works fine as it is, and it works fine if you cut it down (the right length) to fit it somewhere you otherwise wouldn't be able to.

I've replaced the MCX connector on my DVB/ADS-B dongle with an SMA and I put a stubby antenna on it. (Paul B ignore this sentence! :D )

Incidentally a BALUN stands for BALanced/UNbalanced. It's a sort of transformer for RF to do two things - 1) Convert from a balanced antenna/feeder (such as a diople or a ribbon type feeder (balanced) to coax (unbalanced) ) 2) Change the impedance.
#1535814
I caused myself an issue by 'improving' the ADSB antenna over the one supplied. I made my own dipole and was getting traffic consistently over 400km, occasionally over 500km. Sounds good and PAW did well listing them, but Skydemon was struggling to keep up withe a result that potential threats were not displayed, or just displayed for a second or two. Going back to the stock antenna restored normal service. Using an original iPad Mini may not have helped the matter, but there is absolutely no need to see traffic more than about 40km
#1535825
I was in contact with Tim Dawson, and it is not confirmed that SkyDemon would have a problem with a large amount of data.
I have an action to try to produce some test data to try to overload SkyDemon in the same way you described in your scenario, until then we cannot be sure there is an issue with SkyDemon here.

By the way Ian which WiFi mode are you setup to use B or G ?
I havent done the calculations but I guess there is potential to overload the available data rate, but even Mode B is 11MBit/s - so should be easily capable

Thx
Lee
#1535922
I'll check this evening. As I noted above it could also be an aged iPad issue, or a combination of several factors. I don't think it's a big issue as we don't really need to know what traffic there is more than 40km, or somewhere around that. I would rather the PAW and SD (other apps...) did not have to process the distant targets as they could be using the CPU cycles for something else?
#1535939
Ian Melville wrote:I'll check this evening. As I noted above it could also be an aged iPad issue, or a combination of several factors. I don't think it's a big issue as we don't really need to know what traffic there is more than 40km, or somewhere around that. I would rather the PAW and SD (other apps...) did not have to process the distant targets as they could be using the CPU cycles for something else?


Agreed, and in the words of Johnny Ball 'think of a number', 40km ? 50 km ?
I think we should look to simply limit the amount of traffic sent prioritised by distance.
Thx
Lee
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By PeteSpencer
FLYER Club Member  FLYER Club Member
#1535976
Though I haven't used it yet the set up I've seen in our arrer is a right royal mess: The thick aerial hits the screen and there seems nowhere for the thin aerial to go.

And there is definite reduction in forward vision

And festoons of ruddy cables every where.

Hmmmm :roll:

Peter