Last Wednesday I added to my collection of computers by purchasing a Samsung N210 netbook - a small, low-power, long-life laptop computer.

My primary reason for purchasing such a machine was for a forthcoming holiday, allowing me to backup photographs, video footage, write a journal and connect to the internet. A standard laptop wouldn't fit the bill - the one available to me was just to big and heavy. My smartphone didn't have the connectivity or storage to allow me to get pictures off from SD cards.

So the netbook option seemed to be the logical choice, and after a lot of searching (it's a crowded marketplace), I settled on the Samsung.

This particular model has a white case, a 10.1" 1024x600 matt screen, 250GB hard drive, 1GB DDR2 RAM (expandable to 2GB), Bluetooth, wifi 802.11b/g/n, built-in webcam, SD card reader and 3x USB sockets. The processor is one of the newer Atom N450 1.66GHz models which features an Intel GMA350 graphics chip as well. This processor, compared to the older Atom N270, features significant power reduction meaning battery life is significantly better than the earlier model.

I had to spend a lot of time seriously considering my requirements and trawling through reviews. Quite early on, I settled for a machine with the N450 processor which fortunately narrowed my search. From here though, machines are very similar with little to tell between them.

What settled it for me was that this model had strong reviews and featured the newest WiFi standard. Although I don't operate a 802.11n network just yet, I'm planning an upgrade in the not-to-distant future and it made sense to future proof the machine as far as possible.

As for my impressions now that I'm using the netbook, I'm very happy. The machine is slightly heavier than I anticipated but compared to an inexpensive laptop, it's certainly small and light. It fits in my backpack easily and I think it'll just fit in to my camera bag. The reduced resolution on the screen is noticeable - particularly in the vertical, but small tricks such as auto-hiding the taskbar and running a web browser full-screen offsets that limitation somewhat. Battery life is impressive and I estimate achieving anything between 5 - 7 hours of uptime depending of course on what it's used for. Admittedly this is short of the advertised 11 hours battery life, but still very good.

There's no doubt that the processor is limited, but day-to-day browsing feels sufficiently fast. Standard definition video files play okay from the hard-drive but I did struggle to use BBC iPlayer through Firefox on the supplied Windows 7 Starter. Video playback stuttered and full-screen use was out of the question.

I've configured my machine to dual-boot Windows 7 with Ubuntu Netbook Remix 10.04. I've divided the disk into multiple partitions to accommodate the two operating systems, the restore partition and a shared data partition. I find myself booting more and more into Ubuntu. It feels snappy and iPlayer here is much more successful although full-screen playback is still a struggle.

There are a few niggles with the open source system - after installation there is no wireless connectivity until an update is done via wired ethernet, and some additional software needs to be installed to make some special keys e.g., brightness work. I've also noticed the wireless does not always resume when waking the machine from a sleep state although this is intermittent and a reboot easily fixes it. I also needed to enable multiple desktops using gconf-editor which I think is essential on a limited resolution screen. Now it's configured though, I think it's a very usable and snappy system.

The Windows installation needed some work too. As seems to be the case with bought computer systems, a lot of extra - unnecessary - software was pre-installed. It took some time to install this as part of the initial setup and then more time again to remove it. I'm talking about Microsoft Office 2007 (trial), Microsoft Works, various non-standard games, McAfee virus scanner - all applications that hog disk space and have the potential to slow down the machine. Fortunately once I'd cleared all this I was able to take a snapshot of the system with one of the useful pieces of software - Samsung Recovery Solution 4.

So all-in-all, I think this was a sound choice and I'm looking forward to putting it through it's paces. As well as the uses I mentioned earlier, I will also see how it performs next to my radio equipment - I wonder if it emits a large amount of RF? As it has a large battery life I'm considering how useful it could be for operating a portable PSK amateur radio station. I suspect that it will be like other laptops I've used - on battery it'll be fine. It'll be the mains adaptor that pollutes the spectrum.

At the time of writing, the Samsung N210 was available at Amazon UK for £278 (white model) or £333 (black model).

