Saturday, 11 December 2010

JT65-HF - remarkable!

I've been using Joe Taylor's weak signal modes for a while now, mostly WSPR, but recently my attention has been drawn to an interesting spin-off which calls itslelf "JT65-HF".

Clearly many people have been there before me, as there is quite a bit of activity in this mode, which seems to be able to produce quite remarkable and astonishing results.

Having downloaded the software, set it up (easy peasy) and left it running for some hours, the resulting decodes have never ceased to amaze me, given the modest aerial setup I have here.

I presume that much of this is due to the "FEC" (Forward Error Correction) associated with this mode of transmission. Stations such as mine with modest capability therefore stand a good chance of getting their messages through, or conversely can successfully receive weak transsmissions from elsewhere to a remarkably high degree.

I would recommend anyone at least to have a look at this mode, and at what it can do.

Wednesday, 1 December 2010

ROPOCO SSB - a selfish rant

I will be the first to admit that this is a very selfish point of view, but I really am quite annoyed (well as annoyed as I will allow myself to be over something which is a hobby/leisure activity) that the "powers that be" whoever they are, have turned one of the twice-yearly ROPOCO contests from a CW challenge to an SSB or phone one.

Especially ROPOCO1 (April) in which I have previously participated many times.

I am not a contester at all, but I really enjoy this particular challenge as it is, quite frankly, just that, a challenge.

What it challenges, from my own selfish point of view is one's CW sending and receiving ability/technique.

It does this in quite a different way to that of most if not all other contests in that _ACCURACY_ is prized above all else.

Most other contest have so many elements which are predictable (report, serial number, region, and so on) that "quantity" rather than "quality" carries enormous weight, whereas in ROPOCO accuracy is king.

Sending technique and accuracy is challenged. In other forms of amateur CW communications the odd sending error is normally of little consequence - the operator who knows he has made a mistake in transmission has to decide whether or not to correct that mistake, and if he decides to correct it, he has numerous methods open to him how to achieve that. In CW conversation, he will often just let the mistake go and rely on the operator at the other end picking up the error and dealing with it in his own way.

With ROPOCO this concept just doesn't work, and the challenge is for both the operator sending, and the operator receiving knowing how to deal with what they think might be a mistake in either transmission or reception. Mistakes lose points!

If you have never participated in ROPOCO this notion might be somewhat lost on you, but those of you who have will know exactly what I mean.

It could be argued, and I am sure that it will be, that this format should translate perfectly well to a "phone" format, and I am sure it will, but my point is that the corresponding challenge in speech communications is quite different to that in telegraphy.

For my money, I "they" wanted to try out ROPOCO in speech form, they should have had an _extra_ contest for the speech boys and left us brass pounders with our twice-yearly bout of fun.

The reason why I am so narked that the April test has been changed is simply because that is the one I usally participate in!

How selfish is that?!

Sunday, 21 November 2010

I've finally made my peace with (Pendrive) Linux!

I suppose I am about to admit that I've been wrong all along, that I didn't really understand what Linux is all about, etc, etc.

Undoubtedly that's true.

What has changed my view is the fact that I've been using for some little time now a "Pendrive Linux" Ubuntu distro, and that has served me very well. So well that I really ought to be grateful and revise my opinions about Linux in general.

With this software, which as has been hinted at above, is installed on a USB "PenDrive", I have been able to (for example) surf the Internet using my "work laptop" (fairly well locked down by my company's IT department) whilst working away from home, staying in hotels, and so on.

This distro has performed without any problems for several months, other than running out of space, and that was down to me not setting it up with adequate space to start with, rather than it being a problem with the software itself.

I can connect to my POP3 Email accounts at will, and even do other arcane stuff such as analyse configurations of whatever WiFi network I am connected to as required and work around them if possible.

For a piece of free software, this has to be a Good Thing!

Sunday, 14 November 2010

Old School WSPR

[copied from my blog]

Today, I think for the first time, I have unleashed one of my "old ladies" into WSPR action.

The "old lady" I am referring to is an FT-101ZD Mk3 which I brought back from the dead a few years ago. An EBay "tech special" in US terminology, or "spares or repair" in terms of UK terminology.

