2014 Winter UHF/VHF Field Day

This weekend I packed up my portable gear, checked off my check list and headed out to the summit of Mt Coot-tha (grid square QG62LM) to participate in the annual Winter VHF/UHF Field Day.

My intention was not to chase any of the awards but merely to try out my new portable station that consists of an FT-817, and a 2m quarter wave ground plane antenna. The rig would be powered by a 2 a/h battery.

I found an unoccupied BBQ area, parked the car and set up my station. I would be concentrating on working SSB on the 2m band only. Power output would be 5 Watts.

 

My gear set up on the BBQ bench.

My gear set up on the BBQ bench. Note the antenna on a short pole.

I also had with me an Wouxun 2m/70cm hand held and a Yaesu FT-250 hand held (both FM units) just in case.

I spent two hours operating and made 11 contacts, so it was a case of mission accomplished.

The battery did well; to start with there was just on 13v and on completing there was 11.86v.

The battery did well; to start with there was just on 13v and on completing there was 11.86v.

Next time I will take along an antenna that will allow me to work the 70cm and 6m bands as well.

A stand for my FT-817

One of the drawbacks of the ubiquitous Yaesu FT-817 is that when it is sitting on the bench ready for use, it’s so difficult to read the display. This is because it is on the leading edge and not the top of the rig as is common with trial-type designs.

So to see what others had done to rectify this situation, I took to the internet and ran a search. I soon come up with the web page of Alex, KR1ST and read about how he turned an old DVD case into a stand for his FT-817. Check his page out here: http://www.kr1st.com/ft817stand.htm

I followed his instructions to the letter and ended up with a fine business stand for my FT-817.

The old plastic case, once I had cut it as instructed.

The old plastic case, once I had cut it as instructed.

Then it was time to put it together and try it out.

OLYMPUS DIGITAL CAMERA

The proof of the pudding is in the eating, as the old saying goes. Time to put the radio onto the stand.

Fits perfectly, as if it were made to measure.

Fits perfectly, as if it were made to measure.

A view from the operating position.

Now the view of the display is just perfect.

Now the view of the display is just perfect.

Reverse polarity protection

Now that I am a 100% QRP station, I rely more on battery power than ever before. Sure, I do have power supplies but I tend not to use them, preferring to make use of renewable energy whenever possible.

This brought into focus the importance of reverse polarity protection because the last thing I’d want, especially during the hurly-burly of setting up in the field, is to connect up the power the wrong way round and destroy my rig.

The first thought I  had was to insert a diode into the positive line of the battery feed line, but on second thoughts, quickly discarded that idea. You see, suffering a drop of around 0.7V simply because of the diode doesn’t make sense, especially seeing I’d only have around 12V at my disposal.

Better to make use of a Schottky diode, but then again, even though the voltage drop would be far smaller, when you’re dealing with QRP you want to squeeze out as much voltage from your battery and be able to have it at your disposal as you can. OK, Schottky’s have only a 0.3V drop, but I wanted to do still better.

This meant I’d have to think about using a FET.

I asked Jan, VK4EBP, if he had a spare that I could use as I didn’t have any in my junk box. He said he did and supplied me with three FQP27PO6’s.

The idea is to chose a FET with a SDS On Resistance of around 0.07V or better, and a maximum gate-source voltage well above the typical voltage I’d anticipate using. These are rated at around 25V, which would do me fine. Their drain source voltage is also around 60V, so I had a starter.

Next I had to draw a quick circuit diagram so I wouldn’t make a mistake and fry my rig. I had to remember that as I would be using a P-Type FET it would be inserted into the positive line, not the negative.

My quick drawing of what I needed to construct.

My quick drawing of what I needed to construct.

I decided to solder the FET onto a piece of vero board, to which I’d also solder the wires. The idea was to have something rigid so that the contraption wouldn’t fall apart in the field.

Rough and ready, but it'll do the job.

Rough and ready, but it’ll do the job.

I used a rotary tool to grind away the copper trace where necessary. I prepared enough vero board to make two units as well.

Next, it was simple a case of soldering the FET and the wires into place.

Soldering done and waiting for the insulation tape to seal.

Soldering done and waiting for the insulation tape to seal.

I then sealed the board with some insulation tape.

Now came crunch time. I connected the cable up to a power supply in the right order and measured the output voltage at the plug with a DMM. Perfect.

Voltage reading as expected. So far so good.

Voltage reading as expected. So far so good.

Now for the moment of truth. I reversed the leads to the power supply so that the black (negative) lead was connected to the red (positive) terminal on the power supply and the red lead to the negative terminal.

When the DC voltage is reversed, the gate is pulled LOW relative to its source, and the FET turns off.

When the DC voltage is reversed, the gate is pulled LOW relative to its source, and the FET turns off.

All working as intended. I now have a good reverse polarity protection that has a minimal voltage drop across the protection device.

John Moyle Field Day 2014

One of the aims of the John Moyle Field Day is to test your ability or readiness for portable operations. This is an even I like to take part in as it not only allows me to prepare for remote operations, it also guarantees contacts.

This year as always, I prepared my kit, made a check list and ensured I had thought of everything. My mode of operation would once again by CW only on the HF bands. My rig of choice was my Elecraft KX1 and my antenna my new Buddistick. My location would be up on Mt Coot-tha, which is not very far from my QTH.

This year I took the added precaution on including a few backup options, and boy was I glad I did. These included a long wire antenna, extra batteries and a multi-tool.

