Stories
Slash Boxes
Comments

SoylentNews is people

SoylentNews is powered by your submissions, so send in your scoop. Only 18 submissions in the queue.
posted by NCommander on Monday September 25 2017, @04:00PM   Printer-friendly
from the KD2JRT-calling-CQ-on-146-point-52 dept.

As I've said in passing before here on SoylentNews, I'm a ham radio operator, (KD2JRT - Tech). Due to a lack of time and money, I've only been able to afford relatively cheap equipment, primarily two BaoFeng UV-82s, and an external antenna mount for the car. Many of the older ham radio ops decry the Baofengs as cheaply made Chinese junk, but I wanted to see what these radios are actually capable of. Historically, I've had decent success with an external antenna and decent positioning, but I recently conducted an impromptu experiment testing the propagation characteristics with these radios and seeing how well they actually work, and perhaps creating a baseline for more in-depth radio testing in the future.

Over the weekend, I took a day trip to the southern tip of New Jersey, out to Cape May from New York City, and along the way, using a hookup from the radio to my phone, I connected my radio to the national APRS (Automatic Packet Reporting System) network, and used it to measure distance and propagation effects. Since most of the readership of SoylentNews aren't radio techs, past the fold, I'll talk a bit about Baofeng radios, APRS, digital modes, and my results.

Automatic Packet Reporting System

APRS is one of the more interesting possibilities one can do with a ham radio system. At its most basic core, APRS is a store-and-forward mesh network that is traditionally used on the 2M VHF band, and interconnected by a series of digipeaters that can use the internet to tie the entire system together. Due to its architecture, an APRS mesh exists in any location where two radios are broadcasting on the same frequency in the same general area, and APRS itself has a long history of being using in disaster recovery efforts as a low bandwidth/high efficiency reporting system. APRS information is encoded in an AX.25 UI packet (AX.25 is a level-2 protocol used in ham radio).

KD2JRT-7>APDR13,WIDE1-1:=4041.55N/07359.99W$178/039/A=-00045 Out for a drive. Msg for QSO

Broken down, this becomes:

  • Callsign: KD2JRT
  • SSID: 7 (Handheld Radio)
  • Client: APDR13 (APRSdroid)
  • Relay Path: WIDE1-1 (I want to be relayed one hop)
  • Packet Type: = (Positioning data without timestamp)
  • GPS Location: 4041.55N/07359.99W (40 degrees north by 73 degrees west)
  • Course and Speed: 178/039 - Travelling 178 degrees at 39 knots
  • Altitude: A=-00045 I'm 45 feet below sea level
  • Comment: Out for a drive. Msg for QSO

Quite a bit of information in a tiny packet to say the least. Obviously my phone's altitude sensor (which was the source of the GPS information) does have some issues since I'm fairly sure I didn't drive underwater at any point in New Jersey.

It's also possible to use APRS without positional information, and to transmit digital messages from terminal to terminal, which can be relayed over the internet allowing for world-wide sharing of information, as well as post digital bulletins. Gateways exist to allow APRS messages to be sent to email, SMS, and Twitter. Unlike typical repeater systems used for voice, APRS is a simplex protocol; all messages are sent and received on the same frequency and does not guarantee delivery of a given packet. Receipt of a packet is usually in the form of digipeating; that is, a client hears its own packet back as it passes through relays on the network. In the modern era, APRS packets are also forwarded onto the internet, and are recorded by services such as aprs.fi.

Due to its nature, APRS is a perfect way to test propagation effects of radio signals from various locations. As I'm driving, the phone's GPS automatically records my position, and it's broadcast over the air to digipeaters without any intervention from myself. Now that we're got the basics of APRS out of the way, let's talk about the radio.

BaoFeng UV-82 and Antenna

The UV-82 is a simple two band handheld radio, which out of the box is capable of transmitting FM signals on the 2m VHF band, and the 70cm UHF band at up to 5 watts of power. Despite the reputation, Baofeng radios have become popular with new ham radio operators for their cheapness. For this test, I was using the Baofeng with a Nagoya UT-72 antenna magnetically mounted to the roof of the car (which acted as a ground plane) as seen in this photo.

