2m FM APRS w/Android (or Windows laptop), HT, and APRS-K2 cable

Discussion in 'General Technical Questions and Answers' started by N4VDI, Feb 15, 2021.

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  1. N4VDI

    N4VDI Ham Member QRZ Page

    A few days ago, I won a 2m/70cm HT (Wouxun KG-UV8H). It's my first HT, and I haven't used a 2m radio for anything for... well... about 25 years... and even back then, the only thing I ever used 2m for was packet.

    Unsurprisingly, the first thing I did was order a BTECH APRS-K2 cable, so I could use my Android phone (LG V20) or laptop (running Windows 10) as a software-implemented TNC after listening to 144.390 and confirming that I could, in fact, hear occasional packet activity there.

    Well... the cable came today, and I installed & fired up APRSDroid... then discovered that all the app seems to want to do is transmit location updates to its server.

    Is there any way to have the app basically just sit quietly without transmitting, listen to the audio being fed to the phone from the radio, decode it when the occasional burst is received, and dump it to the screen? You know, the way an old TNC (like the Kantronics KPC-2) did when you turned it on, connected to its serial port using a terminal program, and left it running while connected to the radio's mic and headphone signals without sending any commands to it? Or to use it for things besides just posting location updates to a server?

    While I'd prefer to be able to use digital modes (like packet) with my phone (my primary envisioned use case is, "in Titusville to watch a rocket launch, the local cellular network within a quarter mile of the Max Brewer Bridge has melted down & collapsed like it always does, and I'm feeling painfully disconnected & desperately need to connect to something digitally using my phone and radio), even getting it to work with my laptop would be a good start.

    Just as importantly... does packet like I remember even still exist anymore? Or are the days of being able to CQ and chat with someone 5 hops and 300 miles away on 2m using packet via digipeating now effectively a thing of the past? Do clubs still run digipeaters capable of connecting to others across the internet, so someone in Miami could effectively be "3 hops from New York/London/wherever" (connecting via packet to a nearby digipeater, tunneling over the internet to another internet-connected digipeater, then chatting with someone there as if you were a local across town)?

    I've spent a few hours monitoring 144.900-145.300, but so far I haven't heard packet-like sounds anywhere besides 144.390. I don't remember the site I looked at, but I saw one that purported to map recent packet activity, and it didn't give me a lot of hope... it looks like digipeaters as I remember them have basically ceased to exist in the the Miami/Fort Lauderdale area... though there's apparently still activity further north in Palm Beach County (but probably too far to do me any good, at least when I'm at home).
     
  2. KD4UPL

    KD4UPL Ham Member QRZ Page

    I run APRS droid on my phone connected by bluetooth to a MobilinkdTNC. The TNC connects to my HT or mobile radio, depending on what I'm doing. For some reason the software won't just "monitor". You have to have it set to send out a beacon too. I don't see why that's a problem but it is kind of odd. I have used the phone with APRS droid over just the phone's data connection thru the cell phone network. This works but certainly isn't "amateur radio". Same problem however, you do have to be beaconing for it to receive.
    I've got two Yaesu radios (FTM-400XDR and FT1-XD) that have APRS built in. I think you can turn off the transmit function and just monitor the frequency for APRS packets but I don't think I've ever tried that.
    Around here most 2m digital activity that isn't APRS seems to have moved to Winlink. I know a lot of the local hams are sending emails and messages around on the Winlink network.
    By the way, you can send messages thru APRS too. (and emails) I use this function to contact my wife often when I am working in isolated areas with no cell phone coverage. You can even use APRS to send an SMS text message directly to a cell phone.
     
  3. N4VDI

    N4VDI Ham Member QRZ Page

    Yeah, I discovered by accident yesterday that you have to be actively tracking for APRSDroid to decode anything.

    I finally managed to get at least one station to hear me, but it looks like I have to be within 2-3 miles to be heard, and less than a mile away for them to be able to break through the radio's stupid feast-or-famine squelch AND successfully decode. This is problematic, because VOX won't trigger unless squelch is on. I've gotten the impression that radios like this have hidden settings that can be tweaked, and specifically that many/most Wouxun and Baofeng radios actually have 64 squelch levels (not just the 10 exposed by the menu), but I don't have access to a programming cable, and from what I've read, even "real squelch level = 1" (vs "menu squelch level = 1") is too aggressive for APRS & packet to really work properly.

    My all-time record so far was successfully receiving and decoding K4ABB-1 from approximately 8.6 miles west-southwest of him... but as far as I can tell, his radio didn't hear me, and I obviously had squelch off at the time.

    aprs.fi's listing of "stations which heard {callsign}" and "stations heard directly by {callsign}" is completely wonky, almost to the point of total uselessness. When you query MY callsign, it doesn't list ANYONE who's heard me, yet obviously SOMEONE heard me and reported my location to them. It shows "N4VDI-7>APDR16 via WF2C-1,WIDE1*,WIDE2-2,qAR,K4ABB-1" for "last path", but I don't show up in K4ABB-1's list of "stations heard", and literally nobody shows up in WF2C-1's list.

    From what I can tell, aprs.fi's wacky logic is that {station1} heard me over the air, digipeated it to {station2}, and {station2} posted the update to the internet, but since {station1} != {station2}, they don't bother to note either one, so I'm left not even really knowing who actually heard me.

    Plus, I'm pretty confident that k4abb-1 did, in fact, directly hear me when I was parked 100 feet away yesterday. When I queried aprs.fi yesterday, it was drawing lines directly from me to k4abb-1 (the lines from yesterday's drive between my call and WF2C-1 instead of K4ABB-1 just started to appear today). But my callsign has never appeared in the list of stations heard by K4ABB-1, and WF2C-1 doesn't show anyone as having been directly received by him (presumably, because it doesn't report directly).

    I checked out Winlink, but it appears that the only Winlink node within a hundred miles of South Florida is HF-only.

    Palm Beach Packet Group has a website, but it's almost devoid of information, and their South Florida packet map is a broken link. I'm seriously tempted to drive an hour north and make a 2m DXpedition to Loxahatchee with my laptop and Direwolf to see whether I can actually connect to K4PKT-1 and use it like an oldschool packet node, but before I spend $20 on gas & tolls, I'd like to try and get packet working a little bit more reliably. It's just a hunch, but I suspect that if I can't even send a location update while parked across the street from someone, then hear & decode THEIR digipeating attempt a moment later, driving up there would be a waste of time.
     
    Last edited: Feb 19, 2021

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