Wednesday, June 21, 2017

APRS on motorcycle vs. RF density levels

I recently sold my off-road motorcycle and replaced it a few days ago with a Kawasaki Versys 650
LT. The LT stands for "light touring" and I plan to do a bit of that once our Texas heat subsides in late September. That gives me three months to familiarize myself with the bike on morning rides. And to install an APRS transmitter.

Fortunately, I already have what I believe may be the most suitable APRS set-up for the limited space available - a Byonics Micro-Trak RTG.

Thursday, June 15, 2017

A brief WSPR transmitter comparison

WSPR is a fantastic mode to use for investigating propagation paths. I'm often surprised at openings that defy conventional wisdom - 10m openings late at night, long-path openings detectable with sub-watt power levels and others.

There are several ways of transmitting a WSPR signal that don't require a computer and I've tinkered with most of them. Each has its own advantages and disadvantages:


This is the only method of those listed here that I haven't used. As supplied, it is a dual bander (20 and 30 meters) with additional filters available for 40, 80 and 160 meters. It is tiny (easily portable), operates from a 5V power supply and puts out 200mW.

Thursday, June 8, 2017

630m kit completed, tested

I finished building my 630m transverter kit last night and tested it today.

The build was simple enough even for a first-time kit builder - minimal parts, generous real estate on the board, all components labeled and good instructions.

Even the three toroids were noticeably easier to wind than the smaller T-50 types that make up most HF QRP kits.

About an hour and a half, start to finish, including set-up time and finding the beige capacitor that I dropped onto beige carpet...

Monday, June 5, 2017

Kit arrives: Preparing for 630 meters

For several weeks now I've been exploring what's available to allow me to be active on 630 meters once that allocation is granted here in the US.

And, although I don't yet have an antenna for that band, I am able to receive several of the experimental stations currently operating as WSPR beacons on 474 kHz using my Flex 6300 and (gasp!) triband Yagi (my 30-80m dipole is down for the summer thunderstorm season).

Thursday, June 1, 2017

Further additions to the Ultimate 3S

I soldered together the accessory relay board today along with a few additional low-pass filters. This converts my U3S from a monobander to a 6-band multibander.

While it may have been easier to build it this way all at once from the very beginning, the addition of the relay board required minimal reworking of the main assembly and so I chose to get the rig working and proven first in its basic configuration before moving on with additions.

Wednesday, May 31, 2017

Farewell to the FDM-Duo

After not quite two weeks my Duo is on its way to its new owner.

My initial frustration with the radio's functionality (posted here) only increased as I implemented more and more of the radio's capabilities. I came to appreciate that spec not often mentioned in reviews and lab reports - ergonomics. The Duo is capable of both stand-alone and linked-to-the-computer SDR - unfortunately, the sorry state of ergonomics is abundant in both modes.

Thursday, May 25, 2017

Testing DXplorer with my WSPR reports

Since wrapping up the latest round of additions to my Ultimate 3S I've been transmitting with 200 mW on 20 meters. Low sub-watt power outputs give a finer indication of the moment a particular path opens and closes and 200 mW is also the output of the WSPRlite sold by SOTABeams.

But it seems as if the resolution of the graph is insufficient at showing band openings represented by just a few spots.