Go4lo Accessibility and Construction Review

Go4lo Audible SWR and Power meter Building and Accessibility Review

By Kelvin Marsh M0AID and Neil Robertson G0ORG

April 2017

Background

IT is a fairly good bet that a radio amateur will, at some stage, want to know if their

antenna is a good match for a given frequency. You could just rely on the internal ATU to make sure the radio sees a 50 ohm match, but the time will come when this is not enough. Therefore, an SWR meter will become an essential item to have in the amateur’s toolbox .

Photo showing the finished boxed unit with foam packing added to keep the battery from moving

The finished boxed unit with foam packing added to keep the battery from moving

A sighted amateur may have several SWR meters, either inserted into the feedline to the antenna, or built into the radio itself. Whilst some modern radios will verbally announce the SWR reading to a blind operator, many will not, and so an external meter giving audio feedback is needed.

There have been some reasonably priced ‘accessible’ meters produced over the years, (See the evaluation of the LDG TW-1 Talking SWR/Power meter), but these have been discontinued. There are also units such as the Power Master 2 from Array Solutions that will read SWR and power when combined with a HamPod, (See the Power Master 2 review), and whilst a terrific solution, it is an expensive option and will set you back the equivalent price of a small amateur transceiver.

My interest was therefore peaked by the Go4lo SWR/power meter from SOTABEAMS. The Go4lo is supplied as a kit and plays audio tones to indicate SWR. LEDs also show power ranges below 5 watts, 5 to 25 watts and from 25 to 100 watts.

SOTABEAMS offer the name of an amateur willing to assemble and calibrate the meter, for anyone unable to do it themselves or find a friend with the necessary skills.

Neil G0ORG offered to assemble and calibrate a Go4lo for evaluation by Active Elements, and describes his experiences building the kit, below.

The kit

Photo showing the many components

The many components

The kit arrived in a Jiffy bag and was well packed. The version of the kit PCB was 2.0 and marked May16. No instructions were supplied with the kit, however a full printable guide was available from the SotaBeam website. The optional hardware pack was well protected and well thought out. A small packet of sweets were included from SotaBeams proprietor Richard Newstead G3CWI, which was a nice touch.

Photo showing the kit parts and enclosure

The kit parts and the enclosure

The size of the finished meter is 110mm wide x 80wide x 40mm deep. It weighs approximately 190 grams when fitted with a 9 volt battery. The box is black and has a transparent lid, the PCB mounted LEDs are viewable through it, the only protrusions are the two BNC sockets and one momentary push switch. The transparent lid is etched with the labelling of the LEDs, the sockets, switch and other details.

Building and testing

The kit was relatively easy to construct and alignment was simple, just requiring an accurate volt meter and a good quality 50 ohm dummy load with a 5 watt transmitter. A small potentiometer is adjusted for correct voltage at two test points, the accuracy of this set up determines the overall later performance. The volt meter needs to have good resolution as the tolerance when aligning is plus or minus 0.05 of a volt. All components are conventional with no surface mount. The Microprocessor is a pre-programmed Pic device.

Go4lo The fully assembled PCB

Photo showing the fully assembled PCB

The PCB is unusually thin, approximately 1 mm, but is of good layout and well annotated. Some of the ¼ watt resistors where a little tight to fit as the resistor component hole spacing is minimal. I had to be careful not to stress them when fitting them. From a previous career spent in the Electronics industry I have experience of fractures that can be caused to components if leads are bent to close to the component body, to make sure I did not do this I formed the leads using needle nose pliers to allow a slight return on the leads.

The fiddly bits are the Toroid transformers and the sampling coax assemblies that pass through them. These form the basis of the SWR Bridge, one for forward and one for reflected power sampling. Each toroid has a specified number of turns and the coaxial cable has to be carefully prepared as per the drawings. Once assembled I opted to hold each of the transformers in place with a blob of hot melt glue.  One component to be careful with when soldering is a voltage converter marked as U1. The legs of this device are very close together and the solder pads are very, very close together.

Photo showing the LEDs during Testing

The LEDs lit during Testing

The PCB mounts on the lid and the PP3 battery is inside the unit, it has a typical battery snap connector lead which is directly soldered into the PCB. Careful removal of the battery when changing it is needed otherwise over time the soldered wires may break at the solder joint.

It may have been better for SotaBeams to have supplied a Molex type two pin connector and header to help with durability here when changing the battery. Care is needed to do so and is quite fiddly.

The battery is located between the PCB and the end of the enclosure to this end the battery has space to rattle around (and jiggle the connector wires). As the device is also intended to be used portable I think a small piece of foam between the top panel and the battery side is a worthwhile addition.

Observations and further ideas

For those with sight difficulties the recommendation would be to get help changing the battery although for permanent use I don’t see why a 9v regulated mains adaptor cannot be used. There is enough space to add a power connector to the enclosure if required.
If the PCB were added to a different hardware box then coaxial leads could be used to connect to SO239 connectors, if required.

