SOTA VK1AD – January 2021 2m – 23cm Activations

The purpose of this post is to share information with fellow radio amateurs, which demonstrates how you can achieve VHF-UHF Dx contacts with as little as 5 watts output on 144.200 MHz and 2.5 watts to 25 watts output on 1296.150 MHz.

Yes, you can also qualify a SOTA peak with a mono or dual band HT on 2m and 70cm. You can achieve greater distances with the use of an external antenna such as the 2m Oblong Loop antenna.

2 January 2021 – Livingstone Hill VK2/SM-093 QF44NG 932m ASL

Longest path – VK2TWR at Nimmitabel 88km on 1296.150 MHz SSB

2 January 2021 – VK1AD SOTA activation Livingstone Hill on 2m and 23cm – Image courtesy of SOTA MAPS
TimeCallsignBandModeNotes
00:09VK1RX2mSSBQF44NN Al s59 r59
00:13VK1MA2mSSBQF44MT Matt s56 r51
00:21VK1MA23cmSSBQF44MT Matt s51 r51
00:22VK1RX23cmSSBQF44NN Al s59 r59
00:29VK2DO2mSSBQF54CH Chris s56 r52
00:39VK1MF2mSSBMatt s54 r57
00:48VK1KW2mSSBQF44MT Rob s59 r59
00:50VK1KW23cmSSBQF44MT Rob s59 r59
01:03VK3PF/P40mSSBPeter s59 r57 S2S VK3/VE-265
01:09VK2TWR23cmSSBQF32PL Rod s59 r59 88 km 1296.150
01:12VK2TWR2mSSBQF32PL Rod s59 r59
01:16VK3AFW40mSSBRon s59 r59 S2S VK3/VT-022
01:22VK1MA2mFMQF44MT Matt s59 r56
Extract VK1AD SOTA activator log 2 January 2021
2 January 2021 – VK1AD and VK1DA Joint activation of Livingstone Hill

7 January 2021 – Mount Stromlo VK1/AC-043 QF44MP 782m ASL

Equipment – FT817ND, 5m telescopic pole and a 2m flower pot antenna

7 January 2021 – VK1AD SOTA Activation Mount Stromlo on 2m – Image courtesy of SOTA MAPS
TimeCallsignBandModeNotes
07:06VK1DA/P2mSSBAndrew s59 r59 S2S VK1/AC-048
07:08VK1DB2mSSBDermy s59 r59
07:15VK1MIC2mFMWade s59 r59
07:16VK1MA2mFMMatt s59 r59
07:20VK1CC2mFMConrad s59 r59
07:24VK2XDT/M2mFMs59 r59
07:25VK1JP2mFMJohn s59 r59
Extract VK1AD SOTA activator log 7 January 2021

SOTA – Bobbara Mountain on 23cm 212 km to Nimmitabel

Sunday 10 March 2019 – Bobbara Mountain grid square QF45HI, 753 metres ASL is 86 km north-west of Canberra GPO, near the sleepy hollow township of Binalong, NSW.

I left home at 5:30 am for a 1.5 hour drive from Canberra heading north-west to Binalong. Access to the summit is via a public gravel road within a private property.

The summit hosts an air navigation facility en route radar, mobile phone and commercial radio services. The Trig station and summit surrounds are covered by a dense cover of dead thistle plants, it’s not a place to visit at the height of spring. To prevent your legs turning into blood soaked human pin cushions one needs to wear long pants. Seriously a field of dead thistle spikes crack a major ‘punch’ on soft human skin! 😦

My aim for today’s activation is to work 2m, 23cm and 13cm chasers in Canberra 86 km south-east on voice SSB and FM. To my great surprise Chris VK2DO located on the NSW south coast 188 km east (116 miles) and Rod VK2TWR 212 km south-east (136 miles) at his home QTH in Nimmitabel, NSW, popped up on 1296.150 SSB. That’s right 212 km on 1296 MHz at 2.5 watts, pretty good if I do say so myself. 🙂

At the conclusion of the 23cm activity I tested my new homebrew telescopic 2m 1/2 wave dipole. I sent a message to Wade VK1MIC via WhatsApp seeking his assistance. Wade called on 144.2 MHz using 2.5 watts QRP into a 2m 1/2 wave vertical located at his home in north Canberra (QF44NT). Signal reports were S52 and R51 over 76 km with mixed polarisation, that’s a good resul. 🙂

On 13cm 2.403 GHz Jason VK1JA and I attempted a contact over 97 km via aircraft enhancement. We failed to make the distance.

