Kurth Kiln Regional Park

Australia Day public holiday 2019 – Monday 28 January 2019

On Sunday afternoon, I finally got around to looking at the feed impedance of a home-made ZS6BKW doublet antenna. I constructed the antenna using some stainless steel multi-strand wire (about 2 mm OD) for the doublet section and some 450 ohm balanced line for the feeder section. I used a terminal block to connect the two sections together along with three 3D printed antenna “egg” insulators.

I set the antenna up in the backyard and connected the antenna analyser. The antenna is designed to be resonant in the 20 m band and usually allows operation on 40, 20, 17, 12 and 10 m amateur bands.

Initial measurement showed resonance at 13.8 MHz, so the total length was too long. This was expected, as I had cut the balanced line section long to allow for trimming: nothing worse than cutting a balanced feed too short – better to cut long and them trim back to adjust to the length required.

After adjustment, I saw resonance at around 14.180 MHz – close enough for initial use. I rolled the antenna onto a couple of winders and stored it in the vehicle.

I was a little slow getting going on Monday morning. I worked Peter VK3ZPF/p in Great Otway National Park VKFF-0405 and then started getting organised.

I decided to head for a Park that I have driven through a few times, about 100 minutes to the west of home.

Kurth Kiln Regional Park VKFF-0971

I had stopped once previously in this Park, down near the Kirth Kiln Picnic Ground. It was a couple years ago, on a week day afternoon and HF conditions were terrible. 20 minutes of calling yielded NO responses, so I gave up and headed on to a late afternoon engagement.

This time I decided to head for Egg Rock, Beenak. The approach was straightforward – head towards Gembrook and then turn into Beenak East Road and on to Egg Rock Track. Only one issue – the target track has no sign and does not show on the in-car GPS mapping…. As I passed the hard left junction, I thought “That is probably Egg Rock Track”. The heavy gate was open. I continued a short distance to Ash Landing Road to turn around and head back to the corning. I drove up the track to spot a vehicle parked at the base of the fire-watch and communications tower and drove around to the NW corner of the cleared area. I stopped and greeted the fire watch person atop the tower and indicated I intended to “play radio” for an hour or two. I got a positive response, so started to set up the antenna – the ZS6BKW.

I tossed a line over a tree branch at about 10 m and strung out the antenna. Due to the length of the open feed line, I moved the vehicle a little further away and set up on the tailgate, using the IC-7300 connected to the secondary battery in the vehicle.


The Park sign, showing some damage from “shooters”


My station at Egg Rock

I switched on at around 0015Z, and heard Liz VK2XSE/p in the middle of a contact. I listened for a couple of minutes and missed Liz when I called – a stronger station had drowned me out. I checked ParksnPeaks on the ‘phone and saw that Peter VK3ZPF was still on air, so moved up the band and soon had a Park to Park (P2P) in the log – Peter VK3ZPF/p in Great Otway National Park VKFF-0405. I moved back down to 7.144 MHz and soon had Liz in the log from Mudjarn Nature Reserve VKFF-2674.

I moved back up to 7.155 MHz, as Peter VK3ZPF had advised that he was about to close. Peter also spotted me, but it was slow going after a couple of initial callers. It took 15 minutes of calling to raise the next contact! After another 15 minutes of calling, I moved down to 40 m CW and spotted myself, resulting in five callsigns in the log in the next few minutes. I then went back to 7.144 MHz to find the frequency unused, so spotted myself there and started calling. Contacts were again sparse, with lots of calling and few replies. Was it the antenna or conditions? It seems probably conditions and by now it was in the middle of the lunch break time…. I worked Peter VK2KNV/m and Liz VK2XSE/m, now headed back towards home, with a 200 km trip in front of them. I continued calling until around 0150Z, when I moved up to 20 m SSB. Lots of calling gave no results in 15 minutes, so I tried CW lower down the band. This move yielded three contacts from SE Queensland. I then tried 17 m, spotting myself once again. Nick VK3ANL responded and we worked SSB and then CW on the same frequency. I changed back to SSB but saw a signal on the spectrum scope, so went back to CW and soon had John VK4TJ in the log on 17 m. John also called back on SSB, so the contact tally was starting to rise.

I then tried 15 m SSB, again working John VK4TJ on voice followed by CW. Just after 0300, I moved up to 12 m, not really expecting any responses. I soon had Scott VK4CZ in the log, followed by a little while later by John VK4TJ on CW, together with Nick VK3ANL. Nick was actually contact number 45, so the Park was finally qualified at 0319Z, three hours after I switched on. I was about to spot myself on 10 m when I saw a spot for Ian VK1DI/2 in a new Park, so changed back to 40 m SSB to work Ian from Oakdale Nature Reserve VKFF-2694. After working Ian, I moved up to 7.155 MHz and worked the last few contacts, finishing off with Paul VK5PAS and Marija VK5FMAZ.

I shut down at 0400Z and started to pack up. I had 54 contacts in the log. I believe that the antenna was performing adequately, as several others reported on the patchy propagation and rapid, deep QSB on the bands. One nice feature of the IC-7300 is the voice memory, so one can call CQ lots of times by simply pressing the correct “button”….

Whilst packing up the antenna, I felt something odd on my neck. I swept my neck with my hand and found a stick insect on my hand. I dropped it on the ground and took a couple of photos using the phone before resuming the pack up.


The stick insect


A view through the trees near the operating position

After ensuring that I had left no trace, I started the trip home. It was a little slower and dustier than the approach, as I ran into a group of 4WD vehicles part way back down the route. Slow and steady until I reached the bitumen, when they stopped and allowed me to pass.

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