HF APRS

  

In the past, I ran an HF APRS gateway on behalf of KL7AA on 30 meters, using Robust Packet as the transport layer.  It worked well enough, however using a proprietary undocumented mode over amateur frequencies left a bad taste in my mouth.  Supposedly the SCS tracker we were using at the time could handle both robust packet and 300bd ax.25 on the same channel, however I never saw any evidence of 300bd bell being decoded.  The equipment to run robust packet was also expensive, which severely limited uptake.  The killing blow came late last year, when the radio running this HF igate seemed to go deaf, and so I pulled it off the air.

 

Fast forward to this summer, and a fellow ham turns me on to HF APRS again, this time using the VARA softmodem as the transport layer.  A little research turns up WA8LMF, who has already done a lot of the low-level work needed to operate this mode.  So after work one day, I attempt a experimental igate to see if it would be worthwhile.  Within 30 minutes of operation, I pick up a beacon from WA7GMX in the Seattle area!  I definitely think this is something worth pursuing.

 

First order of business is a permanent full time igate.  I haven't quite figured out what form this will take, but I'm inclined to start with an igate at the KL7AA club station, and perhaps another at my home station after I get VHF APRS back online.  With work, it may be possible to gate stations heard over HF to VHF.

 

Vehicle trackers may be a more interesting problem to solve, but thanks to the work of KM4ACK on 73 Linux, VARA has been shown to run reliably on linux and even raspberry pi platforms.  A pi and usb gps interfaced to a mobile HF rig may be a nice tidy platform for a basic HF tracker.  We shall see. 

Unexpected Fossil

Went to buy firewood from the local rock quarry.  Quarry man said he found some fossils and let me pick one out.

🦐 IT'S AS SHRIMPLE AS THAT 🦐

Helped a neighbor pull shrimp pots and was paid with a portion of the catch. Nothing quite like ocean to plate in three hours.

Ham projects for 2025

 2025 has dawned with a fresh list of aspirations for myself.  While some goals, such as a new job, are outside the scope of this blog, there are multiple items that deserve to be listed here, mostly to hold my feet to the fire.

Site Summit BBS:

 I've managed to convince holdouts on the KL7AA board to let me move forward with an upgrade/replacement of the packet node on Site Summit.  The plan is to install a full featured linBPQ based packet node with BBS, forwarding, and Winlink capabilities in its place.  There will be a 1200bd port on 145.010MHz and a 9600bd port on 440.050MHz.  Ideally, this will also be links to the Wasilla node too, although I haven't yet approached the MatSu club on this matter.

Robust Packet HF APRS igate:

 The radio running the Robust Packet HF igate on 10.1473MHz USB has apparently seem to have gone deaf, although I have not dedicated time to in-depth troubleshooting of the system.  For the time being, the igate has been pulled offline, pending future troubleshooting efforts.  The future of this system is, at this time, unknown.

Home shack master plan:

Utilizing my current Hermes Lite 2 and shack pc running Linux Mint, plus hopefully a Hardrock50 amp if I manage to save up the money, my purely personal goal is to have a fully remote HF operating position.  I also plan to bring my VHF igate back online.  I also have a SEA-222 marine HF transceiver, which, if it is stable enough, I plan to press into service as an HF packet node on 14.105MHz LSB (technically 14.102MHz USB, since packet doesn't care, but who's counting).  If all this jank actually ends up working, I may crosslink the HF packet and VHF APRS port, but that's much further down the line.

There's a lot up there, when you start dissecting each piece, and that's before you factor in other obligations, but I think I can pull it off.

~moose

Junkbin GPS Stratum 1 NTP Clock Source (A Work in Progress)

I don't know where most of these parts came from, but when I opened my electronics junk drawer the other day I found an Orange Pi Zero+ and a serial GPS of dubious quality that also featured a PPS out.  With these two parts in hand and a suitable project box, my weekend free time is suddenly consumed with a pending project: build a stratum 1 NTP server using only parts on hand.

OK, but what even is that word salad of a title?

Network Time Protocol (NTP) is a method of synchronizing clocks over the internet.  Wikipedia has much better information than I could ever hope to provide here, but the gist is NTP servers are organized hierarchically based on their distance from known stable clock sources.  This distance is referred to as the 'stratum' of the server.  Stratum 0 is a master clock itself, such as a GPS, atomic clock, WWV signal, or other authoritative time source.  Stratum 1 is any NTP server directly attached to a stratum 0 clock.  Since my junk drawer project welds a microcomputer and GPS receiver together, it will (eventually) qualify as stratum 1 (with caveats).

Pulse Per Second (PPS) is a signal put out by time sources to define the precise beginning of a second.  A GPS connected via serial port can vaguely define the time in its NMEA sentences, but PPS provides a stable 'tick-tock' to the time sentences.

New Years' Day aurora

Weather has been weird this winter, with precious few clear nights for stargazing. We got a decent one a week ago though, right as a big solar storm ripped through. I took these shots from my bedroom window.  You can see my weather station and one of the HF antennas in the foreground.

Gull Rock Trail

Hiked about halfway down Gull Rock Trail in Hope today. Reminded me just how out of shape I am, but it was worth it. Hard to take a bad picture on this trail.