On 2m 144.2 MHz SSB all contacts were made at 5 watts using a 2m 3el yagi antenna.

During the descent my friend Andrew VK1DA suggested I drop in at his property near Yass. Thanks Andrew I was grateful for a nice cup of tea.

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Sunrise 7:15 am

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View east at 7:30 am

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Bobbara Mountain Trig Station 753 metres ASL Latitude: -34.6393 , Longitude: 148.5903

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Dual band 2m/70cm yagi and 13cm yagi. 23cm yagi is leaning against the tripod

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SG-Lab 23cm transverter and a homebrew 12el DL6WU yagi beaming south-east towards Canberra. Operating frequency 1296.150 MHz

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2m dipole mounted on a lightweight telescopic pole

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close up view – 2m 1/2 wave dipole

Homebrew telescopic 2m dipole construction and assembly

Extract of VK1AD SOTA Activator Log: 9 March 2019 UTC – Bobbara Mountain QF45HI

Time Call Band Mode Notes
20:58z VK1KW 144MHz SSB QF44MT Rob s58 r55
20:59z VK2COW 144MHz SSB QF44OX Dimitris s57 r58
21:01z VK2DO 144MHz SSB QF54CH Chris s58 r55
21:03z VK1JA 144MHz SSB QF44NO Jason s55 r55
21:04z VK1MT 144MHz SSB QF44NM Matt s52 r33
21:14z VK1MIC 144MHz SSB QF44NT Wade s52 r51
21:15z VK1MA 144MHz SSB QF44MT Matt s51 r51
21:17z VK1FXNZ 144MHz SSB QF44NT John s55 r52
21:18z VK2TWR 144MHz SSB QF43PL Rod s52 r52
21:21z VK1JA 1296MHz SSB QF44NO Jason s55 r53 97 km
21:23z VK2DO 1296MHz SSB QF54CH Chris s55 r52 188 km
21:26z VK1BG 1296MHz SSB QF44MS Ian s58 r52 77 km
21:27z VK2TWR 1296MHz SSB QF43PL Rod s52 r51 212 km
21:28z VK1KW 1296MHz SSB QF44MT Rob s59 r59 74 km
21:32z VK2COW 1296MHz FM QF44OX Dimitris s59 r59 FM 71 km
21:37z VK1BG 1296MHz SSB QF44MS Ian s59 r59 74 km
22:11z VK1MIC 144MHz SSB QF44NT Wade s52 r51 75 km – 2m dipole

Photos: © Copyright 2019 Andrew VK1AD

SOTA – 23 cm S2S – Livingstone Hill to The Peak 78 km

Sunday 23 July 2017.  During the week I pushed an email to the VK1 SOTA group seeking interest in a 23cm SOTA activation planned for Sunday 23 July 2017.  Al VK1RX called me Saturday evening suggesting we try a 23cm 1296.150 SSB Summit to Summit (S2S) contact between Livingstone Hill and The Peak, that’s 78 km (48 miles) as the crow flies, locator QF44NG to QF43NN.   Al was very keen to activate The Peak (1230 m ASL) for 11 points and thought that a 23 cm SSB S2S contact whilst achievable, would present a good challenge @ 2.5 watts output.  We discussed expected signal reports over a 78 km path to which we pondered the possibility of achieving a S2S contact, we agreed a 5-3 signal report would be a satisfactory outcome at 2.5 watts.  Little did we know…

Livingstone Hill is a 40 minute drive south of Canberra near the country township of Michelago.   The Peak is a 1.5 hour drive south of Canberra along the Monaro Hwy via Cooma and Rock Flat.  Both summits feature in the New South Wales (NSW) Snowy Mountains region, of course Al is much closer than I to the actual Snowy Mountains Alpine region.

