VK3ARR's SOTA Blog

Ego loqui ad viros super montes

Month: July, 2016

4 element 2m Yagi

As the HF bands drop off, I have decided it is time to up my portable capabilities on VHF. Having already tried out 6m with some enjoyable success, the option is to move to 2m or 70cm, the latter having shorter antennas but more critical dimensions, and the former being larger but more tolerant of poor construction (much like me).

The other requirement was for a short boom length, so 12 elements on 2m wasn’t going to fly. I went looking for designs and settled on a 4 element 28 ohm DK7ZB antenna, listed as very easy for beginners to build. I concur. The total length would be 76cm, and the widest element was 1030mm, which was roughly in the ball park of what I wanted (longest dimension 1m).

I ducked down to Bunnings, and grabbed some 10mm aluminium tube, and a 20mm square section aluminium boom. Had I still had my old car, I would have bought a 3m piece of 10mm tube plus another 1m section, but instead grabbed four 1m sections, as hacksawing the tube down in the car park to fit in the new car doesn’t quite gel with my style.

The dimensions for 10mm tubes are:

  • Reflector: 1030mm
  • Driven Element: 990mm
  • Director 1: 937mm
  • Director 2: 857mm

The elements were cut to length using a tube cutter, before a 30mm section was cut from the offcut of one of the directors, and stuck onto the reflector. To do so, I took an 8mm wooden dowel, chiselled it down to fit, and jammed it into the two pieces of tube so they wouldn’t move, then wrapped aluminium tape around the join for good measure.

A small addendum to the reflector, MacGuyver style

A small addendum to the reflector, MacGuyver style

Once the elements were cut to length, I used 3/8″ P-clips to attach the non-driven elements to the boom in the right locations. Two p-clips at each position, held in place with M4 bolts through the beam.

The driven element was marked in place using a 3-way junction box ($1.26 at Bunnings) and I used a 13mm barbed poly tube joiner to act as a spacer. I chose the Holman brand rather than the really cheap home brand version as it had a bit more clearance and the 10mm tube slid into it perfectly. I predrilled holes for screws to hold the elements in place, put in a BNC connector I had handy, and connected up the DK7ZB match.

The DK7ZB match is a parallel section of 75 ohm line to act as a 28-ohm to 50-ohm match. I used RG-59, again from Bunnings, at 70c for a single metre, cut to 42.5mm lengths (quarter-wave for 145MHz at a Vf of 0.82). Once I had everything in place, I fed through the driven elements and connected them to the other end of the match.

Gratuitously large amounts of silicone (and a wedge of paper) were used to hold the driven elements in the right place in the junction box. Saddle clips should probably have been used, but it is unlikely I’d break down and reassemble the driven elements on a summit anyway; I’d run out of saddle clips, and I had gratuitously large amounts of silicone handy at that point. This is a portable antenna, but not a bush-bashing one.

The DK7ZB match

The DK7ZB match

The junction box was attached in the right spot with two M4 bolts. The match points forward out the third hole in the junction box. It is held parallel with some heat shrink. The BNC connector is accessible from the rear of the antenna.

I connected up the antenna to test it out and SWR was fairly flat across the band – a little higher at the 146MHz end. My FT-857 is Japanese spec, so I can’t transmit outside of 144-146MHz without desoldering some links on the main board. I’d say it’s resonant around 144 MHz or perhaps a little below. SWR is barely noticeable on transmit between 144 and 145.

I intend to get out and test the antenna in the wild sometime over the next two weeks; keep an eye out for alerts.

The finished antenna - I will remove the section of boom at the front to shorten it.  Resting on two beehive supers - another hobby

The finished antenna – I will remove the section of boom at the front to shorten it. Resting on two beehive supers – another hobby

JMMFD Certificate

I came home the other day to discover a large manila envelope and inside was a certificate for finishing 13th in the John Moyle Memorial Field Day Single operator 6 hour division.

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As certificates were issued to all who went out portable for the weekend, this reminds me of the sort of “third best trier” encouragement award that seemed to be in vogue for a few years there during school, but one mustn’t be ungrateful 😀 A certificate is a certificate! Next year, I’ll aim to finish 12th!