There is scope to add a further sound modification if required in place of the 3 power LEDs for the sight impaired, this could be a further tone to indicate some approximation of power level however the levels would remain an approximation as the power resolution between each LED is quite large.

For those who want to measure power exceeding the 110w level (400w for example) there is scope to make a new SWR sampling head and modify to the PCB. The only restriction is that careful modification will need to be made to handle the plus or minus voltage within the maximum voltage tolerances required to create the comparison error measurement. As it is a microprocessor circuit then it would probably be prudent to shield the PCB from the SWR sampling head and use feedthroughs for the voltage measurement connections at these power levels.

Conclusions regarding building and testing the kit

The kit does require a level of skill to construct, especially the transformers and sampling coaxial cable. Some solder joints are close together so good soldering techniques are required. If in doubt I recommend the use of a test meter to check for any solder bridging.

Audio Demonstration

You can hear an audio demonstration of the Go4lo in action here.

Click here for Go4lo MP3 audio demonstration

Overall Conclusions

I think Richard Newstead from SotaBeams has provided a great little item here that has visual impaired accessibility built in, possibly without realising it.

Although aimed at the portable market for SOTA it is ideal for visually impaired Amateurs as the sound is the most important element in this instance. The kit is priced correctly and has been well thought out. All items are of good quality and it was a pleasure to construct. As the clever bit is the Microprocessor there is scope to modify it if needed for further ease of use by visually impaired Amateurs.

The device is useful to any Radio Amateur, during testing I appreciated how quick it was to find a drop in SWR when using an antenna tuner. The unit is very accurate and overall a pleasure to use.

Further notes on usage

Holding the oblong box with the BNCs at the top, the left one is Transmitter and the right is the Antenna.  Just below the two BNC in the middle of the box is a power switch, the unit powers on with a dit dah and powers off automatically with a dah dit a few seconds after no use or if it has not seen any RF.

The power up time can be short if the transmitter is not activated but if it goes off a simple button press puts it back on again.  On power up the red SWR LED blinks then goes off, nothing else is displayed. When power is applied the appropriate power LED, green for 0.25 to 5 watts, orange for 5 to 25 watts or red for 25 to 110 watts light. The red SWR LED flashes in line with the beeps of the measured SWR. Sotabeams claim that the pp3 9v battery will last over a year as in standby it only draws a few micro amperes.

From Sotabeams product information:

Our latest product is something that I have wanted to develop for a long time: it’s an audible SWR-Power Meter. Unlike conventional SWR meters, the Go4Lo indicates SWR by sound. Basically the worse the SWR, the faster it bleeps.

This type of user-feedback makes it much easier to adjust antennas than using conventional SWR meters. If you want to know actual SWR, it is just half the number of bleeps per second (e.g. six bleeps per second = an SWR of 6/2=3:1). To make tuning even easier, the tone of the bleeps reduces below an SWR of 2:1 too giving additional feedback: this SWR meter really lives up to its “Go4Lo” name.

In addition to the audible feedback, we built in two types of visual feedback. Firstly the SWR is indicated by a flashing LED which flashes at the same interval as the SWR bleeps. But that’s not all as we incorporated a three-stage power meter showing 0.25-5 Watts, 5-25 Watts and 25-100 Watts. The transition at 5 Watts is especially useful for QRP operators as it makes setting your power level accurately to 5 Watts, simple.

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Power Master 2 and HamPod Accessibility Review

 

Power Master 2 watt meter and HamPod Accessibility Review

By Kelvin Marsh M0AID December 2016Photo of PM2 front panel

Background Photo of Hampod

I have been using the Power Master 2 watt meter (PM2), from Array Solutions, and a HamPod, from Rob K6DQ, for a couple of years. The PM2 and HamPod combine to give a blind operator a talking Power and SWR meter.

Initially, the purchase could be seen as an indulgence, particularly as I also own the LDG TW-1 talking watt meter, but I had a particular requirement, as I wanted to automatically and instantly stop the amplifier from transmitting if there was a mismatch or high VSWR in the system.

The PM2 meets this safety requirement, by being inserted into the electrical PTT loop to the amplifier. If the loop is broken, the amplifier is prevented from transmitting. I have several items in the loop and if any one of them is adjusting or has a problem, the electrical circuit is broken. My PTT loop includes the PM2, the amplifier, the auto ATU and the SteppIR antenna. When a predefined power or SWR value Is exceeded, the PM2 issues an alarm and the loop immediately goes ‘open circuit’.

As I use a SteppIR antenna, the elements automatically adjust to the correct length, and there is normally no need for an ATU. I wanted to be able to switch from band to band, have the antenna adjust, the amplifier automatically switch to the correct band and then be able to transmit without further thought. The PM2 gives me the confidence to do this. I know that if I’ve made a mistake or there is a mismatch or technical issue, the alarm will sound and the amplifier will be by-passed.

