PilotAware
British Forum => Technical Support => Topic started by: dougblair on June 20, 2016, 12:35:31 pm
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I have found it useful for audio testing that when you change the volume via the configure panel a nice young lady says " Pilotaware " If this is not in the instructions then it would be a useful inclusion. As described in the instructions the test setting of Mode S also provides audio warnings that are a usefull test.
Doug
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I tested audio airborne last night. OK on the ground but ( on max I think but is there any way of proving it ?) not loud enough in the Jodel. I was using a redundant audio in feed from an old adf.
What is the Pi output levels ? Next plan is to try a mic input with the Pi any comments ? I am working thro a 4 place intercom.
Doug
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There is a bug at the moment where if you increase the volume it doesn't save it, so on power up it defaults to the low setting. It's on Lee's list of things to do.
So it may have been OK at home, but did you turn it up again when flying?
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Probably not. There would have been several power down / ups before getting airborne and bright sunlight slightly bumpy and being solo conditions meant I did not do much fiddling in the air. I will pause or take note
until the bug is sorted. Maybe the web page could indicate the level set. That would be useful.
I did have fun with the other a/c that had my old PAW with new bridge in it and we re set up on the ground and did an air to ground demo to a few of the Mona Flying Club members.
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Hi Doug,
I found for my purposes that the audio output level from the Pi 2B isn't loud enough ( though my kids ARE saying I need a hearing Aid!). I wanted to combine the audio output of my tablet with PAW to then feed to the aux input of the integral intercom of our Becker 8.33khz radio. The little mixer I made up was passive and so effectively reduced the PAW level even further. The radio aux input sensitivity was set to max.
I had noticed that PAW didn't remember the audio volume setting in the Configuration page, that Jeremy refers to. Extremely useful that "PilotAware" is spoken every time the volume controls are pressed.
So I ended up making an amplifier to put inside the mixer, one based on the Texas Instrument LM 386 8-pin chip. I priced out the components from RS Components but because you have to buy in multiples it was working out pricey for a couple of resistors, capacitors, the chip and some Vero Board.
Maplin was the saviour! They have a range of little project kits. They had two different amplifiers using this chip and include a small PCB and all components. I opted for the 1Watt Output version that can be connected to 12v DC power. It worked out half the cost of buying components individually from RS and features a preset gain control that I can access through a hole drilled in the case of the mixer unit.
When powered up in our Eurostar, I noticed a faint audible clicking interference through the headset, but reducing the sensitivity of the radio aux input to near minimum effectively suppressed this. In the air I was satisfied with the audio levels and was able to pre-set them close to what I was receiving from the Tower via RTF. If I need to mute either the PAW or navigation audio from the IPad this is easily achieved by turning down the appropriate volume pot on the mixer which I have velcro'd to the bottom edge of the panel adjacent to the central throttle control.
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Care to share the link to the item you bought from Maplin as they seem to do a few types :o
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I would imagine it's this one
http://www.maplin.co.uk/p/mindsets-1w-mono-amplifier-solder-kit-n48fl
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or like this:
http://www.maplin.co.uk/p/mindsets-low-noise-stereo-pre-amplified-kit-n47fl
::)
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Bryan,
The amp I used was the one that Brinzlee posted a link for, also I remember paying £8.99 for it. Gain is 50 and is sufficient for my set-up. Higher gain is possible by altering the capacitor value between pins 1 and 8 of the chip I recall. Plenty of info on the net if you google LM386. I chose the 1Watt kit because of its greater drive (output) capability compared to the pre-amp kits.
Regards,
Chris
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how about this ?
http://www.ebay.co.uk/itm/LM386-200-Gain-Mono-Audio-Amplifier-Board-Module-Adjustable-Volume-A18-/321764438415?var=&hash=item4aeaa7b18f:m:m4Inb1KpjcSsmmDoTq-Wevg
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I have ordered a little amp board just in case. I am hoping to use an audio input that was once used for an ADF. This will be neat as I can switch the paw audio off if need. I also noticed the clicking interference but it was not really significant.
I will have a fiddle with a head set at home and next time at the plane reset the vol at power up plus have a co pilot. Last night I was engine warming in a 15 - 20 kts wind so really needed to have my eyes outside.
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I found the transponder used to cause a clicking noise through the intercom/radio by a very poorly wired unscreened avionics setup....Also maybe check strobes if you have them ?
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Hi all, I have installed the little amp that Lee pointed out on e bay. I can get good volume. Testing in the hangar I am getting an annoying amount of interference. All other electronics, stropbes etc are OFF except intercom. There is a distinct click click plus some white noise. If you turn the PAW on and off you can hear it go thro a start up sequence. Depower the PAW or disconnect the audio lead and it disapears. I have also tried moving the PAW away from the little amp board with no success.
I need to ask pretty please that the PAW volume reset on power off bug is de bugged. If I turn the PAW up I get enough signal for the s/n to be ok.
I am convinced that the audio is the best feature of PAW.
Doug
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Hi Doug
Volume issue is fixed in the next release - it remembers the volume level after reboot
Thx
Lee
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Great, and well done. Do you have a release date?
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Hi all, I have installed the little amp that Lee pointed out on e bay. I can get good volume. Testing in the hangar I am getting an annoying amount of interference.
Would the spare USB on PAW power a USB powered mini speaker like this one on eBay? May be worth a try?
http://www.ebay.co.uk/itm/181174656013
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Hi Everyone,
I'm also looking to boost audio from PAW & iPad.
At present I have these wired in parallel with a Smart Ass airspeed speaker into my non adjustable intercom aux line (3 into 1).
They are all faintly audible but drowned out by the headset mics.
Would it be OK to feed all three through the same LM386 amp?
Has anyone found a better solution without the reported noise issues which I'm keen to avoid!
Grateful for any suggestions.