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Tags: computers, reviews, gadgets, amateur radio

Today seems to be a day of negative digital radio news - and not necessarily entirely accurate news at that. Be warned, I'm going to ramble on for a bit. If you can't be bothered to read it all, I sum up my point at the end.

An Open Letter to Rt. Hon. Ed Vaizey MP

First I read an open letter from Rob Mannion, the editor of Practical Wireless Magazine, which was sent to the Telegraph newspaper aimed for the attention of Mr Ed Vaizey MP and reproduced here:

Dear Sirs: With the right Hon.Ed Vaisey about to make a statement regarding the imposition of DAB radio on Band II v.h.f. radio services, to replace the practical f.m. broadcasts, it is to be hoped that the new coalition government have listened clearly to all the criticisms regarding the impractical technology and the difficulties of receiving DAB radio services on portable equipment using simple antenna systems (a service the public has been used to for many years).

With the much mentioned huge spending cuts announced by the government, it will be unfortunate indeed if pensioners and those out of work should face the prospect of buying new equipment - all made in Far East - that would most likely provide inferior reception.

I implore Mr Vaisey to take the opportunity to repeal the legislation that will force listeners to buy equipment that's not necessary, and at the same time will also send money overseas to support another country's economy. Keep the money that would be spent in the UK, keep the service that works so well on simple portable receivers and enable as many people to carry on enjoying the essential broadcast radio services as before with simple to use receivers that don't require large amounts of power to operate them and work efficiently. With DAB radio on Band II that's certainly not possible.

Please Sir - Dump the DAB on Band II.

Rob Mannion

Editor Practical Wireless magazine
Broadstone
Dorset BH18 8PW

Whilst the theme of the letter may be sound, I find the arguments put forward here to be quite surprising particularly the mention of the source of DAB products - the Far East. I fail to see the issue with electronics being made in foreign countries. It is indeed the case that a significant majority of our products are manufactured outside of the UK and I daresay this is true for analogue radio products. Yes it would be nice for the UK to have a thriving manufacturing industry, but at the moment it simply is not the case. The sale of digital radio products will still occur on these shores however and that will generate revenue for the UK economy.

I also take issue with the inference to expensive digital radio sets. Prices are falling all the time, and a DAB radio receiver can now be had for £20.00. It wasn't so long ago that the lower price was £50.00 and when I first obtained a DAB receiver, it was £100.00. Switchover isn't happening this year or next - it's pencilled in for 2015. That's five years for prices to fall further and for people to gradually replace sets. I'm sure also that as technology improves, so will the power consumption.

It also may be the case that people may choose not to replace some sets. With many digital radio stations broadcasting via digital television some may find that all the radio they need is already available to them in a post TV switchover country. Let's also not discount online radio.

Lastly in respect of this letter, if you're going to emplore a minister to listen to your viewpoint and in an open letter at that, it's probably worth at least spelling his name correctly!

The Daily Mail Jumps On The Bandwagon

The second source of negative reporting comes from that bastion of quality news(!) The Daily Mail.

The news report itself is linked to via Related Links on this entry, but the key points are thus:

• Motorists face a bill of £300 to install digital radios,

• the government is pushing ahead with plans to switch of AM and FM broadcasting,

• 100 million analogue radios will be redundant following switchoff in 2015

• New car head units cost £300; conversion kits cost £100

• Most ordinary homes have 2 or 3 radios

In typical sensationalist journalism, the body of the story contradicts the headline as can be seen in the points above. The headline that motorists will have to pay £300 to replace their radios simply is not true. Let's do some research:

I conducted a quick search through Google UK found a JVC DAB head unit for £148.99 - half the price quoted by the paper. Unfortunately, for a quick search, that was about the only result but one result at half the price is still not £300.00 in my book.

The Mail does mention conversion kits and acknowledges that these are cheaper than head units (there's the contradiction). More research again:

A search for the Pure Highway DAB receiver, which mounts on the windscreen and re-broadcasts a digital station on an FM frequency that any plain old car radio from the last 20 years can receiver, resulted in a number of hits. The cheapest source for this product (from a major known retailer) was Amazon UK at £68.00 - a whole 32% less than the cost of a conversion kit quoted by the Mail.