HL/SL-006 – Guryongsan

Guryongsan was not a new summit for me, but it was for Andrew HL5ZBA, so we organised to meet up for hiking followed by beer. One of my ex-employees in Seoul, Hwanii, is still in regular contact with all of us, and hiking and beer is something he enjoys (more of the latter, I think), so he said he’d pick us up around 8am, ready for the climb.

Andrew and his wife Georgina were staying in Gangnam at a slightly less ostentatious hotel than mine, and after calling Hwanii to work out where he was (he’d fallen back asleep again), we finally got on the road about 8:30am.

Guryongsan is easily accessed from a number of points. It forms a summit pair with Daemosan, and, perhaps obviously, sits atop Guryongsan Tunnel. Looking at the tunnel heading south, there is access from the left by a shanty town, or from the right via a steeper set of steps. We took the shantytown option as I’d done that with Jason HL4ZFA last year and in theory should know where I was going.

In practice, I didn’t, but it doesn’t really matter. You are essentially climbing up to the saddle between Guryongsan and Daemosan and most roads in the shanty town lead there, and you keep walking until you hit the fenceline, which is a military area. Don’t go in there, but turn right and follow up to the top of the mountain. It’s signposted fairly clearly once you leave the shanty town and start climbing.

We reached the top around 30 minutes later, taking a few breathers along the way, and I was able to set up using a park bench and keeping the 40m dipole rolled up and only using the 20m links to tie off to trees. Again, I used the 4m shrinkenpole, and decided to keep this one primarily a CW activation.

A helipad atop the mountain, with Georgina and Andrew in the background.  There's too many trees for a helicopter to properly land.  I set up on the bench next to Georgina.

A helipad atop the mountain, with Georgina and Andrew in the background. There’s too many trees for a helicopter to properly land. I set up on the bench next to Georgina.

I started on 15m, and worked Rick VK4RF and John ZL1BYZ, before a summit to summit with JJ1SWI/1 on JA/TK-012, to complete the JA association for Mountain Hunter. A QRZ later, and all hell broke loose.

This was my first real CW pileup – basically just a constant tone as everyone tried to call in at once. I tried very hard to bring in Tony VK3CAT for a S2S, but he never quite picked up out of the noise to give me my signal report. From then on, I worked a fairly steady stream of chasers, finishing on 15m with a S2S with JF1NDT on JA/YN-012. 20m yielded one contact with Take JS1UEH out portable, before we decided to pack up, roughly an hour since my first contact. The entire hour was filled with many South Korean hikers peering over the top of me, with Hwanii acting as my marketing arm.

Andrew and I then proceeded up and down the mountain to work each other for SOTA Completes, but this rapidly turned into an exercise in diagnosing what was wrong with Andrew’s antenna, although we completed the contacts easily enough once he used the dodgy one. After a rapid descent, we found beer and fried chicken (and burgers), before dropping Andrew and Georgina off at the train station for their trip back to their home.

Thanks to Andrew, Georgina and Hwanii for another great SOTA day. Next time we go further out!

Seoul from Guryongsan.

Seoul from Guryongsan.

JA/IB-003 Tsukubasan 筑波山

Given my last SOTA dinner had resulted in a nightmare hike the following day, it was a surprise to awake early but sober. I packed my bags up as I was due to fly out that evening to Korea, and checked out – laptop and usual backpack inside my suitcase, and SOTA backpack on my back. I headed into Terminal 1, left my luggage there, then caught the 0623 SkyAccess train via Minami-Nagareyama to Tsukuba station (on the Tsukuba Express line).

I met my friend and colleague Takumi, who was present on the last adventure around Takaosan, and we took the bus from Tsukuba Station to the Tsubukasan Ropeway – the last stop on the bus. This costs about $10 AUD one way, with the first bus around 8am. We made the first ropeway trip up, and from the top of the ropeway station to the summit is only about a 5 minute walk.

There are two peaks on Tsukubasan, Nantaisan and Nyotaisan. Nyotaisan is the SOTA peak, being higher by a few metres, and is closest to the ropeway station.

