Its All Part of The Service! October 31st, 2013
I know that I have spoken about the ease of removing the front panel of the K3, but I don’t recall having shown a photo of the process. So here we are with a photo of a K3 today with its front panel removed. It took less than three minutes! Try doing that with any other radio.
It is standard practice in the workshop to remove and replace the K3 front panel with a test unit if we are uncertain of the fault area. Modern day rigs depend so much on firmware and DSP, that this is an easy way to isolate the fault.
When building K3s it is our standard practice to store the configuration that has been programmed into the particular radio against its serial number. This means that if we get the radio back for service, we can send the original file to the radio and make sure that any fault is not that of the owner changing a menu item accidentally.
In fact this happened on a KPA-500 linear amplifier recently where a customer reported that the amplifier had developed a fault and the thermal operated cooling fan was now running all the time. After a bit of head scratching here, we went into the menu system and deep down there is an option to have the fan running all the tine at speeds from low to high. This menu had been changed to do just that. A quick reprogram of the amplifier and all was well again.
Not all problems are this easy, but we are seeing more of these. Another example was an Icom transceiver returned as faulty because the `FM mode was not working. In fact the owner said the option was missing from the panel menu. Now had the customer telephoned us rather than sending the radio back, we would have been able to explain that to switch to FM mode you need to select AM and then hold the mode button in for about two seconds. In this instance the mode change from AM to FM took 4 days of travel to and from Hockley! Peter G3OJV.
Operating Disabilities October 30th, 2013
I was interested to read Julian, G4ILO’s blog and his recent progress after his major brain surgery. It is good to learn that he is back and able to post the occasional blog entry.
I can empathize with his vision problem as I have some blind spots in my left eye, and also a blind spot in the centre of the right eye. Fortunately they work together to give me some good panoramic vision, but my left eye is doing all the focusing. However, with these visual problems comes the loss of 3D vision and the ability to judge distance. If you have normal vision, then try closing one eye and then pouring water from a jug into a small cup. It’s not easy! However, you do eventually adapt and like so many other physical restrictions, you tend to master the difficulty to a significant extent such that it becomes less of a problem and more of a minor nuisance. One that you learn to live with and make the appropriate adjustments.
Visual problems are more common than many realise, and of course they are invisible to others. I know that there are many ham operators who suffer with vision difficulties, and of course, many of us suffer with failing vision as we get older. The good news is that in most cases it is possible to adapt and to continue with the hobby. It may require some changes in the way that we operate and it may well mean that any form of building is no longer possible. But even when it comes to building, it is quite remarkable what some hams manage to achieve.
When `i was in Scotland in April this year. at the Sottish DX Dinner, I met up with an operator who was blind, yet was building his own VHF Yagi antennas. He explained to me how he managed this task. It was all very logical, and it did demonstrate to me that the disability in itself was providing an added challenge that once conquered brought its own satisfaction in a somewhat ironical way. I am sure that there are many other similar stories. Peter G3OJV.
The Storm Arrived October 28th, 2013
Well the forecast storm arrived here in Essex and [peaked around 8am as expected. frankly it wasn’t as bard as was feared and locally there was not visible damage. My own antennas were fine. but there was not much to damage anyway. On out main works building we lost one antenna, which was a Despole for 10 – 20m. We had taken the precaution to guy it earlier in the year so that if it did come down it would fall on the flat roof. which it did.
I know there have been a few hams that have suffered damage, but the warming have been around for a few days now and I think a large number have taken the necessary precautions and lowered towers and masts.
It was a good job that the storm hit the UK today, Monday, as it did not interfere with the weekend contest, There seems to have been publicity of this pending storm overseas, as I received an email from a friend in India who had heard about it. Based on previous years, it does seem that this windy weather is becoming a regular event as we head towards winter.
One of the things that many of us regularly moan about is the lack of space for large antennas to towers. But it is on days lie we have just had, that hams tike me with small gardens and little room for much more than a wire, come out smiling.
With all the problems of today it was good to learn that we will get a Dover of some more SDR radios from Apache Labs. The demand for these new SDR radios has been steady. As the word spreads and the number of happy users post their experiences on the various forums, so orders flow in.
It looks as if there will be more exciting products from this Indian supplier. As soon as I lean more I will let you know. Peter G3OJV
The Importance of the Right Washer October 27th, 2013
We recently had a puzzling service problem. The customer had an Elecraft K3 which we built for him some six months ago. He then decided that he wanted to add a voice recorder module. This is not a terribly complicated task, but does involve removing the front panel. Unlike other radios, the K3 front panel can easily be pulled forward and in our service department it is a job that only take a few minutes. Then it is a case of removing the DSP board from the back of the front panel in order to install the voice recorder.
The owner of the radio had decided to do this work himself, but when the work was completed the voice recorder failed to work and the received audio was intermittent. The classic error of doing this job is to fail to use the insulated plastic strew to fasten the voice recorder. A standard metal screw can cause a short or an intermittent problem. But the owner had checked this and all looked fine. He had even gone back through all his work and still no cure. Even the removal of the voice recorder now did not bring the radio back to normal. It still had the audio problem.
It was agreed that we should collect the radio from him. The first thing we did was to replace the entire front panel to make sure that the problem was in this area, It was! We took the original panel and removed the voice recorder, but this did not help. The next suspect area was the DSP board. We removed this and decided to swap this board for a new one. The voice recorder is mounted on this DSP board via a metal post. Whenever we take things paart like this we always do it over a plastic tray to catch any small items that might otherwise roll across the bench and onto the floor. As we took the post off, onto the tray fell an inside toothed washer, This is larger than the normal split pin washer that should have been fitted. We then looked at the board and it was immediately obvious that this slightly larger washer had shorted across the track and was the cause of the problem. It had done no harm and as soon as the correct washer was installed, everything was back to normal. So it was not the voice recorder that had caused the problem, but the mounting of the support post. Another problem solved and another happy customer. Peter G3OJV.
Busy End to The Week October 26th, 2013
Well it was good to receive a delivery of some more IC-7100 transceivers. It has certainly been a very popular radio. Over half our stock of these went up to Bill, at Jaycee mi Scotland. So there should be some happy faces up there now. I guess there will also be an increase in 4m activity.
This weekend there are going to be a lot of hams in the southern part of the UK who will be looking towards their antennas as the threatened storm approaches. we have already had some damage to the antennas on our roof from an earlier storm some few weeks ago. However, this was not major. What the coming storm will bring who knows.
Not everybody realises how international our business is, We are constantly shipping goods all over the world. Yesterday for example we shipped a consignment to Germany and to India. We also received a £50,000 export order earlier this week. All this is over and above our normal amateur radio business.
This weekend is a big contest weekend and if you are not keen on contests then I guess you will either remain QRT or head off to one of the WARC bands. My antennas are wound down and I will probably migrate to 18MHz. That is, if I still have an antenna. Peter G3OJV
Crystal Gazing October 23rd, 2013
It is quite surprising how often radio turns up when you are out an about. A few days ago I was returning from Northampton traveling down the M1 and decided to stop off at Stoke Bruerne, by the canal. There is a very interesting Canal Museum there and several places to eat. As the weather was not really suitable for walking I decided to have a look around the museum. It’s not a large museum, but there are quite a few things to look at and amongst the relics I found an old crystal set with headphones.
It is when you see such simple equipment that you realise how much things have progressed in a relatively short space of time. And of course it required no power to operate it. I guess that it was quite easy to erect a wire above the boat and there would have been an excellent earth available. I do have an old crystal set of my own. It is years since I tried it, but I do remember as a young lad that such a radio was all I had and I used to listen on the medium wave regularly at night in my bedroom. The selectivity was pretty poor and if you tried to listen to a weak signal, you had to put up with the Home Service. Radio 4 to you youngsters! Peter G3OJV.
EFW October 22nd, 2013
We all have our favorite bands to operate on and mine are 40m and 20m. The 40m band is open almost all the time and provides both local and DX contacts, depending on conditions. And 20m is primarily a DX band that is open for long periods, well into the evening and frequently all night.
At my current QTH I have a small garden and a vertical is the obvious choice. I have for about two years been using a home built dual band vertical. On 20m it is a full quarter wave long and on 40m I use top loading and a capacity hat. The top loading for 40m acts as a choke on 20m, cutting off the top section and thus operating as an auro switching dual band vertical. It works well.
But recently I have been considering a change that should improve the performance on both bands. This involves increasing the length to a full quarter wave on 40m which will make it a half wave on 20m. This should improve performance a little on 40m but could make a big difference on 20m I have long considered a vertical half wave as a serious DX antenna. It has a slightly lower angle of radiation than a querier wave vertical and importantly does not depend nearly so much on a good earth beneath it. I would anticipate several dB of improvement in 20m DX performance. My only problem is how best to feed it on 20m, because clearly the base impedance will be high and require a matching unit. And additionally, this matching unit will need to be bypassed on 40m. I am still considering the options for doing this remotely. Peter G3OJV
From Hunter to EFW October 20th, 2013
Well today, I was hoping to have a look inside the Sywell Aviation museum in Northanpton, but it remained shut, save for a couple of workers. They insisted that despite the notice in the window saying it would be open at weekends throughout 2013, it will in fact be shut until Easter next year! Well I suppose it is a voluntary project, but I was not the only visitor to be turned away. The nearest I got to it was looking at the aged Hawker Hunter that was sitting outside. Ah well, another time perhaps! So back to work.
