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APRS audio produced by an app or software?


#1

APRS uses audible audio range to transmit data. I do not own an APRS enabled device. It seems to me that if I could produce an APRS audio data signal I could be able to key up on 144.390 and just send the audio from an app or software via cable or speaker–>mic and spot myself without cell phone service. I could even produce the audio before I left, place it on my phone or other audio device and play it from the summit.
Thoughts?
Clifford
KK6QMS


#2

Yes Clifford, that will work!
I have the app “PocketPacket” on my iphone. It lets you create messages and transmits it via the speaker. I made a cable from the headphone-jack of the phone to the mic jack of my KX3 - it works perfectly with the APRS2SOTA service!
So I save weight as I do not have to carry an APRS-capable HT with me.

But you have to be sure the frequency is clear at the moment you transmit. Therefore it does not work everytime but if you resend the message 2 or three times it will go through - APRS2SOTA will only spot you once anyway…

Found no better solution until now to spot without cell phone service and without carrying a separate HT.
Would love to see one developing a gimmick that connects to any transmitter and lets you send and receive messages…
Kind of SideKar would be great!

Tom, OE2ATN
www.oe2atn.at


#3

Ahhhh, excellent news, thank you! I have an Android device so will have to look into it further but now I know the concept is sound and can actually work in practice! I will report back here with any developments.
Thanks again!
Clifford
KK6QMS


#4

Hi Clifford, Tom said he has an app on his iPhone. I’ve just taken a quick look at play.google.com for an equivalent app for Android and can’t see one. What are the tones used if the are AX25, I definitely don’t see any Android app. If PSK31 tones are used, then DroidPSK from Wolphi might work for you.

Or do you intend writing your own app in any case?

73 Ed.


#5

Or use APRSDroid:

https://aprsdroid.org/


#6

Andy’s link might hold all you asked for.

Another option is the AP510 all-in-one APRS unit for 2m.
https://oh2fxd.wordpress.com/2014/12/19/into-to-the-wild-with-sainsonic-ap510-aprs-tracker/
also discussed on this reflector: http://reflector.sota.org.uk/t/aprs-sota/10187

It is available from various online sources.

73 Heinz


#7

Thanks guys. I emailed the dev of APRSdroid to see about audio output possibility, that would be great! That Sainsonic is $130 I’d rather save that money for an APRS capable radio or put it towards an 817 or 857.
Cheers,
C


#8

Well APRSdroid works on my old “landfill” Huawei Android phone. I grabbed the APK from the APRSDroid web page and installed on a slow limited Huawei G300 (1GHz Cortex A5 CPU 512MB RAM Android ICS) and within a minute had it sending APRS location reports from the inbuilt GPS over the speaker. Sounds just right.
All you would need is a cable from you phone’s headphone socket to the radio you use. Most phones use the 4 pin 3.5mm Jack. It’s an easily available plug or you can buy a cheap set of phone earphones/mic and use the plug and lead from them to connect to your radio.


#9

Thanks. I bought it and can get it to produce audio if I choose “single shot” from the menu but have yet to figure out how to send a custom message via audio. I am getting an APRS2SOTA account and will see if there are other ones I might consider. I also applied for the APRS-IS passcode. Lots to learn. Thx.
C


#10

What’s the difference between the free version and the paid for version?


#11

I did not think to look anywhere but the Google Play Store.

“If you really like APRSdroid, you can support the author by buying the Market version. You will get automatic updates and a good feeling.”

I experimented with it tonight and could not get a spot up through APRS2SOTA- likely user error.
I did see it was working though online with phone in airplane mode and transmitting the audio on 144.390 from speaker on phone to mic on my Icom radio. It showed up online which was cool to see and which digipeater I was going through.
Unfortunately I do not yet see how to simply send a message more than once without a lot of steps to resend. I will have to send the message a few times to be sure it goes through. I am also seeing that without decode as well I will miss any ack messages etc.
C


#12

You might also look into the Mobilinkd TNC - it works well with APRSdroid. Cable from HT to TNC, then connect to TNC via bluetooth from your droid phone.

SurvivalTech Nord did a good how-to video on his YouTube channel. http://www.youtube.com/watch?v=g1UsaF6r8Rw .


#13

Did you ever get this to work?


#14

No. I did get single shot to work but afaik messages are still only sent once and only when tracking is enabled. The app has no way of showing message transmission easily. I lost interest temporarily. The easiest way I think would be to record the signal with the message and play that instead of trying to use the app in the field. I will reply to the dev who asked me for a log about a month ago but I never got around to replying. Anyway it is just too complicated at this time to be useful as a quick and reliable way to self spot in the field.
I will start looking into it again and report back with any developments.
C


#15

FWIW I was able to use Aprsdroid to post a test spot via APRS2SOTA a few months back. I did use the TCP interface. Lately I’ve been playing with “AFSK via Speaker/Mic” settings.

BTW, did you request access to the APRS2SOTA manager? And message is formatted correctly?


#16

I have used it to post using AFSK via Speaker/Mic but takes 7 steps to re-que the message and there is no visual feedback as to what is being sent either. The issue is not getting it to work but getting it to work in a way that is “worth” it to me. I would get the Moblinked bluetooth TNC but it ONLY does APRS and cannot be utilized for packet or anything else which is not worth it for me.
Thanks-
C


#17

I use APRStrack an app on my phone these days it is very reliable to show my whereabouts as long as the Location is turned on in the phone. It displays my position on the normal aprs.fi page. the aprs radio system in vk is too hit and miss with hand helds or portable packet kit usually.
not real radio I know but it shows my chasers where I am and how far off the summit I might be.
cheers
Ian vk5cz …


#18

Thanks for the info. At least now I know that it’s not a viable option. :smile: