Practical Wireless July 1998 Review of SG-230 Smartuner™
Reprinted from the July 1998 Practical Wireless Magazine with express permission.
Anytime, Anyplace, Anywhere...
Everybody has their favourite Amateur Radio pastime. for some it's Packet, others v.h.f. DXing but for me it's definitely mobile h.f. working. I always take my Icom IC-706 when I go away camping and use it in the car with a mobile whip antenna. However, over the past few years I have found myself wanting to set-up a portable station. but I can never bring myself to pack the antenna tuning unit (a.t.u.) and all the other 'gubbins'. My a.t.u. is very nice but it's over twice the size of my IC-706!
It was therefore with more than a little interest that I agreed to have a look at the SG-230 Smartuner. This is a microprocessor controlled automatic antenna coupler.
The SG-230 unit is designed to be situated outside. It's a strong black plastic box, (a little larger than a family size box of breakfast cereal), has moulded brackets with fixing holes and looks extremely rugged. The SG-230 unit is waterproof at half a meter for half an hour and is supplied with a very easy to read manual. It has nine meters of coaxial cable terminating in a PL-259 plug, which connects to the radio.
Also sheathed with the coaxial cable are four small colour coded wires. Two of these wires are for powering the unit the other two are for the optional Smart Lock control and optional L.e.d. indicator. The only other external connections are the insulated post for the long wire antenna and the earth post. The unit only works with end-fed antenna systems.
The Smartuner is highly portable as it's completely self contained, weighs 3.5kg and could be packed away very easily or bolted to a trailer or vehicle. It can be operated with any type of h.f. transceiver covering 1.6-30MHz and will work with inputs from 3 to 200W p.e.p. The coupler network configuration used by the SG-230 is of an 'pi' or 'L' type.
I decided to read the manual before I used the SG-230, this is good advice with any piece of new equipment, especially when you have never used anything like it before and it is not yours to blow up! It very quickly became apparent that if the SG-230 did everything it claimed to do it would be a very simple to use and could be adapted to different operational preferences.
Non Volatile Memories
The Smartuner has 500 non-volatile memories, these automatically remember antenna and transmitter conditions. On first tuning-up on a given frequency it may take anything up to a few seconds for the Smartuner to tune. However, if you tune off that frequency and then return to it later, the Smartuner will recognize that the conditions are the same and tuning will be done within 1D milliseconds.
The SG-230's memories are fully automatic. when you have filled all 500 the unit will then lose the oldest one and replace it with the new information. As if this was not enough the Smartuner will always check that it has the best tuning solution. Even when using a memory it will still check to make sure that this is the optimum tuning solution.
If you want to use the Smartuner to tune the bands and see what is about by just using your antenna without the tuning elements in circuit this can be easily achieved by turning the power to the Smartuner off for just over two seconds and then turning it back on. This resets the Smartuner to stand-by.
The tuner will not engage any of the tuning elements until it sees r.f. energy and therefore find a solution. If it's desirable for the tuning elements to be by-passed all the time when in receive, this can also be done. You simply have to move a jumper on the printed circuit board. Similarly the 500 memories can also he by-passed if desired by the use of a jumper. The coupler is designed with 64 different input capacitor values, 32 output capacitor values and 256 inductor values, this provides about half a million different p or L configurations. The Smartuner requires an input of about 5 to 150W to operate. it runs on 12V DC but will also run on 24V DC with an optional extra.
The SG-230 Smartuner is designed with the toughest jobs in mind. The weather proofing is designed for mounting the unit on the weather decks of vessels. It can be mounted any way up and in almost any position. The instruction book gives examples of helicopters and tugboats. However, the SG-230 is less easily attached to a normal family car. Those of you who own recreational vehicles may find there is a good chance that the unit would bolt directly onto the vehicle, if not, an optional extra is available called the 'Quick Mounting System'. This attaches the unit to the outside of vehicles.
The SG-230 is designed for use with end-fed unbalanced antennas such as whips and long wires. (It can however also be fed to a dipole.) The radiating portion of the antenna is connected directly to the coupler through a high voltage insulator. It will work with any antenna more that 2.5m in length however, the longer the antenna the better. In any case you ought to be looking for at least 114 wavelength. Just because you may have to use an end-fed wire antenna your options are not limited. If they are it is only by your lack of imagination!
