$40 APRS plus Upgrades

APRS is challenging and intimidating but a useful tool in our hobby. discuss APRS in this forum.
User avatar
Crismateski
Posts: 388
Joined: Thu Dec 10, 2009 8:32 pm
Call Sign: KJ6DZZ
Location: San Antonio Heights Ca
Contact:

$40 APRS plus Upgrades

#1

Post by Crismateski » Sat Mar 15, 2014 1:15 am

Sorry this has taken so long, I was going to post this about 2 weeks ago, but I have been refining and upgrading. Now that I have the system running I will share. I have been wanting to do an APRS rig in the truck for quite a while and have not had the funds to do it. A couple of weeks ago Derek Shared this video

[video=youtube_share;8-9_8HVkvgc]http://youtu.be/8-9_8HVkvgc[/video]

If you dont want to watch the video, I will sum it up now and give you the details later. In short, you can plug your old cell phone (just needs gps no plan or data) into your cheap radio and have aprs via afsk output to vox input. (details later)

I immediately thought, I am cheap, but I can come up with $30 and I already have a Samsung Galaxy Tab in the truck that I use for navigation. Within a few minutes I was well on my way to the $30 budget for this project by purchasing 2 Baofeng UV5R radios off of Amazon for $30.17 each ($60.34 total)

I already had a 3.5 mm to 3.5mm phono cable and already had APRSDroid so i just had to wait for the delivery..

Since I had time to kill, I went ahead and set up the app. It is pretty simple, for the connection type select AFSK, and pretty much everything else is optional.

When the radios came in I plugged everything together, went into the menu on the radio and set it for a freq step of 2.5, and turned vox on to lvl 10 (what the video recommended) then set the radio to the proper freq of 144.390 Went to APRS droid and hit start tracking. The radio lit up right away telling me it was transmitting so it was off to openaprs.com to see if it worked. To my surprise, I was on the map.

I was very excited, but now I wanted more. I wanted to see other people on the map, not just transmit. This lead me to Google, and lots of reading about parts of APRS I will probably never understand, but I did find the information I needed. APRSDroid will listen, which means I needed to get the audio output of the radio back into the tablet. The problem is the radio uses a 2.5mm phono plug for the speaker and the 3.5 for the mic while the tablet only has one 3.5mm jack. The Tablet and most phones use what is called a TRRS jack (Tip, Ring, Ring, Sleeve) That means that it has an extra connection from your standard stereo phono plug so it can do audio output and mic input on one plug at the same time. This means i need to make a cable to get from the single plug on the tablet to the 2 plugs on the radio. So I ordered up a 2 pack of TRRS connectors off of ebay for $5.50 (total now $65.84) and was planning on cutting the plug off of the headset that comes with the radio to make my cable. Then I got lazy so it was back to the internet. My first stop was to Monoprice where I found this. It is designed to split the TRRS plug so you can use headphones and a mic with an ipad. $11.76 with shipping (total $77.60) I happened to have another 3.5mm to 3.5mm cable and got a 3.5mm to 2.5mm adapter from work. Surprisingly it worked, I could see people on my map, and I could transmit.

Again, I celebrated, but this lead me to 2 problems. The first is it looked like this
Image


and in the truck Image

The second problem is APRSdroid uses Google Maps, but does not have a way to cache the maps, so as soon as I drove away from my wifi, I was seeing people on a blank map.

More reading and I found that this problem has been addressed, and is easily fixed. From the aprsdroid website, you can download a modified apk which allows you to use different map sources, and even links you to free maps that can be used. The instructions are pretty clear on the website so I will just give you the link instead of retyping it. aprsdroid.net/osm

I was now up and running with 2 way communication, a working map and an ugly tangle of cable.

Time for google again which lead me to a video that pointed out some flaws with this setup, and a solution to that flaw that also solves my ugly cable problem. Unfortunately I cant find the video but it basically said that while aprsdroid is listening to receive information it has no problem interrupting the incoming info if it decides it is time to transmit. This makes it unreliable as it is fighting itself, and it is also causing lost information for the entire aprs system. The solution the video suggested is a bluetooth TNC made by http://www.mobilinkd.com/ The TNC itself is $49.95 plus $9.95 for a much shorter cable. With shipping this was $69.90 (total $147.50)

Well, this setup came in today. It is pretty, it is small, and was simple to setup. Turn off vox on the radio, plug cable into radio and TNC. Hit the button and watch the pretty blue light on the tnc flash, then pair up the bluetooth (code 1234) Then in APRSDroid, change the connection from AFSK to Bluetooth, then in connection settings select the mobilink tnc hit start tracking.

