February 2014 – Page 2 – AB4UG Radioblog

10m Moxon assembled

After a few hours of reading instructions, screwing and clamping things into place, then undoing it all and redoing it properly because I didn’t read the instructions thoroughly enough, I got the 10m Moxon antenna assembled. The bent tubes were easy enough to straighten out, and the one tube that had 2cm broken off was still long enough to work with. I managed to lose a hose clamp somewhere along the way, but fortunately I was able to find another one that worked in one of my toolboxes. Ended up with a bunch of extra lock washers too that didn’t seem to be in the parts list in the manual.

Here’s the feed point, which I’ll probably zip tie (or some other tie) onto the beam.

It’s a pretty big antenna, at right around 3.97m (12.4 feet) long. Here it is up against the car for some scale.

Now to figure out how I’m going to get it up into the air…

Straight key base

Finally got around to working on making a base for the straight key. I cut off a section of some 1×4 lumber, sanded it nice and smooth, beveled the edges and covered it with a few coats of clear gloss polyurethane.

For some grippiness so it doesn’t slide around on the desk, I spray-glued a piece of some rubber shelf liner to the bottom.

It’s not a heavy base, and I might decide to change it later on to something more interesting looking. For now, it looks reasonably decent and gives the key a slightly bigger footprint and elevates it a little bit for more comfortable use.

Across the world on 35W

Managed to work another Australian station (VK6WB in Perth, Australia) tonight on 20m PSK using just 35W. According to qrz.com, it’s 18525.7 km away. That’s 1.9 mW/km!

I had to do a double take and wait until he called a couple times to make sure fldigi was decoding it properly. He was as loud as most of the other US stations on the waterfall.

This breaks my previous record for QSO distance (with VK3TDX) by a few thousand km.

Really loving this hobby now.

Hamfest antenna

One of the bundles of wire I picked up at the Charleston Hamfest last weekend turned out to be a dipole cut for 10m, according to the paper tag that was tied to it.

Each leg of the dipole is about 2.8m (9.2 feet) long and there is what appears to be a trap near the end of each leg.

At the center is 6.9m (22.6 feet) of BNC terminated coax.

It appears to have seen a few seasons out in the elements, judging by the amount of oxidation on the wires and the condition of the coax. Still seems to work pretty decently. Using an old painter’s pole and some of the extra rope tying off the current antenna, I was able to measure an SWR of 1.3 at 28.5 MHz with the center about 2m off the ground.

I didn’t check to see if it was resonant anywhere else. Once I figure out how to suspend it a reasonable distance off the ground, I’ll check it out a little more thoroughly.

A day on 20m PSK

Like with my previous 10m experiment, I left the radio listening to 20m PSK (14.070 MHz) with fldigi sending the spots to pskreporter.info. Throughout the day, I grabbed screenshots of the map showing the spots at roughly 1-2 hour intervals. From about 2014-02-04 1100Z to 2014-02-05 0149Z (about 15 hours), these are all the stations that were spotted (click for the ginormous version).

There was the usual progression of a few EU stations during the early morning and then lots of US stations throughout the day, moving from east to west. West coast stations were starting to come in pretty well by the time i decided to turn things off. I can usually hear a lot of South American stations when I’m playing PSK, but I guess most of them weren’t transmitting yesterday.

I was also pretty surprised to see that Austrailian station (VK2KM) in there as well (spotted around 2100Z). Wish I was home to try to work it.

You can check out the entire collection of spots over in my Radio Spots album on Google+.

I think these are interesting experiments to do. I think 40m will be the next one. Might also be interesting to let it run overnight to see if the radio hears anything.