Archive for the 'VHF' Category

After APRS, what comes next- part 2

You may want to look at part 1 first.

After a week of playing around with APRS– I’m done, for now. Mostly, that’s due to classes starting next week. My free time over winter break is just about used up. As I said before, I like APRS. I can definitely see trying to apply APRS connectivity to some of my outdoor activities, especially camping. As far as the home station, though, I’m done getting things set up. I can reach the closest digi in town, and that’s really all I need to do with APRS right now.

After APRS, what comes next?

Back in the day– mid 1990’s– I did some experimenting with packet radio with an MS-DOS laptop and a Baycom TNC. It was not fancy, but I could sit outside on the lawn at LSU-Shreveport and connect to other stations and nodes. The Internet hadn’t become widely available quite yet, Wifi hadn’t either, and it was cool being wireless. I played around a little on the local DX Cluster and BBS’s, and was able to eventually receive a packet (yes, one packet) of data from space shuttle Columbia as it flew overhead. I also experimented a bit with TexNet; it took some effort to get to the nearest node in east Texas, but once there I could connect to anywhere in Texas.

I am also inclined to remember farther back in the day– mid to late 1980’s– when I connected my 1200 baud modem to the telephone system, and made use of Telenet and Tymnet. These networks were packet switched networks that allowed you to connect to a local node on the network, and from there connect to any host on the network through a shared backbone circuit. On Telenet, I’d type “C 41412″, and that would connect me (my terminal) to whatever host was connected to node 414 12 (414 being the area code, and 12 being the individual host).

There were all kinds of hosts on Telenet– most were businesses, some were universities, some were government agencies. Most people didn’t connect to Telenet for recreation (although some of us did- *cough*). Generally, if you were dialing in to something like Telenet, you were doing so because you needed to access resources on the host at the other end of the circuit.

In the 1990’s I got bored with packet radio because, while it was cool to say I could connect to the other side of Texas via TexNet– there was nothing to connect to once I got there. (At least with Telenet, there was the challenge of trying to gain access to the host at the other end once you’d connected. Again, *cough*.)

Today, as I’m writing this, I have Xastir running on my other monitor, watching APRS. I can see stations from all over Wisconsin, eastern Minnesota, northeastern Iowa, and northern Illinois. Most of those stations are repeaters, igates, and weather stations (and many of those are all of the above). There are a few people driving around the state, including truck drivers. I occasionally see a notice for a net, or an ARES meeting attached to a station. Technically speaking, I’m not really “on” APRS– I don’t have a keying circuit connected to my radio (yet), so I don’t appear on the map (yet). But I can watch packets coming in.

It’s interesting reading online about how APRS routes traffic, and then watching the raw packets. The picture becomes even more clear when I watch aprs.fi on my other monitor– aprs.fi graphically shows the route an APRS packet takes, and I can compare that to what I see on RF. There’s a lot of learning going on here: setting up devices in Ubuntu Linux to get soundmodem and Xastir working, making the hardware connections between sound card and radio, watching how propagation on 144.390mhz changes from day to night (and on PropNET).

I can see 103 stations on my map. A few of them provide weather data, a few provide position data, a few are repeaters showing frequency and PL info. I’ve been able to scroll around, and look at areas where I like to get outside and play– places like Eagle River, WI– and see what kind of connectivity I can expect when I’m camping in the middle of a National Forest next summer. That’s valuable information as well; many of the places I like to camp are without reliable cell voice service, much less data. It is useful to know that some guy in a truck that lives 4.6 miles from my future campsite can reliably reach a digipeater– that means I probably can, too.

APRS is popular, and for good reason. I’ve become a fan, and I think APRS is a cool application of amateur packet radio. I’ve been learning a lot from playing with APRS. I think it’s important, though, to remember that APRS isn’t the only application for AX.25. DX-clusters and Winlink2000 are also both useful applications– but in the 40-odd years amateur radio operators have been tinkering with AX.25, is this it? Isn’t there something else useful we can come up with, between AX.25 and the Internet, that we want to do at the other end of the circuits we create?

