Activating Mt Cotton VK4/SE-115

This was one summit I have wanted to activate for quite some time, partly due its proximity and partly due to the excellent Sirromet Winery nearby. So when Sunday 30 April dawned with beautiful clear skies, I knew it was time. My wife decided this would also make an excellent day out.

The drive to the base of the summit took about 40 minutes. We parked at the bottom in a designated car park and headed for the gate that heralded the beginning of the path up.

This is the beginning of the path up to the summit.

Fortunately the path up is sealed, which made walking up easier, even though it was rather steep at times.

It took us 22 minutes to walk up to the summit.

Once at the top it was simply a matter of seeking out the best operating position. This was important as there are a couple of communication towers there and I didn’t want interference.

The going was tough at times.

I found a suitable spot among a pile of rocks, so I erected the long wire antenna on my squid pole, and connected it up to my Elecraft KX1. It tuned up beautifully on 20m and 40m. For power I use six internal AA 1.5v batteries that give me between 1 and 2 watts output to play with.

It was quite comfortable, really.

I put out my first call on 20m and within seconds was answered by VK3CAT in Victoria. Not bad for 2 watts. I then switched to 40m (only 1 watt) and worked VK2NP, VK2BJT and VK4TJ.

I find the Pico Paddle a wonderful device to use with the KX1. It is magnetically held in place on the tin plate on my home brewed QSO board.

That was sufficient for the activation to count, so it was time to pack up and head off down and to lunch at Sirromet.

Preparing my Buddistick for the next SOTA activation.

On Sunday 2 August 2015 we are having a SOTA party in the ACT. As many of us as possible will be activating as many summits as possible, especially seeing there is a 10m and 6m challenge on at present.

So to add to the fun, I decided to see what I can do on 10m. This means I won’t be using my trusty Elecraft KX1 but my Yaesu FT817. The Buddistick will still be my antenna of choice.

Seeing I haven’t used the Buddistick on 10m before, I thought I’d better tune it up beforehand so as not to waste too much time on location.

I headed out to my usual spot behind the Australian War Memorial and set up my portable station, using 28.059 as the frequency. All I then had to do was to connect up a spare connector onto the coil for a tap, and sort out the correct length of wire for the counterpoise.

I connected up my lightweight antenna tuning unit to confirm that I had a good 50 ohm match. This ATU is the Hendricks BLT tuner.

I found the best tap to be at turn 2 and a third of a turn to the left on the main coil, with about 8 turns of counterpoise wire let out. That’s about 8 feet. At this setting, the little LED on the tuner went out, so that’s about as good a match as can be had.

The blue cap is the tap for 10m.

The blue cap is the tap for 10m.

Luckily I spent the time sorting out the tuning as I also found the power plug to be broken. The rig was actually working off the internal battery and not my 12V gel cell. So it was back to my apartment to make hasty repairs. Fortunately I had a spare power lead, one that had a cigarette lighter plug on the end, so I was able to cut that off and crimp on spade connectors. This is a temporary fix as my reverse polarity protection that was attached to the original lead now no longer works, so it’ll be a matter of double checking before connecting up the power. Not having a soldering iron here in Canberra is a nuisance, but such is life.

Upgrading my Elecraft KX1

The time has come to upgrade my Elecraft KX1. To make this little rig even more versatile, I will be adding an in-built ATU. This comes in kit form and needs to be assembled and installed into the rig.

I will also be adding the custom paddle as it will mean I no longer need to take a separate key or paddle with me when going portable.  This too comes in kit form.




Curing RFI in the shack

I have been suffering from the dreaded RFI in the shack. I knew this because every time I keyed the transmitter, my digital clock would flash and my computer would play up or even shut down. Something had to be done.

After much talk with locals VK4CBW Wallace and VK4ZW Ray, I decided to get back to basics and start from scratch. I rebuilt the earthing system to ensure the connections were good, I removed the two external speakers I had rigged up and I removed the antenna switch that wasn’t grounded. This didn’t cure the problem.

Then I installed a 4:1 balun (thanks Wallace) and removed my G5RV and replaced it with a 20-10m dipole that I had shipped in from the US. Much better but still some RFI on one or two bands.

I then made a current choke by winding five turns of coax in a circle 8 inches in diameter at the feed point to the balun, which I mounted just outside the window to the shack where the coax enters. This did the trick.

The choke and LDG 4:1 balun outside the window of the shack.

Building a Ten Tec Regenerative Receiver Model No 1054

I have always found radio fascinating. I have also always been amazed at the way the old fashioned regenerative receivers from the 1920s worked, so when I received the Ten Tec 1054 as a Christmas gift this year, I couldn’t wait to get the soldering iron out and begin building.

This is the kit as it arrived.

The PCB is huge, which means there is a lot of space. This is nice as it allows you to go about populating it with all its components without fear of solder bridges or making other silly mistakes.

This kit is built in two stages: the audio amplifier is tacked and tested first, then the RF amp, regen detector and frequency tuning/switching. It also comes with a nice metal front panel.

I always use a vice to hold the PCB as it makes soldering on the underside easy.

The audio amp is the ubiquitous LM386, which is a smart choice. This hardy integrated circuit is so well tested, stable and easy to mess around with and it puts out a decent volume too.

One interesting feature of this kit is that it relies on two power sources: battery A, which is a 9V battery and battery B which is a 9-12V DC source. The reason for this is to keep the voltage supply independent of the audio amp to eliminate the chances of oscillator instability or AC hum, which is the curse of regen receivers of old.

Testing the first phase. Note my speaker box.

Once phase 2 had been completed, it was time to adjust the coil. This is easily done with the aid of a second receiver tuned to 6.9MHz. There are four bands that one can select by means of the band selection switches on the front panel. Band 1 covers 5.9 to 6.4MHz, band 2, 6.9 to 7.4MHz, band 3, 8.5 to 10.2MHz and band 4, 11.5 to 16.5MHz.

Once the board was completed and tuned it was time to fit the front panel. No knobs or enclosure comes with the kit. That’s my next project.

So, how does this little rig perform? Surprisingly well with only 10ft of wire as an antenna. It is easy to tune and the volume from my stand alone speaker is fine for listening to across the room. I listened to the Boxing Day Cricket Test and thoroughly enjoyed it. So far I have only managed to pick up the ABC and one or two CW transmissions but that’s not the fault of the rig. The bands have been getting quieter by the year.

The Ten Tec 1054 on my shelf.

Next I will add some knobs and build a wooden enclosure to complete the project.