Roger
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Hi Roger,
The iPad audio output is higher level than that from PAW. I realised this when about to join the LAA 70th tour, having left my mixer/amplifier at home, in error. The EasyVFR Nav program which I use has its own system of audible alerts triggered by PAW so I connected the iPad audio directly to the radio aux input, adjusted the iPad volume and all was fine for the subsequent flights. The alerts volume matched the level from the radio OK.
Personally I would be uncomfortable just connecting audio from different sources together, without a resistive mixer network to compensate for differing voltages. Once correctly combined, no problem with passing the combined audio through a single amplifier, LM386 or similar.
Regards,
Chris
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As an extension to the previous post, if you add a volume control to each audio input of the mixer/amplifier, you have an easy way to mute any audio should the alerts become overwhelming or a distraction, a facility Lee is being asked to implement for PAW at present.
Don't forget that if you are connecting to the audio jack of iPad or IPhone, it's best to purchase SLIM 3.5 mm plug cables (from eBay) as these fit better.
Regarding interference, I did detect a faint periodic clicking through the headphones when using the Maplin 1W amplifier, though in practice in the air it's undetectable!
Regards,
Chris
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Thanks Chris,
So I probably need an adjustable, 3 channel resistive mixer, to balance the 3 outputs.
Is something suitable available ready made do you think or would it be soldering iron time?
Cheers,
Roger
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Hi, May be something like this ?
http://www.aircraftspruce.com/catalog/avpages/gretzAudio_mixer.php
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Or see the AP60 6 channel audio mixer from aircraft spruce at only 85$.
I ended up building mine (3 channel) for about £20 max including abs box, 3x 10K pots, knobs, some 1K resistors, a power socket for 12v input, 4x 3.5mm audio sockets; the amplifier kit from Maplins was £9 of that. Now I do have an LAA aircraft so if you have a CofA or need to be EASA compliant maybe something from Aircraft Spruce may be more appropriate.
I got the mixer circuit off t'internet posted by someone called Nighthawk. Details are on this or another audio thread somewhere on this forum. Alternatively, I could sketch out the circuit if anyone's interested.
It probably possible to find something already made up on eBay, but it might have 1/4" audio sockets and you need to match the supply voltage for your aircraft.
Chris
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Thanks for the suggestions. I have made some progress but find myself, once again, wrestling with the mysteries of audio integration and hoping someone's advice can help me out.
I soldered up a resistive mixer & ebay amp which made my 3 audio devices nicely audible on a test flight during which I only monitored the VHF com. (There is a faint ticking noise when the iPad is charging)
This week I flew again & discovered that, when transmitting, my microphone sounds noisy & distorted (to me & also atc). De-powering the amp cures the problem.
Amplifier output goes to the intercom aux channel, not the comm, but of course the comm output does also go to the intercom.
The new problem only occurs when transmitting.
I will try reducing the amp gain & see if that helps but am otherwise unsure how to proceed.
Any advice most welcome.
Roger
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Roger,
I don't know what radio you have but I would have thought you would want to connect your audio amp to you radio's "ext audio in" rather than "intercom aux".
I suspect the impedance of your amp is affecting your radio's microphone circuit.
Or experiment with a series resistor between your amp output and "intercom aux" connection. Try 150 ohm and then up to 600 ohm.
Tony Nowak
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Our Becker 8.33khz radio's integral intercom has a gain setting for the Auxiliary Input, via the menu system. I juggled with both this and the gain control of the mixer amp for best results. Sweet as a nut via intercom, and as far as I know TX comms unaffected, certainly sidetone sounds fine when transmitting. Used this input so that both occupants will hear the audio alerts.
Not sure if there is a separate "ext audio input". If there is, I suspect this audio could find its way onto your TX when the PTT is pressed!
Sounds as though you could be overloading the intercom so reducing amplifier gain should help, but still unclear how the amplifier can be causing distortion on the mic input. Presumably the amplifier output is decoupled (has a series capacitor on the output to stop any DC, something like 10uF minimum)?
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Incidentally Roger, you didn't seem to notice any distortion on the first test flight, so is this a more recent problem? Could one of your audio sources have been unwittingly turned up to now cause this problem (though you would probably notice it being louder than the others).
The lowish level of the PAW audio output is the limiting factor so I would just start with this, adjusting intercom and mixer/amp gain (with individual channel volume pots set at max, if these are fitted) for satisfactory distortion free level into your headphones, as a "pre-set", then other sources can be adjusted to match. Then use channel pots to reduce or mute individual audios for flight, as required.
Regards,
Chris
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Thanks Chris & Tony,
I will try your suggestions.
No distortion noted on first flight as there was no transmitting & it only occurs when I press the ptt.
Roger
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Finally got my audio sources balanced & radio behaving - thanks to all who contributed advice.
I added a 10k potentiometer to the amplifier output & was able to dial out the distortion when transmitting.
Think I now need a mute switch for the PAW channel for use in the circuit & on the ground!
Cheers,
Roger
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Hi Roger,
Lee made some changes recently in response to audio issues AlanG and I identified during testing some weeks ago in relation to FLARM and Bearingless Target Alerts. These have improved things significantly and are presumably incorporated in the new software due to be released later tonight (which I haven't had a chance to test run yet as I have been driving down to Telford all day).
Regards
Peter
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Hi All
I don't know if it's just finger trouble on my part but since updating to the latest software and trying both my units at home I seem unable to alter the volume setting and save it.
I can tap the volume control and select 10 (or any other number) and it apparently changes in the box alongside but pressing the test button sees no difference in the volume and when I then try to save this setting it just reverts to the default 5. Even if I don't click save it reverts to 5 with the next refresh of the page.
Any ideas what I'm doing wrong.
Regards
Alan
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Hi Alan
I think test, she moly sends an audio signal.
Try this
Select 10
Press save
Press test
Thx
Lee
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Sorry Lee
No joy, just simply jumps back to default 5. Tried everything I can think of. :-\
I've not used the PAW audio previously as I usually bluetooth audio to intercom from tablet using EVFR audio alerts.
Regards
Alan
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Alan,
I'll set up my spare and see what happens here.