So we can clearly see that The Daily Mail is simply wrong with it's figures. It's also wrong stating that a switch-off of the analogue bands will happen in 2015 but this is more forgiveable. Major national and local stations are intended to be moved from FM to DAB by 2015. The resulting space on the FM band is earmarked for community stations. A similar prospect is on the cards for AM, but there is an intention to close this by moving community stations found here to FM.

As can be seen from the above paragraph, with FM being used for community stations it does not mean that all analogue radios will become redundant although it's true that the requirement for them will be reduced. There's no reason to fear that these will end up simply trashed though - old radios could be recycled and sent abroad to countries where digital radio has not become established.

So let's take a final look at costs. The article states that most homes have two or three radios (although a later quote mentions four or five, we'll go with the Mail for the purpose of this bit of maths). Let's say that all of these radios are replaced with digital sets. At the cheapest cost of £20.00, that's a replacement cost of £60.00. Adding on a new car head unit at £148.00 results in a total replacement cost of £208.00. Okay, it's still not cheap but that's every radio replaced for less than the cost stated for motorists only.

Going back to my earlier point about other sources of digital radio, we could perhaps assume that only two radios will be needed - one for the kitchen and one for the bedroom with the living room being served by digital television. Take £20.00 off the above total, that's £188.00.

There's five years remaining to replace these radios, so no immediate rush. The cheaper sets could be replaced over the next two years - easy enough by saving £1.70 per month. Then there's a further three years to save for that more expensive car head unit - £4.11 per month assuming prices don't fall.

What's My Point?

Digital radio is here and it's going to stay. I don't think there's any two ways about it, and at the moment 2015 is earmarked as the date when we should be using some form of digital radio as our primary method of receiving radio broadcasts.

DAB has its problems. At the moment, coverage is less than FM and there are issues around audio quality. Yes, receivers currently use more power than FM and yes, they do cost more.

All I ask for though is some perspective. There's five years for problems to be ironed out. Coverage can be improved, power consumption can be improved. Audio quality is subjective but there are solutions to that too (increased bitrates, codec changes), and a good quality DAB signal does provide generally better audio than a poor quality FM signal.

Whilst DAB is digital radio, digital radio is not just DAB. Satellite, cable and online services all provide digital radio and in many cases the audio quality is excellent.

It also occurs to me that perhaps there is some hate for DAB simply because it's not analogue.

I know I'm asking to much of our press, but let's look at the both the pro's and con's of digital radio compared with analogue radio and have a balanced report written in light of the situation we're in now - not as though switch-over is taking place next week and we're all being conned out of our hard earned cash.

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Tags: broadcasting, radio, dab, amateur radio

I've made some slight changes to my magnetic loop aerial. Nothing major, but useful none-the-less.

The original design, as copied from G4ILO, featured a T shaped mast with hooks on the left and right of the top bar to support a loop of RG-213 coax. The biggest problem I found with this was establishing the correct loop shape to create a good match. It was easy to squash or expand the loop which could destroy a previously good match.

To overcome this, I've redesigned the mast to a + shape. The same coax is used for the loop but it is now much more rigid than before meaning if I collapse the aerial and re-assemble it later, I am more likely to maintain a good SWR reading.

Other than that, I've now got a large run of RG58 coax to connect the rig to the aerial meaning positioning is much easier. I've also obtained a better fitting knob for the tuning capacitor. The one I was using was too big for the shaft making it off-centre, wobbly and more difficult to tune.

So what do I have still to do? Well G4ILO's design features an inbuilt SWR indicator which I might incorporate although it's not essential for me at the moment.

I'm still thinking about remote motorised control as well although gears seem to be more complicated than I thought. It is only the gears which are the problem though. The capacitor housing is large enough for a motor which will be connected to a long cable run (as long as the RG58) terminating in a small control box which can set next to the radio. All it needs to incorporate is a momentary push button control to activate the motor and perhaps a variable resistor to control the motor speed.

