Messages

1

Technical Support / Re: Ghosting

« on: August 13, 2021, 05:59:23 pm »

Hi Andy
PAW does rely on acknowledgement for the GRID Uplink
This stops us filling the airwaves unnecessarily

We track your PAW position, and uplink information based upon where you are.
this is for Traffic and METAR

Regarding ghosting - so long as the ICAO is the same - this should not happen
I also sent an email Andy, did you see this ?

Thx
Lee

Ah fair enough, I'd forgotten about that GRDI uplink :-)  Yes, have seen your email.  I'll try to get the data.. I need to get it from my flying buddies really because I can't tell on my unit.

Cheers
Andy

2

Technical Support / Re: Ghosting

« on: August 13, 2021, 01:23:13 pm »

Yes.... very much suspect it is related to this.

I have PAW and ADS-B out.  My ADSB out (Trig TT21) is fed by a separate Garmin GPS unit, not PAW.  So yes they are totally independent.

I really should update the PAW GPS dongle, because the one I have looses its marbles sometimes..  It was even mis-reporting my altitude, once by approximately 4,000ft!

FWIW maybe if we have an ADSB out facility, we should be able to switch off PAW TX and only Receive PAW...... Thus relying on ADSB-out only if available.  AFAIK PAW doesn't rely on packet acknowledgments, it just receives and decodes what it gets without providing an ACK.

Cheers
Andy

3

Technical Support / Re: Ghosting

« on: August 10, 2021, 05:37:04 pm »

I'm seeing a similar issue.  Didn't know until we were flying along on FlyUK the other week and my flying buddies said they could see me twice.

I just told them to get a new pair of specs! :-)

Andy

4

Technical Support / Re: Pi3b+

« on: June 19, 2019, 06:35:16 pm »

Ok thanks.

Never did resolve the WiFi dropping in and out on the 2B version with dongle!

something's going on with dhcpdp I think.  Power supply is fine.  Quite keen to move to 3B+ to get rid of this issue.

Thanks
Andy

5

Technical Support / Re: Pi3b+

« on: June 19, 2019, 05:11:25 pm »

Ah... I was in the process of doing the same, to get the Wifi built in etc. 

Is the current version of SW not compatible?  I've been trying to install it, but it gets part way there and suffers from the 'Power Flash' icon issue and gets stuck... (despite having a good power supply)

Cheers
Andy Fell

6

General Discussion / Re: Traffic Awareness in the new version of Air Navigation Pro

« on: April 05, 2017, 07:53:32 pm »

4G LTE networks actually work quite well in the air, better than 3G.  So it'll take a while for 4G networks to become more ubiquitous, but it's an idea that can work.

7

General Discussion / Re: PAW in Australia?

« on: June 12, 2016, 11:36:53 pm »

You can use the 900MHz band, but the RF transmitted power limit is lower if not using FHSS.  Australia use the same rules I think as the US, although they don't use the whole band.

To avoid having all the hassle associated with hopping the TX power can be dropped to 0.75mW (~-1dBm), so it's quite a hit on range in comparison to the current ~+25dBm. 

The good thing about it is that the TX masks are easier to pass.

Or just use hopping.  It's doable, but a non trivial protocol change. If using hopping, up to 1W can be used (USA at least, can't remember for Australia).

8

Technical Support / Re: Radio inteference

« on: May 28, 2016, 09:50:31 am »

Didn't think that would take long.
 

That's quite an assertion!  There are many such power supply ICs around as I'm sure you will know.

It would be wrong to give the impression that a PAW effectively costs twice as much as advertised by requiring a Roll Royce power supply... this would be very misleading and goes against the grain of keeping it low cost.

No dispute that the charge2/4 devices are well engineered with a target in mind and if people are prepared to pay for it, that's fine.  But let's not give people the impression that it is a requirement for PAW, because it is not!

9

Technical Support / Re: Radio inteference

« on: May 28, 2016, 08:51:46 am »

There are alternatives if you're happily working outside the land of bureaucratic BS.

If you are a bit handy with a soldering iron it's fairly easy to put yourself together a power supply that is capable of 3A.. you can get little switch mode power supply modules off ebay which are based on a popular Texas Instruments chipset (LM2596).  They only cost about £3.
I have used these many times with success...

However, it helps also to add a little extra filtering in the form of inductance and capacitance, but this is easy to do.  (actually on mine I've only added a little extra capacitance and it's been fine)

In the majority of cases the interference is conducted switching noise going back up the 12V aircraft supply, which is then fed into your radio.  What happens is that the power supply has a switch inside which is turned on and off very quickly..  the advantage of this is that the voltage is converted down to 5V without wasting power.. the disadvantage is that this on/off switching can create disturbance of the voltages if not properly dealt with - which leads to interference.

This can be sorted by filtering the 12V input to the little power supply to stop it injecting noise into your aircraft 12V (i.e. adding capacitance and a series choke inductor) - just like you would do with a suppressor in car ignition systems.  This helps prevent the noise from then getting into the radio from its' power supply.

These little units will happily run at about 80-90% efficiency, so when supplying 2A to the PAW they won't get too hot:
http://www.ebay.co.uk/itm/DC-4V-38V-to-1-25V-36V-5A-Step-Down-Power-Supply-Regulator-24V-12V-9V-5V-UK-/121981769588?hash=item1c66ae1774:g:f54AAOSwo6lWI2Do

The blue potentiometer can be adjusted to ensure you get enough voltage at your device, but you will need to use decent gauge cable as has been mentioned above.

But, only use one of them per device... so don't try to run a PAW AND a tablet off just one of them, it wont work... and don't forget to use an in-line FUSE!

Put it in a small metal box and this will also help get rid of radiated noise (if it's an issue).


Cheers
Andy

10

General Discussion / Re: Connection to Trig TT21

« on: May 24, 2016, 09:27:44 pm »

Hi Paul,

I use my Garmin 96C for my NMEA feed into the TT21.

Works well, also the garmin acts as a useful backup GPS and has features that skydemon is not so good at.

The other benefit is you don't need to worry about RS232 level translation, since the Garmin uses conventional +/-12V signalling, which is what the TT21 expects.  So you only need two wires.. data and ground, none of this USB conversion and level translation hassle.

Cheers, Andy
See you on FlyUK!

11

General Discussion / Re: Don't power up without main antenna.

« on: May 22, 2016, 08:31:15 pm »

It won't be a problem with PAW radio, only a few hundred mW... it's only a concern with higher power amplifiers, although with modern power amps they can tolerate it these days.

12

General Discussion / Re: Correct Antenna Position

« on: March 21, 2016, 08:29:06 pm »

Looks like an airlock on the ISS!

13

General Discussion / Re: AHRS incorporation

« on: March 20, 2016, 10:08:08 pm »

Keep in mind that the 869MHz (the frequency which the P3I associated transmissions are) is not a license free band in the USA.

You may not have been thinking about using the P3I bit in the USA, but it would not be legal there if you wanted to.  The license free band is at 902-928MHz and the rules are quite different to Europe.

14

General Discussion / Re: Correct Antenna Position

« on: March 20, 2016, 10:01:23 pm »

Great topic to raise, and in a perfectly timely manner.
We have been out today testing different antenna types and positions.
Too early to report anything specific, other than to say, radio waves really
Do like a clear line of sight - no surprises there right

So avoid ...
People
Engines
Metal shields

There is a reason why that transponder antenna is placed where it is !
We are experimenting with monopole, dipole, and soon to be horn antenna.

More info to follow

Thx
Lee

No bragging about the size of your horn :-)

A yagi may be more cost effective at 869MHz?  Select length to suit beam width requirements (assuming you're thinking of ground stations).

Cheers
Andy

15

General Discussion / Re: Reducing the cost of ADS-B - Today's announcements

« on: March 18, 2016, 11:13:57 pm »

I'm with you, John.  Asking for £250 for a SW upgrade which fixes something that is supposed to work is a bit of a cheek!

I was the one on the NATS trial who had the TT21 with old software in (early adopter!), so I had no way of setting SDA/SIL to 0.  NATS picked this up and were ok for the period of the trial, but I since sent my TT21 back to Trig; they updated the software and posted it back to me FOC.