UV-3R and APRSdroid

[bob-the-scanner-man]

I'm trying to build a duplex cable so that I can use APRSdroid with my UV-3R via VOX. I'm wanting to try out APRS before I spend the money to buy a TNC. However, I can't seem to get things to work correctly.

I made a simple cable using the attached diagram but I did not use any resistors since I wasn't sure if they were necessary.

The problem I have is that when I plug the cable into the phone and then into the UV-3R the phone sends the sound through its internal speaker instead. If I disconnect the UV-3R the phone then acts as if a pair of headphones is connected and no longer plays the APRS data through its internal speaker. Once the UV-3R is connected the phone switches over to its internal speaker and ignores the 3.5mm cable connecting it to the radio. The phone is a Samsung Galaxy Centura.

What do I need to do to fix this? Do I need to go back and add the 500ohm resistors from the diagram or is there something else I need to add? I double-checked my wiring and everything is wired together correctly.

 

[bob-the-scanner-man]

Did some more tinkering with the cable and still haven't had much luck.

I first tried 500ohm resistors and was able to activate VOX and report my position. The problem is that this didn't last very long before the phone switched back over to its internal speaker. I could never receive any audio from the UV-3R an no other stations appeared on APRSdroid. I then tried 1500ohm resistors since I read a few sites that suggested using them to force the phone to use an external microphone. Vox worked occasionally but I could never get the phone to receive any audio from the UV-3R with this setup either.

It seems almost like the UV-3R is receiving audio from the phone fine, but for some reason the phone does not like the audio from the UV-3R. As soon as the UV-3R receives a signal the phone switches back over to its internal speaker. I've tried various volume settings on the UV-3R and nothing works.

What else should I try?

 

[K7XRL]

Maybe try some audio isolation transformers.

I used this with a uv5r to send and receive SSTV images and it seemed to work well.

Unified Microsystems SCI-6 PC Sound Card Interface Kits SCI6

I had to buy a cable adapter that splits the 4 way cell phone speaker/mic cable into two separate speaker and mic jacks like a regular computer sound card, but it works using an android phone to send and receive the signals. And of course, I had to use vox on the radio since there was no convenient way to activate the PTT from the android device.

This thing comes in kit form and takes about a half hour to solder it up and clean off the flux. It took me longer to get the radio end of the cable wired up than it did to build the interface, but the uv5r uses a 2 prong Kenwood style mic plug.

 

[OZ5MB]

The simplest way to receive APRS is to do it without a cable. Just tune the radio to the APRS frequency and it will start "playing" packets into the air. Set APRSDroid to use AFSK over speaker/mic. Click "start tracking" (or something like that my interface is translated into Danish without any possibility of manually selecting English). Put the phone next to the radio. It should now receive the packets played into the air by the radio. If it doesn't work the try to adjust the volume of the radio.

Sendt fra min SGP521 med Tapatalk

 

[AE7TO]

Direct coupling of UV-3R to Android

It took me a while to get my UV-3r (and UV-5r) to work with my Android (Samsung Galaxy) tablet and phone because there is a 2-3 VDC bias on the Baofeng microphone and speaker inputs. That was causing the tablet and phone to disable the headphone connection. All it took to get it working was a 10 uF AC coupling capacitor in series for both microphone and speaker lines. I simply soldered a small electrolytic cap in the line (positive terminal towards the UV-3r/UV-5r) and used heat shrink to tidy up the bump in the wire. Works great. Chokes on the audio cables are also a good idea.

 

[miserytom]

I'm kinda having the same trouble with my uv5re , when the radio is receiving a signal the phone volume goes down by itself lol and I don't get any info on the app , are these the caps you used or will these work ?

SODIAL(R) 10 x 10uF 50V 105C Radial Electrolytic Capacitor 5x11mm https://www.amazon.com/dp/B00JFOO062/ref=cm_sw_r_awd_QEWiwbMM09YEC

 

[miserytom]

I actually found them on amazon , I dunno why the link is Walmart lol

 

[K5MPH]

what cell phone are you using not all cell phones input jack are all the same.......

 

[miserytom]

Galaxy s6 , I already made a cable , all Samsung Jacks should be the same , radio transmits fine through the app , just the issue when I actually am near something to receive the ringer volume goes down by itself , so I'm sure the phone hears something

 

[viper3k]

AFSK Without Cable

Should AFSK work in a peer to peer setup without a cable? As in key the mic on one radio and then tap the single shot button, or send a message. On the other setup have the radio next to the android device and it will receive the audio and display the message/location on the screen? I have been trying this and have been unsuccessful. I'm just playing with the app trying to get the basics down before I move to a cable or Bluetooth setup.

 

[DODGEIT]

I am using a UV5R with a Mobilinkd TNC Soundcard device and using a Andriod phone with Bluetooth for GPS and to see the list of stations that beacon. Using APRSDROID. I have it connected to a magmount on my truck. It works great in my area since we have several IGATES and a Digipeaters. Pretty simple setup. Mobilinkd sells a cable for the Kenwood style plugs for the Chinese Plastic Fantastic radios.

 

[WyoDuner]

I'll second the Mobilinkd solution. I have one and it works fine and is really easy to use. I have it connected to my Kenwood TM-V71A mobile but like DODGEIT said, they have cables to fit different radios.

 

[kc0kp]

I am using Mobilinkd with a VX-7 and a Droid Bionic. I also have the cable to run it with my FT-857 but never have done that. After getting the levels set, it works like a champ.
Disclaimer, I know through my wife the guy that developed it so take it for what it is worth.
Craig