Antenna on RAV4 roof

The feed line for the antenna is run in through the tailgate, and then back to the front where the Baofeng sits in a cupholder. A data cable connects the phone (a Samsung Galaxy S6 Active) running APRSdroid. Out of the box, the Baofeng doesn't support any digital modes, so a fair question to be asked is how am I doing APRS with it. The answer is that I'm essentially treating the radio as a simple acoustic coupler. APRS/AX.25 packets on VHF are encoded in Bell 202 audio frequency-shift keying at 1200 bits per second. The radio is connected to the phone's mic/speaker jack, APRSdroid listens for the modem tones, and simply modulates its replies the same way. The radio is set to operate in VOX (essentially speakerphone) mode, and tuned to 144.390 simplex. In the future, I may buy a simple TNC that can automate this process for me.

VHF 2M Signal Propagation (or What To Expect)

Before going into any test, it's a decent idea to outline what to expect. The 2-meter band is what's known as a very high frequency band. As such, radio signals sent from the surface of the planet aren't (normally) reflected by the atmosphere, and continue out into space. As such, successfully two-way communication can only be achieved via line-of-sight communications with a maximum range of approximately 75 miles/120 kilometers under absolutely ideal circumstances assuming a relatively high receiving tower. In practice, the antenna design and power drastically influences the maximum range to a much lower number.

Without going in-depth into radio propagation theory and boring everyone half to death, there are two basic types of antennas: directional and omnidirectional. As the names suggest, a directional antenna focuses RF emissions in a specific direction, allowing you to get more bang for your buck, at the cost of focusing the beam and cutting out everything else. With a directional antenna, it's generally possible to transmit and receive upwards of 50-60 miles line of sight on 2Ms through obstructions, and there are reports of people using yagi directional antennas and handheld radios to successfully communicate with OSCAR satellites and the International Space Station in low earth orbit.

Omnidirectional antennas, like the Nagoya UT-72 instead emit signals in all directions, drastically lowing the signal strength as the power is dissipated out in all directions. Handheld radios (known as HTs) are inherently low power (also known as QRP) radios. In practice, the general rule of thumb is to expect 20-25 miles (30-40 km) at best. Within the heart of New York City, with all its obstructions and the same antenna, I usually can get a signal to propagate about seven miles from Manhattan to the W2VL repeater from the waterfront. This is compounded by the fact that the UT-72 is a compromise antenna, and uses electrical lengthening techniques to allow it to properly emanate a 2M radio signal. If I had a proper dipole antenna rig mounted to the car, I could expect far better results.

One final consideration for my mobile setup is the fact that APRS (and its base AX.25 protocol) is a digital mode. Transmission and reception is an all-or-nothing game. Unlike voice FM contacts which can usually be made out despite static (QRN ), a digital signal must be heard clearly to be successfully decoded. In other words, I'm essentially only going to be registered on the network if the signal is extremely clear. This is very much a torture test for the little Baofeng and its whip antenna.

The Raw Data

Before we go deeper into methodology, let's look at the raw data as seen on aprs.fi - track. aprs.fi only retains tracks for seven days so I'll summarize the most interesting data below.

Here's the route I drove, starting on Roosevelt Island in New York City, and ended in Cape May. Red dots represent location reports from my phone.

APRS map

Testing was only conducted North->South, due to forgetting to recharge the handheld's battery, and having it die on me upon reaching Cape May.

I was heard by the following stations.