Operating

Of course, as well as the safety features of the alarms, the PM2 also gives you accurate readings for Forward and Reflected power and SWR. It is also highly configurable. In practise, I find I am using the PM2 continuously while I am operating. It is a real pleasure to have accurate measurements available, and as the RF power output from the amplifier will vary slightly from band to band, it is great to be able to make sure I’m transmitting up to the power limit, but not over it.

The PM2 is not accessible to a blind operator without the addition of the HamPod. This accessibility evaluation is therefore about how the HamPod interacts with the PM2 and how the visual alarms and configuration are converted to aural tones and speech output.

Visual Description

Chris M5AGG adds further description here and some additional detail of what he sees on the display, from the perspective of a sighted user:

“The pm2 display indicates swr and power simultaneously. Power is displayed by a fast moving bar graph and numerical displays above this show power and swr.

The bar graph is ideal for tuning as peaks in power can be easily followed. The coupler can be sited remotely from the meter connected via a screened audio jack lead. Photo of PM2 coupler

Two couplers can be used with the meter ranging from 3 to 10KW maximum power. Each is supplied with calibration offsets which when set up in the meter menu ensure accurate results. Despite the high 3KW of the lower power coupler, the meter senses maximum power in use, to ensure the bar graph always displays a high resolution, with many segments illuminated whether the power is 50 watts or 3kw.

Also on the front panel are two leds that light up when swr or power exceed preset settings.

The alarms can also break the ptt line to avoid any damage that may occur. Settings can be adjusted via the menu button on the front panel.
The owner’s callsign can also be displayed too, but as soon as RF flows this is replaced by the bar graph.”

Audio Demonstration

Writing this review, it seemed like a very good idea to reread the documentation for the PM2 and HamPod, and the first thing that struck me was the joy of having the HamPod manual in text format! Quite refreshing not to have to convert documentation, so it can be read by a PC screen reader.

I’ve recorded a series of short demonstrations, looking at different aspects of the PM2 and HamPod, and you can download the zipped MP3 files here:

PM2 and HamPod audio Demonstration

The MP3 tracks are:

1 General Description 3:04
2 Basic Operation 8:24
3 Audio Tuning Mode 8:16
4 PM2 Configuration 13:25
5 HamPod Configuration 7:34

Conclusions

The Power Master 2 is a useful addition to the shack, and highly desirable for anyone running high RF power from an amplifier. When combined with the HamPod it becomes very accessible for a blind user, and Rob K6DQ has again done an amazing job in making the meter ‘talk’. I know that Array Solutions were very helpful in tweaking their firmware, so Rob could have full compatibility between the devices. The result is superb! I would encourage you to listen to the audio demonstration to learn if the PM2 and HamPod combo will meet your requirements, and if it does, you have the knowledge that it can be fully used by a blind amateur.

PST 2051 Rotator Accessibility Review

Accessibility Evaluation of the ProSisTel 2051D rotator.

By Kelvin Marsh M0AID

July 2013

My first HF beam was a fairly lightweight 3 element Cushcraft A3S. I was fortunate to be given an old Kenpro KR600 rotator, and my friend G4JZL adapted the control box with a tactile pointer to show the heading. When I changed the A3S for the heavier 3 element SteppIR, it was time to beef up the rotator too.

At that time, back in 2009, I did not know any other blind amateurs with rotators. I was intrigued when I discovered that there were rotators available with computer control via RS-232 serial connection, and as I use a PC for logging and amplifier control, this seemed an intriguing possibility. I then had to satisfy myself the software could be used by a screen reader user. There was little point in investing significant sums in a new rotator that was controlled by clicking on a picture of a compass comprising of a large and inaccessible graphic!

I became aware of the ProSisTel range of rotators, as they were recommended by the UK supplier of SteppIR antennas. The PST 2051D was the recommended model for the 3 element SteppIR. The PST rotators use worm drives instead of the more traditional planetary gear wheel system, And have the advantage of being extremely sturdy and self braking. The PST 2051D is at the lower end of the model range, and PST has several much heavier offerings for very large antenna arrays. The PST 2051D is classed as a heavy duty rotator, capable of turning a full size 3 element HF beam. The rotation torque inch / lbs is 1720, and the braking torque inch / lbs is 10800 (figures taken from the Vine Communication rotator comparison table).

In a way, this evaluation is more of an accessibility review of the D type control box. Whilst I suggest this should be carefully checked before purchase, the control box should be capable of running any of the modern range of PST rotators.

The D type control box is the unit that sits in the shack, and is the hardware you would normally interact with. The box is very chunky, with an approximate height of 120mm, and a width and depth of 210mm plus front and rear panel protrusions. I only ever touch the controller when I switch it on. Whilst the control box is extremely simple to use with sight, it is not directly accessible by a blind amateur.

