Going Mobile

QRV Mount Rumney

Mobile test run at Mount Rumney. not a bad view!

For a long time it has been a goal to take my own station portable to work HF. This week I finally achieved that goal.

It’s taken me a long time to get there, with the project starting in 2006 when I purchased a portable aluminium mast for the car that can be assembled as high as 12m (39.3 feet). With the help of Bruce (ex VK7MBD) a custom tow bar mount was made, allowing the assembly and raising of the mast to be possible by 1 person. After this, things went quiet on that project as a result of my hiatus from the hobby.

I was determined however that this year I would make the portable station a reality, and there have been a number of projects I was working on in order to edge closer to the end game:

  • Standardisation of power connectors (Anderson Powerpoles)
  • Power Distribution Board (See this blog post)
  • Soundcard interface for working digital modes with my IC-706MkIIg

With all the projects now complete, it was time to see if everything actually worked.

On the 28/12/2015 around 6pm, I hastily prepared for a short expedition to Mount Rumney, which was near home. At an elevation of 350m ASL, it provides a great take off for radio signals, though I did discover that is was rather difficult to locate my car in a position that would allow me to raise the dipole antenna in a way that did not interfere with the public carpark or road much.

The custom towbar mount. A metal hinge allows the mast to be walked into an upright position

The custom towbar mount. A metal hinge allows the mast to be walked into an upright position

What i did find was that it was much better received signals than my home QTH, which is in the saddle of two hills and as an elevation of 20m ASL. A lot more stations were heard, and many of them Signal Strength 5 or greater on 20m, with 15m also with many stations heard (for reference, my home QTH it is rare to hear anything on 15m, and rare to hear anything on 20m greater than S3). In the limited time I had up there (less than 1 hour operating), I only made 1 contact with ZL90IARU, but was quite content listening to all the activity on the bands I hadn’t heard before.

One thing I did find peculiar was that the rig would shut down intermittently when I went to transmit at higher power levels. Given I was running off the car battery that is less than 6 months old, I found this rather odd as the battery should have been more than capable of delivering the 18A required for transmitting 100W. The next day further testing found that I could only transmit around a maximum of 50W from the car. It took me quite a while to realise that this was because the wiring to the radio was only 10A wire, so this was replaced with a 25A cable, which testing resolved the issue

Another issue discovered that the feed line I has was not what I thought it was! being second hand and having the right connectors on it I didn’t think too much about the quality until RF started getting into everything when I transmitted. Investigation found that the shielding was almost non existent, with very little braid shield and mostly foil. That feed line is now in the bin and a new feed line is in place.

This is my "Lite" portable station, when only working SSB. Full portable station has laptop and rig interfaces for working digital

This is my “Lite” portable station, when only working SSB. Full portable station has laptop and rig interfaces for working digital

On new years day I put it all into practice by heading up to the springs on Mount Wellington. The following was a report I submitted to the local radio news broadcast:

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Ben writes:
On Friday I decided to get one of my new year’s resolutions done early and take my station portable, ideally somewhere high. After test runs at Mt Rumney and at the REAST clubrooms, I packed my car and headed to The Springs on Mt Wellington.
I was not quite expecting the crowds of people at the parking spaces just off Pinnacle Road and ended up relocating to the site of the Springs Hotel. Again, the most difficult part was finding a suitable space to set up because there were so many cars. With the lack of wind at the site, I was able to raise the 9m mobile mast without needing guy wires and was QRV on HF around 3.30pm local time using a trapped dipole as the antenna.
Despite the 650m elevation working conditions were quite difficult, with auroral activity during the day causing depressed conditions along with strong static crashes due to storms in northern Victoria. Mostly working on 40m, contacts were made into VK2 and VK3 with many of those stations performing SOTA activations. I also worked Graham VK7ZGK and a VK5 station. Finally, only 2 DX contacts, ZL1BHC and K5MVP just before I went QRT around 7.40pm local.
Another fun aspect of the portable station was watching other mountain visitors swing around the corner in their cars and then crane their necks upwards at the mast as they drove past. I also had several bemused bushwalkers come up to me to have a chat about what I was up to and I think a couple are now considering on dropping by the clubrooms on a Wednesday for more information.
I can easily see why SOTA can become so addictive having now operated my portable station, but the configuration that the car provides is much more convenient to do longer operations with.
If you would like to take a look at my portable station, just drop by my website – The URL is in the text edition of the broadcast
Happy New Year All
Portable Station, The Springs, Mount Wellington

Portable Station, The Springs, Mount Wellington

One comment

  1. Nice setup. I plan to add a trailer hitch to my Jeep in 2016 and have a similar setup when I operate from local parks.

    I also find that when I operate from parks that I receive much better than from my home which has a high noise level.

    I work QRP from my FT817 but sometimes use my TS590 at 100W powered from a 35 AH Gell Cell. I operate CW ~99%

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