Callsign Pkts First Heard - EDT Last Heard Longest (tx => rx) Longest At - EDT
N2MH-15 13 2017-09-24 02:45:02 2017-09-24 03:44:08 17.6 miles 283° 2017-09-24 02:45:02
WA2FPB-5 3 2017-09-24 04:24:24 2017-09-24 04:44:39 2.8 miles 151° 2017-09-24 04:24:24
W2AEE 6 2017-09-17 21:32:51 2017-09-24 02:47:45 6.5 miles 357° 2017-09-24 02:47:45
K2GE-13 2 2017-09-24 03:49:16 2017-09-24 03:56:12 5.4 miles 186° 2017-09-24 03:49:16
KC2QVT-15 1 2017-09-24 06:08:33 2017-09-24 06:08:33 35.2 miles 350° 2017-09-24 06:08:33
KB1EJH-15 1 2017-09-24 12:15:47 2017-09-24 12:15:47 23.1 miles 257° 2017-09-24 12:15:47
CLAYTN 1 2017-09-24 05:46:08 2017-09-24 05:46:08 34.8 miles 282° 2017-09-24 05:46:08
K2DLS-15 9 2017-09-24 03:46:39 2017-09-24 04:02:53 11.1 miles 158° 2017-09-24 03:46:39
WX2NJ-14 1 2017-09-24 05:08:57 2017-09-24 05:08:57 2.1 miles 104° 2017-09-24 05:08:57
BARNGT 8 2017-09-24 04:57:43 2017-09-24 05:46:40 20.8 miles 193° 2017-09-24 04:57:43
TOMRVR 6 2017-09-24 04:25:35 2017-09-24 05:10:58 16.4 miles 198° 2017-09-24 04:25:35
MATWAN 5 2017-09-24 03:04:19 2017-09-24 04:18:34 16.7 miles 210° 2017-09-24 03:04:19
K2RHK-10 1 2017-09-24 02:28:49 2017-09-24 02:28:49 1.9 miles 286° 2017-09-24 02:28:49

NOTE 1: W2AEE in Manhattan is showing more packets than it should as I can't filter by day on aprs.fi and I was testing the APRS setup last week. In total, approximately 50 packets were received by the APRS backbone.

NOTE 2: Despite being in a vehicle, the track shows a phone icon as I forgot to change the APRS reporting symbol

Due to complications with APRSdroid, I don't have an accurate count of how many packets were sent by the handset, but I suspect its approximately 50-100 for reasons that become clear below. Furthermore, I don't have an accurate count of which stations I heard due to stupidity. Now that we've got the raw data out of the way, let's draw some conclusions, and figure out how to refine the testing methodology.

Conclusions

All and all, for my first serious field test with the APRS system, this is a fairly healthy result. As I set out simply to play with APRS, and not actually do an experiment when I went out on Sunday, I didn't have in-depth methodology and logging set up. I also learned a few things about how APRSdroid (or more specifically, the SmartBeaconing system) works which drastically reduced the amount of traffic I sent which degraded the results even more. Despite that, I can draw some initial conclusions from this data, and perhaps do further radio propagation tests in the future if the SoylentNews community finds these types of articles interesting.

As expected, within urban areas, my signal propagation was total garbage, only being heard 1-2 miles under best case scenarios by the APRS gateways in Manhattan. Once I got south of the island and running along the waterfront, and on the Queens-Brooklyn Expressway did the signal start being received by the N2HM digipeater in New Jersey ~10-15 miles distant. Signal propagation continued to increase as I crossed the Verrazano Narrows into Staten Island, and then onward into New Jersey. As I stated before, APRS is a digital mode, and being understood is an all-or-nothing thing; if I were using FM voice, it's likely the effective Rx distance would have been further. Supporting that data, in the relatively flat areas of Jersey Coast, I was routinely being heard upwards of 15-20 miles out by the track due to lack of line-of-sight obstructions, and at two points, I was heard over 35 miles (56 km) away by two separate digipeaters!

Unfortunately, due to a lack of IGates south of Atlantic City, I wasn't heard again until I reached Cape May, and picked up by a digipeater on the other side of Delaware Bay

One thing that partially compromises the testing results however is the APRS SmartBeaconing system. As I put in the overview, APRS includes direction and speed information as part of its transmissions. As an optimization of the system, APRS clients can use SmartBeaconing to reduce the amount of traffic they're reporting. In effect, SmartBeaconing uses dead-reckoning to determine if it needs to send a packet. If I send a position report at a location travelling south at 60 MPH, and two minutes later, I'm two miles south of the previous report, SmartBeaconing will not send a new position since I am where I can realistically expected to be. Since I had cruise control enabled, and the Garden State Parkway runs roughly in a straight line North-South past Sandy Hook, SmartBeaconing drastically reduced the amount of data I was sending. Annoying, APRSdroid still shows phantom reports it didn't send on the log of my station history; and several times, I'd see a report show up in the outbound log, but no red light on the radio saying it was sending.