Peter
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Lee / Alan,
Mine is doing the same thing Lee. Unit started up on Volume 10. I adjusted it to 5, pressed 'Save' and it immediately goes straight back to Level 10. I have tried this several times.
Not sure what version you are running Alan. This one I have here on my 'spare' is showing as 20161130, which I installed off your USB stick at Telford Lee, so I guess Alan may be using the same version. I meant to ask whether this is the same as the 20161124 'Release' version, or whether the one on your stick is a later 'work in progress' - which might explain the audio setting problem.
Regards
Peter
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Same here last time I was switched on. Defaults to 5
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yes hands up - introduced a small bug there that the audio volume is locked
Apologies, we can make a fix to that single change
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Thanks Lee,
At least we now know.
Peter
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Hi Lee,
Has a fix been made to the bug. If I download the latest version again, that includes PAW Radar, is the audio volume facility unlocked?
Thx,
Chris
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Not yet
Will make an announcement when done
Thx
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Glad I read this post as I thought I was going mad ;D ;D, I'm also having the same problem, in my case stuck at volume 10. I want to try to reduce this as I seem to be getting a lot of interference coming through my headset. I have some Bose A20 Bluetooth version and I'm using the audio jack for my pilotaware connection, I'm hoping by reducing the volume this problem will go away ;) ;)
I forgot to mention I'm running the latest software as Peter kindly updated mine at the last show.
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Since coming back from a local flight and doing some further testing, I notice you get some background noise when using the sound card on the PilotAware. But if I plug my mobile into my headset there is no background noise, so is the sound card on the PilotAware always on, even when no alerts are being transmitted, if this is the case this maybe my issue with some interference within flight.
The volume is nice and clear when the alerts are being transmitted, it's this annoying interference which is causing a problem.
Is anyone else able to test there PilotAware on the ground and see if you get this background noise, then if you test your mobile there should be no noise.
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Hi Alan,
Just for reference I don't get any sound interference from the PAW, My setup is Funkwerk Transceiver with built in audio intercom and AUX sound input which is fed by a PA-60 Audio Mixer http://www.fdatasystems.com/ap-60-audio-mixer/ to which PAW is connected along side SMARTASS. I have added a separate volume for PAW to my panel, so the I can set the volume to very Quiet on the ground/Taxi and turn it up when settled into flight it all works a treat.
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Hi Allan,
What is your power supply ?
I have read a few reports of power supplies contributing to audio noise,
Maybe a small ferrite on the power line could compensate ?
Do you know the impedence of your headset input
Thx
Lee
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Maybe a small ferrite on the power line could compensate ?
A ferrite won't really help much on the USB lead, especially as the cable should be shielded anyway. To be of any use they really need to be the right size and with the right number of turns of wire through them. Both of these depends on knowing what need to be suppressed, getting it wrong can actually make things worse.
If you need to add one to the 12v side feeding the power supply then the supply is terrible and I'd be really concerned what else it may be emitting.
If you have made up an audio lead and are using shielded cable, ensure to only ground the shield at one end. What type of plug are you using in the Pi audio socket?
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Hi Allan,
What is your power supply ?
I have read a few reports of power supplies contributing to audio noise,
Maybe a small ferrite on the power line could compensate ?
Do you know the impedence of your headset input
Thx
Lee
Hi Lee
I use the Anker Power Drive 2 socket as per the link https://www.amazon.co.uk/Anker-Charger-Adapter-PowerDrive-Samsung/dp/B00VH84L5E as recommended by pilotaware, I don't get any interference with my radio, with my iPad and other electrical items running including PAW, which is great. The only time I get some additional noise is when I use the sound output from the PAW and this's connected directly to my headset via the 3.5 jack. I even get some noise when just trying this at home, but when flying this is amplified with engine interference I guess. :( :(
Not sure what the impedance of my headset are, all I know they are BOSE A20 GA with Bluetooth connectivity.
I thought with reducing the PAW volume this might resolve this, but until fixed I am unable to test :D
When I next pop up I will just plug my mobile to my headset using the same cable that's supplied to see if I also get some interference, I'm pretty confident all will be ok tho ;) ;)
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Just done some more testing today with a friends PAW at home and you also get some background noise, this starts from once powered up. Now after putting my fingers either on the Ethernet port or the metal section round the PAW aerial not the ADSB one, this noise disappeared, so earthing seem to resolve this.
Is this recommended or should I live with this noise as I see the PAW is not causing this, its being caused by the Raspberry PI board itself :-(
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Ok I have tried my Bose A20 Bluetooth and they are fine with the lead connected to the rPi and the A20 control box, completely silent apart from traffic alerts of course....I made my lead using the 4 pin plug and not the stereo plug that shorts out the video so I am not sure if that makes a difference.....I also have a bluetooth adapter that I plug into the rPi audio output and that injects audio via bluetooth into the Bose A20 without any leads and that works a treat..my preferred connection. Its such a tiny unit and sits on top of the PilotAware....I hate wires !!
Are you using a battery or aircraft power and step converter to power the PilotAware ?
Regards
Brinsley
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Hi,
I'm using aircraft power and one of these as per the link. https://www.amazon.co.uk/Anker-Charger-Adapter-PowerDrive-Samsung/dp/B00VH84L5E.
Its great that you don't get any noise, I've tried the audio jack that's supplied with the BOSE A20 and I have also tried a different cable like the one you would use to connect sound card from a PC to a the speakers within a monitor and get the same result.
I don't have any low down noise if I plug a mobile device in, only the Raspberry PI boards.
I'm running the latest PAW software too, I've even tried a new Raspberry board with nothing installed and once powered get this same low down noise coming through. It goes quite if you touch any USB, LAN, HDMI part thus earthing them.
It's like hissing sound, it's low in volume but you can here it, until the board is earthed.