The EFW (end fed long wire) has long been a popular antenna, because it is just about the simplest antenna you can imagine. There is no real downside to the antenna but there are some considerations.
The first is that the antenna needs some form of matching in order to feed power to it. It is seldom anywhere near 50 Ohms and often presents a very high impedance. The nearest it comes to 50 ohms is when it is a quarter wave long. And whilst this will work directly into some radios, it is a poor radiator in practice because the point of maximum radiation is just at the point where it would enter the transceiver. Usually that point would be indoors in the case of an EFW. It also needs a good earth to work properly. So the ease of feeding it is somewhat nullified by the “cons.”
One form of EFW that is a much better proposition is the half-wave EFW. The point of maximum radiation is at the centre of the antenna, it has a predictable radiation pattern, and can be directional if used as a sloper. And because it presents a very high impedance at the feed point, there is far less current flowing here, and the earth becomes far less critical in terms of being able to handle high current with minimum resistance. But we still have the question of matching the high feed impedance.
A design that we first introduced many years ago as a commercial offering was the Japanese Sagant end fed half wave. This had a tuned matching network at one end of the antenna and thus could be fed directly with any length of coax cable. Inevitably this design offers mono band performance, but for some base station work and for a lot of portable operation, this was a popular choice. It was never a cheap antenna and now is rarely seen because of its price.
However, we are pleased to announce that we will shortly be introducing a new range of EFW antennas that are much cheaper, yet will handle a lot of power. So please keep in touch and check our new web site and adverts. Peter G3OJV.
Dining Beside a BC636a Receiver October 19th, 2013
I have spent the night at Sywell Aerodrome, a place that i have never visited before and indeed, know little about. It was used primarily for maintenance during the war and the main aircraft repaired were Wellingtons and Lancaster Bombers. It also had a record of RAF pilot training. Now days it has reverted to a private flying field and a considerable amount of industrial buildings have grown up within the aerodrome, some connected with aviation and others for completely different purposes.
One of the most distinctive buildings are those that originally formed a terminal and mess dating back to the mid 1930s. These have now been converted into a hotel and function rooms. They have however, been preserved in an Art Deco style. There is also an interesting museum built into an extremely elongated nissen hut.
What really caught my eye was the several display cabinets within the restaurant housing some interesting radio equipment. Most of it I recognized as having seen before and in our museum, including the ubiquitous R1155. The one piece I did not recognize was the BC636a communications receiver. This I believe is an AM VHF receiver, and by the look of it, was used as a base station unit. It was out of its case and so it was easy to see the inside. It looked like a simple superhet design but was probably quite advanced for its day. There are a number of other interesting items there, so if you live in the area, I would suggest you perhaps call in for lunch or even a cup of coffee in the lounge bar.
Julian has posted his first detailed message on his blog and it is good to learn that things are improving. I am sure we all join in wishing him well and to see his call back on the air as soon as he has regained hi strength and motivation. Good to see you back Julian.
PC or not to PC October 17th, 2013
What is it about SDR that makes it so popular with some users whilst others find that it has nothing to offer them? It’s a good question, yet one that probably has no one answer.
I first came upon SDR around ten years ago and was very excited about it. It certainly wasn’t that I expected it to offer me better performance than I could get with my analogue gear. And that certainly proved to be the case. But I was not disappointed. It was the novelty of using a radio system that replaced discrete components with a computer. That for me was the attraction. And in some ways it made radio a lot simpler because it was possible to build an interface with just a few components that when coupled to a computer, produced a very respectable receiver wiit good filtering and a digital display.
Well since those days, things have moved on a lot and we are now into the fourth generation of SDR. And if the past few months are anything to go by, it looks like it has come of age and is now a force to be reckoned with. The development in the hardware, coupled with that in computer development, has now resulted in some of the most advanced equipment ever to be offered to the ham radio market.
But it does require a different type of operation and has its operational limitations. There are no knobs and that means that you either rely on a mouse, keyboard shortcuts, or you employ one of the computer control knobs that gives you back a traditional VFO and some other conventional controls. But you have to remember that since the 1970s we have thad to master control with a mouse. So we do change our operating habits when we have to. SDR can’t be used for all our operating. It cannot be used for mobile communications and for portable work a laptop does not sit well with the elements or bright sunlight.
So there is a place for the old and the new. And many will want to own both types of equipment. That is probably the way that SDR will go over the next few years. Beyond that, who knows. Perhaps we will have a PC that has built in radio signal generation and demodulation. Time will tell Peter G3OJV