Ropeway up the mountain

Ropeway up the mountain

Whilst on the ropeway, Takumi had to take a photo of me. When asked why, he said it was to prove to his wife he was with me (and presumably not with some other lady or knee deep in Pachinko!). Satisfied he was just with some weirdo and a radio, we continued to the summit. This is hardly strenuous, but once you reach the top, you realise how difficult it would be to string out a dipole on HF.

At the top!

At the top! Look at those well-defined calf muscles!

I had suspected that HF from the top was going to be tough – Google Earth showed a rocky summit, and talking with a few of the SOTA Japan folks, it was strongly suggested that attempts to string a dipole would result in heading off the side of some quite steep cliffs. I opted against it in any case, and had only spotted on VHF. Even with the first ropeway trip of the day, there was quite a crowd at the top. By the time we finished, the crowd was becoming a throng.

I set up towards the Tokyo side of the mountain – there’s a small dip in the rocks, and I felt this would be perfect to be out of the way of the crowds. Equipment was the FT-857 and my 6m SOTA antenna based on Andrew VK1AD’s version of the VK2ZOI flowerpot antenna. This and its mast was rested against a convenient rock.

The shack

The shack

4m shrinkenpole with VK2ZOI flowerpot antenna for 6m on it.

4m shrinkenpole with VK2ZOI flowerpot antenna for 6m on it.

Phone coverage is good from the top, so I checked out SOTAWatch, and saw Jun JI1IHV operating on summit JA/KN-021 on 50.230. I moved to his frequency, and after hearing him wrap up a few QSOs, called in for a Summit to Summit. The QSO was completed easily, 59s in both directions, and 857 to 857. This was an important QSO for me: it was association 17 activated, it was 1000 summit to summit points, and it was my first JA summit chased. The greatest aspect was that I’d had dinner with Jun the night before, and it was great to get an RF contact to “complete” the circle!

Tokyo and the Kanto plain

Tokyo and the Kanto plain

The view from the top would be fine on a clear day: we instead had a lot of cloud haze around, making Tokyo all but invisible from the top. Still, a mountain view is a mountain view, and when my wife texted me asking me what I was doing this fine day, I felt obliged to send her a selfie from the top of the summit. A phone call later from the airport closed that particular circle too!

Selfie atop Tsukuba-san, Takumi in the bottom right corner

Selfie atop Tsukuba-san, Takumi in the bottom right corner

We operated for about 30 minutes in total. I had 4 contacts fairly quickly by that point for the 6 points – JP1QEC portable in Saitama being number 4 in the log, and I told Takumi about my theory that if you are low on contacts, simply call “Final call”. This never fails to work, and this time another 3 contacts were made in quick succession. Nobi JA1JCF emailed me later to suggest that my phonetics were perhaps a bit difficult to understand for Japanese, with the India of my callsign sound more like a Kilo. Who said the International Phonetic Alphabet improves readability?

There was plenty of insect life at the top of the summit; a spider on my neck being close to the final straw, but I survived biteless. A pretty lizard with iridescent blue markings on its tail also came out for a look; I don’t feel the picture below really captured its colours.

An interesting lizard

An interesting lizard

After a quick pack up, we headed back via the shrine atop Tsukubasan and walked over to the Cable car station. This is a separate method of reaching the top of the mountain, and is about 15 minutes from the summit of Tsukubasan and much closer to Nantaisan.

Takumi near the shrine

Takumi near the shrine

Having reached the cable car station, there are a number of souvenir places and restaurants. We stopped to grab some lunch and beer. The local ramen style was recommended by the lady running the restaurant, and it was very nice. The beer went down well too!

Tsukuba ramen

Tsukuba ramen

We took the cable car down to the second bus stop, walking past another shrine at the base of the mountain. Takumi stopped to pay his respects. We then descended, Takumi politely telling me off for walking too close to the center of the path (being reserved for the god of the shrine to walk up). Won’t do that again.

Shrine at bottom of mountain

Shrine at bottom of mountain

The bus stop was another 5-10 minute walk, but we’d just missed one, so I bought us both ice creams and we ate those as the day heated up. It was probably about 30 degrees by that stage, but around 80% humidity. We also got a summit map for free from the information centre – perhaps a little late, but I do like my maps. It was a copy of the map that was on several signs along the mountain, which I had already photographed.