I see you made your cable, I was looking at doing the Bluetooth connection, but like the idea of keeping that free in case I fancy some music as the AUX connection gets priority :) :) done some testing and works well ;) ;)
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Hi Alan / Brinsley,
When I first connected my PAW to my Flycom intercom way back in early testing days, with the PAW running on a battery pack, I had no problems whatever with a made up 4-pole TRRS jack to mono phono plug as here
http://forum.pilotaware.com/index.php/topic,376.msg5117.html#msg5117
http://forum.pilotaware.com/index.php/topic,420.0.html
Unfortunately, when I connected the PAW to aircraft power I started to get significant background 'computer sounding' audio interference which was coming from the Raspberry Pi. Like yours, this disappeared if I touched the Pi metalwork with my hand. After discussing this with Jeremy Curtis and on his advice, I re-wired one of my leads to short the outer audio cable 'screen' (which transfers video out from the Pi in the [Maplin] cable I was using) to ground and have had no problems since, despite the fact that this means that (contrary to Jeremy's latest advice above), the cable 'screen' is effectively grounded at both Pi and Flycom ends.
Certainly in my experience worth trying grounding the screen (at least at one end). This doesn't seem to bother the Pi at all.
Regards
Peter
p.s. Brins, could you post link to where you got your bluetooth unit - it certainly looks pretty sound.
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Have you tried using ferrite cores on the power lead
http://uk.rs-online.com/web/p/products/7413056/?grossPrice=Y&cm_mmc=UK-PLA-_-google-_-PLA_UK_EN_Passive_Components-_-Ferrite_Cores&mkwid=sa0YjBZMt_dt%7Cpcrid%7C88057072923%7Cpkw%7C%7Cpmt%7C%7Cprd%7C7413056&gclid=CMvB3M_CptECFQg6GwodglEKzA (http://uk.rs-online.com/web/p/products/7413056/?grossPrice=Y&cm_mmc=UK-PLA-_-google-_-PLA_UK_EN_Passive_Components-_-Ferrite_Cores&mkwid=sa0YjBZMt_dt%7Cpcrid%7C88057072923%7Cpkw%7C%7Cpmt%7C%7Cprd%7C7413056&gclid=CMvB3M_CptECFQg6GwodglEKzA)
When I was looking at amplifying the output of the Pi I got a clicking sound which seemed to be induced from the Psu. Worth a try. Make sure the firrites that you get fit snugly round the cable
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If the hum goes away when you touch the ethernet socket, then it really sounds like a ground loop. Probably caused by a poor earth on the power feed or the audio system somewhere. You could try an audio isolator and see if that fixes it. It doesn't need to be much, even a slightly corroded/oxidised terminal can cause it. Try rotating the power plug in the socket too, just in case there is a poor connection there?
https://www.amazon.co.uk/Ground-Isolator-HAVIT-Speaker-Filter/dp/B01IETQQQK/ref=pd_lpo_263_bs_t_2?_encoding=UTF8&psc=1&refRID=98GFXG3N5A2AJPZSVWYX
Like yours, this disappeared if I touched the Pi metalwork with my hand. After discussing this with Jeremy Curtis and on his advice, I re-wired one of my leads to short the outer audio cable 'screen' (which transfers video out from the Pi in the [Maplin] cable I was using) to ground and have had no problems since, despite the fact that this means that (contrary to Jeremy's latest advice above), the cable 'screen' is effectively grounded at both Pi and Flycom ends.
The thinking here was to ground the video out, to prevent it causing issues. It isn't signal ground that should be only at one end, but any cable shield. Depending on the quality of the cables some skimp and use the cable shield as signal ground too. The shield should only be connected to ground at the audio output end.
edit: I notice that Amazon has popped up that people who buy the Anker PSU also often buy the isolator too. Might have to dig out the one I bought and run some tests when I get some time...
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As Jeremy suggests possibly a ground loop. I never liked the idea of shorting the video pin with a stereo 3.5mm jack.....but plenty do and have no issues. CPC sell the correct 4 way 3.5mm jacks, I buy a stereo to stereo pre-made lead then cut one of the plugs off and re terminate with the new one..........
Have you tried a battery on the PilotAware that would rule out the ground loop, if it still does it I would suggest checking the continuity on the screening on the cable to either end of the 3.5mm Jack.
And Peter here is the link for the Bluetooth Adapter......works great for the Bose A20 Bluetooth or when ground testing a I uses a wireless Logitech Speaker.....A single charge lasts about 8-9 hours.....and uses bluetooth v4.00...Perfecto !!
http://www.ebay.co.uk/itm/2-in-1-Wireless-Bluetooth-Audio-Music-Transmitter-Receiver-Adapter-Two-Way-A2DP-/272048764056?hash=item3f575eb498
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Have you tried a battery on the PilotAware that would rule out the ground loop, if it still does it I would suggest checking the continuity on the screening on the cable to either end of the 3.5mm Jack.
Tried using a power pack instead of mains power and yes no background noise, but I would prefer plane power :) :)
Out of interest does the Bluetooth option resolve this, although I would prefer the wired option
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If you have a ground loop caused by the aircraft power supply and the heaphone shield then I guess having no hard wired lead between the raspberry pi and the headset has to remove the ground loop....Its worth a try....the bluetooth transmitter is a cheap box to buy.....it might be worth a try.....although if it were me I would like to fault find and find the cause first..
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Hi Brinsley
Thanks for the info on the ground loop, but I also get this at home when using a power supply. My aircraft just been built and I don't get other noise like transponder, fuel pump or even when I power up my iPad via USB. I only get this low down hum when I use PAW for warnings. I have read up on another forum that this seems to be a common issue with the Raspberry Pi. What I've done in the meantime is ordered one of those ground loop isolator as recommended so finger crossed my problem will disappear ;D ;D
Ive tried a ferrite on power supply and also on the aux lead and that's made no difference, the cable I'm using has 3 pole connection, so the only thing I've not tested is a 4 pole connection.
Regards
Allan
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It really does sound like the lead to me....Where did you get it from....where are you based ?....maybe another User can lend you their lead as a quick check.....Have you got a powered speaker you could try the lead into instead of the headphones...just trying to rules things out.....If you are still getting the hum at home I presume the A20 has only one signal from the 3.5mm jack from the rPi and that you haven't got the two aircraft jacks or lemo plugged in......if that's the case its not a ground loop.