For receiving characteristics, I checked the phone at each rest area I stopped at, and I was seeing a healthy list of stations show up in the tracker. However, because of the store-and-forward nature of APRS, it's difficult to tell at a glance what stations I was hearing directly, and which were being echoed by a digipeater. It's possible to determine this information by decoding the received APRS packet as repeating stations amend their call sign to the WIDE1-1 line as the packet moves through the network. I also found that I frequently didn't hear myself on the network. I believe this is due to the fact the Baofeng has a relatively slow switch from transmit to receive mode. As such, the radio was cutting itself off and not hearing its own packets come back.

For future experiments, I need to modify APRSdroid to operate as a beacon station and regularly send positional reports on a given interval, as well as log all transmitted and sent APRS packets to files so I can post-process them into a report. I also need to write a method of gaining data from the APRS-IS backbone; many APRS stations are receive only and as such I won't see my own packets if I'm heard by such a station, and possibly use the APRS messaging functionality to confirm two way operation from the network at regular intervals.

Despite the difficulties in testing, I'm pleasantly surprised by the performance of the UV-82, at least when it's using an external antenna. For the most part, I was getting results consistent with QRP operations, and was being heard at distances that my non-expert mind believe are consistent with HT/2M operation. When time permits, I'd be interested in repeating this test in the future, as well testing other types of radio. If any other SoylentNews readers are ham radio operators, and have equipment they'd like to see tested, feel free to get in contact with me via email or IRC. If people find this article interesting, I may run additional ones on radio operations. I'm hoping before the year is out to get everything together to be able to do satellite operations, and make two-way contact with the International Space Station, or one of the two OSCAR satellites currently in operation. If I can get my hands on the equipment, I may even be tempted to try for Earth-Moon-Earth communications.

I'll also be upgrading my license class to General in the next few weeks and pending money, I can also try propagation experiments in HF bands.

Until next time, 73 de KD2JRT

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
(1)
  • (Score: 2) by c0lo on Monday September 25 2017, @04:21PM (1 child)

    by c0lo (156) on Monday September 25 2017, @04:21PM (#572705) Journal

    with a Nagoya UT-72 antenna magentically mounted to the roof of the car

    Really, I looked for magenta on the photo as hard as I could, there's nothing to be seen.
    Before I start coding something to look for magenta pixels, are you sure it's not a typo? ;)

    --
    https://www.youtube.com/watch?v=aoFiw2jMy-0
  • (Score: 2, Interesting) by Anonymous Coward on Monday September 25 2017, @05:32PM (8 children)

    by Anonymous Coward on Monday September 25 2017, @05:32PM (#572722)

    Driving around in a '63 Econoline van in rural Wisconsin collecting 2m field strength readings from the repeaters from
    Milwaukee down to Lake Geneva off of my Motorola PD33 Handie Talkie.

    Now, get off my lawn!

    • (Score: 2, Funny) by Anonymous Coward on Monday September 25 2017, @06:27PM (2 children)

      by Anonymous Coward on Monday September 25 2017, @06:27PM (#572740)

      LOL... 1970s driving an Econoline 100 with a modified Gemtronics 40ch SSB CB that had 20 extra channels above and below, a 100 Watt dual tube linear amp, freq counter, a modified turner power mic, coax matched as close to 1:1 as possible, and stainless whip because the base load ones melt. Lots of Q-cards.