Add another band to the list– 6 Meters

Okay, so I don’t have a microphone working for my IC-735 yet, and I have all but given up on the code for now.
I’ve had my eye on the Alinco DR-M06 6 meter rig for a while now, Okay, so it’s not Alinco’s newest model, I like it anyway– it was also slightly cheaper. Since I don’t have a base antenna up yet (here we go with getting antennas airborne again), it’s going to live life as a mobile for a while. I did some Googling about 6 meters, and discovered that WBAY-TV 2 in Green Bay WI has a well written FAQ article about how propagation affects their low VHF signal (they transmit on 55.26mhz). Also found a list of modifications for 6 meter rigs, including the extended receive unlock for the DR-M06T. Didn’t even have to void the warranty. :D

Yeah, there’s a lot of stuff I could have bought that would be a lot more practical in an emergency. Oh well, this radio’s about fun.

Alinco DJ-V5T 2m 70cm dual band HT

I have a new toy^H^H^Hpiece of amateur radio equipment, an Alinco DJ-V5T. I love the radio; the manual, however, has some issues when it comes to programming memory channels. Here are the steps I’ve been following to get amateur radio repeater frequencies and settings programmed into the radio. (These steps replace the right column of page 21 in the manual.)

(NOTE: If you are looking for repeater frequencies, check the Wisconsin Association of Repeaters listing.)

To store an amateur radio repeater’s frequency and settings in a memory channel:

  1. Look at the bottom row, left corner of the LCD screen.
    • If the bottom row of the screen is blank, skip this step. If you see “M” followed by C1, C2, or a two digit (01) number, look for the key labeled “A V/M MW”. It’s the button in the upper right hand corner of the keypad. Press it once.
  2. Using the keypad, enter the frequency you want to store in the memory channel. (For example, 4 4 4 */. 3 7 5)
  3. Set the power output level for this frequency by following the “Setting Transmission Output Level” steps on page 20 of the manual.
  4. Set the repeater shift for this frequency by following the “Repeater Shift” steps on page 30 of the manual. If you are unsure of what the shift should be, check the Wisconsin Association of Repeaters Band Plan [PDF].
    • Look for the output frequency of the repeater in the band plan first.

    • If the input frequency is lower, the offset is -.
    • If the input frequency is higher, the offset is +.
  5. Set the tone encoder/decoder frequencies by following the steps in 5-1 “Tone Squelch Frequency (CTCSS)” on pages 36-37. Most repeaters in south central Wisconsin use 123.0hz for both encode and decode (you’ll need to set both).
  6. Press FUNC/LOCK once. You will now see a memory channel number in the lower left corner of the screen.
  7. Rotate the Dial knob to select the memory channel that will receive the frequency you are storing. Memory channels are numbered 00-199, and C1 and C2.
  8. Press V/M MW once. The memory channel number will disappear. All of the information (frequency, power output, tone squelch, offset) that was entered in VFO mode is now stored in the selected memory channel.

    Hope this makes things a little easier; if you have any additions, corrections, or questions please let met know in the comments.

    Steve, KC9JMF

Christmas microDXpedition report

Merry Christmas!

Made a trip to AES this weekend, and picked up a new MFJ-1422 2m/440 dualband mobile antenna– so one more piece of the mobile operating puzzle is in place. I’m able to reach the 2m repeaters in town, the wide area repeaters in Baraboo, and out as far as Cambridge and Hollandale. KC9JME also got the same antenna for Christmas, and she was able to reach the MARA repeater going south past the Dane/Rock County (Wisconsin) line. We’re both using the same radio (Alinco HT, ~5 watts).

Since she was coming back the same way today, Danielle and I decided to try getting in touch on simplex on her return trip. We weren’t able to meet up on simplex though. I was able to hear someone at one point (although couldn’t copy callsigns), and she was able to hear them a little better (but still unreadable). So I suspect that if we had each been running enough power, or if I had been on higher ground, we might have been able to make it. Maybe.

It’s cold on Christmas in Wisconsin. My equipment performed well, even though we didn’t make contact on simplex. After 45 minutes I was starting to get chilly; but based on today I’m sure I could deploy myself to a parking lot and operate from the car in emergency mode for a while, perhaps even all day if I had somewhere to go inside and get warm. A gas station parking lot worked pretty well. I think a rest area, truck stop, or office/medical building parking lot would work equally as well. We’ll definitely be doing more experimenting with the new antennas, and I’m working on a list of potential operating locations that are on higher ground.

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