Photos: © Copyright 2017 Andrew VK1AD

Livingstone Hill near Michelago township

beautiful chilly morning at Livingstone Hill Trig Station

8:52 am – One hour in to the activation the temperature is a cool 3 degrees C at (22:52 UTC)

VK1AD 23cm SOTA station – Yaesu FT-817 IF on 144.150 MHz into a SG-Lab 23cm transverter.  Antenna feedline is a 1 metre length of LMR195 coax cable.   FT-817 is powered by a 12 volt 3S 2.4 Ah LiPo battery while the SG-Lab 23cm transverter is powered by a 13.2 volt 4S 4.2 Ah LiFePO4 battery.  The transverter draws 80 mA on receive and 800 mA (0.8 amps) on transmit.

VK1AD 23 cm SOTA Shack at Livingstone Hill.  My 23cm PCB antenna used later in the activation  is sitting on a plastic container.

VK1AD beaming south to The Peak VK2/SM-068

VK1AD 23 cm SOTA station.  View east Tinderry Range at 1560 m ASL

VK1RX SOTA Shack at The Peak beaming north to Livingstone Hill over a 78 km path.  Al is using an ICOM IC-706 IF at 144.150 MHz SSB mode feeding a SG-Lab 23cm transverter for output on 1296.150 MHz SSB.  Al’s transverter and antenna are both mounted above the tripod pan head.  You can see the IC-706 sitting on the concrete pad (trig point) below the tripod.  His 23 cm antenna feedline losses are negligible.

Al reported strong winds at the summit.  In the photo you can see AL gathered a few rocks to stabilise the tripod in the face of a strong north-westerly wind.

I started my SOTA CQ calls at 2155 UTC with the antenna beaming south to Nimmitabel.  At 21:59 Al responded to my call with an unexpected 5-9 signal report, a huge signal, way beyond our expectations.  🙂      You know what that means, that’s right we need a new 23cm S2S challenge with two summits 100 km+ apart working our way up to 200 km+.

Having over achieved with 5-9+ signal reports later in the activation we decided this 23cm S2S challenge would not be complete without one attempt at using PCB yagi antennas at our respective summits.  Did we make the distance, we sure did!  Signal levels were peaking 5-9 each way.  😉

On 23 cm Al and I went on to work Rob VK1KW, Ian VK1BG, Rod VK2TWR and Matt VK1MA.

VK1RX 23cm SOTA Shack at The Peak

Extract of VK1AD SOTA Activator Log:  23 July 2017 Livingstone Hill VK2/SM-093 on 23 cm 1296.150 MHz

Time Call Band Mode Notes
21:59z VK1RX/2 1240MHz SSB Al s59 r59 S2S VK2/SM-068 1296 78 km
22:08z VK1KW 144MHz SSB QF44MT Rob s59 r58 61 km
22:11z VK1MT 144MHz SSB QF44NM Matt s59 r59 30 km
22:15z VK1KW 1240MHz SSB %QRA%QF44MT% Rob s58 r58 1296 61 km
22:16z VK1BG 1240MHz SSB %QRA%QF44MS% Ian s59 r59 1296 56 km
22:26z VK2TWR 1240MHz SSB %QRA%QF43PL% Rod s59 r57 90 km
22:34z VK1RX/2 144MHz SSB QF43NN Al s59 r59 S2S 144.2 78 km
22:39z VK1BG 433MHz SSB QF44MS Ian s59 r58 432.15 56 km
22:39z VK1KW 433MHz SSB QF44MT Rob s51 r55 432.15 61 km
23:02z VK2NSS 144MHz SSB Steve s55 r55 45 144.2 86 km
23:18z VK1MA 1240MHz SSB %QRA%QF44MT% Matt s51 r31 1296 61 km

VK1AD 23cm 12el Yagi.  The mountain range to the right is Clear Range spanning 1300 m to 1500 m ASL.

looking down the barrel of a 23cm 12el yagi – Al VK1RX is well over the horizon 78 km south

23cm 12el yagi

23 cm signal from Livingstone Hill to The Peak bearing 180 degrees south over a 78 km path

SOTA – Homebrew 23cm 12 element Yagi Antenna

Sunday 18 June 2017. I recently purchased a new 2.5 watt 23 cm transverter from SG-Lab in Sofia Bulgaria. The package includes a 2el HB9VC PCB yagi which has turned out to be a great addition for portable work, particularly from a hilltop with a good uninterrupted view of the horizon. Today from the summit of Mt Taylor VK1/AC-037 locator QF44MP, I worked Rod VK2TWR in Nimmitabel over 130 km, not bad for 2 watts in to a tiny PCB antenna.