      • (Score: 2) by NCommander on Monday September 25 2017, @06:39PM (1 child)

        by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Monday September 25 2017, @06:39PM (#572743) Homepage Journal

        CB radio has an interesting (and checkered) history. In the 1970s, technically speaking, CB radio operators had to be licensed by the FCC and assigned a callsign, and power was (and still is) greatly restricted. Due to a fairly large disregard of the rules, you got more or less anarchy on CB, with people running far more power than the limits allowed. Because CB operates in the 11 meter band (directly above the ham radio 10m band), it's a HF frequency and signals can be reflected by the atmosphere, allowing for hundreds of miles of operation.

        Quite a few older hams got into amateur radio by being a child of the CB era and getting a Novice license, or learning Morse, and getting a tech license. As things stand now though, there's no Morse requirement to get licensed, just the exam.

        --
        Still always moving
        • (Score: 3, Informative) by fyngyrz on Tuesday September 26 2017, @09:23AM

          by fyngyrz (6567) on Tuesday September 26 2017, @09:23AM (#573001) Journal

          Because CB operates in the 11 meter band (directly above the ham radio 10m band), it's a HF frequency and signals can be reflected by the atmosphere, allowing for hundreds thousands of miles of operation.

          FTFY

    • (Score: 1) by a262 on Tuesday September 26 2017, @02:28AM (4 children)

      by a262 (6671) on Tuesday September 26 2017, @02:28AM (#572902)

      Hanging a 2M J-Pole in the juniper tree outside my basement window while my dad was out at work so I could hit the local 'net from the bottom of the river canyon we lived in. It lasted about two months until the father made me tear it down. Apparently he though there was a small chance of water ingress from the coax. Mind you, I left the coax outside of a sealed window. When I wanted to operate, I opened the window and connected the coax to a handheld a neighbor lent me. Water ingress, my ass. The old man would find any excuse to break my dreams.

      Speaking of broken dreams, I gotta get my amateur license again. It's been a few years since it has expired. I still have the old Yaesu-Vertex VX-6 that I saved allowance for a couple years to afford. It's great to be a successful adult - I could buy a VX-6 once a month and hardly see the dent in my budget. If you're reading this, father, you gave me nothing. Fuck you. I'm a self-made man.

      • (Score: 0) by Anonymous Coward on Tuesday September 26 2017, @03:37AM

        by Anonymous Coward on Tuesday September 26 2017, @03:37AM (#572923)

        > The old man would find any excuse to break my dreams.

        That really does sound bad, my condolences.

        Just the opposite here, I fooled with a crystal radio kit before age 10 and then the house had an extra room put on. I was able to spec a dedicated earth/ground wire, which was routed inside the wall before the drywall went up. Outside antenna wires that ran through the window (or even a sealed hole through the wall) were encouraged.

      • (Score: 2) by NCommander on Tuesday September 26 2017, @12:28PM (2 children)

        by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Tuesday September 26 2017, @12:28PM (#573064) Homepage Journal

        If your license was still in good standing when it expired, you simply need to take the Element 2 test (Technician) to regain all your original privileges. Due to the great reshuffling of license classes, you may end up with higher privs, or lesser ones. The FCC database has all the historical licenses, search for your call sign, and see if you can find it; you might have to jump through some hoops to get a FRN attached to it, then you can reactivate it if the call hasn't been recycled.

        --
        Still always moving
        • (Score: 1) by a262 on Wednesday September 27 2017, @03:48AM (1 child)

          by a262 (6671) on Wednesday September 27 2017, @03:48AM (#573653)

          Good to know! Thanks!

          • (Score: 2) by NCommander on Wednesday September 27 2017, @03:04PM

            by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Wednesday September 27 2017, @03:04PM (#573827) Homepage Journal

            Just as a follow up: http://wireless2.fcc.gov/UlsApp/LicArchive/searchArchive.jsp [fcc.gov] is what you need

            If you were a Novice, Tech, or Tech Plus, then Element 2 exam will get you what you had before as these license classes were folded together and then some. Tech Plus is now what the current Tech is. If you were General, Advanced, or Extra, bring an official copy (not a reference copy) of the license to a VEC exam and pass the Element 2 (tech) exam, and you'll be re-instated with those privileges as long as your license was in good standing at the time of expiration. As a note: if you were Extra, you might have gotten kicked down to Advanced depending when you were licensed and may have to repass Element 4 to regain all privileges.