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Tags: amateur radio, magnetic loop aerial

On 1 April 2010, Ordnance Survey opened up a lot of it's data including a cut-down version of Code-Point - a database of UK postcodes.

Since this data is available free of charge, and has a licence aligned to the Creative Commons Attribution 3.0 Licence; I decided to download the data and incorporate it into an SQL table for use on this website.

I've now completed the import of the data (1,696,088 records not including code definitions) and have created a webpage which can be used to query this information. A user can input a postcode and have all open data which I have available displayed.

Not only that, but I have also been learning about converting geographical data in to different systems. The Code-Point data provides co-ordinates in the British Coordinate System of six-figure eastings and northings. My new page converts this data into latitude/longitude, National Grid Reference, Worked All Britain (WAB) square and Maidenhead Grid Locator. By having latitude/longitude data, a Google Map can also display a marker showing where a postcode is.

Now I've got a bit of a grasp on how to convert data, I hope to extend the page to accept input of other forms of geographic data and have it convert in the same way. For now though, I'll leave it at postcode only.

There's nothing particularly unique about this. Many sites across the internet allow postcode searches and data conversion. This was essentially a two day project which I decided to do simply because it costs nothing but server space (over 150MiB), I fancied doing some coding and I find this information useful from time-to-time as part of my amateur radio hobby. If anyone else finds this information useful then that is a bonus.

Find the link in the navigation menu, above.

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Tags: this website, amateur radio

I've been further testing my magnetic loop aerial over the last 24 hours, but haven't made any changes to the setup as such.

I did find out why, just before writing my blog yesterday, I couldn't get a good SWR reading despite doing so the day before. Rather foolishly I'd let the bare braid from one end of the RG-213 loop touch the outer contact of the phono plug to which the coupling loop connects to. Whoops! Once I'd realised that, getting a match didn't prove to difficult.

In actual fact, I think I may be getting used to tuning the aerial. I'm having very few problems setting up for 14.070MHz for PSK31 use. 7.035 doesn't match quite as well, but I can still get about 1.75:1 I'm hoping it's possible to get this better by tweaking that coupling loop - either fine tuning it's length or adjusting the shape.

Disappointingly though, I still haven't managed to make any contacts. I've been calling CQ using PSK31 on 20m and 40m, and also using SSB on 40m but to no avail. I'll keep trying but I'm not entirely sure how well my signal is getting out. The only indications I've had that I am transmitting are the appearance of markers on the PSKReporter map which indicate that a monitoring station has heard me. This has happened three times - in Sweden, Germany and Italy.

It does sound promising, but until I exchange some reports I'm really just speculating as to how well this aerial is working for transmission work.

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Tags: amateur radio, magnetic loop aerial

About 6 months ago, I visited the website of Julian, G4ILO who had detailed how to build what he has called a 'Wonder Loop' - a small indoor magnetic loop aerial. Following this visit I was inspired to build one myself.

As is my way, I've taken a little while to get around to building this but I have now completed my first build with moderate success.

I've used a 30-310pf (approx) tuning capacitor which I found on eBay for a few pounds, a loop made of RG-213 coax cable and a coupling loop made from some high current cable.

The capacitor is housed in a rather large plastic box (again an eBay purchase) using a couple of screws and a couple of cable ties to hold it in place. The terminals of the capacitor run to two terminal posts to which I can connect the main loop. The coupling loop is connected to a Phono socket, which runs directly to a BNC socket on the rear of the box. From this socket runs a patch lead to the transceiver.

I haven't been particularly precise in the construction - so imprecise in fact that when drilling holes for screws to secure the capacitor, I managed to mis-judge where on of the holes went. I ordered 2m of RG-213 for the main loop, and initially I used the entirety of this, only trimming it slightly during first tests. The coupling loop was one fifth of the size of the main loop, but since the trimming this is now slightly out of proportion.