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Hi Brinsley
I think you may have resolved my issue, i have only tried the one cable within my aircraft, and that's the one supplied with my Bose A20 headset. I've tried another cable at home and was getting the same result, so automatically assume this would be the same in my aircraft :-). And yes when i am at home i don't have the GA sockets plugged in so yes i get the humming sound but if i plug into my amp all goes away. I will try and test this other lead when i pop up to Sywell over the weekend and fingers crossed all will be ok.
Out of interest both these leads are 3 pole 3.5mm sockets, should i be changing, or even trying a 4 pole socket cable as i know the Raspberry Pi 2 also transmits video, but if plugging into my bose headset surly these will be connected together, ie ring 2(ground) & sleeve(video) ....
(http://www.raspberrypi-spy.co.uk/wp-content/uploads/2014/07/Model-B-Plus-Audio-Video-Jack-Diagram.png)
If so i will need to purchase one of these and try..
Regards
Allan
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Allan,
I have always used a [Maplin] 4-pole TRRS 'lead' - cut in half and adapted to a single phono plug for mono audio output at the other end to input to my Flycom Intercom audio input as per my May 2016 posts referred to earlier in the thread. On Jeremy C's advice, I shorted the outer braid 'video' to ground in a successful attempt to cure exactly the problem you are experiencing - i.e. computer 'hum' from the RPi coming through into the intercom. This effectively gives pretty much the same thing as a 'standard' stereo 3-pole TRS jack which 'automatically' shorts the sleeve to ground, so I'd be surprised if changing to a 4 pole makes any difference.
Probably best to wait and try your ground-loop isolator first.
Regards
Peter
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Brinzlee
Thanks for the link to the Bluetooth TX/RX adaptor, I took delivery of one today and I now have the choice of alerts from the PAW audio as well as the EVFR audio from my tablet wifi, straight into my intercom box with no wires trailing around. Still to test on the aircraft but transmits PAW audio into my Bluetooth receiver with a set of headphones plugged in. It works in the aircraft from the tablet so can't see why it wont work with the PAW. ;D
Cheers
Alan
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What is the situation regarding the clipping of the first part of the alert, when on BlueTooth?
Or is that what the background hum is for :o
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AllanBirt I think there may be an issue with the rPi socket.....there is a possibility you are not connecting the ground pin in the rPi audio out properly and its using the video as a ground which would lead to all sorts of problems like you are describing.
I purchased a stereo to stereo lead 3.5mm to 3.5mm jack, cut one of the plugs off then bought a 4 pin 3.5mm plug from CPC and soldered the braid to pin 3 and then the other two wires to pins 2 and 1 respectively. That way it keeps the stereo separation in the Bose.
AlanG glad you managed to get a bluetooth adapter so quick.....it's a neat little solution and one more wire less, to tangle!!
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It depends what bluetooth adapter you are using.....mine is v4.0 and doesn't suffer any clipping at all
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Hi Ian
The Blackstar Tone Link bluetooth receiver http://www.gear4music.com/Guitar-and-Bass/Blackstar-TONELINK-Bluetooth-Audio-Receiver/1EOD (http://www.gear4music.com/Guitar-and-Bass/Blackstar-TONELINK-Bluetooth-Audio-Receiver/1EOD) that I use to get the audio from my tablet to my intercom did suffer from clipping originally but working with Rob Weijers (PocketFMS software guru for EasyVFR) he introduced a small wake-up tone in front of all the alerts which overcame this. Strangely enough, using Brinzlee's Tx/Rx device as Tx from the PAW and receiving directly to the Tone Link attached to headphones there appears to be no clipping. There is a very faint hiss behind the speech but not enough to be irritating. So far so good, still to be tested live in the aircraft . I'll let you know how it goes probably next week now.
Alan
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Thanks guys, I am using audio direct by cable from PAW. At the moment, and have SkyDemon anyway. No noise issues as I run off battery packs.
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Ok
I have modified my cable to a 4 pole socket and wired as per Raspberry Pi layout, this plugs into the PAW and on the other end I have the standard 3 pole socket, which then plugs into my Bose headset. Guess what..... still get the hiss !!!!
After looking though the raspberry forums this is a common problem, it seem you can still use a standard 3 pole sockets for audio only, if video is required than a 4 pole socket is required.
I have also copied one of the post below, regards to eliminating the hiss
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1. Add disable_audio_dither=1 to /boot/config.txt
2. Use an amplifier. The output is not meant to drive headphones directly.
3. Pick up a $7 USB audio adapter.
4. Pick up a $15 HDMI sound extractor.
The RPI was not sold as a high-fidelity audio device. These solutions will help. Try your HDMI extractor and please let us know how that worked for you!
--------
Out of interest has the: disable_audio_dither=1 been added to the PAW boot config file.
Maybe this is worth a try, I have not tried a ground loop isolator yet as still waiting for it to be delivered.
Not sure if I mentioned this but I even get this hiss from a brand new Raspberry Pi 2 v1.2, nothing installed, just powered straight from the box..... would this have a boot file from standard !!!
Kind regards
Allan
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This really is strange.....have you plugged any other audio source into the Bose A20.....try using the same lead to say your iphone and play an audio file.....have you paired the bose to sky demon for audio alerts do you get any distortion with that ?
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Hi Allan
Can I ask if this hiss is there all the time the units are connected or only when speech comes through.
As I mentioned above I can hear a very faint hiss when an alert is transmitted. It is not detracting from the speech, it is only really apparent as the speech stops, there is possibly a half to one second of hiss as the alert message ends then it is silent.
This is running the PAW in the house from a battery using the Bluetooth devices (as above post) into a pair of bog standard stereo headphones.
Alan
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This really is strange.....have you plugged any other audio source into the Bose A20.....try using the same lead to say your iphone and play an audio file.....have you paired the bose to sky demon for audio alerts do you get any distortion with that ?
