About Grant McDuling

I am a retired writer and enjoy amateur radio in my spare time. I operate CW most of the time and run 100% QRP. I have written a book on QRP, it's called QRP, The Zen of Amateur Radio and is available here: http://www.amazon.com/dp/B00T74ID7W. My latest book is called SOTA, Taking Amateur Radio to new Heights. You can check it out here: http://www.amazon.com/gp/product/B019H4LB66?*Version*=1&*entries*=0

First C4FM SOTA contacts in Queensland

Going through the Activator Roll of Honour results for QLD recently, I noticed that there were no results for Digital Voice. Checking the state of play for the other states, I saw that the Australian Capital Territory and Victoria had one each.

It was time to put that right, so on Saturday 23rd June, I headed out for Mt Cotton (VK4/SE-115) with nothing more than my Yaesu FT-70DR hand held radio.

I had activated this summit more than a year previously, so if I logged at least four qso’s, it would count as another activation and my tally would increase by one point.

The climb up to the summit was uneventful and I headed to a clearing that featured a rather tatty picnic table and a good view.

I set the radio’s frequency to 147.400, the calling frequency for digital modes, and the mode to DN (Normal Digital Mode).

I had pre-arranged with Wal, VK4CBW, to listen out for me on simplex. His was the first contact I made. The distance between us was 26.33 Km (16.456 miles) and his Yaesu FT-2DR connected to a beam antenna sounded excellent. I ran a few quick tests too, to see what difference it would make to the signal if I placed my radio flat on the ground while he spoke. It made absolutely none!

Trying to get more height when calling CQ.

I am well used to using FM simplex on summits and noticed immediately that with C4FM there was no background hiss at all. The audio was as perfect as can be, very similar to that of a mobile phone.

I then had a long qso with George, VK4HGT, followed by Phil, VK4MOT and Bob VK4YA. All contacts were remarkable in that the audio was perfect. I think C4FM is far superior to FM analogue and it’s a mode I’ll be using more often in future.




The John Moyle Field Day 2018: Another successful field day.

Another Field Day success. This time my main goal was to rake up a few contacts during the John Moyle Field Day, operating from Mt Coot-tha in Brisbane with my FT-817 and Buddistick antenna. But this time, instead of squeezing the most out of 5W, I hooked up my new HF Packer miniHFPA2 Edition linear amp that puts out a massive 30W. And the beauty of this is that I would only need my 7 A/H gel cell to power it.

My set up for the day, from left: Yaesu FT-817, HF Packer miniHFPA2 amp, LDG-Z100Plus tuner. Behind: Yaesu FT-70D, Sotabeams powwerpole distribution box on top of 7 A/H gel cell.

I mounted my Buddistick antenna to a BBQ grill behind the operating bench that looked as though it had seen better days. Fortunately the G-clamp just fitted.

The Buddistick did a good job and was easy to erect. I chose it over a dipole as there was no ready method to secure my squid pole close to the operating bench.

Well, at the start of my 40 minute activation, my battery showed 12.69 V and at the end, 12.60 V. And that was after continuous SSB work on 40m. So 9 QSOs later, I was content to pack things up and head for home.

First real test of the HF Packer Amp

HF conditions are terrible at the moment, so when could be better to put the latest version of the HF Packer Amp, the miniHFPA2 edition, to the test?

The amp is set to accept an input of 5W for an estimated output of around 30W. It also has the 60/40 and 30/20 Low Pass Filters installed.


A side view of the amp enclosure with the side panel removed, showing the clip-in LPF board.

I chose to look for a station operating on 40m as this is the best band for local (VK) signals during the day. My luck, the band was dead. Then I heard Gerard, VK2JNG calling CQ from Lake Innes Nature Reserve (VKFF-1955). I returned his call and received a report of 5/9.

I was delighted as I seldom receive such good reports when using my Yaesu FT-817 at 5W into VK2. You see, a quick check on Google Maps told me that we were 445 Km apart. So I asked Gerard if he could give me another report, this time with the amp in bypass mode. He gave me a 5/3. He went on to say that with the amp switched on, my signal was “crisp and the audio nice and clear.”

So there we have it: the amp certainly does what Virgil, the designer, set out to achieve.

I have LPFs for all bands and will use them when the time is right.


The LPF boards are professional quality.


Each board is marked with the bands they are designed for. The while guides aid with slotting them into place.

Each LPF is a 2×1 inch plug-in circuit board that is interchangeable in the field with the entire family of same size modules. Each LPF has a unique ID, and the panel LEDs inform you which LPF is active. Two LPF boards are plugged into the enclosure, one on each side. To select the one you need, all you have to do is flip the LPF toggle switch on the front panel of the amp. Field replacement consists of removing a side panel, unplugging an LPF and sliding in a different one.

To find out more, visit http://www.hfprojects.com

Beating the downturn with the miniHFPA2

Everyone’s been complaining lately about poor propagation when it comes to amateur radio. But I think I have found the answer to my situation, especially considering I run an essentially low power operation.
I ordered a miniHFPA2, a linear amplifier that is made for portable operation out in the field.
This little beauty is the 5th generation HF Packer amplifier that comes pre-assembled, tested and calibrated. All I had to do was to hook it up to my Yaesu FT-817, then feed the output through an SWR/Power meter and Antenna Tuning Unit to my long wire antenna.

All set up and ready to test on air.

I happened to notice, on checking SOTA Spotter, that VK2IO Gerard and VK2/G4OBK Phil would be activating three summits, VK2/IL-001, 002 and 005 on Thursday 8 February 2018.. This would present me with an excellent opportunity to try out the new amplifier.