The system is running faster, wirelessly, and is getting into the system reliably

The TNC sitting next to the Baofeng UV5R
Image

The tnc "mounted" to the radio
Image
the other view of the "mount" I will probably remove the clip and just velcro it to the back of the radio
Image


One change I would recommend (because I read it) is to change the digipeater path. By default APRSdroid uses WIDE1-1 I changed it to WIDE1-1,WIDE2-1 and it does seem to work better. There is a lot of really detailed information on what that means, but the site that made it so I understood it was http://wa8lmf.net/DigiPaths/NNNN-Digi-Demo.htm

Here are some extra photos

Me on the map (KJ6DZZ)
Image

other aprs systems that I am recieving
Image

the connection log showing the "raw data" in and out of the system
Image
2006 Dodge Power Wagon @BlkWgn
Family Off The Map http://www.familyoffthemap.com
Kilo Juliet Six Delta Zulu Zulu

EMR (Emergency Medical Responder) Certified via San Bernardino County Fire
San Antonio Heights C.E.R.T Founding Member
San Bernardino National Forest OHV Volunteer

User avatar
DaveK
Site Admin
Posts: 3184
Joined: Tue Mar 11, 2008 10:33 am
Call Sign: K6DTK
Location: Southern California

Re: $40 APRS plus Upgrades

#2

Post by DaveK » Mon Mar 17, 2014 11:22 pm

Cris

Great tech article and very clever. One of these days, we will get a tech section going and this would be a good addition.

If you will make the Redondo M&G, please being your set-up for us to see. Thanks for the info!!
DaveK
K6DTK


Extremism in the defense of liberty is no vice.
Moderation in the pursuit of justice is no virtue.

User avatar
Crismateski
Posts: 388
Joined: Thu Dec 10, 2009 8:32 pm
Call Sign: KJ6DZZ
Location: San Antonio Heights Ca
Contact:

Re: $40 APRS plus Upgrades

#3

Post by Crismateski » Tue Mar 18, 2014 9:07 am

Now That I have had it running for a few days there is something else I have noticed. When I was hooked up via the cables and vox, each transmission was approx 3 sec, by the time APRSDroid triggered the vox, mad the transmission, then the radio holds open to make sure the transmission is over. The TNC actually triggers the push to talk, so there is no wasted air time. The transmissions are approx a second. Which helps to open the freq for others.

An added bonus
2006 Dodge Power Wagon @BlkWgn
Family Off The Map http://www.familyoffthemap.com
Kilo Juliet Six Delta Zulu Zulu

EMR (Emergency Medical Responder) Certified via San Bernardino County Fire
San Antonio Heights C.E.R.T Founding Member
San Bernardino National Forest OHV Volunteer

jimbiram
Posts: 3
Joined: Sun Dec 23, 2012 5:40 pm
Call Sign: K6JKB

Re: $40 APRS plus Upgrades

#4

Post by jimbiram » Wed Mar 19, 2014 11:18 pm

Nice write up Chris. I've had one since December and have enjoyed working with it, A couple of months ago I wrote up a less in depth review for LandOps, .link to article is https://www.dropbox.com/sh/qgmvzryh5mljuav/hMDmpo1eVJ. Sure a cheap way to try aprs if you have an Android tablet. Unfortunately the Mobilinkd doesn't work with IPads.

User avatar
DennisDawg
Posts: 240
Joined: Wed Mar 31, 2010 5:36 pm
Call Sign: K6DOB
Location: Placentia, CA

Re: $40 APRS plus Upgrades

#5

Post by DennisDawg » Thu Oct 23, 2014 1:05 pm

I have a similar little setup using an old Motorola Droid phone with APRSDroid OSM via Bluetooth to the Mobilinkd TNC and a Baofeng UV5R hooked to a Tram mag mount on the roof. It works fine and I can send messages with it which I cannot do with my other, cable tangling mess of a system (viewtopic.php?f=124&t=2476). The old Droid has a slide out keyboard that makes messages even easier and there are no cables. Tested with my tablet also, worked great.