While at the airfield today tried my iPhone using the same cable and all was ok, but if I plug into the same USB socket as the PAW to power my mobile I get this interference noise.
I'll have to have a look at this Anker USB socket as it must be this causing this problem, I wouldn't expect this as this is no cheap unit.
I don't get any other interference when 2 devices are being powered by this, i.e. iPad & PAW, no noise via the radio which I would expect if there are earthing issues.
Another job for tomorrow.
I was also told to remove the earth connection within the AUX cable which connects both together and this made no change
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have you paired the bose to sky demon for audio alerts do you get any distortion with that ?
Morning,
Are you able to tell me what type of alerts will come from SkyDemon, would this be similar to the PAW, if this is the case I may use this method for getting traffic announcements :) :)
Allan
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No they are different....SkyDemon are alerting tones for airspace restrictions, terrain etc....whereas PilotAware is recorded voice announcements for traffic....
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Well after a day of taking my plane apart I believe I may have found the culprit which is causing the ground loop.
The problem is actually the earth on my Trig TY91 radio, if removed the problem goes away. Now what I've done was test all the earthing points on the 25 pin socket that connects directly to Trig radio only to find out that pin 22 has been joined with 9 & 19. Now I don't know if this is actually causing the problem as I'm unable to unsolder pin 22 as this has been all wired together with wire and then soldered too.
This was all done by Airworld UK when I purchased my Trig setup, I'm hoping that a fellow pilot may have the same setup as me with this pin not being wired to pins 9 & 19.
(http://i38.photobucket.com/albums/e142/allanbirt/Trig%20Ty91_zpsunzodtb1.jpg)
What I will do is speak to Trig tomorrow to see if this would actually will cause this interference !!!
With this connected I don't have any other issue, with internal intercom, talking to the ATC, no interference at all, that's until I hard wire my PAW using the AUX cable to my Bose headset.
I have tested my mobile using the same power supply as my iPad and created a Bluetooth connection to my Bose headset and all is ok, so it looks like my only option is to purchase a Bluetooth transmitter as recommended by Brinzlee.
I'm also waiting on delivery of my ground loop isolator, maybe this would resolve this too.
I am really annoyed if pin 22 is the culprit as I paid good money to have this wiring loom made up :-( :-(
Well tomorrow after work I'll have to put half my plane back together ;-);-)
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Allan,
Looking at that diagram, it certainly looks like there should be no direct connection between the system ground (pins 9 & 19) and pin 22. Definitely worth a call to Trig. They are generally very helpful. Any problems let me know as I have contacts locally (they are just down the road from me).
Regards
Peter
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I concur with Peter.....there should be no connection between those pins.....Sounds like a mistake on install
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Morning Peter & Brinzlee
I sent them an email late last night fingers crossed hope to get a reply today.
Peter, being you have a direct contact at Trig, if you are able to find out any info, that would be much appreciated as I know they can take some time in replying to emails.
Allan :)
I've taken the below from the Trig Installation manual, so not sure who could be in the wrong ;), although wiring diagram say something different.
________
5.6.12 Ground Returns
There are only 5 ground pins on the 25 way connector, at pins 1, 9, 10, 19 and 22. A full wiring loom with speaker, two headsets, two microphones, the TC90 connection, power and ground requires 9 ground connections. It is therefore necessary to double up connections to ground pins. This is usually achieved by bringing a short ground wire from a pin that then acts as a bus point inside the D shell.
________
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Hi Allan,
A later version, does show this connected :-\
https://www.trig-avionics.com/library/SUP%20TY91%20003%20Issue%201%200.pdf
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Thanks Lee,
After many hours of trying to identify this issue on a newly built SKR and now I'm back to square one...
I know its nothing to do with any power supply & groundings within the aircraft as I have fully gone over everything yesterday, plane still in bits, even tried 3 USB car power sockets and get the same result, 2 of them being the Anker brand as recommended :o
Strange thing is, when the PAW is powered off all is ok ::) ::), when you power up using plane power then the noise begins :'( :'(
So I'm at a lost.... I see your aircrafts been buried at the back of the hanger ;D ;D
Allan
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Hi Allan,
I tried my Trig contacts earlier, but for some reason they are not answering. I left messages so they will hopefully return my calls. In the meantime I have been reading the Trig Documentation and re-reading all your posts in this thread yet again to try to get to the root of your problem.
The only thing that has come to notice is that you say you connect your PAW audio lead directly to your Bose A20 headset, i.e. bypassing the radio/intercom. Have you tried feeding the PAW audio via the Aux Input (pin 20) on the TY91 instead?
I would be tempted to make up a 'screened' lead using your 4-pole 'TRRS' jack plug for the PAW end. You can use either left or right audio from the Raspberry Pi 'Tip' or 'Ring 1' as the PAW audio alerts are Mono. Connect ground from 'Ring 2' via one of the other wires inside your cable and also connect the cable braid to 'Ring 2' at the PAW end only to ground the screen at the PAW end. You should be able to make a temporary connection from your chosen wires to pin 20 and ground in your TY91 plug for test purposes. Worth a try!!
Regards
Peter
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Hi Peter
would love to use pin 20, for AUX input to Trig, but I'm currently using this for my MGL Efis Explorer lite, I may have to go down the Bluetooth option
Allan
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Sorry Allan, I forgot about that.
It just occurred to me that feeding the PAW audio via the TY91 would tie the two grounds to the same level which might negate any 'loop' issues. I take it your ground loop isolator hasn't arrived yet?
Peter
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I see your aircrafts been buried at the back of the hanger ;D ;D
Yes, no need to remind me :(
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I take it your ground loop isolator hasn't arrived yet?
