SOTA – VK1AD portable 70cm update #11 – Mt Mundoonen

Easter Monday 28 March 2016, planned SOTA activations of three peaks in the vicinity of Yass township, NSW

  • Mt Mundoonen VK2/ST-053, 810 metres ASL Mundoonen Nature Reserve, Maidenhead Grid Locator QF45ME
  • Mount Bowning VK2/ST-042, 792 metres ASL Maidenhead Grid Locator QF45JF
  • Spring Hill VK2/ST-036, 876 metres ASL Maidenhead Grid Locator QF44NV

Today Al VK1RX and I have teamed up to activate three SOTA peaks, Al’s plans include operations on HF, 7 and 14 MHz while my aim is to activate and qualify each peak on 144 and 432 MHz.   Today’s SOTA activation will be my 13th attempt at qualifying a SOTA peak on 70cm 432 or 439 MHz, 13 will be my lucky number!   So far my tally for 2016 is 10 out of 12 peaks with a strike rate of 88%. Summits not qualified on 70 cm are Blackfellows Hill and of all places Mt Stromlo only 6 km from my home QTH in Canberra.

Mt Mundoonen SOTA 70cm activation
Radio: Yaesu FT-857D, UHF 70cm frequencies 432 MHz USB and 439.00 MHz FM
Power Level: 15 watts
Antenna: 7el Yagi
Distance to Canberra GPO (VK1):  51 km (31 miles) at 171 degrees
SOTA Alert: Yes
Date posted alert: 26 March 2016
Notice Period:  2 days
Outcome:  Qualified Mt Mundoonen on 70cm  🙂
Duration to qualify on 70cm: 36 minutes  😉
My 2016 70cm challenge: qualified 11 from 13 summits activated

Photos: © Copyright 2016 Andrew VK1AD

Weather on the summit: 15 degrees C, light winds, foggy in the cloud   🙂    Water consumption one litre.

For directions to this summit see my post SOTA – Mt Mundoonen 13 December 2014.  The ascent to the summit is 110 metres over 1.2 km (0.8 miles) taking 20 minutes.  On this occasion Al VK1RX and I had a heap of antenna gear so we elected to drive to the top of the asphalt road and parked the car next to the LF compound.

In the picture below and on the ground with nature, VK1AD SOTA station consisting of Yaesu FT-857D, 2m 90 watt amplifier, powered by 4S 8.4 Ah LifePO4 and 4S 4.2 Ah LifePO4 batteries, antenna switch to select the 2m or 70cm yagi, iPad running FlightRadar24, 2m 4el yagi and a 70cm 7el yagi, plus other bits and pieces.  The FT-857 has a single rear N connection for 2m and 70cm hence the need to switch antennas on changing bands.    While operating on 2m and 70cm, Al and I discussed the pros and cons of my antenna switch (rated to 600 MHz) versus a 2m/70cm duplexer.  Hmm I can see a new piece of kit in the mail, even before I leave the summit!

VK1AD SOTA shack on Mt Mundoonen - FT-857D accompanied by a 2m 90 watt amplifier

VK1AD SOTA shack on Mt Mundoonen – FT-857D accompanied by a 144 MHz 90 watt amplifier

No shortage of chasers on 70cm, with the FT-857D output power set to 15 watts, I qualified the summit in 26 minutes working Ian VK1BG, Rob VK1KW, Ian VK1DI, Matt VK1MA and last but not least Chris VK2DO at a distance of 143 km (89 miles).  My current 70cm distance record stands at 173 km from a QSO with Dimitris VK2COW QF44OX near Gundaroo, during a SOTA activation of Mt Perisher on Sunday 20 March 2016.  Dimitris and I were operating Yaesu FT-817s at 5 watts output, that’s a terrific result for 5 watts on 432 MHz.  🙂

My aim for 2m is to work Bernard VK3AV, a regular HF SOTA chaser on the north-east fringe of Melbourne and now a new entrant to VHF Dx.  During the week Bernard and I exchanged emails where we discussed the likelihood of a SOTA contact on 144 MHz aided by Aircraft Enhancement (AE).  Based on my limited experience with AE, which dates back to 2013 where Allen VK3HRA and I made the first VK VHF Dx 2m SOTA S2S contact over 490 km, leading up to this activation I was confident Bernard and I would make a valid signal report exchange.  Today I am using the same homebrew 2m 4el yagi as I did in March 2013.   On 2m the VHF Dx contacts were (IMHO) impressive!  The furthest contact was with Ian VK3AXH at 560 km (347 miles) followed by Arie VK3AMZ at 528 km (328 miles).

I am very pleased to report Bernard and I made two SOTA contacts on 144.160 MHz USB the first at 21:29 UTC and just for fun the second at 21:52 UTC, just to prove the first attempt wasn’t a fluke.  The exchange of signal reports was achieved when commercial aircraft were flying over Lake Hume, 227 km south-west of Mt Mundoonen and yes you guessed it, 227 km north-east of Bernard’s QTH exactly mid way between our two stations.  Each of the two VHF 2m AE contacts lasted about 3 minutes.

