VK1 S2S on 2.4 GHz

This evening between 0800 and 0900 UTC, VK1 had three activators on 2.4 GHz (2403.150 MHz); Matt VK1MA at Black Mountain VK1/AC-042, Andrew VK1DA at Mt Coree VK1/AC-023 and myself Andrew VK1AD on Mt Taylor VK1/AC-037.

Having completed our first ever S2S QSOs on 2.4GHz, we moved on to 1296 MHz.

VK1 SOTA activity on 1296 and 2.4GHz is set to grow, we have a good future on UHF and SHF bands.

I have a feeling this evening’s VK1 2.4 GHz S2S achievement is the first for VK.

73 Andrew VK1AD

P.S. I am trying to load my photos but they don’t display correctly.


I tweaked your photos with GIMP, rotated, resize and saved at lower quality. The quality and scale changes wont be noticeable on here but they went from 2.2MB to about 150k. https://www.gimp.org/

Anyway, great news on the 13cms success.

Good work. How far apart were you?

Mt Coree is the 4 pointer on the left, Black mountain is the 1 pointer top right and Mt taylor is the one pointer bottom right. the sacle is on the bottom right of the map.

To me that looks like about 20 Km between Mt Coree and both Black Mountain and Mount Taylor and about 10 Km between Black Mountain and Mt. Taylor.


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Close, 26km is the longest I think.

Nothing better than massive success all round for the 1st real S2S tests.

Even when doing true LOS paths, it’s still immensly satisfying when practice meets theory and they agree!

On September 2017 Mark-KE7MSU and Etienne-K7ATN completed a 2.4 gHz S2S over a 177 km path (110 miles) from W7W/LC-058 - Silver Star to
W7O/CC-001 - Marys Peak. SSB signals were an easy S9 using SG-LAB transverters (~2W) and 18el yagi on one end, and a ~1m dish on the other. We followed with FM on 1.2 gHz with an Alinco HT on one end and 2el and SG-LAB transverter on the other. Only S5 or so on that band.
There’s a lot of S2S potential on those bands.

Thank Andy, that was a little frustrating.

So last evening was a test of our individual station set up and transverter tweaks. As you can see from the pics I am yet to mount my 13cm Bi-Quad.

As for antennas I have a 20el yagi almost complete, that will help with paths greater than 100 km, but for now we are just testing the waters.

Looking ahead to Sunday, we are planning to have 4 possibly 5 2.4 GHz equipped stations on summits for a 13cm S2S Party. In the coming months we expect to move further way from Canberra and start testing 100+ km paths, that will be exciting!!

I forgot to mention in my earlier post, Al VK1RX joined the 2.4 GHz chase working his SG-Lab 13cm transverter from his home QTH. Thanks Al great work!

Pics of the 13cm Yagi… work in progress. Top 23cm below 13cm.

Actual folded dipole mounted on a N-Type panel mount, next the addition of a 43 mm RG402 balun :slight_smile:

Experimenting with a prototype folded dipole


In the interest of sharing antenna construction projects.

Today, I finished constructing a 20el 2.4 GHz DL6WU yagi for 2403 MHz. Tomorrow morning from 8 am local (21:00 UTC) VK1 will have five 2.4 GHz stations on local Canberra peaks.

73 Andrew VK1AD

Have you tried playing RADAR yet? Planes flying North/SOuth on great circle routes fly over a beacon on Broad Law GM/SS-029 (which is 45km South of here) and then fly over my house at 30000+ feet. They give brilliant secondary RADAR returns of GB3CSB which is 30km NNE.

This was a 747 or A380 or A340 as there were 4 contrails and being a big plane it produced an echo that was only 6dB down on the direct signal. Not too long a pass though only giving about 20secs reflection.

The vertical line is the constant carrier of GB3CSB and you see can the reflection dropping in frequency as the plane flies away from me. The sudden jump in GB3CSB is when the CW ident starts.

You need a beacon of somekind and somewhere where you can see lots of planes. You can get a feel of how strong the reflections are. Once you are armed with that info, you can arrange with someone to try for some aircraft scatter contacts from a summit over non-LOS paths.


Here’s one where the beacon is sending the ident in JT4. A 737 has just taken off from Edinburgh airport and is on the East to West flight path. I see the planes flying over Cairnpapple Hill GM/SS-254 through the shack window. Smaller plane on a worse alignment. Still enough time to exchabge a callsign and report though.

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Last evening Al VK1RX and I were testing our hombrew 2.4 GHz DL6WU yagi antennas. I operated from Mt Stromlo while Al had set up at Mt Ainslie, distance is 14 km line-of-sight. We each had 30 minutes to play radio after work.

My reference antenna is a tiny 2.4 GHz ‘Big Wheel’.

Our respective 24 and 20 element yagi antennas worked as expected.

A few pics to keep you interested.

In VK1 we now have 5 SOTA activators on 2.4 GHz. Chaser numbers are likely to increase over the coming month with the addition of two dedicated chasers. Interest in 2.4 GHz is growing. :slight_smile:

What’s next? Select two summits ~50 km apart followed by a second pair 100 km apart and so on.

Cheers Andrew VK1AD


On Sunday 22 April, Al VK1RX and I will attemp a 13cm S2S contact over a 150 km path between The Peak VK2/SM-068 and Spring Hill VK2/ST-036.

Equipment: SG-Lab 2.5 watt transverters combined with homebrew 20 element yagis.

The primary LOS RF path is free of major geographic vertical obstructions. Both simmits are free of eucalypt vegitation.

73 Andrew VK1AD


Hi folks

As per the previous note, Al VK1RX and I completed a 13cm 150 km SSB S2S on Sunday 22 April 2018. Equipment SG-Lab 13cm transverters operating at 2.5 watts, my IF source is a FT-817 on 435.150 MHz. My antenna is a homebrew 20el 13cm DL6WU Yagi. You will observe in the video fog was a major problem with water condensation on antennas and tripods. Water was dripping off antennas and tripods on to the radio equipment below.

This is my first attempt at publishing a video using my Mac Air notebook. The 12 minute video is a compilation of still pictures and three short videos taken at the summit.

12 minute video - VK1AD/2 at The Peak VK2/SM-068, 22 March 2018

73 Andrew VK1AD


That brought to mind the 150km test that Dave G4OIH and myself undertook in 1987 using 10GHz wide band FM equipment. It was raining heavily at the time and water was pouring off the dishes, but we made the contacts between ourselves on Ruabon Mountain in North Wales and a group operating from the Old Man of Coniston (G/LD-013). Both sets of equipment at our end worked without fault, but we got thoroughly soaked and my car seats took two weeks to dry out!

Well done on the excellent achievement. If the buzz you got from the success of this activation is anything like that I experienced 30 years ago, then you will be wanting to get out there and try even longer paths. I wish you continued success.

73, Gerald G4OIG