Photo of rotator control front panel displaying a bearing of 333 degrees, with switches for direction and power, plus a manual rotation control

Rotator control unit front panel

The current compass bearing is shown on a large digital display, and the new direction is selected by turning a rotary knob. The physical revolution of the knob bears no direct relationship to the ultimate direction. The sighted operator rotates the knob until the desired bearing is shown on the display. The knob could be rotated a few clicks, or could be turned completely several times, as there is no end stop.

Whilst I have noticed there can sometimes be a relationship between the clicks of the rotary knob and the heading for small movements, there is no reliable control possible.

Usefully, the rotator has the ability to automatically decide on the direction to turn. Just a small alteration in direction can cause the rotator to turn clockwise or counter-clockwise, to reach the desired heading with the minimum of movement. This probably sounds counter intuitive, until you understand the rotator has the potential to overlap by up to 70 degrees on either side of the selected stop position.

This probably needs a note of explanation. The rotator can be setup with a North or South stop position, and with a choice of turning ranges. Firstly, the rotor can be set to only turn by one complete revolution or 360 degrees. Secondly, to have up to a 70 degree over-lap either side of the stop position, giving a potential 520 degrees of movement. I use a 20 degree over-lap on either side of the stop position myself, so as not to overly strain the coax.

Here in the UK it is much more usual to be pointing the beam towards the South, so I decided to have a 0 degrees North stop. This means the rotator can be turning in a clockwise direction from 290 degrees West, through 0 degrees North, 90 East, 180 South, 270 West, 0 degrees North, and then keep on turning clockwise passed the North position, to a maximum of 70 degrees East. All this sounds complicated, but in reality it means you don’t have to turn the beam by almost one complete revolution, if you are wanting to point the antenna a few degrees either side of North.

So, back to the sighted operator directly using the control box. They just turn the knob to the desired heading on the digital display, there is a pause for a few seconds to allow for changes, and then the antenna turns. The control box automatically decides which way to turn to get there in the shortest time possible.

The 2051D control box also has the traditional Clockwise and Counter-Clockwise paddle switches. Again, these are of no real use to a blind operator as the display cannot be read. There is mention in the manual of the paddles being used to halt the rotator if it has been preset with the rotary knob or computer software, and there is also a warning that turning the rotator using the paddles does not invoke the slow start and stop facility.

When I first bought the rotator we set it up on the ground, without the antenna being attached, and I experimented with it. It soon became apparent that the slow start and stop feature only worked if the heading was changed using the inaccessible rotary knob, or by using computer software. If you are turning a large heavy antenna, it is highly recommended that you always use the slow start and stop. This causes the rotator to gradually reach the maximum turning speed over a few seconds, and minimises the shock to the antenna and tower of an instant start and stop.

In this photo the tower has been tilted over and the rotator is being bolted to the cage on the tower.

Close up of the rotator during installation

Therefore, the only practical method of a blind operator controlling the PST rotator, is via the PC and the serial interface. If you don’t use a computer with your amateur activities or want to directly move the antenna using the control box, it will be worth reading the Yaesu G1000DXC rotator evaluation elsewhere on the Active Elements site.

As mentioned previously, I initially had concerns regarding the accessibility of any interface software. Any blind computer user will be familiar with the perils of buying and installing that vital program, the one used by all of your sighted friends, only to find that what can be done so easily with a few mouse clicks, is impossible with a screen reader. It was at this point I contacted Don G0MDO. Don has written a very accessible logging program for blind operators, and fully understands what screen reader software needs to work successfully. Studying the PST documentation, it seemed that third party software could be used to control the rotator, and when approached, Don G0MDO, the creator of White Stick Log, began work on White Stick Rotor.

I know Don had to jump through all sorts of programming hoops to write White Stick Rotor, and had to write simulation software to mimic the PST D type control box itself. At that time, neither Don or myself owned any PST hardware! We were fortunate to have the help of Ron at Vine Communication, who was happy to conduct some tests On a real control box.

Without doubt, White Stick Rotor was the last piece of the jigsaw, and gave me the confidence to buy the PST 2051D. Over the years, Don has continued to refine WSRotor, and perhaps there is still some improvement to be made. The software is beautifully simple to operate, and Don has even made itself voicing. There is an audio demonstration of White Stick Rotor on the Evaluations page in the Software section. Suffice to say, you type in the desired bearing, press Enter, and the antenna turns.

Subsequently, I have also used the N1MM contest software to control the PST 2051D. The program can be used stand alone, but is also able to automatically turn the rotator to the bearing of the callsign just entered. I cover the N1MM rotor setup and use on the Evaluations page.

This photo shows the rotator mounted in the cage at the top of the tower

Rotator finally installed.

Finally, the rotator is designed to be fixed inside a rotator cage. The manual warns against sitting it on a surface that is likely to collect water, as this can be drawn up through the drainage holes in the casing. There is a sturdy circular revolving table on the top of the rotator with fixing holes, and there are a variety of mast clamps available to mount the stub mast.