The assembly of the aerial was completed yesterday after various trips to Maplin and B&Q to get parts, and initial tests are promising. As a receiving aerial I'm really quite happy. Sitting in the flat, it out performs my whip aerial when tuned correctly. Transmitting is a slightly different matter. Yesterday I managed to get a good match with SWR readings of around 1.5:1 or better on 40m and 20m and the PSKReporter website showed my CQ calls on PSK31 being received in Italy with 10w of power. Unfortunately today so far I can't seem to get a match on either band.

I'm experiencing an issue with the sharp tuning of the capacitor. I don't have a reduction drive so I'm having to be extremely precise with the tuning knob - possibly more precise than I am able to control. Another issue is the effect my hand has on the SWR reading. I've notice today that when tuning I can perhaps get a lowish reading but when moving my hand away, the reading worsens. Strangely I didn't notice this yesterday. I can't think of how to overcome this unless I can motorise the control. I'm not sure how possible that is.

My next steps I think are to look at the dimensions of the loop, and perhaps shorten it a bit. I will also try re-creating the coupling loop ensuring it is one fifth of the size of the main loop. I'd like to investigate the possibility of creating a reduction drive to allow for fine control but I need to source cogs and rods and figure out how to fit them into the existing design. If any readers have ideas of where to get such parts, please do leave a comment below.

Despite these initial set-backs, it's been fun to create what is my first home built aerial and to have it work albeit temporarily. Credit of course goes to G4ILO for his design, which I have pretty much copied, and write-up which was very helpful in aiding construction.

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Tags: amateur radio, magnetic loop aerial

A new digital mode is on the scene called ROS - a spread spectrum mode ideal for weak signal/QRP use.

The mode can operate at two symbol rates - 1 and 16 baud; the former is ideal for very weak signals with the user guide stating transmissions can be decoded with at up to -35dB S/N. Unlike WSPR (another weak signal mode), this is a 'live chat' mode allowing users to converse in a way not dissimilar to PSK31 (at 16 baud anyway).

I'm keen to have a go. I'm quite fond of digital modes, and anything that means my disadvantage with aerials is not so much of a problem is certainly welcome. Unfortunately though, the software is Windows only.

I know using Linux is my choice, and with that choice comes the expectation that some software will be out-of-reach. I do think that this should not apply to amateur radio software though. In the spirit of the hobby, such software should be portable. It could be just that the source is published so that others can port the software, but however it is done, those that do not use the popular OS should not be left out.

WINE (the Windows compatibility layer) could be a quick option, but a quick attempt has not been successful. I will put some more effort in to getting it going but there's no guarantee of success.

Fortunately the author has promised to release the source once the application is finished. When that will be however, is anyones guess and until that happens, us Linux (and presumably Mac users too) are left high and dry.

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Tags: amateur radio

I know I said I wouldn't do anymore serious testing until I'd built a new PC, but I just couldn't help myself. Over the last few days I have been active on 20m with reasonable success.

After experimenting with different settings on the computer soundcard and the audio levels on my interface, I came to the conclusion that running the sound output from the PC at 100% for both the master volume and PCM volume was a bad idea.

I can't say why this didn't occur to me before especially considering I'd noticed audio distortion on other computers when listening to music with the levels at 100% - I'd always reduce them slightly with significant improvement. So it was, that after various tests I came to settle on the master volume at 90% and the PCM fader at approximately 50-60%. Further adjustments would then be made at the soundcard interface.

The other conclusion I came to - and this is almost certainly ludicrously obvious to all seasoned PSK operators out there - is that adjustments to the audio level need to be made after each change in frequency made on the computer. The higher the audio tones (higher frequencies) the louder the audio going in to the radio needs to be. When changing to lower frequencies, the audio volume needs to be reduced to maintain the same power level.

Now I've made these discoveries, I've had a lot more fun! Since I had today to myself, I decided to make it a radio day and have been pretty much stuck to the keyboard calling CQ and answering the calls of others. I'm still limited to around 10w of power since higher levels continue to interfere with the keyboard; but - and here is another revelation that will be obvious to the old-timers - power isn't everything.

