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.

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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.

New battery power for my FT-817

I have long wanted/needed to upgrade my battery power for my Yaesu FT-817. The prompt came when the internal battery died. My choice was the kit put out by Windcamp; a 3000mAh internal LiPo battery and new battery compartment lid for the radio that comes fitted with a PCB and charging circuitry that allows the supplied mains charger to charge the battery while inside the radio.

The parcel arrived from China beautifully packed. The battery and the new replacement lid came packaged in very nice plastic cases, which, together with the instructions and charger, all fitted into a compact cardboard box for shipping.

The contents of the parcel.

After extracting the individual components from their packaging, it was time to think about installing the battery into the radio.

It is a tight fit but the components plugged together as intended. Note the PCB on the underside of the new lid.

When the battery and associated wiring was all nice and snugly fitted, I popped the lid closed and got ready to charge the new LiPo battery.

The new lid in place and ready for charging.

The charger has a double-coloured LED to indicate the state of the charge: red for charging and green for a completed charge. The initial charge takes around 5 hours to accomplish.

According to the supplied documentation, the rated voltage of the battery is 11.1V, with the output voltage range stated as between 9 and 12.6V. The maximum output current is 4A.

Now to test it in the field.

Springbrook National Park dissapointing

Sunday 21st May 2015 was to be a good opportunity to work some Park to Park contacts as the VK5 mob had organised a mass activation to coincide with the WIA AGM. So I decided to activate Springbrook summit VK4/SE-011 and Springbrook National Park VKFF-0463.

The only problem was that Cyclone Debbie had washed away all bridges leading up to Springbrook. The only access road was a back road through the Numinbah Valley. So my wife and I set off nice and early on the 1 hour 40 minute run, but missed the crucial turn and ended up going the normal way up, via the Gold Coast. By the time I realised my mistake it was too late; we were committed.

Just as we drove into the Springbrook National Park, we encountered a road block. Those manning it told us what I suspected. If we wanted to reach the summit we’d have to retrace our route back and go the back route – an additional 40 minutes they told us. So we decided to set up the station along the banks of the river just inside the boundary of the park.

My shack for the activation. Nice cover at least.

My rig for the day was the Yaesu FT-817 with an LDG Z-100 Plus ATU, 7a/h gelcell and an endfed antenna supported by a squid pole. My paddle was the Pico Paddle from Palm Radio in Germany.

This was the first time I used my new Sherpa pack. Fabulous.

All went well and I heard loads of traffic on 40m, all working the various VK5 parks. It was the first time I had been working against pile-ups! Fortunately I was able to tail gate a few contacts and worked two parks: Gerard VK2IO in VKFF-1278 and Rob VK2AAC/2 in VKFF-0004. That was the end of my SSB contacts as my 5W was no match for the 100W stations I was competing with. So it was out with the Pico Paddle and within a few minutes I worked Mike VK2CCW and Ian VK2BJT. CW is really great as it allows you to make contacts despite being low power.

I wasn’t able to activate the summit for SOTA; that will be another time now as I have unfinished business. But we did get to log four contacts towards WWFF and saw first hand the damage a cyclone can cause.

DSC01800

These are some of the trees that were up-rooted during the cyclone.

Building SOTABeams’ PowerPole PP-4 Way power distribution board

One of the challenges I was having while operating portable was making sure that my power polarity was correct. Fiddling around on a mountain peak with red and black connectors on a 7a/h gel cell is fraught with danger. And when I have two or more components to connect, well …

The answer I found on the SotaBeams web site (http://www.sotabeams.co.uk/).

I placed an order for their PowerPole PP-4 Way power distribution board.

A week or so later, a padded envelope arrived in my mail box.

The contents of the envelope.

Construction was easy as the kit is very simple. All that was needed was a soldering iron and some solder.

 

The power poles ready for soldering.

I ordered the kit only (without the enclosure), so I headed to the local supermarket and bought a cheap plastic sealable container that would do just fine. All I had to do was to cut out a piece wide enough from the lid for the connectors to stick through.

The PCB sits under the lid with the connectors sticking through. I secured it into place with four nuts and bolts.

The power supply connects to one set of power poles and the radio, atu and other items connect to the others. Simple.

Works like a charm. Will make a difference in a park or on a summit.

Activating Mt Cotton VK4/SE-115

This was one summit I have wanted to activate for quite some time, partly due its proximity and partly due to the excellent Sirromet Winery nearby. So when Sunday 30 April dawned with beautiful clear skies, I knew it was time. My wife decided this would also make an excellent day out.

The drive to the base of the summit took about 40 minutes. We parked at the bottom in a designated car park and headed for the gate that heralded the beginning of the path up.

This is the beginning of the path up to the summit.

Fortunately the path up is sealed, which made walking up easier, even though it was rather steep at times.

It took us 22 minutes to walk up to the summit.

Once at the top it was simply a matter of seeking out the best operating position. This was important as there are a couple of communication towers there and I didn’t want interference.

The going was tough at times.

I found a suitable spot among a pile of rocks, so I erected the long wire antenna on my squid pole, and connected it up to my Elecraft KX1. It tuned up beautifully on 20m and 40m. For power I use six internal AA 1.5v batteries that give me between 1 and 2 watts output to play with.

It was quite comfortable, really.

I put out my first call on 20m and within seconds was answered by VK3CAT in Victoria. Not bad for 2 watts. I then switched to 40m (only 1 watt) and worked VK2NP, VK2BJT and VK4TJ.

I find the Pico Paddle a wonderful device to use with the KX1. It is magnetically held in place on the tin plate on my home brewed QSO board.

That was sufficient for the activation to count, so it was time to pack up and head off down and to lunch at Sirromet.

Reverse Polarity Protection

As the Yaesu FT-817 doesn’t have any reverse polarity protection or an in-line fuse, I decided to build myself one seeing I do a lot of portable work on summits or in parks.
Diodes work fine but they do incur quite high losses in eventual output power, so with only 5W max available, this isn’t desirable.
The answer lies with the P channel MOSFET (FQP27PO6)
A quick search on line turned up this schematic.

Only one component!

This is quite a simple affair: when the battery is connected up correctly, the MOSFET is turned on allowing current to flow. When connected up incorrectly, it turns off.

It works thus: when the gate to source voltage is around -4V or less, it turns on. So if the battery is a 12V gel cell (as in my case), the voltage through the MOSFET  = 12V – 1V loss (due to the parasitic body diode) which equals 11V with respect to ground.The voltage at the gate is 0V as it is connected to ground. This means that Vgs = 0V – 11V = -11V. This is less than -4V so it turns on.

If the battery is connected up incorrectly, then we have Vgs = 0V –11V = 11V. so the devise turns off.

I mounted the MOSFET on a piece of vero board and used an ice cream stick as strain relief. I also included an in-line quick blow 5A fuse in the positive line.

All the components before final assembly.

Once the heat shrink had been slipped over the component, I heated it up with a hairdryer to achieve a nice, tight finish.

While I was at it I built another one for my Elecraft KX1.

Now it was time to test it.

 

All working as expected with the battery connected up correctly.

Now to switch polarity.

No voltage with reversed polarity.