SOTA Activation – VK7/SC-052

View east towards Tasman Peninsula and Iron Pot

View east towards Tasman Peninsula and Iron Pot


On Saturday the 11th of October 2014 I undertook my first SOTA activation and the first activation for VK7/SC-052 – Tinderbox Hills. It was a rushed affair with work and family meaning I was not properly prepared come Saturday morning. But after an initial stumbling block (15 minutes into my walk, realising I’d left my batteries at home) I did successfully activate the summit.

The summit is easily accessible via a good track maintained by Kingborough Council. With both easy parking found at the end of Estuary Drive, and then a clearly signposted start of the track. And as per the sign, it’s a ‘moderate’ walk taking at most 45 minutes to get to the top.

Start point (car park) for VK/SC-052.

Start point (car park) for VK/SC-052.

Along the way you’re presented with rather nice views both east and west – as after all, you’re walking along the single ridgeline of a peinsula. To the west you look down over Northwest Bay to Margate, and out to the east you can clearly see Iron Pot, Opossum Bay and onto Tasman Peninsula – and also clear to New Zealand (but obviously not visible). And if you look back down the track you can see Mt. Wellington rising above the tree line.

Overview of the walk for VK/SC-052.

Overview of the walk for VK/SC-052.

There are a couple of rocky areas and some step bits to keep the heart moving, however I did see two ladies arrive at the top after me arrive on mountain bikes.

Of note though – and something readily seen on the maps from LIST map – is that the summit is actually on private land. This is further emphasised by signs from the Council as there is no fence line. However, the boundary is between about 10 to 15 meters vertically of the summit, and luckily SOTA rules are that you must be within 25 meters of the summit (vertically). And better yet, the sign-post provided for a reasonable support for my squid pole extend and 2m half-wave dipole attached.

(The boundary line can be seen as the grey line intersecting the close up map on the right.)

Map showing set-up location right on the private boundary line - noting the summit of VK/SC-052 is actually on private land.

Map showing set-up location right on the private boundary line – noting the summit of VK/SC-052 is actually on private land.

My plans for the day were to activate on 2m FM, 2m SSB and 40m SSB. As it was, on 2m I only made three contacts (not enough for an activation), so lucky 40m than filled in the remainder by providing 18 contacts.

A resulting rough breakdown for 40m:

  • VK7 x 2 (however, I think neither had heard of SOTA so I’m not sure they’ll be logged)
  • VK2 x 2
  • VK5 x 1 – as a S2S (and obviously my first for that, and his – VK5CZ – to a VK7 summit)
  • VK3 x 13

I’m hoping that in future I might have more success on 2m – especially some SSB – but I think I’ll need to make sure I attempt to make more locals aware of the activation. Indeed, I would love to be able to activate some of the local peaks (Mt. Wellington – VK7/SC-001 and Mt. Rumney – VK7/SC-045) with nothing but 2m. But we’ll have to see what can be done.

But that all said, a fun time was had and some lessons were learn’t – such as, I carried far more battery power than I needed, and seeing they were two 4Ah SLABs, it would’ve been great to have taken only one. And I’m definitely looking to get organised and get another activation happening soon!

Thanks to everyone who took the time to reply to the calls. 🙂


Bendix Radio – Cape Bruny

Was taking another visit down to the Cape Bruny (Tasmania) lighthouse a couple of weeks back. While there I took some time to capture the Bendix radio setup in the museum there. It’s a transmitter and receiver combo made up of:

  • Receiver: Bendix RA-10FA
  • Transmitter: Bendix TA-12D

These were WWII era and there are some snippets of info online (especially regarding the TA-12 series of transmitters). Also, they seem to pop up for sale on eBay and the like from time to time.

Enjoy the pics!

WSJT-X Going the Distance – 16,900 km

JT65 QSO with AB1J at some 16,917 km.

JT65 QSO with AB1J at some 16,917 km.