            The morse code (Element 1) requirement is dead and buried so you don't need to worry about it.

            --
            Still always moving
  • (Score: 2, Interesting) by liberza on Monday September 25 2017, @06:44PM (3 children)

    by liberza (6137) on Monday September 25 2017, @06:44PM (#572744)

    For what they are, they work. Having cheap HTs available lowers the barrier to entry a bit, and it probably helped me get into it a while back. Now that I have my extra though maybe I should upgrade from my Baofengs....

    • (Score: 2) by richtopia on Tuesday September 26 2017, @12:27AM (1 child)

      by richtopia (3160) Subscriber Badge on Tuesday September 26 2017, @12:27AM (#572859) Homepage Journal

      Do you recommend the UV-82 NCommander used? I just received my technician license in order to fly FPV drones, but figure I should buy a cheap radio now that I'm a member of the club. Unfortunately on the low end it is hard to find unbiased reviews.

      • (Score: 3, Funny) by NCommander on Tuesday September 26 2017, @12:16PM

        by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Tuesday September 26 2017, @12:16PM (#573056) Homepage Journal

        The Baofengs work more or less on par with most HTs on transmit (though you might want a UV-82HP which gets you a bit more oophm). The problem is they don't have the greatest Rx frontend and can overload from interference. This is a problem for me since I can't use my Baofeng radios in the same room as a wifi router. They're also an utter pain in the arse to program from the keypad; you'll want a programming cable if you go this route. One final issue is a bunch of them have issues with DTMF dial tones, they can't properly encode a B signal which can be annoying when dealing with IRLP repeaters.

        The stock rubber ducky antenna isn't great. While it works, you'll likely want to replace it ASAP.

        You need to figure out what you want to do with your license, and honestly, this is the biggest suggestion that I can recommend to a new ham. While it's very much area dependent, VHF/UHF repeaters can be remarkably empty. If your repeaters support IRLP, you can use them to dial into various reflectors or nets if you want. If you want to do APRS operations or perhaps play with packet radio, you can use a Baofeng like I have, a phone or TNC modules + a RPi for a more permanent base station. I'm likely going to unretire my old Galaxy Nexus and turn it into a dedicated APRS beacon for the car. If your goal is to do satellite operations like mine is, then you'll want a UHF/VHF rig that can do FM and SSB. A couple of birds are FM capable; ATM, ISS, and OSCAR-51 are operational, and OSCAR-80 should be coming online soon once it finishes it's primary meeting. Most of the others want SSB, and a few like to use 10m which generally precludes handhelds. OSCAR-7 which is the miracle bird (launched '74, died '81. Resurrected itself in '01 when the batteries degraded and shorted open, allowing the satelite to run on solar power) is a SSB bird (plus Mode A uses a 10M downlink).

        For EME, you're in one of the few cases where MOAR POWER is very much the answer as sending a radio signal to the moon is not what I call a trivial undertaking.

        --
        Still always moving
    • (Score: 2) by rufty on Tuesday September 26 2017, @06:50PM

      by rufty (381) on Tuesday September 26 2017, @06:50PM (#573378)

      The Baofeng radios are about 30% worse feature- and performance-wise than the Kenwoods, Icoms and Yaesus. So you get 70% of the performance for 10% of the price. My advice? Get a Baofeng, get a decent antenna and it'll have a place in your kit as a knock-about HT for the repeater rag-chew.

  • (Score: 2, Informative) by nimbius on Monday September 25 2017, @07:56PM

    by nimbius (6088) on Monday September 25 2017, @07:56PM (#572771)

    All and all, for my first serious field test with the APRS system, this is a fairly healthy result.

    im not sure anyones decrying the average quality of signal for a working baofeng, however in my experience the "out of the box" functionality is wildly unpredictable.

    i bought one that died in 3 days, another with a dead LED light, and a third that couldnt hit a VHF repeater in line of sight on Catalina Islands only airport. Programming a baofeng is also nothing short of retaking my college assembly class.
    What hams are critical of I feel is the use of such a device that may one day be called upon to service a disaster scenario or life threatening situation.

