Is mobile HF APRS feasible for an overlanding vehicle?

kb1ejh

Member
The tracking while moving from APRS is not always a sure thing. If you want a "we arrived here at camp" to be guaranteed then your best bet would be winlink via HF. If you send the position report it will get posted and you will get a confirmation email back that your position was posted. You can also add a short message to the position report on whatever you feel may be important for those following you; all is well, going to stay an extra day here, having minor mechanical issues. Sailors have used this feature for years on winlink when doing laps around the world. It works and once you have the gear, cheap.
 

KE7JFF

Adventurer
One person I know who has ran HF APRS in the past on 30 meters with his RV had a rule; if he was doing 55+ MPH on the highway, he would beacon every 30 minutes; if he was stationary, he would set it to beacon every 1.5 hours.
 
I've gotten a chance to play with both APRS and Winlink. I tried each on VHF and also on HF. I used the direwolf software TNC and winmor with my IC-7100s from a Win10 virtual machine running on my Mac laptop. These modes are not as good as robust-packet or pactor, but I didn't want to shell out money for dedicated hardware for this test. I tried each on my home station and in my Jeep using only the attached screwdriver antenna.

kb1ejh, I see what you mean by Winlink being a better "I've arrived in camp" solution.

I was able to get VHF APRS working from both the home antenna and in my Jeep. APRS does not seem to have a way to send a confirmation that the email was delivered. Also, when you send an email from APRS, there does not seem to be a good way for a non-ham to respond to that message. I can get a confirmation of location packets being received, by getting my own location back from the digipeter on VHF.

I was able to get Winlink working both at home and in the Jeep on VHF. I was able to send both position reports and emails though the node on Crystal Peak over San Jose. I was also able to get read receipts from the emails and receive responses from my non-ham family members. Winlink specifically states that 3rd party (non-ham) traffic on the Winlink system is allowed in the US, so responses are OK.

I was not able to send any APRS messages or position reports on HF. It looks like there is only one HF standard frequency for APRS and that band wasn't really open this weekend. I tried from both my home dipole and from the Jeep, neither were successful. If I didn't have internet access, there wouldn't be any way for me to know that it wasn't successful. I also left the laptop running overnight on the home antenna on the HF APRS frequency with the TNC enabled and it didn't receive a single packet all night.

I was not able to connect with HF Winlink from my Jeep. The RTTY contest this weekend filled the digital parts of 17m, 20m, and 40m. The Winlink upload frequencies were all full of RTTY signals. I don't have an antenna that will tune to 80m or below so I didn't try there. I wonder if people on boats are having trouble sending emails this weekend due to the contest activity...

I found one uplink frequency that appeared to be clear to a node in Baja, MX. I was able to send a HF email with Winlink from my home antenna to it, however the antenna on the Jeep appears to be insufficient to send that far away. I will try again after midnight tonight here on the west coast, after all but the most dedicated contesters have gone to bed.

All in all, I think it was a good test. It's pretty much a worst-case-scenereo for the HF spectrum right now. It's near the solar minimum, and the bands are full of other signals making it that much harder to get through.

So far, I believe that Winlink will probably work for me on HF if I get out the big inverted Vee that I carry along with to camp. The camp antenna is actually a better antenna then the one I have at home, since I can put out a full length OCF dipole at camp, and I need to use a coil-shortened center-fed one at home since my property is not long enough for a 80 foot long antenna. I have the same TX power available at camp and at home, the antennas are at about the same height, and at camp there would be less interference and buildings near the antenna. The only issue with the big inverted-Vee is that setting it up in a situation where I need to call-for-help due to an injury may be problematic. It takes me about an hour to get that antenna put together.

I am still hopeful that Winlink HF might work from my vehicle, but I'm not sure I want to commit to planing my remote trips around avoiding digital-mode contest weekends. I need to play with this a little more.
 
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Thank you for the feedback on your experiment. I will admit I have neglected thinking about Winlink. It looks very promising. I had neglected Winlink because I thought it took dedicated expensive modem. I might have been confusing it with Pactor. I am not interested in constantly sending my location so that it can always be seen publicly but Winlink does seem to be a good way to send email reports to a 3rd party. The "I have arrived, have departed, headed to, or having troubles" would be extent of my messages.

Would it be possible for a 3rd party to originate a message to me, such as "hurry home health or family emergency"?

Since this is actually email via RF I am going to ask this and I can just about guess the right answer. Email encryption? Since messages are sent in the open anyone can see the message and at times there maybe an instance where you do not want everyone to read it. Yes I do know encryption is illegal for us hams, so I would say that the answer would be NO.

I will dig more into Winlink as I think it has more value to us than APRS.
 

captadv

Spectator
Yes, anyone can email you at your callsign@winlink.org address.

No, as with all Ham radio communications, you may not encrypt or use codes to obscure meaning. Note may you conduct business transactions.

Hope that helps!