Nope... still patiently waiting, should of been here on Friday. Not even received today so emailed them this morning to find out they're on holiday till the 14/1/17, but it was posted on Wednesday. Hopefully it might turn up tomorrow :)
Lee, popped into Sywell on my way home this evening and noticed they have removed your wings and stripped the coverings...... oh sorry that wasn't yours that's in for a major overhaul ;D ;D
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Lee, popped into Sywell on my way home this evening and noticed they have removed your wings and stripped the coverings...... oh sorry that wasn't yours that's in for a major overhaul ;D ;D
???
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Hi Lee
Just sent you an email for a replacement licence
Allan
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OK, update on my interference issue.....
Trig saying all wiring to my TY91 is all OK, as standard communication is all clear, only when there is no transmission taking place you get the interference with PAW being plugged into my headset.
They have quoted the following 'USB chargers/adapters are fast becoming the no.1 RF noise problem for installers', now I've tried 2 Anker USB charges as well as another brand I borrowed from another SKR (not yours Lee ;) ) and I get the same result. I am now looking to changing my cigarette socket that this plugs into to see if this could make any difference, I don't think it would but I don't know what else to try.
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I give you full marks for perseverance !! So in summary in can only be a ground loop even though Trig are telling you that you're wiring is correct.....this would be solved with either bluetooth transmission or ground loop isolation transformer....I would try the transformer first......Then if it still persists, its the power supply....The best solution to that is the charge2 / charge4 device installed
http://charge4.co.uk/
The specification on these units far exceeds the cheaper Korean/Chinese plug in adapters, especially if you have sensitive issues. I really wouldn't think changing the 12v cigarette lighter socket will do much
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Allan,
Out of interest, who was it at Trig who replied?
I concur with Brinsley, worth waiting and trying your ground loop isolator first. If not successful I can definitely recommend one of Jeremy C's power supplies. I have had a Charge 4 running in my Flexwing for almost a year now and it's the bee's knees. The smaller Charge 2 version comes as surface or panel mount. Both highly recommended.
Regards
Peter
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Out of interest, who was it at Trig who replied?
The contact at Trig was Lindsey Christie, same person I was emailing when I had issue with MGL and Trig compatibilities, all resolved now tho :)
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Thanks Allan,
Thought it would probably be Lindsey or James.
Regards
Peter
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Great thread about the audio output from PAW. I fly a single seat aircraft so no intercom. I have had to use a slightly different setup than most. The amp and PAW are behind my seat so I was hoping to fine adjust the volume on my ipad, having set it max in the amp. All seems to be fine, just waiting for the volume fix, mine is permanently on 10. Attached diag of my setup.
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Hi John,
Thanks for the info. Looks like a neat setup. Hopefully we'll get the audio setting problem sorted soon.
Regards
Peter
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Fixed my issue..... Bluetooth was the way to go :)
(http://i38.photobucket.com/albums/e142/allanbirt/270d05a2-125b-474a-9c2e-9a9cf6806a00_zpsb6uwynuc.jpg)
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Great - glad to hear it is solved!
Thx
Lee
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Well done....It's good isn't it..!!
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Well done Allan,
I bought one of the bluetooth units recommended by Brinsley, just to try it out.... then realised I don't have any bluetooth speakers or headphones, so bought a small speaker during our weekly Tesco shop but got home to find it isn't bluetooth - .....Bu**er! Guess I will need to take it back tomorrow.
I see your bluetooth unit is different from Brinsley's Allan, can you post a link so we can take a look please.
Regards
Peter
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£12.99 on Amazon and free delivery. Just ordered one :)
https://www.amazon.co.uk/d/Bluetooth-Adapters/Wireless-Bluetooth-Audio-Music-Transmitter-Receiver-Adapter/B01LZ3U2AK/ref=sr_1_1?ie=UTF8&qid=1484473689&sr=8-1&keywords=2+in+1+Wireless+Bluetooth+Audio+Music+Transmitter+Receiver+Adapter+Two+Way+A2DP (https://www.amazon.co.uk/d/Bluetooth-Adapters/Wireless-Bluetooth-Audio-Music-Transmitter-Receiver-Adapter/B01LZ3U2AK/ref=sr_1_1?ie=UTF8&qid=1484473689&sr=8-1&keywords=2+in+1+Wireless+Bluetooth+Audio+Music+Transmitter+Receiver+Adapter+Two+Way+A2DP)
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This is the one Allan is using.....slightly different to mine....but same result....
https://www.amazon.co.uk/Bluetooth-Transmitter-Receiver-TaoTronics-Simultaneously/dp/B016UF7J5C/ref=pd_sbs_147_4?_encoding=UTF8&psc=1&refRID=D85BFMZ3W9S3JQ9X5MYE
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Thanks Brins,
Funnily enough it magically appeared in my Amazon homepage this morning under 'Related to items you've viewed'. Scary or what? (- OK What ;))
Peter
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There's quite a few Bluetooth devices out there, when looking I was making sure it had a good battery life and also using the latest protocols available.
Peter.... no Bluetooth headset 😂😂😂, love the shopping trip too 😬😬😬😬
I would certainly recommend the Bluetooth option to anyone that has Bluetooth headsets, less cables, no interference etc 😁😁 thanks Brinzlee on recommended this
I spent many hours checking things out to get to the bottom of this interference, everything was wired correctly, tried new power sockets, screened audio cable but to no avail didn't fix it so Bluetooth was the way to go...
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I say it again Allan - definitely a good job well done!! ::) ::)
Just thinking - our CFI uses Bose A20s in his flexwing (fitted into his existing helmet) via a fancy Lynx intercom. His students/ passengers still use Flycom helmets. I have just finished installing PAW for him and integrated the output from his PowerFLARM Core, but deliberately didn't connect up PAW audio yet to avoid potential conflict during instructing/trial flights. Looks like a perfect candidate for a bluetooth connection as he can then decide whether / when he wants PAW audio to his headset only.
Regards
Peter
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Latest update, after some weeks waiting for my ground loop isolator, which by the way supposed to have been delivered from the UK within 2 days. ;D ;D
Tested this on my aircraft today and it also fixed the problem.... what a result.