  • (Score: 3, Informative) by dbe on Monday September 25 2017, @08:25PM (3 children)

    by dbe (1422) on Monday September 25 2017, @08:25PM (#572779)

    This is what this site should be about!
    I picked up a license to participate in emergency prep situation in the SF bay area but never really explored the digital communication, rag-chew does not really attract me as listing to other people talking about their dog is not my cup of tea so i'm not really active on the waves. That said using transponder change your radio into a modem is pretty cool. I picked up an old FT-60 I should try APRS using a cellphone and cable :)
    A few questions:
    - how do you handle the PPT button? (push to talk for the non-ham, like talky walky)
    - can you config APRSdroid to tag your message with a counter ID? to get a better idea of the lost packets
    - can you change the smart-beacon config to only take the distance in account, so that you would get a packet sent every X miles even if the direction stay the same?

    Keep them coming!
    Cheers
    -dbe

    • (Score: 2) by NCommander on Monday September 25 2017, @10:29PM (2 children)

      by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Monday September 25 2017, @10:29PM (#572819) Homepage Journal

      I have the handheld in VOX mode so if there's activity on the port, it will automatically key up. The Baofengs however have good 500-700ms delay you need to account for from when it keys up to when its actually usable. A few people have homebrewed cables which do the necessary shorting to force the radio to key up on it's own as though a hand-mic was attached.

      APRSDroid is open source so if I can't, well, I can fix it. I may end up homebrewing something specifically to do this with a RPi or something similar as working in Java and Android's limitations can get annoying. I believe I can change how SmartBeaconing works, but I may have to use the source so to speak. When I cross-linked this to Reddit, I also was pointed to that digipeaters will automatically disregard packets that have been heard and echoed before hand so I could be hitting additional repeaters and been unaware of it. I've got a thread going there now.

      --
      Still always moving
      • (Score: 2) by dbe on Monday September 25 2017, @11:40PM (1 child)

        by dbe (1422) on Monday September 25 2017, @11:40PM (#572845)

        Thanks for answering, I searched a bit and I do not have a VOX function on the FT-60 also that delay is kind of a killer if you want to do any kind of packet exchange.
        Thinking about it, the easiest solution would be to probably use the second output stereo channel for PPT, you do not want to have to deal with another hardware IO type and it gives a perfect synchro with the generated packet signal.
        The way it could work is:
        - generate the packet audio
        - add a tone in the voice band to avoid filters on the second channel, you can have a configurable pre/post delays for the tone to let the radio switch
        - on the cable, a small rectifier followed by a FET should let you short the PPT contact?
        Just thinking...
        Mmm I saw the project on Github, should not be too difficult to add the tone in there, I should have a look.
        -dbe

        • (Score: 2) by NCommander on Tuesday September 26 2017, @12:32PM

          by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Tuesday September 26 2017, @12:32PM (#573066) Homepage Journal

          I'm starting to suspect the switchover problem is a problem on the phone side, and not the radio itself. The delay to transmit is pretty normal; most HTs seem to have it, but I think the phone holds the VOX circuit open longer than it should hence why I stomp on myself; a dedicated TNC might solve the problem. I need to get a second radio setup for full AX.25 ops and measure just how bad the problem is. Unfortunately, packet radio is almost extinct in ham circles so it's hard to find someone to experiment with, esp since when I'm home, until I finally build a yagi, I've got a serious range problem.

          --
          Still always moving
  • (Score: 2) by VLM on Monday September 25 2017, @08:34PM (5 children)

    by VLM (445) Subscriber Badge on Monday September 25 2017, @08:34PM (#572782)

    My favorite use of APRS is finding tropo ducts. So normally KD2JRT's packets, or anyone elses, only make it dozens of miles on their own, mountainlake looks for packets RXd more than 100 miles away from their transmission coords due to tropo ducts or sometimes Es propagation etc etc.

    http://aprs.mountainlake.k12.mn.us/ [k12.mn.us]

    Mountainlake is pretty accurate most of the time.