Sent from my Nexus 6P using Tapatalk
 

kb1ejh

Member
APRS and Winlink both have advantages and disadvantages. APRS is more of a live/tactical reporting system. On 2M it is great to see where others are and how far out you may be from them. It is also good for short messages back and forth if both of you have message capability. Most times you will get an "ACK" back that the other station got your message but not always so there is sometimes the uncertainty that they actually got your message. You can send and receive SMS messages via APRS if the local infrastructure is capable. Most of the time it is but there are areas where it is not fully twoway capable. So if all is working well you can SMS another person who may be at home keeping an eye on things with a cell phone who can keep tabs on you or send the help you may need. Winlink is good for sending position reports like we talked about before and for sending short or long emails. You can put your lat/long in the email so that home base knows where you are but it is not posted publicly if you want to run stealth. Home base can also send a small picture or directions to you to make that field repair so you can get going again if needed right to your winlink address. APRS is much faster at posting a position report if it goes through OK, Winlink will take longer as it sends/receives to make sure all of the message data is 100% correct. So if you want speed or accuracy you decide on which one you want. Winlink is not allowed to be encrypted on the ham bands as you well enough know but I have heard of friendly deal that has never been taken up that if you can intercept the message and read it they would be willing to pay. The way it is designed you would really have work hard to figure out what band and what frequency at what time the stations are on to try and intercept the message and even then it would have to be uncompressed. No, it's not fool proof but a lot of work to decode a "were at XXXXX camp having a great time exporing, will call you in a few days." type of message...
Last fall I took a trip to the Great State of Maine to see Downeast, the beginning of US route 1 and the Allagash trains. I was definitely out of cell range but was still able to post reports and email back home.
Hopefully attached is 2 pics of my tracks, one is just 7 points which was Winlink, blue were older and the red was the last posting. The other pic should be HF APRS running via a SCS tracker to a Yaesu 857 in to an old ATAS-100 antenna on 30M. Band conditions as you can see were off some days but the tracker was set to beacon every 4 minutes. I used the same radio and antenna tuned to whatever band was needed but usually stayed on 30M due to laziness to post the Winlink messages. For that I used Pactor via a SCS DR-7400. Is all of this better than a Delorme/Garmin Inreach? No, they all have their ups and downs, I just felt like fiddling with APRS and Winlink since I had the stuff.
KB1EJH
 

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kb1ejh:

Since you have one, did you find the Pactor modem to be significantly better then using Winmor? I'm considering if it's worth the extra space in my teardrop to haul around a modem.

I would be using it in conjunction with the IC-7100 and external tuner in the trailer.
 

kb1ejh

Member
I do like the SCS Dragons. They aren't cheap but I have spent more on things I haven't used as much so for me I don't mind. I got the bluetooth option in them. So if you have a tablet or droid you can run aprs programs on the devices via BT to the Dragon. You can also run Winlink via the BT connection. The nice part of the Pactor stations is that there are more choices for connections. It is also a bit faster than Winmor. You can't use P4 here in the US but if you travel out of the US and can operate in that other country you can use the faster P4 connections. There is less fiddling with SCS Dragons too. They are more of a plug and play type unit rather than adjusting the sound card settings for Winmor. Winmor works, I just like the simplicity of the Dragons but they come with a price tag. So to summarize, yes, I do find the modem to be significantly better and to me worth the investment.
 
It appears I have a tons of reading and studying to do. Back when Winlink and Pactor became available there was a huge uproar about unattended stations transmitting and causing interference on the bands. I shied away from the arguments and gave no consideration to making use of the new modes. It seems now I should have paid attention. The HF radio I intend to use has a built in USB sound card and am hoping that I don't have to spend extra money for interfaces and keep the radio package small and uncomplicated. Until I can get the wife licensed I need to keep it simple in case anything happens to me while we are out. Having a great radio package with all the bells and whistles will not do us any good if the wife can't figure out how to call for help.
 
I've tried a few iPhone apps. They all have an issue that you have to figure out how to interface the phone to your radio.

I don't have enough space in my rig for a radio or antenna dedicated to aprs, so I'd need to unplug my mic and change a bunch of settings to get a phone plugged in. I've decided that it just isn't worth it for me.

I did wind up setting up winlink though. That works remarkably well.
 

adriatikfan

Observer
I've tried a few iPhone apps. They all have an issue that you have to figure out how to interface the phone to your radio.

I don't have enough space in my rig for a radio or antenna dedicated to aprs, so I'd need to unplug my mic and change a bunch of settings to get a phone plugged in. I've decided that it just isn't worth it for me.

I did wind up setting up winlink though. That works remarkably well.

Thanks for replying.

I am at the very begoinning of looking to possibly use APRS, so need to research as much as possible.

Best Wishes,
David
 
Question about Winlink

Winlink Paths.JPG

Reference this path diagram.

IF I am KD7WKO and there is NO P2P link between me and WA4BDS and I am in some country and they decide to pull the plug on the internet so no connections exist between CMS stations. Is it possible to send a message to WA4BDS via the RMS stations? Are all RMS stations linked via RF in a mesh type network?

For example KD7WKO-->VA3LKI-->NoIA-->WA4BDS
 

kb1ejh

Member
Yes and no. Not all RMS are linked via RF. The ones that are part of the hybrid network are. You would pick up to 3 stations that are in the hybrid network and they would be the one(s) that would hold your messages for pickup when you connect to them. That's a short answer on it, more can be found on the winlink page. P2P is a different beast, you would connect directly to the other station and send/pickup mail from them. The messages are not held at a RMS but in the direct sending or receiving station.
 

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