Aaron Kravik: Hey guys,
I thought I’d take a few minutes and talk about something I’ve been tinkering with lately…APRS. I don’t have a radio with native APRS functionality. For a little while I’ve been playing around with a 5w Chinesium handheld and an interface cable that attaches to my phone using an app called APRSdroid. Very cool little app. However, with the HH radio, using it in my vehicle is just about impossible. So I got together with a buddy last night and we built a proof-of-concept interface cable for my mobile radio.
It looks ugly…just like a proof-of-concept is supposed to. Soon, I’ll be putting together a more robust version.
Essentially, I’m using the Cat-5 mic input to get audio from my phone to the radio, and the headphone jack for the return trip allowing two way data communication.
This is a very under-used resource for people who travel off the beaten path and out of cell range. I can use it on the trail to track my wanderings and anyone call follow me by logging into APRS.fi and searching my callsign. I can use it for two way SMS text communication for letting the wife know I’m not dead…or more importantly for texting for help if my situation has gone south. Vocal ham is great if there’s a) someone listening and b) if they care enough to help. Using APRS SMS, I can text anyone’s cell phone anywhere and provide them my exact co-ordinates. I could also set it up to beacon a more general distress call, but again, at the mercy of anyone paying attention.
For me, this is a very viable alternative to the expensive satellite options (inReach, SPOT, etc). No monthy service fees and no additional expensive equipment to buy. At least in the PNW, with the density of digipeaters and Igates, I would be very hard pressed not to be able to reach one if I needed to.
The pictures show my cable, how it hooks to my radio and phone, and the various displays I have access to using the APRSdroid app.
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John Russell Wrote:
I have the Kenwood 710G dual-bander in the truck and have 1 channel set up for APRS. Any time I have the radio on, it’s pinging out to the world. Also set it up with SMSGTE so I can send and receive txts through it (but boy is it clunky). Probably need to set that up again to make sure I’m still stored in their database.
Depending on areas, it can be real hit or miss on reaching a digipeater that will reach a gateway to APRS.FI. Around here it is pretty well covered, with terrain constraints to be dealt with always. There’s a lot of areas that have been surprising to me with lack of coverage (i.e. the eastern Sierra).
Haven’t devised a good solution to output to a course plotter to see others in the area, there was a specific Garmin (Nuvi 350) that worked pretty good as it wouldn’t retain the beacon info on the screen. (it would refresh when a new position was reported, rather than just filling the screen with dots). Of course whether something like that or APRSDroid, it comes down to a way to get the info out of the radio and I just haven’t spent enough cranial intercourse on devising an overly complex solution.
From the December/Christmas-Solstice Run. Bounced off of both Mission and Badger, then onto various gateways in BC, Eastern OR, and even back over the Cascade to Baldi (On APRS.FI, you can search by date per call sign, and tehn each point will show how it was relayed, pretty cool)
📷
Elk Summit Lookout area near Elk City, ID, was transmitting through the whole area but only picked up at the top📷
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Aaron Kravik Wrote:
Texting through APRSdroid is as easy as using any other messaging app with the exception of there not being an address book. You have to type in the number each time. But I’ve set up a set of aliases and SSIDs for people I would most likely ever text so that makes it pretty easy.
Are you beaconing at full power in those regions you’ve had limited success?
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John Russell Wrote:
That assumes you have the APRSdroid device connected to the radio, that’s where I haven’t progressed. I do have alias stored in the radio, but using the number keys on the mic is a pain
Yes, full power. If you look at the APRS.FI map you can see there isn’t much, if any traffic in some of those areas. Maybe aircraft that can hit repeaters pretty easily, but that’s about it. Look around Tonopah, there’s some weather stations and a couple of repeaters but no APRS traffic, and no gateways
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Ole Hellevik Wrote:
John, how do you like the D710? I’m still new to ham, I have progressed from stage one (Baofeng in the vehicle) to stage two (Baofeng with external antenna). I’m looking for a dual band mobile with remote head, which looks to be in the $300+ range and I’m thinking I might as well add another couple of Benjamins to get the integrated APRS.
In your opinion, is it worth getting a TM-D710GA instead of a TM-V71A?
From what I’ve read, the D710 TNC doesn’t support sending text from APRSDroid, only receive. Not sure if it’s a big deal for the 60 or so characters you can send in a message over APRS.