    For many years I had a decent SSB station for 6M up to 432 and I hope to put the antennas back up someday. Ham radio is an extremely large hobby and SSB VHF is an interesting corner. Other than 160M I don't think there's a band out there with more propagation modes than 6M aka the magic band. I've been toying with setting up a rover 10G station... tropo is even more important for microwaves... Anyway the point is APRS is useful to hams in both direct and highly indirect ways.

    The thing I like about ham radio is I've only been a ham like 30 years and I'm a 3rd generation ham and there's still tons of stuff I've never experimented with. Its a REALLY big hobby. The ops who do 75M ssb and never touch the band or mode switch are really missing out on a lot of fun.

    In the "old days" of packet radio like 80s/90s I did a lot of fooling around with packet, it wasn't much slower than my 1200 baud telephone modem and there are no per minute charges LOL unlike BBS stuff. That's what all that "stuff" was used for before APRS mostly took over in perhaps the 00s.

    • (Score: 2) by NCommander on Monday September 25 2017, @10:34PM (3 children)

      by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Monday September 25 2017, @10:34PM (#572821) Homepage Journal

      Bookmarked. Tempted to go out to the park since there's ducting in my area right now and call 146.52 simplex and see if someone picks up for a change.

      That's an awesome resource. Just to check though, is it properly checking for direct APRS packets, or accounting for digipeated packets?

      --
      Still always moving
      • (Score: 2) by VLM on Tuesday September 26 2017, @11:59AM (2 children)

        by VLM (445) Subscriber Badge on Tuesday September 26 2017, @11:59AM (#573050)

        is it properly checking for direct APRS packets,

        AFAIK yes, but I'm mostly interested in using it as a tool rather than interested in it itself.

        In VHF contests I'd look at it constantly. The system load must have spiked a lot LOL because many other people did too. You'd call CQ for Es propagation mode on 6M and when/if mountainlake shows anything interesting locally-ish then switch over to 2M and start calling there.

        • (Score: 2) by NCommander on Tuesday September 26 2017, @12:34PM (1 child)

          by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Tuesday September 26 2017, @12:34PM (#573069) Homepage Journal

          I've only once ever heard a contact on 146.52 and wasn't able to establish two way communication to get a QSO :(

          --
          Still always moving
          • (Score: 2) by VLM on Tuesday September 26 2017, @06:57PM

            by VLM (445) Subscriber Badge on Tuesday September 26 2017, @06:57PM (#573380)

            2M FM now is very quiet compared to the 80s pre-cellphone era.

            Its a pity because the equipment is amazing compared to even dreams in the 80s.

            SSB and FM are really two different bands with the exception that some of the sideband guys will switch to FM for 222 mhz during contests.

    • (Score: 2) by NCommander on Monday September 25 2017, @10:50PM

      by NCommander (2) Subscriber Badge <mcasadevall@soylentnews.org> on Monday September 25 2017, @10:50PM (#572827) Homepage Journal

      Second follow-up. Non-APRS packet radio is mostly dead as far as I can tell. Supposedly there's still one or two packet BBSes here in the NYC area but I There's a fair bit of digital and RTTY modes in HF land but AX.25 would be dead entirely if APRS wasn't built around/ontop of it. If we're ever in a situation where you think we could make a legit VHF contact though, I won't mind trying to do a quick and dirty AX.25 two-way conversation.

      --
      Still always moving
  • (Score: 2) by fyngyrz on Tuesday September 26 2017, @09:27AM

    by fyngyrz (6567) on Tuesday September 26 2017, @09:27AM (#573005) Journal

    This kind of article makes me wish I could mod the article up.

    Not just because I'm a ham - but because of the level of detail. That was a very good read, the kind of thing that is well worth encouraging regardless of subject matter.

(1)