A close up photo of the specially made adapter. Part of this fits inside the stub mast and is anchored to it. The remainder is bolted to the rotator.

Close up of the machined adapter

The best solution for me was to have a mounting plate with a solid shaft custom machined by G0WSC, to bolt to the table and to fit up inside the stub mast. The stub mast is then secured to the shaft and plate with a pin. This solution means that as the table revolves, the stub mast is perfectly centred and there will never be any slippage due to loosened clamps.

Related Downloads

PST D type rotator MP3 manual.zip

HamPod SteppIReader Accessibility Revieww

Evaluation of the HamPod SteppIR Reader

By Kelvin Marsh M0AID

March 2013

Photo of SteppIReader Keypad

I have been using a 3 element SteppIR antenna since Autumn 2010. It is a large antenna, and requires a rotator and a substantial mast. In other words, it represents a significant investment, both financially and in execution. The advantage of the SteppIR antenna is its ability to automatically adjust the element lengths, giving a perfectly matched aerial system on the majority of HF frequencies. As the antenna itself is outside, the operator will be controlling it by interacting with the SteppIR control box. This will sit on the bench, and in General mode will automatically adjust the antenna as needed. You can read the accessibility evaluation of the SteppIR controller elsewhere on this site.

If the transceiver interface board is fitted, the antenna is automatically adjusted by the radio, and Apart from the Power button, the only button in very regular use is the Direction button. On the original controller, this button cycles through Forward, 180, and Bi-directional modes. As my normal method of working DX Is to Search and Pounce, the ability to have the rotator pointing West, but within seconds have the beam electrically rotate to the East, is a terrific feature of the SteppIR. Within seconds you can check both the Long and Short paths, Whereas it might take you minutes to swing a traditional beam through 180 degrees and back.

The downside to using the Direction button, for a blind operator, is the constant need to check its status! Because the Direction button cycles through 3 positions on the original controller, I found I very easily lost track of my button presses, and constantly needed to remind myself of the direction.

I did this using an audible light probe. This is a pen shaped device that emits a tone when pointed at a light source. My SteppIR controller uses LEDs to show the direction of the Yagi, and I found I was feeling for the slight indentation of the LEDs, and then checking their status, on almost every long distance QSO. As a DX operator I’m listening for signals on the absolute limit, often 10 thousand miles away. If I found a weak signal in the Pacific, it was natural to also check the Long path, and to press the Direction button to rotate the antenna by 180 degrees. The result of all this was that I was using my light probe literally hundreds if not thousands of times over the course of a year!

OK, it’s taken me a page of meanderings to get here, but you can understand why the SteppIReader, http://www.hampod.com, caught my attention. It seemed I could send my SteppIR control box to Rob K6DQ, and he would make it talk!

If you have read my accessibility evaluation of the SteppIR controller, you will know the Setup menu is not accessible. The need to Calibrate, and create or modify the element lengths requires sighted help. Whilst you can live without this access, the SteppIReader gives you spoken feedback, and complete independence.

My SteppIR control box took less than three weeks to travel to Rob K6DQ and back. I don’t think I have been so excited to receive a parcel
for a long time!

The control box functions in exactly the same way as it did before the modification, but is now fully accessible. I think I would have purchased the mod just to
have the directional modes spoken, but of course there is so much more to it.

The SteppIReader comes with a 4 button keypad and speaker unit that plugs into
the rear of the controller. The only visible modification to the SteppIR control box itself is the addition of the port for the new keypad.

The LCD display on the SteppIR control box has two lines of 16 characters. The first button on the SteppIReader keypad reads both lines of the display, plus the antenna direction which is taken by new internal connections to the LED’s.

Button one therefore reads the control box mode, the frequency, and the direction.

Typically, it might say:
‘General Mode, 18.050mHz, 180.’

Button 2 reads the top line of the display, and button 3 reads the bottom line. Button 4 toggles automatic speech on and off.

I have the original SteppIR control box, and in Ham mode the antenna can be adjusted manually. As the band buttons are pressed, the controller’s frequency is now spoken by the SteppIReader. ** I understand the terminology for General and Ham modes has changed in the new SDA 100 controller.

In general mode, the antenna is adjusted automatically if the interface board is fitted. In this scenario, the frequency is now spoken as new bands are selected using the radio, and is again spoken as the antenna adjusts every 50kHz, as you tune through a band. I really like this feature, as it is wonderful to have the SteppIReader unobtrusively telling me what the antenna is doing.

There is a potential to damage the antenna if high power is used while it is adjusting, and it can be very easy to miss the visual indicator, even for sighted users. The SteppIReader handles this by beeping when the antenna elements are moving.