Also done some nice flying too ;) ;)
So at the end of this, anyone with the same issue then you have two options
Ground loop isolator or a Bluetooth transmitter
Both will work fine 8) 8)
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Hi Allan
Great news
Can you post a link to the ground loop isolator for others.
Thx
Lee
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I think Jeremy posted the link back on page 4.
https://www.amazon.co.uk/Ground-Isolator-HAVIT-Speaker-Filter/dp/B01IETQQQK (https://www.amazon.co.uk/Ground-Isolator-HAVIT-Speaker-Filter/dp/B01IETQQQK)
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Hi Allan
Great news
Can you post a link to the ground loop isolator for others.
Thx
Lee
This is the one I got http://www.ebay.co.uk/itm/Mpow-Ground-Loop-Noise-Isolator-Car-Audio-System-Home-Stereo-With-3-5mm-Cable-UK-/152353458215?hash=item2378f94827:g:yEsAAOSwXSJXPVsY (http://www.ebay.co.uk/itm/Mpow-Ground-Loop-Noise-Isolator-Car-Audio-System-Home-Stereo-With-3-5mm-Cable-UK-/152353458215?hash=item2378f94827:g:yEsAAOSwXSJXPVsY) although delivery time was rather slow ;D
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Paul and Allan - My audio is usually perfect with no noise even with PAW installed in the C42. However, for the first time today I plugged an audio lead between PAW and my Bose A20. The video I recorded today illustrates the noise I am now getting on my headset. The minute the comms kicks in the Bose overrides the PAW audio and there is no noise or interference. Do you guys believe that the little device you have identified will get rid of this noise if I plug it into the audio connection between PAW and my Bose? Thanks....video is at https://youtu.be/OP0cq9J8Oew
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Evening Roger
You've got exactly the same problem as I had, I also have a Bose A20 headset, with Bluetooth.
I can confirm using either a Bluetooth TX as shown in this thread or even the ground loop isolator, this will fix your problem. I spent many days trying to resolve this, thought it was a wiring issue, even spoke to the manufacturer for my radio.
I'm currently using the ground loop isolator for my PAW and then I use the Bluetooth side on my headset for my iPad, giving me warnings from SD and also making calls via my mobile ;) :)
Kind regards
Allan
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In regards to receiving audio via Bluetooth, could any one advise if the following scenario is achievable:
I don't have a Bluetooth headset but want Bluetooth audio via PAW in the clubs aircraft - I fly a different aircraft each week so a permanent install is not a possibility.
If I was to purchase two of the following Bluetooth adapter (as mentioned earlier in the thread) - https://www.amazon.co.uk/Bluetooth-Transmitter-Receiver-TaoTronics-Simultaneously/dp/B016UF7J5C/ref=pd_sbs_147_4?_encoding=UTF8&psc=1&refRID=D85BFMZ3W9S3JQ9X5MYE
Attach one to the PAW directly and configure it to communicate with the other Bluetooth adapter, purchase a 3.5mm jack to audio in for the plane so that I can use one of the rear passenger sockets and plug in to that.
In theory, would that give me Bluetooth audio via the plane so I could hear it in my headset? If the above device cant do it, does a Bluetooth receiver exist for the same scenario?
I know I could just go straight in to plane audio from PAW but I've read about various issues with the volume not being loud enough - I'm thinking this method may solve that and give full flexibility etc.
Thoughts?
Appreciate any input! :-)
Thanks
Rob
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Rob,
AlanG used to use a similar setup, though he now connects the Bluetooth 'receiver' into a dedicated auxiliary input on his intercom.
I have also tested a similar setup, but currently have no problems with a hard wired cable connection direct from the PAW to an auxiliary audio input on my (Flycom) intercom.
One problem you might experience going in through the 'back door' is that the audio level could be too low. Although I've never had a problem, several users in the early days of audio alerts had to introduce small amplifiers to boost the relatively low audio level from the PAW.
Regards
Peter
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I have two BT using and used them as described, but not yet tried feeding into a spare headset socket, so not sure what levels you will get.
You do not want an amp between the PAW and the BT transmitter, that would be too much for the input. Monitoring my BTTX to BTRX setup with earphones I have to turn the PAW down to about 4 or 5 as the volume was excessive. That bodes well to feed an aircraft headset, though it's anybody’s guess as to what the different impedances will do in different aircraft wiring installations.
Trying to work out if I can test it at home with all my bits and bobs
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Brilliant - thank you so much for the replies.
Looks like some more money to spend on gadgets! :-) Interesting to hear that you have no issues going directly from PAW to the aircraft via cable - I have no experience but seem to think I had read many replies about low volume - hence why I was looking at a Bluetooth setup. I know that every aircraft is different but I fly a PA28 - any thoughts on cable vs Bluetooth for this in regards to audio volume levels?
Thanks as always - everyone is very helpful
Rob
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To date I have been feeding into a spare Mic socket. Just hope Lees's lass does not pipe-up when you have the tit pressed. Guess who it happened to :-[
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Lol - I know that will happen to me!
Any pointers on the cable required to go from PAW to the Mic socket direct - I've looked on Amazon and can see ones for the plane head phone socket but not the Mic socket? I've probably missed it! Doesn't seem to be much for 5.25mm to 3.5mm - assuming I'm looking for the right thing!
Thanks
Rob
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Mic plugs are not easy to get. IIRC mine was cut off an old headset. You are looking for PJ068B . A few seconds Google is your friend. http://www.pilot-europe.com/pjo68b-microphone-jack. Effing expensive, so a scrap headset is the way to go. I cut one end off a stereo 3.5mm extension lead, and connected it to the jack.
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Brilliant - thank you! I'll see if the club have got any old headsets I can cannibalise!
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Bear in mind the Mic jack will put out DC to power the microphone's internal amplifier. You might want to block this using a capacitor.
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Thanks Paul - I would never have given that a thought!
This is where it starts to get complicated - no idea what to do with a capacitor (I know what they do but my electronic skills aren't good for making things). Might have to reconsider doing any of this as I don't want to implode the PAW just for some audio!