KX3 v FT-817ND and FT-818   June 28th, 2014

Cornwall QRP

One of my pleasures in ham radio is portable QRP operation, Readers will know that I recently made a trip to Cornwall where I took my little KX3 transceiver. I have seen much written about the comparisons between the FT-817ND and the Elecraft rig.

Clearly they are quite different radios and unlike some critics, I have used both. There is no doubt that the KX3 has the better receiver by a long way as testified by Sherwood engineering internet reports. The KX3 also has a multitude of options and features that the FT-817ND can only dream of. But the FT-817ND does win if you want 2m and 70cms and want to pay less than £500. The KX3 will shortly add 2m and 4m to even things up a bit. For HF only I would certainly say the KX3 is streets ahead and can even beat almost any other HF rig no matter what price. The rigs are in fact poles apart and so are the prices. QED!

But back to the Cornwall operation. I used the Alex loop for my antenna as it is very compact and very efficient. It also covers 40m to 10m and all stations in between. I can set my KX3 to any power from 100mW to 5W using the internal AA cells, but prefer 3W. At this power level or less, the KX3 operates in super efficient mode. I used CW in conjunction with the matching paddle key. My best DX was UA9 and I worked mostly European stations. The Alex loop was pure magic and did not require the use of the KX3 internal ATU. Headphones were my Apple iPhone earbuds.

The whole station worked well and was great fun. The unmatched selectivity control of the KX3, in conjunction with the audio filter, made copy of other weak QRP signals so easy. On the FT-817ND it would be near impossible.

I have seen some rumours about the coming FT-818. I have heard nothing official and some “pictures” have clearly ICOM and Photoshop to thank. I doubt that any new model will be called FT-818. but it is an interesting rumour that probably has been derived from possibility rather than reality.

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KX3 Operation in Cornwall   June 14th, 2014

My operation in Cornwall was by no means intense, but I did make a few excursions with my Folding bike, together with KX3 and my Alex loop. This gave me operation on all bands from 7MHz to 30MHz. With this combination powered by internal AA cells, I operated at power levels from 2.5 got 5W. Best DX was into UA9. All operation was on CW using the Elecraft paddle key.

The wholes station, including the antenna, easily packs into a small rucksack. With the Alex loop I didn’t need to use the KX3 ATU and switched it to bypass in the menu system. For listening I used my iPhone ear buds and logged on my iPad which also doubled as my map.

All in all, an enjoyable few days. Peter G3OJV

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Cornwall By Accident   June 9th, 2014

Tern bike

My few days holiday in Cornwall did not start as anticipated. An accident on the motorway resulted in a probable write off of my car, but fortunately no injuries. So the journey was completed with the help of an RAC rescue vehicle and a and hire car.

I purchased a folding bike a few weeks ago and this has proved useful in some portable operation. My KX3 is working well, but with one thing and another, I have mot worked too much so far owing to lack of time and some antenna problems.

But working lots of stations is not what it is all about. It is the challenge and the fun of achieving what you can within limitations that happen and need to be overcome as best they can. That is true ham radio. Peter G3OJV.

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Elecraft KX3 On Holiday   June 6th, 2014

A few days holiday gives me the chance to get my KX3 transceiver into my rucksack and hope for some fine weather. I invested in a Tern folding bike as well, so that I am really able to enjoy some portable operation.

My main antenna is an end fed wire and matching counterpoise. The KX3 makes this an easy option as the optional internal auto ATU is more than capable of feeding random wires. How many other transceivers can offer this?

My operation will be CW only as I still love this mode for QRP operation. This evening I was playing around with the selectivity control and when this is married up with the AF filter, you get an incredible level of selectivity.

A set of rechargeable AA cells will be my power source and I will be using the little paddle that is available for KX3. A complete station that easily fits in a small bag.

There is so much to love about the KX3 transceiver. Peter G3OJV.

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Shared Apex Loop Array   June 4th, 2014

Shared Apex Loop

An interesting antenna ti say the least!

One of the biggest problems of working DX, particularly on the LF bands, is actually hearing it. Here in Europe we have lots of QRM that often masks the weaker DX signals. And if you are running high power, the matter is even more of a problem. So here is a very simple and practical answer.

The Shared Apex Loop Array comes in three sizes, the smallest having a central mast height of just 16ft, yet covering LF MW to 25MHz with 8 remotely switchable directions offering good F/B ratio. The idea of being able to steer your antenna,, particularly on the LF bands, is something that many of us have dreamt of. The smallest antenna requires an area of 20 x 20ft, just above the ground. The larger arrays have more gain but a lower upper limit.

This antenna is protected by world patents. We hope to have supplies within the next few weeks.

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Choke Baluns   June 3rd, 2014

I have long been an advocate of choke coil baluns. If I can avoid using ferrite then I do. Losses, heating, saturation, material specification, power handling and so on, do not always inspire confidence. I can make a choke balun for a fraction of the cost of a ferrite one. I know that there are occasions when ferrite is the easy option, where impedance transformation is needed. However, for a 1:1 application I avoid the use of ferrite.

There have been extensive arguments about the benefit or otherwise of a balun, but for me, it is something that I always try and include in my antennas. One reason is that it tends to make antenna adjustment a little easier and VSWR measurements become a little more meaningful. But how do you know if your choke balun is doing the job?

A choke coax balun is in essence, simply a coax coil that is placed in series with the coax feed right at the feed point of the antenna. In fact there is no reason why you even need to break the feeder. You can simply coil it up just before it connects to the antenna. The big question is how many turns do you need? This depends on the band or bands of operation. You can only have too few turns, but rarely too many turns. That is a general rule of thumb for a choke. But clearly you don’t want to put more turns than you need to, so how do you know if you have sufficient?
I have recently been checking out the Array Solutions VNA. And while checking and adjusting some antennas, it reminded me of the way in which I check out if my RF choke is doing its job. Have you ever used an antenna analyser and noticed that as well as the expected resonant dips, you can also see some unexpected ones? These come from odd resonant combinations of the antenna plus feeder. You can prove this very easily. Find one of the unexpected resonances and then coil a few turns of the feeder up anywhere along the line and see if the resonance changes or ceases. This is a sure indication that you need a balun or the one that you are using is not doing its job. If you are fortunate enough to own a VNA, then you can see these renounces very easily and also see how they change with any manipulation of the feeder, be it making a coil as described or changing the feeder length. Ideally all these renounces should not be there. And it is this kind of test that will tell you if you have enough turns on your RF balun choke. Try it for yourself, Peter G3OJV

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