While the PCB antenna is a great addition to the SOTA kit, be it for local summits or perhaps on a long hike 10 km or more, what I really need is an antenna with a fair amount of ‘oomph’ that’s non-techo speak for antenna gain, whilst keeping weight and size or length within reasonable limits.

For SOTA purposes, keeping antenna construction as simple as possible is a key attribute to a successful activation. When Murphy’s Law bites and it will, simplicity in design and construction is the key to a quick recovery.

I have decided to build two 23 cm (1296 MHz) 12 element Yagi antennas (DL6WU format) one with ‘handle’ space behind the reflector and the second to mount on a camera tripod. I figure two antenna options are better than one, plus phasing two in a stack would make for an interesting option!

To simplify the construction and to keep weight down I am using 18 mm square Western Red Cedar as the antenna boom. I am using Yagi Calculator, written by VK5DJ to generate the element lengths and spacings. At 1.2 GHz accuracy in element lengths and spacings are equally important. My spacing tolerances are +/- 0.5 mm while reflector and director element lengths are within 0.01 mm. Design details are shown at the end of this post.

Inputs to the Yagi Calculator software program include:

  • Frequency
  • Parasitic element diameter
  • Element mounting arrangement
  • Boom cross-section type
  • Boom cross-section dimension
  • Driven element cross-section type
  • Driven element cross-section dimensions and gap spacing
  • Non-metal boom
  • Number of director elements
  • Velocity Factor of RG316 69.5%

Materials list:

  • 2 * 1 metre lengths of 18 x 18 mm Western Red Cedar
  • 1.2 metre length of 3.1 mm aluminium rod purchased from Alucom. (Sufficient for one set of elements)
  • 100 mm length of RG316 for an 80 mm balun
  • 1 * RF N Type panel mount socket
  • 1 * 6 mm sprinkler riser (spacer)
  • 2 brass wood screws 25 mm long
  • Araldite or an epoxy resin to protect the feed point/balun
  • PCB Lacquer
  • Cabots Cabothane clear timber varnish
  • Sense of humour and patience 😉

Tools:

  • Vernier caliper capable of measuring 0.01 of a millimetre
  • Marking Gauge
  • Square
  • Coping Saw
  • Pedestal Drill
  • 2.5 and 3.3 mm drill bits
  • Hobby knife
  • Scribe
  • Sharp pencil
  • Steel Rule 150 mm (6 inch)
  • Tape measure
  • Hand File fine-cut
  • Needle File
  • Soldering iron

Photos: © Copyright 2017 Andrew VK1AD

Boom Preparation

I used a marking gauge to mark the center line on opposite faces of the wooden boom.

marking the center line on opposing faces of the boom

Marking out element positions on each boom is a lot of fun, measure twice and mark once. I used the tip of the scribe to mark the hole positions. Make sure you mark the position of the driven element, you will need a reference point later.

Marking out Reflector, Driven and Director element positions on each boom

Two antenna booms – left boom will have space behind the reflector as a hand-held antenna. Right boom will have a tripod mount arrangement

Reflector and Director Elements

The 3.1 mm aluminium reflector and director elements are cut with a fine hacksaw then filed to their specified length. Each element is measured with a vernier caliper to within 0.01 mm. For the time being the elements are stored in a blank section while I continue work on the boom and the driven element.

Reflector and 10 director elements stored in a blank section

Folded dipole driven element

I marked out each of the folded dipole point-to-point measurements. I had a practice session at folding a driven element of 1.7 mm soft copper wire around a short length of 23 mm dowel. This is not the intended finished driven element, however it will serve me well for a shorter 5el yagi.

1st attempt at folding a 1296 MHz folded dipole by hand.

After three attempts at folding the driven element I have the finished product. As mentioned above the top element in the picture is 1.7 mm soft copper wire. Middle and bottom driven elements are each 2 mm solid copper wire found in the junk box. After cleaning the bottom element I will mount it to a female N Type panel mount socket. I will make good use of the spares. 🙂

thee 1296 MHz folded dipoles

Drilling the boom. I started with a 2.5 mm pilot drill followed by with a 3.3 mm drill bit. All holes were drilled using a drill press.

view down the length of the 23cm yagi, I’m pretty pleased with the alignment of each element, my eyesight hasn’t failed me yet! 🙂

Reflector and Director elements fitted to the non-handle version

Reflector and Director elements fitted to the handle version. I plan to cut a second set of parasitic elements

Back to the driven element..