With the introduction of the SDA 100 controller, the little used Options menu has moved to the main Setup menu. This means the Option menu is now displayed on the LCD display, and is spoken by the SteppIReader. The options menu is still accessible using a light probe on the original controller, and I would imagine the inclusion of spoken prompts would have required a lot of complex internal connections for very little benefit.

Undoubtedly, the major achievement of the SteppIReader is the complete access it gives to the Setup menu. The real excitement for a blind operator is to now be able to use the Create/Modify menu. This allows the operator to independently adjust any of the elements, and save the setting. I won’t write pages on the Setup menu, but its use is much more easily explained in the audio demonstration on this page. Also, if you own the original SteppIR controller, the SteppIReader gives you full control over the Calibration and Retraction functions.

Finally, I need to mention the SteppIReader’s own Configurability. The volume of the voice can be raised or lowered by holding buttons 1 and 2, and the configuration menu is entered by holding button 3. Hear you can tailor the voice to your requirements with Volume, Rate, and Tone adjustments, and change a host of parameters. the configuration even allows you to enable or disable speech for various constant indicators on the display, such as the letter M that is shown when the antenna lengths have been modified, or the letter P that is shown when the 6m passive element has been added. Just in this respect, the understanding that there might be a need to suppress unnecessary repetitions on the display is outstanding.

In my experience, it is unusual to find a third party accessibility solution for a piece of amateur radio equipment, and almost unheard of to fine one with this level of technical integration. This is a 10 out of 10 product, and is truly breathtaking in its concept and application.

Related Downloads

HamPod SteppIReader MP3 Demonstration
HamPod SteppIReader Text Manual

Snap Circuits

Electronics Training by Phil 2E0OCD

February 2013

I recently came across something called Snap Circuits. It’s a product made by Elenco intended to be a fun and educational way of teaching children from 8 to 17 years about electronics. Whilst looking at these, it struck me that they could also be an excellent way of introducing blind amateurs to the subject of electronics, and perhaps, even, in enabling them to complete a
qualifying intermediate project with relatively little support.

Snap Circuits are sold in sets. Each set contains everything you need in order to build a number of circuits. Various sets are available which range in complexity from a set enabling you to build 100 fairly simple circuits, up to a set enabling you to build 750 circuits some of which are fairly complex.

One of the mid range sets is called Snap Circuits SC-300. See this link for product info:
(Please note, depending on your browser, you may need to Copy and Paste this link)
http://www.elenco.com/product/productdetails/snap_circuits®=OTQ=/snap_circuits®_300-in-1_with_computer_interface=MzU3
includes all the parts necessary to build 300 projects. Parts include different coloured LEDs, a photo sensitive cell, fixed resistors of different values, variable resisters, capacitors, lamps, switches, a speaker, microphone, antenna coil, a motor and fan blade, transistors, and various integrated circuit components such as RF and audio amplifiers and sound generators, as well as connectors and jump leads, and of course, a battery holder.

Three of the projects which you can build with the SC-300 set are of particular interest: they include a Morse code generator, and a couple of AM radios.

With the SC500 you get further components and you can also build an FM radio.
No tools or soldering are required for any of the projects. All components snap together. Each kit is supplied with a plastic base onto which projects can be built to make it easier.

The manuals are available for download from the manufacturer’s website in pdf format. The manuals provide an introduction to the Snap Circuits concept, a description of every component included with the kit, and a circuit diagram showing how each project should be constructed together with a short narrative for each project which provides some explanation.

The manuals are fairly accessible with a screen reader insofar as the text goes,
but a screen reader will not provide access to the circuit diagrams themselves.

Learning electronics using Snap Circuits is, of course, not the same as doing so whilst getting your hands dirty in a real workshop, but it could be a bit of fun, and it may be the closest some blind folk with no past electronics experience, or who lack the dedicated support of sighted electronics friends, may ever get to messing about with electronics. And I wonder how different this is from buying a simple off-the-shelf AM radio assembly kit and submitting that for your intermediate project – the process, and end result, is similar in either case.

Snap Circuits kits are sold online. Type “Snap Circuits SC-300” into amazon.co.uk and you will be presented with several kits. If you do this, you may also see another, quite similar product, called Hotwires, which is made by John Adams. It works on the same principle as Snap Circuits, and like Snap Circuits, Hotwires has a good rating. Unfortunately, the manual for Hotwires (which I obtained by calling John Adams head office) is completely inaccessible with a screen reader. This makes it significantly less attractive for a blind user.

Has anyone ever used Snap Circuits (or Hotwires), or have any views on how useful they might be for blind people? I quite fancy having a go myself!

I can only envisage two barriers to a blind person using Snap Circuits independently.
First, one would need a verbal description of each of the circuits in the manuals. This would be fairly easy to do because of the way in which all the connection points are numbered and lettered, and each component is likewise separately identifiable. So a simple description might say something like: snap the battery holder with the positive terminal to E2 and the negative terminal to E4. Then snap the Lamp (L1) to C2 and C3. Etc.