The SG-230 manual offers some excellent ideas from Base Delta Loops to a 'Machey' Quad loop, dipoles and groundless loops for boats. I can tell you from previous experiments that playing around with wire antennas can be very educational and a great deal of fun. The only h.f. antennas I have ever used are wire and whip and using them I have 'worked' all over the world.
Recreate A Station
I decided that the best way I could put the coupler through its paces was to try and recreate having to set-up an h.f. station in the middle of nowhere. I do like a coffee while I'm working and I had to look after my youngest son, so for the purposes of this experiment the middle of nowhere turned out to be my back garden!
The first thing I looked for was power, only to find that a cell had gone in my 12V battery. So, a 30A power supply and extension lead later I was imagining hard! I found a length of copper wire in the shack, which I measured in the time honoured 'span' fashion and estimated that it was about 19m. I then found some nylon rope and an egg insulator. The next thing I needed was a radio, that was easy, the Icom IC-706 Mkl. Now, where and how was I going to hang the antenna?
The Smartuner boasts that it's easy to use, it also gives the impression that it can cope with some rather difficult antenna conditions. So, I set-up a little table in the rear garden, hung the wire from the edge of the bungalow and then took it up to the egg insulator that I had attached to the top of my 10m extendable mast, from there it came down on the opposite side of the garden to the wooden fence.
This was now an end-fed "inverted V for the want of a better description. I then fixed the SG-230 to the fence using two screws and connected the wire. I was nearly ready to go, but the ground/counterpoise was my next problem. The ground/counterpoise problem was soon solved by using a car jump lead clamped on to the earth connector of the SG-230 and the other end clamped on to the nearby chain lint fence. That was it I was ready to go! The whole setting-up process had taken about an hour. Were I was sat in beautiful sunshine with a cup of coffee and an h.f. radio, idyllic! So, connecting the SG-230 couldn't have been easier. it really was very straight forward. Once it was 'powered-up' and the radio on. all I had to do was hope.
Speak Or Whistle
To tune the SG-230 all you have to do is speak or whistle into the microphone. I decided to try it out on the l4 MHz band first. I heard EU5HQ (Belarus Republic) calling, there was a bit of a 'pile-up' but I decided to go for it anyway. I tuned away from him to tune up. A couple of whistles later and I heard the SG-230 whiz into action, in less than a second it stopped and glancing down to the SWR bridge I saw that I had a 1.5:1 s.w.r. I called EU5HQ and an instant response came back. Achim EU5HQ gave me a 5 to 7 report from Minsk, he was operating the station of the Russian Amateur Radio League HQ. His own call is DL7VFM. Having had this success on 14MHz I decided to try something a little lower. The tuner appeared to hardly have to think about tuning down on 3.6 MHz. It was all so easy. I then heard a very strong signal from GJBHM. On establishing contact I discovered it was Henry from Wimborne, very close to my own location.
After a very pleasant chat I decided to let Henry get on with cutting his grass while I moved onto try the SG-23O performance on the 7MHz band. It was the same story again on 7MHz, the SG-230 whizzed for a second or so and then clunk! An s.w.r. of 1.7:1 was present. The 7MHz band was very busy indeed. I heard G4KEE, a (QRP station from Exetar. He was a wonderful signal but just as I turned the power down to 5W another station came on very close by and wiped him but. Tuning round I then found GB2IWM, I called and got a 5 and 9 report. The station was situated at the War Museum at Duxford near to Cambridge. Frank was operating the station, he informed me that the GB2IWM was a permanent feature at the museum situated on the airfield from which Douglas Bader used to fly.
I was spurred on by the very interesting contacts I and decided to go the h.f. bands again. All I can say is that the SG-230 was a joy to use. It was an effortless task to change band and frequency and this made operating so incredibly simple. I went on to speak to Vera EA8AZY on Tenerife Island on 18MHz and then zipped up to 21MHz to have a chat with Alex UT4LT from Donetsk in the Ukraine, both gave me 5 and 9 reports. Back on l4MHz Anton UT7CT from Cherkassi gave me a 5 and 5 report. Finally, I decided to try 7MHz once more. There I got another station very local to my QTH. Jim GODYR and his grandson, Christopher 2E1GNW. Jim was very close by and gave me a good report. In total I was operating for about three hours and for someone operating under portable conditions the SG-230 is perfect. It really is effortless.
With a little imagination, some wire, some rope and a radio and the SG-230 just think of what you could achieve. I really can imagine having a SG-230 bolted to the trailer camper and operating an effortless portable h.f. station all holiday long. I'm not so sure that my family would share my enthusiasm though!
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