Tsukubasan from the base

Tsukubasan from the base

Summit map

Summit map

The bus trip back to Tsukuba station was marked by both of us trying hard not to fall asleep. I think I managed to, but I did notice Takumi drop off for a while. From there I reversed my morning travel, getting back into Terminal 1 at Narita, fetching my suitcase, swapping radio backpack for laptop backpack, and jetting off for Korea.

Tsukubasan from the bus

Tsukubasan from the bus

Tsukubasan is an easy summit for folks visiting Tokyo, although it’s not exactly “close”. It is however, a Hyakumeizan – one of the 100 beautiful mountains – and one of the most easily accessible. The saying goes, “Fujisan in the west, Tsukubasan in the east”, and I can attest the mountain is very pretty. Being a Hyakumeizan it is of course very busy, but a VHF activation is easily done here, and I imagine you might even get away with a HT.

Tsukuba also has the JAXA (Japan’s NASA) space museum, which I didn’t get a chance to visit due to time, so if you’re looking for an excuse to head out there, that’s a gilt edged one right there!

SOTA Japan dinner – 17 June 2016

After finishing up at Oogusukuyama, and heading back to Tokyo, I dumped my bags at the airport hotel I was staying at in Narita, grabbed a taxi to the airport (shuttle bus schedule again didn’t align with my schedule) and grabbed a Skyliner train into Nippori, and from there to Akihabara. The reason? Akihabara is the ultimate destination for any radio ham: the stores on the west side of the station are manna from heaven. The other reason, a gathering of SOTA folks from Japan to celebrate 1 year of SOTA in Japan.

I had timed my run poorly, and most of the smaller shops were starting to close up by the time I arrived, but I had a good look around still, bought a few small things, and spent a reasonable amount of time inside Rocket Ham, the biggest of the ham stores in Akihabara. Afterwards, I made my way over to the Central gate, where we were going to meet before heading to the restaurant.

One of my great regrets on this (literally) flying visit was that I wasn’t going to get to sample my favourite Japanese cuisine, Shabu Shabu. To my great delight, when Toru emailed me with the news that we were meeting at Shabu Shabu On-yasai, a chain of shabu shabu restaurants of which I had spent a lot of time in (particularly their Ebisu branch). Three birds with one stone: Akihabara, shabu shabu and SOTA dinner!

I was a little early and no one was there, as well as a little hot, so I found an ice cream place and had a quick ice cream, which cooled me down nicely. I then proceeded back to the gate and saw Toru and Takeshi Abe JG1GPY. We swapped cards and gifts and, after being joined by Nobi JA1JCF, Jun JI1TLL and Jun Hirai JI1IHV, we headed over to the restaurant. We were joined there by Minoru Tomobe JL1NIE and Take JS1UEH, who made the first SOTA QSO from Mt Fuji early in the program.

The meal was excellent, the company even better. We spoke a lot about SOTA, ham radio, Australia, Japan and even astronomy (JG1GPY doing an excellent job of sketching sun spots through an ED80 with H-a filter). My phone battery was almost flat, so I took no photos myself, but have managed to pull together a few from others, and trawling the twitter feeds of the less sober.

L-R: Nobi Hyakutake JA1JCF, Toru Kawauchi JH0CJH, Jun Hirai JI1IHV, Minoru Tomobe JL1NIE, Takeshi Abe JG1GPY, Andrew Ryan JI1GBE / VK3ARR, Junichi Susaki JI1TLL, Takeshi Saiki JS1UEH.

L-R: Nobi Hyakutake JA1JCF, Toru Kawauchi JH0CJH, Jun Hirai JI1IHV, Minoru Tomobe JL1NIE, Takeshi Abe JG1GPY, Andrew Ryan JI1GBE / VK3ARR, Junichi Susaki JI1TLL, Takeshi Saiki JS1UEH. (Photo courtesy Toru JH0CJH)

Much later in the night! (Photo courtesy Nobi JA1JCF)

Much later in the night! (Photo courtesy Nobi JA1JCF)