IMG_20141022_185527.jpg
IMG_20141022_185527.jpg (2.27 MiB) Viewed 19075 times
You can easily just use your own phone, rather than an old one . . . depends on what you want. I have it loaded on all my Androids but the old phone lets me beat on that in the truck and not my real phone.

The Mobilinkd TNC now comes in a nice little case and the cable as a ferrite core to cut down on RF going down the cable. The cost is 65 bucks now but totally worth it.

APRSDroid is indeed not well supported, though it workls very well. The web site is full of bad links. The OSM version (for off line maps) is still here: http://aprsdroid.org/osm/ but the rest of that is a mess. The maps are actually here: http://download.mapsforge.org/maps/ I wrote the author about the links but did not get a reply.

I cannot find topo maps for it but the MapForge offerings have many of the dirt roads in them for CA at least.

All the said, APRSDroid OSM works pretty well. The Mobilinkd TNC is great.
Local Repeaters On Which You Might Find Me (K6DOB):
  • Big Bear K6BB 147.330+ PL: 131.8 - Keller Peak KE6TZG: 146.385+ PL: 146.2 - Sierra Peak KD6DDM 146.610- PL: 103.5

User avatar
DennisDawg
Posts: 240
Joined: Wed Mar 31, 2010 5:36 pm
Call Sign: K6DOB
Location: Placentia, CA

Re: $40 APRS plus Upgrades

#6

Post by DennisDawg » Tue Oct 28, 2014 10:21 am

Tested in Anza Borrego this past weekend. My Old Droid Phone did not seem to work very well as a GPS, whilst my current phone and tavblet had no issue. Swapped phones and all was well. I am going to look for a small tablet, 7-8 inch, GPS and Bluetooth . . .

Baofeng radios are quirky. Tested with two different UV5Rs and both worked for a bit and then lost programming for APRS. A factory reset and just setting the frequency cured that so all is well. I will use a little box to hold the radio and TNC and be able to just toss them in all set up.

The other tester with me was using a radio and Open Tracker/Garmin setup. We had no issue tracking each other that could not be explained by terrain and/or distance. It worked well.

I did miss topo maps . . . so after the trip I looked for a solution and found one.

For those wondering about Topo Maps for APRSDroid, see this tread: https://github.com/ge0rg/aprsdroid/issues/86

You will need the them mentions and the “test” version of APRSDrod linked there.

Still a bit quirky…biking theme seems to show the most off road trails . . . pretty good really!
Screenshot_2014-10-28-10-17-17.png
Screenshot_2014-10-28-10-17-17.png (922.49 KiB) Viewed 19028 times
Local Repeaters On Which You Might Find Me (K6DOB):
  • Big Bear K6BB 147.330+ PL: 131.8 - Keller Peak KE6TZG: 146.385+ PL: 146.2 - Sierra Peak KD6DDM 146.610- PL: 103.5

User avatar
DaveK
Site Admin
Posts: 3184
Joined: Tue Mar 11, 2008 10:33 am
Call Sign: K6DTK
Location: Southern California

Re: $40 APRS plus Upgrades

#7

Post by DaveK » Sun Nov 02, 2014 9:46 pm

We have done a few nets on APRS in the past, the most recent being about a year ago. One of the things we were missing was ingenious setups as described in this thread. The net topic will come up again and we sure could use the kind of information posted here. Cris and Dennis: would be willing to join us on the next APRS net with a description of these set-ups?
DaveK
K6DTK


Extremism in the defense of liberty is no vice.
Moderation in the pursuit of justice is no virtue.

User avatar
DennisDawg
Posts: 240
Joined: Wed Mar 31, 2010 5:36 pm
Call Sign: K6DOB
Location: Placentia, CA

Re: $40 APRS plus Upgrades

#8

Post by DennisDawg » Tue Nov 04, 2014 11:02 am

I cannot commit because I so seldom make the Net anymore.

I did communicate with Mobilinkd a bit about the minor issues I encountered. The Baofengs are leaky beasts and so the ferrite bead on the radio cable is key as is wrapping the cable through it (which I had not done). The bead supplied did not fit well with the wrap, so I used a larger one I had in the junk box.

Without the ferrite bead, RF can get back into the TNC and cause it to reboot and in a rare set of circumstances put the device into the bootloader. When this happens, the firmware needs to be reinstalled. The bead helps prevent this and in my testing with the larger bead, I have had no issue thus far.

The bead does make the cable a bit short. So, depending on how you plan to use it, you may need to address that.