I should mention I did swing the yagi around to the north-east and I posted a number of alerts for CQ Sydney and CQ North-east. Unfortunately there were no takers in that direction.

Extract from VK1AD SOTA Activator Log – Mt Mundoonen on 70cm and 2m

Time Call Band Mode Notes
21:01z VK1KW 144MHz SSB Rob S59 R59 QF44MT 41 km
21:04z VK1BG 144MHz SSB Ian S59 R58 QF44MS 46 km
21:07z VK1BG 433MHz SSB Ian S58 R58 QF44MS  46 km
21:08z VK1KW 433MHz SSB Rob S55 R57 QF44MT 41 km
21:10z VK3AXH 144MHz SSB Ian S51 R41 QF12WI  560 km (347 miles)
21:19z VK3EJ 144MHz SSB Gordon S58 R58 QF24TB 311 km
21:20z VK3AMZ 144MHz SSB Arie S51 R53 QF22FE 528 km
21:27z VK1EM 144MHz SSB Mark S55 R55 QF44
21:29z VK3AV 144MHz SSB Bernard S51 R41 QF22PL 451 km
21:32z VK1MA 144MHz SSB Matt S59 R59 QF44
21:34z VK1DI 144MHz SSB Ian S59 R58 QF44
21:35z VK1DI 433MHz SSB Ian S55 R51 QF44
21:36z VK1MA 433MHz SSB Matt S58 R58 QF44
21:39z VK2DO 144MHz SSB Chris S58 R57 QF54CH 143 km
21:41z VK2DO 433MHz SSB Chris S51 R52 QF54CH 143 km (89 miles)
21:52z VK3AMB 144MHz SSB Bernard S51 R41 QF22PL 451 km
22:03z VK3DUT 144MHz SSB Norm S52 R55 QF32VF 347 km
22:24z VK1WX 144MHz SSB Amanda S58 R51 QF44
22:31z VK1WI 144MHz SSB Amanda S58 R57 QF44
22:31z VK1ACA 144MHz SSB Amanda S58 R57 QF44

Al joined me for a taste of the 2m VHF Dx action.  After calling CQ ‘once’ Al had the pleasure of working Jim VK3II over 514 km.  Al and Jim’s QSO continued for what seemed to be 10 minutes and without AE.  Jim’s power output was 150 watts into a 14 element yagi, my own thoughts, Jim’s antenna, pre-amplifier and radio equipment is doing the hard work, but of course our set up on Mundoonen was sufficient to get a weak VHF signal to Jim’s antenna. 😉

Al went on to work Bernard VK3AMB QF22PL 451 km, Norm VK3DUT QF32VF 347 km and Amanda VK1WX in Canberra

in the picture Al VK1RX working Jim VK3II at QF21RN (514 km ) near Philip Island on the perimeter of Western Port Bay

in the picture Al VK1RX with headphones on working Jim VK3II at QF21RN (514 km ) near Philip Island on the perimeter of Western Port Bay

Photos of the summits surrounds, it’s a cool morning with a cloud gathered around the mountain top


7el 70 cm yagi


4el 2m yagi mounted on a fiberglass squid pole 3.5 metres above the ground pointing towards Melbourne (VK3)


LF Non-directional beacon ‘YAS’ transmitting on 335 kHz.  No interference to Al’s HF gear  🙂

After preparing this post, I hope some of the current crop of VK SOTA activators will take encouragement from this post and try VHF Dxing as a different experience to the reliability of 40m.  There are a few sacrifices to be made, like getting out of bed at 5:00 am, being ready on the summit by 8 am and being patient while you wait for the alignment of aircraft and the elusive weak VHF signal to pop out of the noise.   What’s exciting about VHF Dx is on one hand the unpredictability of who might be calling CQ and on the other hand the ability to predict a short QSO based on the movement of commercial aircraft.  The bigger the aircraft the bigger the lift in signal strength.  In some cases a reliable VHF point to point circuit can develop without the aid of aircraft enhancement.

While writing this post 11 April 2016, I am pleased to report I have set myself a new PB for a 70cm contact from Bobbara Mountain VK2/ST-044.  More on that activation soon.



3 thoughts on “SOTA – VK1AD portable 70cm update #11 – Mt Mundoonen

  1. Great work Andrew. Very interested in the AE and how you have attached the antenna to the squid pole.


    • Hi Chris,

      I will prepare a post and send a couple of pics to you. I mounted an antenna U bolt clamp to the yagi boom and inserted a short length of plastic conduit in the U bolt. I selected a tube diameter where the tube rests on top of the 3rd or 4th section of the telescopic pole. The tube inside diameter has sufficient clearance to allow the yagi to rotate freely on the pole. I should tie a length of 3 mm hootchie cord to the end of the boom to enable easy rotation by hand. At Mundoonen I tugged on the coax (light pressure) to rotate when required.



  2. Pingback: SOTA – VK1AD portable 70cm update #12 – Mount Bowning | Get out of the Radio Shack and Live Life

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