After successfully getting WSJT-X 1.3 up and running last night, I decided to throw out a quick CQ on JT65. Even though my waterfall was showing some interference I still managed to pick up a contact way out over on the West Coast of America some 16,900 kms away!

Other than being my longest QSO to date, what really surprised me was:

  • The fact the QSO was achieved with such high level of interference with the signal barely visible on the waterfall (see below); and
  • That this was with JT65, so imagine what could be achieved with JT9 – shame the majority of activity of the two is JT65!

Looking forward to doing more with WSJT-X!!

Waterfall showing QSO with  AB1J. Note the interference and how weak (visually) the successfully received signal was.

Waterfall showing QSO with AB1J. Note the interference and how weak (visually) the successfully received signal was.

An easy 15,800 with JT9

An easy 15,800 with JT9
JT9 QSO with K8TLC at some 15,813 km.

JT9 QSO with K8TLC at some 15,813 km.

I was passing the shack’s computer last night before dinner and I noticed JT9 showing a very clean waterfall. I saw someone calling but it was really on the edge of my filters passband. So in case someone else was about I threw a CQ out up in a stronger section of my passband.

To my surprise the other caller (K8TLC) saw it and immediately replied. This resulted in a full QSO at some 15,813 km. Full exchange can be seen in the screenshot.

I’ve also found some information on getting WSJT-X versions 1.2 and up working on Windows XP. Seems in my haste I missed the pertinent information in the manual. If all works out I’ll be sure to share.

WSJT-X and DX with JT9 and JT65

Last week I came across JT9 as a mode for DX on HF. I’d not come across it before (possibly being side tracked with WSPR), but before I knew it I was downloading WSJT-X, reading the tutorial and running it up.

However, first attempts to receive were a complete fail. I was sure of success as it was when there was no interference (for once) and I had heaps of JT65 signals roaring in and system time was in sync to ~100 milliseconds. But not a single decode.

I then proceeded to just give it time and let it run some 24 hours. But still nothing…

A bit of searching around the net revealed I wasn’t the only person who had troubles decoding with WSJT-X. Further, it seemed maybe that for those who had troubles all used to work with version 1.1 of WSJT-X.

I proceeded to download WSJT-X 1.1 and lo’ an’ behold suddenly I was decoding signals left right and centre. Both in single JT65 mode (for which there seems greater activity) and also in split mode decoding both JT65 and JT9 transmissions.

Since then I’ve tried again with version 1.3 and also 1.2.1 (a couple of times), but for the sake of me I can not get decodes with either – oh, except a single decode once… And looking on pskreporter (a great site BTW) it would seem very few are using the latest version of WSJT-X. Further, looking at a WSJT-X changelog I note there were changes starting with 1.2 about how the sound hardware was accessed. So I wonder if maybe that’s had a flow on effect to those running on Windows XP (such as my shack PC).

Anyway, at least I have a version that works (just a shame some nice waterfall improvements came in in version 1.2) so I proceeded to try some contacts. My first was with VK5HAM but I made a fair mess of things as I wasn’t as comfortable with the UI as I thought I was. Anyway, the one I was most impressed with was with HA1AD. Details were:

Their grid square: JN87
My grid square: QE37
Mode: JT9
Freq: 14.078850 MHz
Report sent: -06
Report received: -09
Distance: ~12,995
My power: 5W

That is indeed my first true (ie. bi-directional) DX contact.

After that, I was hooked and tried a few more, but often shooting too far (15,000+ kms). It’s amazing how quickly the time passes by with these modes.

So, if you’re yet to try these modes then I highly recommend them. They take WSPR a step further, and with reverse beacon networks such as PSK Reporter you’ve got everything you need (ie. WSPR beaconing but with option for proper QSO contacts)!

One last thing though before I go. Later on my interference returned, but to my surprise WSJT-X kept on decoding. The following two images show WSJT-X picking signals out of the noise. If you take a look at the waterfall @ 23:23 and then just near 1200Hz you can see the signal (just) from ZL3HAM, but at the same time you can see the wonderful interference I enjoy.