Another issue that came up was though the Mobilinkd app would download the web site’s firmware and install it, it would not do so for a local copy for the file. Therefore, if one were out of cell phone range, you could not get a TNC trapped in the bootloader its firmware. Mobilinkd addressed this and released an update to the Mobilinkd App in the Play Store last evening. I tested it today and it all works.

My plan now is to sort of soft mount the setup in the center console of the truck and reuse my seldom used CB antenna mount for a 2m antenna. Then a little APPRS system will always be in the rig without needing much. I can just start APPRS Droid, click Start Tracking and go!

Afoot I am still deciding what to do. One things this setup lacks is tracking, i.e. you and I are both out afoot in the field, both with APRS and you want me to come to you. I cannot select your call sign’s way point and get tracked to you. I am not sure that is important but my Garmin 60/Opentracker+ setup can do it.

One other little issue, the maps. There can be only one. Those one downloads for the USA are by state. So, you can have one state going at a time. For trips that cross states, you need to change the map. If you want multi-state maps, you may need to build your own using the methods for OpenMaps and MapForge.

Right now I am testing almost daily without issue. The next off road test shall be Saline Valley later in the month. That is a good test area without digipeaters and such to improve things. The folks are going in without me, as I will leave late and need to catch up solo. APRS will help me find them and our camp.
Local Repeaters On Which You Might Find Me (K6DOB):
  • Big Bear K6BB 147.330+ PL: 131.8 - Keller Peak KE6TZG: 146.385+ PL: 146.2 - Sierra Peak KD6DDM 146.610- PL: 103.5

User avatar
DennisDawg
Posts: 240
Joined: Wed Mar 31, 2010 5:36 pm
Call Sign: K6DOB
Location: Placentia, CA

Re: $40 APRS plus Upgrades

#9

Post by DennisDawg » Fri Nov 14, 2014 3:22 pm

I am now wireless and hidden. I took a piece of board and painted in black, drilled a few holes, put Velcro on the faces and foam on the edges (so it won make rattling sounds) and then Velco’ed the radio and TNC to the top. On the bottom is a little “power supply” of sorts and a foam “leg” to make it stable. It now sits in the lower console compartment to which I neatly ran 12 VDC and the antenna coax via a small hole I drilled in the bottom of the console compartment.

I repurposed a homemade CB antenna mount I made at one point as the mount for a SBB5. I can swap back to CB (which I have not used in years) if ever I need to (the CB is under my seat).

Anyway, now when I get in the truck and want to run APRS, I just open the APRSDroid App on my phone or tablet and click “Start Tracking.” No wires, nothing much to do . . . easy stuff.

I’ll be using it in this configuration in Death Valley next week to find my friends (who’ll leave about 6 hours ahead of me) in the dark! Fun!
Attachments
IMG_20141113_203515.jpg
IMG_20141113_203515.jpg (976.1 KiB) Viewed 18854 times
Local Repeaters On Which You Might Find Me (K6DOB):
  • Big Bear K6BB 147.330+ PL: 131.8 - Keller Peak KE6TZG: 146.385+ PL: 146.2 - Sierra Peak KD6DDM 146.610- PL: 103.5

User avatar
DennisDawg
Posts: 240
Joined: Wed Mar 31, 2010 5:36 pm
Call Sign: K6DOB
Location: Placentia, CA

Re: $40 APRS plus Upgrades

#10

Post by DennisDawg » Tue Nov 25, 2014 12:11 pm

OK, testing with two rigs with virtually the same setup over the weekend in Saline Valley (Death Valley NP) and it worked great (but for a period where my antenna fell off - - - but I found it). We could see each other just fine for the whole trip. We sent messages and all that just fine. We both used our Android phone as the entire user interface, on road and off road, we showed up great.

So, now with it stashed away and connected full time, it is easy and simple, nothing to it.

Now if more people would adopt Ham and then more ofthem APRS, we’d be in great shape!!!
Local Repeaters On Which You Might Find Me (K6DOB):
  • Big Bear K6BB 147.330+ PL: 131.8 - Keller Peak KE6TZG: 146.385+ PL: 146.2 - Sierra Peak KD6DDM 146.610- PL: 103.5

Post Reply

Return to “APRS (AUTOMATIC PACKET REPORTING SYSTEM)”

Who is online

Users browsing this forum: No registered users and 1 guest