The issue would be to find a reader who was willing and able to record the manual, or at least record a description of the circuit diagrams, as it would be time consuming.

Secondly, one might need some initial help in actually identifying some of the individual components in the set. A battery holder will be readily identifiable, but resisters of different values may be harder to distinguish by touch alone. The components are probably fairly chunky so adhesive braille labels produced using a Dymo gun could probably be used.

Alternatively, tactile markings could be applied to the components using TactiMark or Tulip glass / fabric paint. The polarity of certain components will also need to be indicated as well as the identity of the component. This might be something individuals could get help with from local volunteers.
Any thoughts? Is it a good idea, or a total waste of time? Useful, or not?
Phil

Yaesu G-1000DXC Accessibility Review

Accessibility evaluation of Yaesu G-1000DXC Rotator

By Kelvin Marsh M0AID

January 2013

During a recent conversation with Rob G0WSC, he told me he was installing a new Yaesu G1000 DXC rotator, and he was looking forward to having computer control. I was immediately interested, because if computer controlled, the rotator would be accessible for a blind user. Rob then mentioned he could adjust the bearing by turning a knob and pressing a button. This all seemed very promising, so Rob brought his rotator control box over to my QTH for me to have a look at.

Picture of G1000DXC control box

The Yaesu G1000 DXC is classed as a heavy duty rotator, capable of turning a full size 3 element HF beam. The rotation torque inch / lbs is 950, and the braking torque inch / lbs is 5200 (figures taken from the Vine Communication rotator comparison table).

Looking at the other Yaesu rotors, I would say it is in about the middle of the range. The control box was marked T1AL, and was 200 x 130 x 193mm, and weighs 2.8kg.

It turns out Rob is not actually going to control the rotator from the PC, but from his Yaesu DMU. But, looking at the control box, the rotator appears to be completely accessible as a standalone unit.

My very first rotator was a Kenpro KR600. This rotator had Clockwise and Anticlockwise levers, but the needle was hidden under the glass facia. Fortunately, the axle for the needle protruded through the glass, and we were able to fix a tactile pointer to this central boss, on the outside of the glass. This meant I could hold down either lever and feel the direction of the antenna as the pointer moved.

The G1000 DXC control box is several times better than this. Firstly, it has a tactile knob allowing you to select the bearing. I guess the knob is about an inch in diameter, and has a small bump on the front face. Just turn the bump to the 9 o’clock position, and this will equate to a bearing of 270 degrees, or West. Then, just press the Start button, and the rotator will turn. There is no need to keep your fingers held on either the Clockwise or Anticlockwise buttons!

We then had a look at the glass plate covering the analogue direction pointer. Much to my surprise, the glass plate is designed to be removed, so a more detailed clock face can be fitted! Within seconds, the glass cover was off, and I found the direction pointer to be very tactile. I do not know how robust the needle would be, if the glass cover was permanently removed, and the pointer continually checked.

It is possible to connect the G1000 DXC to a PC for computer control. This requires an additional Yaesu interface box with appropriate cables, but the unit appears to be very expensive. In fact, I found the price to be very slightly more than the rotator itself! The interface model is GS232A and measures 110 x 21 x 138mm, weighing 380gms.

There is also a small knob on the control box to adjust the speed of the rotator. As there is no automatic slow start and slow stop on this rotator, I assume it would be easy to increase the speed manually if you are moving the rotator over a large distance, but decrease the speed again for the stop.

In summary, the Yaesu G1000 DXC seems to be perfectly accessible as a standalone rotator control box. You can either select the heading using the tactile knob and then press the start button, or you can hold either the Clockwise or Anticlockwise buttons and monitor the pointer with your fingers. Connecting the rotator to a computer is possible, but unless I am mistaken, appears to be very expensive.

Finally, if you are looking at the G1000DXC based on this evaluation, please make sure the control box is the same. I can well imagine the rotator could be supplied with another controller. Likewise, other Yaesu rotators in the range.

Comment 1:

By Tim GI4OPH, January 2013

Very interesting. Prior to owning the PST rotor, I used a Yaesu g1000sdx for around 8 years. The controller appears to have been re-designed, as there was no pre-set control on the original unit I had here.

I employed the method of removing the glass facia plate to great effect. The direction pointer was reasonably robust, and providing one wasn’t too heavy handed, it remained in place.

It certainly made for a very accessible method of rotator control, which has been made even better with the addition of the pre-set facility.

