VK/ZL EU-S2S QSO Party from DM/BW-099 – Achalm – 707m (5)


May 1st, 2022  05:10 – 06:40 UTC
My eighth activation of Achalm, one of my local summits, this time for the VK/ZL<> EU-S2S QSO-party.

Wx: Overcast/ misty, approx. 6°C
Walking time: 20 min. up, 15 min. down
Ascent/ descent: approx. 190 vertical metres

Rig: KX3 / 10-15W, 2.5Ah Li-Ion battery (4S), Palm Mini Paddle
Ant: Delta loop for 20m on a 6m squid pole

Conditions were good (SFI = 120, SSN = 50) with a slightly increased k = 3

2   SSB QSOs on 60m, 1 x EU S2S
12 SSB QSOs on 20m, 5 x VK/ZL S2S, 2 x EU S2S, 4 x VK/ZL, 1 x FY
14 CW QSOs on 20m, 4 x VK/ZL S2S, 5 x VK/ZL, 5 x EU

Highlights: Worked 19 x DX, thereof 9 VK/ZL S2S

Lowlights: After about one hour I felt really cold because during antenna set up my feet had become wet.

Activation report:

Less than a week before it took place, I decided to participate in the VK/ZL <> EU summit to summit party with the special event call DL20SOTA/p. The choice fell on my local summit, Achalm (DM/BW-099), because it’s not far away and it offers a good take-off in the direction of the VK/ZL long path. My tried and tested delta loop for 20m was to be reactivated as an aerial. Other equipment included a comfortable camping seat, a stove and a tea pot. For the short hike up, the extra weight wouldn’t matter and it promised a little more comfort during and after the activation.

At 4:00 utc I left home and reached the top 35 minutes later. The ascent at daybreak was nice and quiet, only birds singing and no one around.
Setting up the delta loop the way it was supposed to, took more than 30 minutes – much longer than expected! This was mainly due to the fact that I had not done the assembly for a couple of years. As a result, several steps had to be carried out more than once. In addition, there was frequent walking back and forth between the two legs in the wet grass, which slowly soaked my shoes. Finally, a PL-BNC adapter was missing, but luckily there was a spare one with the backup antenna 🙂
When the clock showed 5:10 utc we were ready to go with an SWR of 1.3 : 1 and a noise level of S1 with the pre-amplifier ON – excellent!

2022-05-01 08.52.13
Delta loop with its broad side directly at the cliff, facing west.

After power on, I almost instantly found VK1DA in a CW QSO. I took over after the end of this QSO and logged Andrew happily on VK4/SE-118 as my first summit-to-summit (S2S) contact of the day. The next QSO was again S2S, with VK2WP on VK2/CT-007 only about 2 kHz higher. And two more followed: VK1MCW on VK1/AC-041 and VK2IO on VK2HU-093. This was incredible: After 15 minutes the summit qualified with four VK S2S-QSOs. There has never been anything like this!
However, no further activators from down under could be found after that. So I looked for a free frequency and called CQ. My „run“ held up for almost 20 minutes and brought several home stations from VK/ZL with a few scattered stations from EU into the log. Most stations were really loud with VK2GR being real 599!
Eventually, no further callers could be heard. A look at SotaWatch showed that also no new activators were QRV in CW. Therefore, I QSYed to SSB.

2022-05-01 08.54.26
Operator’s position with the KX3 on a comfortable (but heavy) seat.

First I checked the latest spots for 20m SSB: VK3LE had just been reported. But when I came to his frequency, Joel was barely readable. Even if he could have heard me, he was too faint to know whether he came back to me. So I decided to try again later and went to the next spot: ZL4NVW was 4/4 and the contact with Matt went into the log without any problems. Again an S2S-QSO, this time with central Otago, ZL3/OT-474.
Afterwards I looked for a free frequency and called CQ. On SSB I didn’t expect too many QSOs, but VK/ZL was calling almost one per minute, separated by two EU S2S and FY5KE from French Guyana, who sounded almost like a local. It was not only easily possible to exchange the summit reference, but also have a basic chat with some stations. VK5PAS was the loudest with a 5/7 report.
When the pileup died off, I tried VK3LE again, but Joel unfortunately had not gotten any louder.
The last S2S contact on 20m SSB was with VK3IO, whom I had worked in cw before. Apparently the path to Down Under was about to close. We exchanged 3/3 and 3/4 reports which was just about enough to complete the QSO.

