HF packet system or bust

VAPN progress slow and steady

This has been a very busy year for the primary developers of VAPN while sharing time with many other priorities of life. VAPN development has been slow, steady, but really needs a big push. Getting on the hill is the logical next step, but that only benefits local users on 6m or above… maybe 10m as well. The rest of the HF bands are just sitting there waiting to be used for digital traffic and they don’t need a hill.

Puerto Rico & Maria

There is plenty of fragmented news about the post hurricane Maria amateur radio activities in Puerto Rico. As is so often the case, the critical details of truth quickly hide behind exaggerated yarns of how amateur radio is either totally useless or god’s gift. A good example exists in this Zed Thread. Through the murk and mire of the usual “crisp insights” of QRZ.com posters, exists a common theme of how to move health and welfare messages off the island and to loved ones in the CONUS. The ARRL’s petition for radio volunteers to spend three weeks on the island perhaps hopes to fill this need for the Red Cross, but details are murky. It shouldn’t take long for authorities and commercial entities to fill this role very quickly. That said amateur radio may have a roll in that critical time from storm to normality.

Digital a common theme

One of the posters on QRZ confirmed his or her lack of understanding of things with the suggestion FT8 could completely solve the health and welfare message egress problem despite the obvious limitation of the 13 or so byte payload of the mode. When challenged this person dug in their heels and, well, that’s the Zed isn’t it?

The poster’s notion to use digital means to move messages makes good sense. During the thread lots of various ways were discussed. All the while I kept thinking this is a rather perfect use of a packet radio style system. One of packet’s purposes is to move and organize messages. Why not use it now? Why indeed until one realizes there are not many packet systems around to access on HF.

Moving forward with HF

It’s too late to see if HF VAPN would help the victims of the 2017 Atlantic hurricane season. This should not prevent us from rolling out an HF capability for the future. So that’s exactly what we are going to do. An HF transceiver study is complete, order made, antenna already in place and SCS Tracker modem on the shelf ready to connect.

Digital Mode for HF

The SCS Tracker DSP TNC has plenty of capability, but the two modes of interest for HF use include the notorious HFPacket and the spiffy Robust Packet.

  • HFPacket – the forerunner 300 bps packet radio mode used for years on HF has serious problems handling interference and propagation in comparison to modern techniques. Still any decent sound card digital program can easily turn almost anyone’s HF rig into a packet client in minutes.
  • Robust Packet – The short and younger cousin of Pactor solutions, Robust Packet goes to great lengths to tolerate the realities of HF propagation, tops out at a reasonable 600 bps and does it all within a 500 Hz window. Unfortunately this is a proprietary protocol, but the bag of tricks it brings to the table are, quite simply, worth the modest cost of the hardware TNC.

To make the most of both modes, VAPN will likely set up in poll mode to listen for a client and lock on to their choice of modulation.

Beware of success

Let’s assume almost nothing happens with this system for years and then, slam, hundreds of H&W NTS messages appear in the BBS from some poor hurricane hit island. What next? How does one efficiently move NTS messages to the next step while keeping them in digital form? We didn’t find a good answer for this year’s field day messages so we eventually delivered them ourselves. Depending on who you talk to, NTS appears to be crumbling at the edges despite the rather useful utilitarian nature of the NTS radiogram format for H&W messaging. There is activity in the NTS ranks, but because of the urgent nature of these messages, we, quite frankly, are not sure we would entrust them to the NTS system.

If such a situation occurs we would probably contact our kids’ high school leadership for some volunteers, space and maybe some telephones to help convey the messages to their recipients en masse. Some of us are quite good at ad hoc community organizing to pull something like this off. The positive optics of such an event won’t be lost on those seeking to increase their personal capital by helping facilitate such an endeavor.


Getting on the hill is still a top priority to help service the local area. While we wait, the prototype is running rather well in the low lands and HF won’t care about elevation. Time to add HF in some form to VAPN.

If VOACAP is half right about HF, opportunity awaits for the VAPN systems.
If VOACAP is half right about propagation between FM18 and KP4, opportunity awaits for this path and more.

UPDATE October 10, 2017

The 30m port is open on Robust Packet at a dial frequency of 10145.5 USB.