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Aaron Kravik Wrote:
That’s easy enough to bypass. The TNCs that are in most radios aren’t all that impressive. My Yaesu has one but I’m not even using it for this setup.
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Aaron Kravik Wrote:
Since the proof of concept was a limited success, I’ve set about making a more robust version. I’m using a j box for all the connections this time instead of hard wiring them so I can easily tinker with it in the future. Discovery 1 is that the TRRS connectors I bought are absolutely hideous to work with. Even with 22awg wire in my cable it’s too crowded in there. Can’t get it to not short out. Said screw it and ordered a TRRS pigtail today. Part was $2 and shipping was 7…so I bought 3 to make it worth my while haha.
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John Russell Wrote:
The D710G is a great radio, more than I will ever utilize (or probably understand). Having the TNC and GPS built in is great but your probably paying a premium over what you could do with separate devices as you need them. The simplicity was worth it to me, still need to figure out an elegant way to get a serial connection out into APRSdroid so I can use the phone as an interface/chart plotter.
Would like to see a group with this capability and being able to track others locations on trails, etc. Jump off to a different frequency so you don’t get any other transmitter adding clutter.
I mounted the head unit in the overhead, would need to route more cables up and down to get a serial connection to it or see if I could cram a bluetooth/serial adapter up there too. Great, I have enough unfinished projects…
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John Russell Wrote:
PS – I have a Bionics GPS5 (if I can find it) and GPS to 2.5mm plug for Kenwood or Yeasu to inject GPS data if anyone is interested or in need…
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Aaron Kravik Wrote:
Pigtail came Thursday. Wired it up and did some testing.
Was able to get my head unit running APRSDroid connected to my TM-D710GA today!
Could not get it work with the radio in APRS mode, but works like a champ with the radio as a simple TNC as described on https://github.com/ge0rg/aprsdroid/wiki/Kenwood-D7x0. Connected a serial cable between the back of the control unit of the radio and one of the USB ports on the Android head unit.
Now I can see where the other stations are, and I can send and receive messages from the head unit! I even plugged an old PC keyboard into the head unit - makes it easier to type out messages.
Looks like there is a Mobilinkd v 3.0 in the works (that means the 2.2 will go on sale...)
https://store.mobilinkd.com/products/mobilinkd-tnc3
If you know anything about me, you know that I can't leave well enough alone. I've been happy with my setup except that it seems dumb that I'm tying up my FT-991 with an autonomous function and using my cheap TYT for comms.
When I bought my TYT, i noticed that it had a cutout fora d-sub 9 connector in the back. I wondered if there was something behind it .well turns out there is.
I ordered up some parts and got going.
Works great and now I get my nice radio back for other uses.
Also heard this comment from the APRS Facebook group
'If the software being used doesn't support bulletins (messages with no acks), it's the same as sending a message. Just send it to "BLN#". The # being a number 1-9. This would send the message out to everyone who can receive it, alerting them they have a bulletin message.'
'You may also consider setting your beacon comment to say emergency or something that implies there is an emergency.'
I think it would be useful to test this functionality out in real-time with a few APRS stations. Obviously not beaconing a real 'emergency', of course.
I found this ..
BULLETINS: To send a bulletin to all stations, simply SEND a message to BLN# where # is a line number from 1 to 9. Like any other message, these BULLETIN lines will be transmitted on the decaying time period and will soon fade out of the system. If you want the bulletin to remain at about a 15 minute rate, then instead of using numerals in the BLN# mesage, use a LETTER. This way, new stations joining the net will quickly pick up the BULLETINS. Since lines are sorted onto the receiver's BULLETIN page, a new BLNx line will overwrite any previous BLNx at all stations making changes and corrections easy. If your bulletin is time sensitive, be sure to include the TIME in the text, since BULLETINS are not time- stamped. When your BULLETIN is no longer needed, simply ERASE your outgoing BLN#. This will stop your transmission of the BULLETIN lines. Receiving stations can erase all old bulletins by using the ALT-E command.
http://www.aprs.net/vm/DOS/OPS.HTM
Any weekend evening would be great - I really want to get this process figured out. Maybe Sat Dec 1 ?
I propose a APRS interest group meet up at Camp Bar (or somewhere) and we can test these ideas. The use of APRS in an emergency needs to be clarified.