In the meantime I had become really cold and I didn’t want to hang around much longer. Therefore I QSYed briefly on 60m SSB to work some friends in EU. But the 20m delta loop did not work well on that band. Although the ATU was able to achieve a reasonable SWR, most of the RF power was just heating up the tuner and my signal was barely audible. After two QSOs, I pulled the plug and fired up the gas stove for some tea water. Now – finally – it was time for a well deserved breakfast. But with wet, cold feet no coziness wanted to arise. Eventually, I started the descent which warmed me up again. After about four hours in total I was back home.

2022-05-01 08.53.19
Station and former castle ‚Achalm‘ on top of DM/BW-099

Which way does the signal travel?

Basically, radio waves can reach any point on earth in two directions: On the direct (short) path or in the opposite direction via the so-called long path.
For radio contacts between EU and Australia/New Zealand in the (EU-) morning hours, the long path is usually a very reliable option. There are radio amateurs with large directional antennas who will confirm this. The signals coming in from the west (for us in Europe) are often surprisingly loud even when using low power.

There are good reasons for that:

  1. After sunrise in EU, almost the complete long path to Australia and New Zealand lies in darkness (see images below). A signal traveling over the night side of the Earth experiences significantly less attenuation than on the day side because of the absence of the D-layer. The only requirement is that the MUF be above the operating frequency along the entire path. For the 20m band this is usually the case, maybe with the exception of the sunspot minimum: Once the sun is above the horizon in EU, the MUF will soon rise above 14 MHz. Further south, darkness is no issue since the MUF is usually higher closer to the equator, even at night.
  2. Moreover, the long path to VK/ZL leads mainly over the ocean and thus offers an additional advantage: A reflection on sea water attenuates the signal much less than a reflection on the ground, which would be the case for most of the short path.

Signal paths are shown for 1.5.2022 at 5:30 utc.

DL - ZL1
Signal path Stuttgart – Auckland: Short path (green) = 18,270km/46°, long path (red) = 21,740km/226°
Signal path Stuttgart – Melbourne: Short path (green) = 16,300km/90°, long path (red) = 23,700km/270°


  • Amazing what 10 watts can do! Radio contacts across almost 24,000 km can be established, even in SSB!
  • A k-index of 3 is no issue for this particular signal path (it doesn’t come near the auroral oval)
  • My trusty delta loop worked very well, even though the SWR might have been a bit high in the phone segment of the 20m band.
  • Achalm is well suitable for VK/ZL S2S
  • Even on easy summits it is necessary to wear robust hiking shoes. The grass can be wet in the morning and sitting there with wet feet is not so much fun.

Thanks to all the activators and chasers and apologies to those I couldn’t hear!
It was lots of fun. We have to do this again!

QSOs during the VK/ZL <> EU S2S QSO-party from DM/BW-099 (map is showing short path which was most likely not the real signal path).

2 Gedanken zu “VK/ZL EU-S2S QSO Party from DM/BW-099 – Achalm – 707m (5)

  1. dl1hbt 9. Mai 2022 / 08:59

    Thanks for sharing your experience and insights, Roman. I totally agree with you … HF qrp is exciting and dun, espacially when solar data is supportive. Cheers and vy73/55 de Tom

  2. Marcel 14. Mai 2022 / 17:32

    Hello Roman.
    Congratulations on the great contacts. Unbelievable what is possible with little power. And of course according to the motto: The early bird catches the worm. Thanks also for the explanation of the signal path and the dependencies.
    73 Marcel DM3FAM

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