Although an extreme example, I have actually had QSOs in amongst lesser interference with WSJT-X this week-end. Something I would have struggled with voice and many other digital modes.

Interference Solution

Interference Solution

Further analysis of my previously  mention interference problems showed two things:

  1. It’s constant (I monitored it with SpectrumLab for a week) and seems to emulate a pattern of a person turning a heater on and off in the mornings and evenings; and
  2. This was not new, as I looked back to one of my 600m mailing list posts around the same time last year where I mistakenly assumed it was due to a change with my mini-whip.

So in a bid to fix it I started to look at Small Magnetic Loops (SMLs).

Using a suitable SML, in theory I should be able to use it’s strong null’s to block interference. So I went about a few ideas but in the end I basically built the amplifier as per PA1M’s page, however I simply re-used the power supply unit for my mini-whip and went with some different loop designs.

Capture showing effects of rotating SML.

Capture showing effects of rotating SML.

Now I’m sure you’ll agree from the image on the right, that the basic principle of a SML’s nulls is working for me. To explain, I started the capture with the loop oriented such that all was well, then in the middle you see when I rotated it such that the interference came back in. Then, at the end I’ve rotated it again to null out the interference.

Interestingly (albeit not surprisingly) the loops orientation is such that it’s radiation pattern is almost perpendicular to that of my dipole.

So, I’m mostly happy as a result.

However! The receive level is well down on the dipoled. For example, without interference and no pre-amp turned on my receiver used to sit at around S7 (and then s9 when the interference kicked in). However now, with the pre-amp on I struggle to see anything on the S meter. 😦

Building the above amp I did use a pair of 2n5109 transistors to ensure all would be well up on the 20m band. However, I fear the biasing network is not setting enough gain for these guys. So I really need to revisit this – or maybe just go and grab one of the commercial offerings.

Lastly, I originally attempted with a loop that was ~1m in diameter and found that on 20m I pretty well had no nulls. Then I remembered that a SML should be no more than 0.1 of the planned wavelength (so ~0.67m for 14.150MHz). So I setup with a 0.5m loop and that’s when I definitely saw the nulls I was after – albeit with degraded receive performance on the lower bands.

Anyway, when I get a chance soon I’ll provide some pics and hopefully also attempt to increase the gain.

Interference Continues

Example interference around 14.070 Mhz

Example interference around 14.070 MHz

I’m still looking into my interference issue and have found a few more tidbits about it. One is that it seems to be seriously broadband in that I tracked it from about 7.9MHz to 23.0MHz repeating about every 5.04kHz. (Keeping in mind that my antenna is tuned for the 20m band so at those ranges any reception is pretty weak.)

Further, I started to wonder if it was my radio, so I swapped from my FT-817 to my IC-718 and the issue was still there.


The interference differs too. Around the main frequency of my antenna I see squiggly lines on the waterfall (as above), however once I get further away I see what I primarily consider straight lines as seen on the right.

Anyway, to visually see things a bit more I also put together two time lapse videos of the last two 24 hour periods. The first being on the Yaesu and the second on the Icom. Unfortunately to show them here on WordPress, they’d like me to upgrade my account – so I’ll have to get back to you as to how I’ll share them.

Another thing I tried, tonight I pulled everything out and now only have the Icom connected directly to the antenna via the wall socket and have it running on a battery. But still the interference persists.

I’ve also done things like disconnected the antenna – waterfall went quiet as expected; turned off the radio – waterfall went quiet as expected.

But the waterfall capture is starting to show me is two things:

  1. There seems to be good digital activity on 20m an hour each side of 1300hrs each day – hopefully I can enjoy it at some point; and
  2. A pattern might be emerging – at least I think I see the interference start around 7pm and stop around 10:30pm – but need many more days yet (and there’s also a possible morning start and stop too. And that makes me further think it’s a person doing something and maybe in the form of heating.

Anyway, hopefully a bit more monitoring might reveal some patterns as I’m kind of out of ideas to try – I’m fairly comfortable to say the source is not from my block.