Can you send a message to email over APRS? Maybe NWOL can set up an email address that auto posts to the emergency forum, or forwards messages to an ‘Emergency Committee’ that can then post to the forum..
From my interneting, it looks like there are few radios out there that can really take advantage of the "emergency beaconing" feature. I guess as a passive method, you could change your comment field to something like "Emergency - Brief Description - Simplex or repeater freq you're monitoring"
Yeah - that makes sense to have each other's phone numbers for SMS (I don't always have APRS on, but my phone is always with me), but I was thinking about a general CQ announcement to all local APRS stations that help is needed. Thoughts ?
We should review the use of APRS for emergency comms - what would be the most effective way to send out a call for help over APRS ?
'CQ' in the message line ?
SMSGTE is great. You can also use EMAIL and send an email. One that I recently discovered is WXBOT will send you weather information since APRSdroid can't decode weather station data.
From an EMCOMM perspective, it's an extremely powerful tool. Being an ad-hoc network, a group could even operate their own local network on a different frequency if they wanted to. Which could be a good feature for SAR etc.
When hiking I set the TM-D710 as a digirepeater and then carry my HT (TH-D74) with me. That way I know I can get a packet out when I am in the middle of no where.
Aaron, you’ve inspired me!
I went out out and got an android tablet, the audio connection cable, and a mount for it. I should be able to start playing with it next week and seeing if I can get it working.
For now I plan to use my handheld Kenwood TH-F6A as my APRS transceiver. Depending on how that goes I’ll do some more research into using my Icom ID-5100 and ditching the handheld. I’m not sure it will be easy with the Icom since it is more setup for DSTAR.
I use SMSGTE for the same thing. It even includes a function #mapme which send a link to APRS.FI with my current location. Last weekend while hiking in the Olympic National Forest at the Sleepy Hollow trail head, I found a dead iPhone. Charged it, found the Emergency contact info. Used a service. recently discovered, WA1GOV to send a tweet to my HAM neighbor N7CPM via APRS to meet me on the PSE Repeater - had him make the contact - bottom line, iPhone returned to owner the next day. This was done with my TM-D710, which I love.
Its awesome - you can argue with your wife when you're out in the woods !
Hey guys - I wanted to post this link on using SMS and APRS. I've been using this amazing system to SMS my wife when I'm out in the woods. I text her over APRS to her cell phone, and she returns text on her cell phone to my APRS station in my truck (KI7RYA-9).
It works very well both East and West of the Cascades, as we are fortunate to have a string of I-Gates running up the middle of Washington and scattered about elsewhere.
Set it up and enjoy !
http://smsgte.wixsite.com/smsgte
Next iteration:
Got JR's Mobilinkd TNC and the Baofeng cable. Played around with it for a bit with pretty good success while waiting for a DIN cable to show up to connect to my FT-991.
DIN cable arrived yesterday! It is incredibly easier using this than the cable interface I'd made. The audio levels for the TNC are a different setting than the speaker audio on my radio meaning I can set up the TNC and then those settings won't change while using my radio for other functions. I'm a big fan so far.
Here are all the stations I picked up on my drive to work today:
Yeah, tying in with BN is great, it would be neat to be able to see others in the group moving and placement on the map. The D710 will show distance but a map would be much better.
I had been playing around with the Mobilinkd TNC on a Baefong but never had any luck with it. It's sensitive to volume and squelch and haven't found the sweet spot yet. If you wanna play with it for awhile, happy to see what you can do with it.
Finally got a chance to really try this setup in the field for the first time on last weekend's Winthrop trip. As Kristal wasn't going to be with me, I wanted her to be able to follow where I was and be able to swap messages. It worked incredibly well. I was unsure how well it would work since the amount of digipeaters and iGates in the region is small.
Here's the track I ended up with:
It looks like most of my beacons were received...cool!
Here's the APRSdroid UI on my tablet:
And the really handy feature of Backcountry Navigator integration so I can see APRS stations on an offline map in real time!
I was able to send Kristal messages from camp Saturday night but she wasn't able to send them back. Looking at the local digipeaters, they're all lower power in the 16ish watt range. I'm guessing my 50w mobile could get to them but they couldn't get back. In any case, it worked in the direction it needed too. Should an emergency have arisen, a team would have had an excellent lead on our location with which to begin a search.
I think the next step will be simplifying the whole mess. Probably going to go with a Bluetooth TNC like the Mobilinkd.