To give an example of the success I have had today, I have made contacts with operators in Spain, Sweden, Italy, Poland, Slovakia, Ukraine and Russia. Perhaps that doesn't sound too remarkable, but considering my balcony mounted whip aerial I'm very pleased. To top it off though, according to the PSKReporter map, which I monitored throughout the day, my signal was reported as being heard in Canada! That is something I'm really pleased about.

What I do find strange though is this keyboard interference. All day I have been transmitting with 10w of power - sometimes creeping up to 14w. The keyboard has been fine. A key may occasionally not respond but it was easily workable. However, about half an hour ago when working RX6BH in Russia, the keys became very unresponsive making typing during transmission a nightmare - it was slower than transmission rate of PSK31! I'm not sure why this would be. Nothing had changed. The power level was peaking at 10w initially, and I even reduced it slightly to no effect.

Actually, I'm wrong. Something had changed. I'd switched on the lights in the flat. Could that be what makes a difference?

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Tags: amateur radio, psk31

Over the last month, I've been preparing my station to operate on digital modes by building a radio to soundcard interface. After various hurdles I finally got the device working and conducted my first on air test yesterday, using PSK31.

Unfortunately it wasn't overly successful. I can only get the radio to output around 10-12W maximum before the ALC kicks in causing horrendous noise on the signal. I also have some interference problems with my keyboard which makes operating difficult. It was originally the case that only a couple of watts of power would cause the keyboard to lock up (and the mouse too after a bit more power). Now I've enclosed my cheap USB hub and slack cable into a metal case to improve shielding. I've also added ferrite beads to the keyboard cable, mouse cable and the USB hub cable. Although it's improved the situation significantly, when the power level gets over about 8w, some keypresses are missed resulting in "wods tped ike is" (words typed like this).

Despite these problems, I did spend a good while calling CQ and had a very brief QSO with Cris, YO5OAW in Romania. We exchanged reports and location information but due to a fading signal and the problems typing I decided not to stop and chat. PSKReporter also showed my signals being received in Portugal and Rome.

Charlie M0PZT did suggest that using a laptop could be the cause of some problems due to its unshielded nature compared to a desktop PC. I think that's quite likely considering the monitor also receives interference which disappeared when testing with a desktop machine.

So before I try another serious attempt, I think I'll replace the laptop. I'll be building a cheap PC which I reckon can be done for less than £140.00 while still being a machine of fairly modern specification (Intel Celeron Dual Core 2.2GHz, 1GB DDR2 667MHz RAM, 80GB SATA HDD, Wireless LAN, onboard Realtek 5.1Ch audio, onboard Intel graphics) with room for expansion should I need it.

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Tags: amateur radio, psk31

Just a quick note to say I visited the National Hamfest in Newark along with Charlie, M0PZT yesterday. It was quite a long trip - about 2.5 hours to get up there, but good fun.

I'd gone with a small shopping list in mind - nothing big, but some bits and pieces that I would find useful. Coming back with 6 out of 7 items suggests it was quite successful.

My haul included a book on HF aerials, a microphone/earpiece for my handheld, a new mag-mount for my 2m/70cm aerial, 2 variable capacitors, two 3.5mm stereo plug > 3.5mm stereo plug cables and a small 4-port USB hub. The only thing I couldn't find (and didn't really expect to find) was a USB to Serial adaptor.

The variable capacitors are needed for my next project which I'll be starting once I'm happy with my soundcard interface which I've been building over the last couple of weeks. I intend to build a small magnetic loop aerial - it'll be the first aerial I've constructed and hopefully will be quite useful in my limited space QTH.

I haven't mentioned the soundcard interface on this blog yet (although it's come up once or twice on Identica/Twitter). Once it's finished I'll do a write up with some photographs. My main stumbling block at the moment is the USB to Serial Port adaptor - the laptop I'm using for radio doesn't have a built in serial port. Curses to progress!

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Tags: amateur radio, events