I used emery paper to remove tarnish from the folded dipole which is now ready for a drop of solder. You will note the socket pin is soldered to one end of the open loop. This offsets the N Type socket by 3 mm to the left or right of the imaginary center line. It is important to remember the 3 mm offset when mounting the socket/dipole assembly to the boom, else the folded dipole will not be centered to the axis of the boom. Next fabricating the RG316 1/2 wave balun and cutting a garden sprinkler riser to make a pair of spacers to fit under the N Type socket.

Folded dipole and N Type socket ready for soldering. Use a small needle file to remove the socket plating and expose the brass.

Oh dear (or other choice words not suitable for this blog), working with RG316 takes a lot of patience, cutting and trimming the coax is as Andrew VK1DA explains ‘character building’. On my third attempt, that’s right 3rd attempt, I managed to not cut through the very fine multi strand center conductor. Phew, time for a stiff whisky! 🙂

If you know the secrets of working with RG316 particularly the center conductor, I’m all ears. BTW, I am using quality 316 (silver plated copper wire with a Teflon (PTFE) dielectric) from Mini Kits in South Australia, which isn’t the copper coated steel (CCS) variety. Now I know why the CCS version is popular with radio hobbyist like me, it’s difficult to cut through the center conductor. Ha ha..

RG174 may be a practical alternative. Remember to adjust the length based on the cable’s velocity factor (vf).

Next is the tricky part. Without destroying the integrity of the balun with an overzealous soldering iron, carefully solder the ends of the balun center conductor (I put so much effort in to that bloody balun!) to the driven element ends, plus solder the outer braid of each end to the N Type flange. This will test your spirit and endeavour to finish the project. Make sure you leave space around the flange mounting hole to accommodate a spacer. Good luck!

Folded dipole and balun (RG316) secured to a N Type panel mount. I will replace the ugly green tape with a section of heat-shrink

As mentioned earlier mounting the N Type socket requires a 3 mm offset due to the 5 mm spacing in the loop ends, if not the driven element will not be centered to the axis of the boom. Use the marker gauge to mark the offset line.

Feed point, folded dipole and balun assembly

Accurate spacing of the assembly above the boom will ensure the driven element is spaced evenly top and bottom. As best as you can have the center of the folded dipole in line with the reflector/director elements. Align the driven element to the markings on the side of the boom.

I cut two 13 mm lengths of 6 mm garden sprinkler riser tube. I am thankful the metal support screws have little to no influence on the VSWR reading. Before tightening the screws check the driven element is perpendicular to the boom. You can measure the spacing of the driven element between the tips of the 1st director and the tips of the reflector.

N Type flange mount and driven element assembly perfectly aligned to the first director and reflector elements.

Finished after 7 days of part-time construction work. You could easily build this antenna in a day. 🙂

Finished 12el 23cm Yagi ready for SOTA action!

To help protect the copper driven element from tarnish I applied a generous coating of PCB lacquer. To help prevent movement of the reflector and director elements, I applied a small amount of Araldite glue to each rod and mounting hole.

I haven’t decided whether to treat the wood with a coat of varnish or leave it as is.

Post update: 1 July 2017, mastering RG-316 1/2 wave balun.

Practice makes perfect, I’ve constructed a 3rd 1296 MHz folded dipole assembly. Best attempt thus far. Best approach to the 316 center conductor is to peel off small amounts of the Teflon dialectric until you expose the fine silver coated center conductor 🙂

Latest update: small wooden block glued to the boom

small wooden block to help protect the folded dipole and to prevent unnecessary movement

top side

Although not shown in the above picture, the boom now has a generous coating of Cabots Cabothane clear timber varnish. 🙂

Photos: © Copyright 2017 Andrew VK1AD

Published: 29 June 2017
Last Update: 5 July 2017

Output of VK5DJ Yagi Calculator

Balun design

RG316 1296 MHz 1/2 wave balun