Comment2:

By Alan R. Downing KD7GC July 2013
The Yaesu rotors are good, particularly the G1000 and G2800. I turned my 4 element SteppIr with a G1000 for 5 years without problems, and when I replaced the 4 element SteppIr with the much larger DB36, I bought the largest of Yaesu’s line, the G2800. I just took the front cover off and I touch the needle to find out where the rotor is pointing, and I have never moved the needle inadvertently. The G1000 and G2800 both have a button that
can be pressed to turn the rotor from where ever it is to a preset direction. the rotor will automatically go to where you had set it up to go. There is a knob that you can adjust the stop point to, so when the button is pressed, the rotor goes to that set point. I set mine to stop at due North. So, no matter where I am pointing, the rotor always returns to North. I don’t know if the G800 has this feature or not, but just call HRO, and they could tell you.
If you intend to only put up a small yagi, the G800 may well be adequate, but if you are putting up a large yagi with many square feet of wind load, then opt for the G1000, or if the yagi will be huge, better go for the G2800.
Yaesu rotors are not cheap. I don’t remember what the G800 costs, but I think I paid about $800 for the G1000, and over $1500 for the G2800.

Related Downloads

G800DXA G1000DXA and G2800DXA rotator and control box MP3 Manual

MFJ 1026 Accessibility Review

Accessibility Evaluation of MFJ 1026 Noise cancellation Unit.

By Kelvin Marsh M0AID

January 2013

MFJ 1026 from the front

The MFJ 1026 noise cancelling system, front view with telescopic whip fitted

Recently, there was an interesting thread on the active elements reflector, regarding local electrical noise sources. These days, many radio amateurs live in electrically noisy locations, often with close neighbours in a modern housing estate.

Potentially, these local noise sources can make it very difficult, if not impossible, for radio amateurs to continue in the hobby. Very often, the electrical interference is so bad it literally overwhelms the weak incoming signals amateur radio operators strive to hear.

I was interested to learn that several sighted radio amateurs used noise cancelling units. Several of these units had been around for many years, but had been discontinued. Checking with the various suppliers, I found the MFJ 1026 was the modern equivalent, and was widely available.

Firstly, the unit is quite expensive. I have no doubt the manufacturer has done their very best to keep the costs down, but the MFJ 1026 is a significant investment at around £200 GBP. Therefore, I felt it was imperative to check the MFJ 1026 is accessible for a blind operator.

Reading the Manual, my first concern was how to handle the MFJ 1026 transmit requirements. Usually, the MFJ 1026 is connected between the radio and the antenna. This means it can receive incoming signals directly from the antenna, but has to potentially handle several hundred Watts of outgoing RF power when the operator is transmitting. The MFJ 1026 has some features to switch it to automatic bypass, but the Manual is at pains to point out, this method is not fool proof and is not recommended. It is suggested the MFJ 1026 is also connected to the radios PTT circuitry, and is thus switched to bypass, when RF power is applied. This means an additional cable must be fitted, and the specification will depend on the type of radio being used. The additional PTT control line may need to be added to the order, as fabricating the necessary cable could be difficult for an amateur with low vision.

Fortunately, my own radio gives access to incoming signals via coaxial links at the rear. I was able to use the appropriate connection and route the RX signal through the MFJ 1026, avoiding placing the unit in the path of out-going RF.

The MFJ 1026 works by receiving signals on two separate antennas. The noise is brought in by the auxiliary antenna and this is used to cancel the noise on the main antenna. The tricky part of the operation for a blind operator, is to balance the noise signal on both antennas. Usually, a sighted operator will use the radios signal strength meter, but I found it was easier for me to match the balance by ear. I found the best method was to turn the main antenna gain to maximum, so you hear the incoming signal and noise at full strength. I then made a mental note of the noise volume, and turned the main antenna gain completely down. I then brought up the noise on the auxiliary antenna to the same level. The final step involves careful adjustment of the Phase Delay, until the noise is effectively removed.

At this point it is worth mentioning, I had good success using the MFJ 1026 internal whip as the auxiliary antenna. This was very effective at picking up a local noise source . Thus, the main antenna would receive both the radio signal and the noise, whilst the whip antenna would only pick up the noise. The unit can also be used with an external auxiliary antenna, but during my limited testing I found I did not have much success in reducing noises from further afield.

Fortunately, I do not have much interfering electrical noise at my QTH. During the test period, the only local noises I found were a couple of spot frequencies on 15m, when my beam was turned towards the south.

You will now hear a recording of Z81D in South Sudan. The signal is very weak, and without the MFJ 1026, would have been affected by the local noise. Either side of the frequency was in fact clear of noise, but Z81D was just on a bad spot! During the recording, you will hear me calling the station myself, and Z81D making three QSOs. Although these are faint they are without interference, but as he is exchanging signal reports with each station, I briefly turn off the MFJ 1026 and you can hear the rasping interference for a few seconds each time. Whilst these signals are on the limit, you can hear that in this instance, the reception would be virtually impossible without noise cancellation.

Z81D on 15m

Next is a recorded demo of the MFJ 1026 in action. I use the unit to eliminate an electrically generated noise from the 80m band

Audio Demo on 80m

1026 from the back

Related Downloads

MFJ 1026 MP3 Manual
MFJ 1026 PDF Front Panel Layout