I tuned up on 40m and responded to their calls. Gerard mentioned that he was receiving me well and gave me a signal report of 569. This was excellent news, given the marginal conditions. I worked all three summits as they were activated and couldn’t have been more pleased. You see, normally my 5W output wouldn’t have been up to it in current conditions.

So what is this little gem of an amp all about?

According to Virgil Stamps, who makes the amps, the aim of his project is to give your signal a boost so you can start making memorable contacts under marginal conditions. It certainly has lived up to that! The amp gives a clean, more powerful output signal from a QRP transceiver with a good balance between output power, physical size and weight. And what’s sure to excite any SOTA or WWFF operator, it can be powered by any battery such as a 7.2 AH gel cell or 4.2 AH LiFePo4 battery. The amplifier provides a full output of around 30-35W with as little as 9V DC, making it very tolerant for outdoor battery operation.

What makes this amp a little different is the heat sink that is secured to the top of the enclosure. It isn’t the more common type that features rows of serious fins; it is a flat metal plate of around 1mm in thickness. And it does the job it is intended to do very well indeed. It lends itself to outdoor use as it can easily be accommodated in any backpack, but care does need to be taken so as not to damage the toggle switches on the front panel.

I particularly like the slim heat sink that is secured to the top of the enclosure.

The amp comes complete with two low pass filter modules (60/40m and 30/20m) but mine came complete with additional ones for 160m, 80/75m, 17/15m, and 12/10m as well. These modules are inserted into place by unscrewing the left and/or right hand side panels of the enclosure. They slip in effortlessly, thanks to cleverly designed guide posts on the LPF boards. I think when I proceed on my next SOTA activation, I will decide beforehand what bands I will be operating on as I think unscrewing side panels in a hostile environment such as on a summit could be a little tricky. Virgil did send along a sealed package containing spare enclosure screws, heat sink compound, two spare MOSFETS and some other items. Great service and attention to detail.

At the time of ordering you need to specify what level of input power you will be using. This could range from 1 to 5W; I chose 5W. Output power is an easy 30W. Spurious products are -40dB or better at 35W, with harmonic content at -45dB or better at 35W.

If you’d like to read up on the specifications, visit the web site http://hfprojects.com


Trends in Amateur Radio

It’s always been accepted that one of the attractions of amateur radio was that it involved the building of kits; if you needed (or wanted) a better or more specific transmitter, receiver or transceiver but couldn’t afford to purchase one from your local retailer, you bought one in kit form and built it yourself.
Kits were ordered over the phone and posted to you. Some were better than others but all had potential risks involved, such as the odd missing component.

The Elecraft KX1 kit came professionally packed with a great instruction manual.

This kit from Virgil Stamps at http://www.hfprojects.com is a good example of a well-produced kit that involves soldering all the components into place in the PCB.

And it wasn’t only on the electronics front that you could heat up your soldering iron and get busy; making a suitable antenna was also a huge part of the hobby.

My homebrew 6m dipole strung up and ready for action.

Baluns are also popular construction projects with homebrewers.

I wound the entire length of coax on a piece of PVC piping I had in my workshop.

Of course, you didn’t have to stick with kits if you needed to construct a radio; you could always build one from scratch with components you happened to have in your proverbial junk box.

I built this regenerative receiver using what I happened to have on hand at the time.

Test equipment is also easy to build from kits.

QRPometer on the left, Hendricks dummy load/power meter on the right.

I have noticed a trend beginning to appear in the world of amateur radio, and that’s a swing away from ‘melting solder’. I first noticed this with the advent of the Elecraft KX3 a few years ago. For the first time this world leader in kit production began marketing a rig that only required mechanical construction; all the electronics came pre-manufactured and only needed slotting into place in the enclosure, which needed first to be put together by the ham. This was due to the high number of surface mount components present.

And now Virgil Stamps, proprietor of the beautifully designed and manufactured HF linear amplifier that is aimed at the SOTA and WWFF fraternity (http://hfprojects.com/) has gone this route with the launching of his latest offering, the HFPacker Amp MiniHFPA2. By all accounts it looks like this new trend in amateur radio is here to stay, but as long as it helps get more people on air, that’s sure to be a good thing.

First portable operation with the Packer 6m amplifier

I decided to take the bull by the horns and activate a SOTA summit on 6m only, using my newly-built Packer 6m 30W linear amplifier. The summit I chose was Tamborine Mountain, VK4/SE-059.

My rig this time was the Yaesu FT-817 and the antenna was a homebrew 6m dipole, strung up as a sloper.

The rig connected to the amp and the LDG antenna tuner. The battery is a 7a/h gel cell. The power cords are routed through a SotaBeams 4-Way distribution box.

As soon as I put out my first call, the game was on. In the space of a short 30 minutes I had made 15 contacts. Wonderful.

The action came thick and fast and the view was excellent.

One aim of the activation was to test the amp, especially how long the battery would last as it draws around 6A.

At the start of the activation my battery had 12.58V, and at the end, 12.49V. That’s pretty incredible, especially seeing I was operating almost continuously. Input power from the radio was 1W and output 30W.

Another test I carried out (with Peter VK4JD) was to get an idea of the difference the amp made to an actual QSO. On bypass, with 1W, my signal was down some 20dB. So the amp was doing a fine job.

VHF Packer 6m Amp alignment

Andrew VK1DA pointed out to me that I had inadvertently set the bias on the amp to 0.5A instead of my intended 0.7A. This meant I had set it up for use on FM instead of SSB.

This was easily corrected; all that was needed was to adjust the variable resister while monitoring the DMM.

Now the bias is set correctly, it’s time to see if it makes any difference to live, on-air operations.

All set for SSB now.