When I reached to top of Mt Coot-tha, I found an unattended BBQ area off the side of the road near the Channel 9 TV studios. Perfect. There was a nice table and bench seat provided too.

I unpacked my gear and started by assembling the Buddistick antenna. Bugger, I had left the all-important antenna mast and stand at home in my haste to get going. And worse still, it had the mounting plate still attached so I couldn’t make use of the small tripod that came with the Buddistick.

Thank goodness for the long wire antenna. I proceeded to cast the end of it up over a high branch of a nearby tree but the weight at the end of it twirled around the branch a few times causing the thing to become stuck. I wasn’t able to pull on it and raise the wire antenna up into the tree. There was now nothing for it but to cut the line loose and try again. Second time around was more successful.

The stand I made to keep the counterpoise off the ground.

The stand I made to keep the counterpoise off the ground.

The rest of the station deployed easily enough and I was able to get a 1.3:1 SWR reading using the new inbuilt antenna tuning unit in the KX1 on the 40m band. No such luck on 20m; 7:1 was the lowest I could obtain and there was no time to fiddle with reducing the length of the wire. I needed to make contacts and score points.

My operating conditions.

My operating conditions.

In total I operated for three hours and chalked up eight QSOs, mostly with VK2 stations. So considering I was only putting out a tad over two watts, I was more than satisfied. Oh, the new paddle worked fine too, even though I found it to flex a little too much for my liking on the enclosure, resulting in some errors in sending. But all in all, I was satisfied.

Listening for signals.

Listening for signals.

Now to wait for the results. At least I have learnt the lesson about being prepared and taking contingencies into account.

 

Building and adding the KXAT1 automatic antenna tuner to the KX1

The final part of the upgrade to my Elecraft KX1 involved building and installing the internal antenna tuning unit.

The kit is remarkably small; it comes in one plastic zip up envelope together with a concise and well put together 12 page Assembly and Operating Instructions booklet. It also contains a note telling you who put the kit together, which is nice and reassuring. If anyone is willing to put there name to something, there must be good reason! Confidence that no parts are missing is my guess, and I think I’d be right because none were. This, of course, isn’t generally the case with electronic kits, as most builders would know.

The kit was very easy to build and align. The instructions are excellent and leave nothing to chance. I found winding the three coils and one transformer easy to do too.

Populating the PCB.

Populating the PCB.

As the KX1 is a small, compact piece of gear, the ATU needs to fit in without touching other components because if it does, the back of the enclosure won’t fit properly. This is one reason both sides of the PCB are used.

The yellow relays are on one side of the board while other components nestle underneath.

The yellow relays are on one side of the board while other components nestle underneath.

The only ‘snag’ I ran into (I always tend to make things more difficult for myself) was when it came to installing the mating male connectors. I misread the instruction to ensure they were fully seated before soldering. I read that to mean the black plastic bodies needed to be fully seated on their female counterparts. So I slid them down further until they did with a pair of long nose pliers. This presented problems when it came to ensuring the ATU’s PCB seated properly, so I returned them to their original positions, soldered them in and all went together well.

Fitting the ATU into the KX1.

Fitting the ATU into the KX1.

Alignment was easy to accomplish. All that was needed was a DDM and an insulated screwdriver.

Time to put it all back together again.

Time to put it all back together again.

The ATU worked perfectly first time. This is a wonderful addition to the KX1 that adds to its functionality.

Review of the Elecraft KXPD1 Plug-in Keyer Paddle

I have now had a chance to actually use my new KXPD1 paddle and must say, I was pleasantly surprised. It works remarkably well.

Picture courtesy of Elecraft.

Picture courtesy of Elecraft.

I was operating from a chair in my back yard. I had my KX1 on my lap, resting on a pile of note paper, that’s all. No table to lean on, nothing but me and a chair. Perfect portable operations.

I found I needed to set my software in the rig to Iambic B and the CW speed to 14. Once that was done, operating was effortless.

Another advantage I found in operating with this setup was that I was able to practice receiving without writing down what I copied. This is a fantastic skill to master. I must confess I wasn’t able to sustain it though; it is very tiring mentally. But I will continue to develop this ability as it does allow you to travel and operate even more frugally. If I can dispense with the need for something like a table, operating portable will be so much more enjoyable.

Back to the paddle.

The spacings as built are fine, in my opinion. I found no need to reduce the gap on the paddles at all. The rubber grips are perfect and give the levers a nice feel. My fingers didn’t tend to slip or slide off during long periods of sending, which is great. They gave me a sense of confidence that I haven’t felt until now.

So overall, I am very satisfied with the paddles. They make a nice addition to the KX1.

A case for my Elecraft KX1

With a view to the upcoming John Moyle Field Day, I decided to make a tough carry case for my Elecraft KX1, its paddle and power lead. I had just the thing in mind: a metal case that housed a cordless drill that had long since given up the ghost.

I started by removing the padding material from the case and cleaning it up.

The case with its old internals ripped out.

The case with its old internals ripped out.

I then got hold of some spare foam material I had lying around gathering dust in my shed and cut it to size.

A modelling knife worked fine.

A modelling knife worked fine.

Once all the cutting was done and the foam pushed nicely into place, all that remained was to insert the components and see how it looked.

Everything in place, and looking good ready for the field.

Everything in place, and looking good ready for the field.

Now all that remains is to try it out.