This features on my web site ( so I won't repeat too much I have already covered elsewhere, but I think I have proved to myself, at least that these old radios can, with care be used reasonably successfully on today's modern computer-generated modes.

I have been spotting stations with this radio for a couple of days, and today, I enabled transmission and others have spotted me.

The principal disadvantage with the older radios is that of frequency stability, or rather the lack of it.

On my "to do" list for this radio is to (hopefully) improve this facet, probably by replacing the zener diode based voltage stabiliser to the VFO with something of somewhat higher specification (eg low-dropout IC regulator, or similar) as this is where I think the thermal stability weakness lies with this particular radio.

However, having allowed the radio to warm up for some considerable time (four hours) the case temperature of the radio is still gradually increasing but at a very gentle rate. Yesterday the case temperature crept up ALL DAY, as did the VFO frequency error!

Nevertheless, I regard the performance as just about good enough for me to join in the WSPR fun. The results will be stashed away in a spreadsheet on my PC and used in a "before" and "after" type comparison once I decide to tackle the thermal stability issue.

In the meantime if any other WSPRers are wondering why their "drift" as received at G4FUI isn't quite as good as they think it ought to be, then the above hopefully provides some sort of explanation!

I don't think that cranking the power down to half a watt from a tube PA is necessarily all that "green", as the PA efficiency must be abysmal, however it probably is a good idea to run the tubes for a few hours to keep the vacuum in them nice and hard!

Saturday, 20 March 2010

Linux - R.I.P.

Here we go again, another anti-Linux rant ...

Well not _exactly_, but here is an illustration of how "naff" Linux is to a long-time Microsoft DOS/Windows user :-

When I set out to learn about Linux, I had two objectives. The first objective was to learn about Linux, obviously.

The second was to run a web server (ie host web sites on my own equipment in my own home).

Both of these objectives were achieved up to a point, but when it came to hosting web sites I also wanted to learn about the analysis of traffic associated with those sites.

To that end I installed "Webalizer" and that is where the problems with Linux really came to a head.

The darned program kept the access logs created by Apache so locked up that Webalizer was unable to access them. No matter what I tried the result was always the same.

For the sake of comparison I then decieded to load both Apache and Webalizer onto a Windows XP machine.

I got Apache up and running on the Windows machine in probably not much longer than half an hour (I was familiar with the way the Apache configuration files worked, so I wasn't exactly starting from scratch), and Webalizer was installed and activated in pretty much the same amount of time.

Webalizer on Windows is now happily producing the web stats I was trying to get from the Linux installation, all with about an hour's worth of effort.

Well at least I tried!

Linux seems to me to be a bit "exclusive", rather like a Golf Club.

Golf Clubs don't really like to see the "ordinary bloke on the street" cluttering up their courses and facilities, so they make membership difficult to achieve (by charging lots of money, or by imposing conditions on would-be members, etc etc) whilst pretending that membership is "open to all". The reality is different, it's a hobby for the "chosen few".

Am I referring to Golf Clubs or Linux in the last statment? I'll leave the reader of this to be the judge of that!

Monday, 8 March 2010

Band I TV - Liege E3 - R.I.P.

Well I've known it's been coming, but today I have finally realised that one of my "favourite" sources of meteor reflections, the Band I TV RTBF-1 transmitter on Channel E3 near Liege (Belgium) is no more.

It was there the last time I checked last month, but today, having a day off work when I though I would just have a little tune around to see what was going on, I received no signals from that transmitter. Fearing the worst, I did a Google search and found out very quickly that the transmitter was turned off for the last time on March 1st.

The YouTube link in the heading points to a recording of the last minute or two of programme from this transmitter.

I expect the equipment is going to be dismantled and be recycled into razor blades or whatever, such is the fate of electronic equipment once it has ceased to be of use.

This transmitter not only was the source of meteor reflections, but its distance from me made it ideal to display the effect of aircraft reflections. I have captured many "waterfalls" of these phenomena.

Now that the digital TV bandwagon is rolling relentlessly through Europe, it's only a matter of time before the remaining Band I TV signals are quiet forever. Digital TV will never be broadcast on Band I, so there isn't even that prospect to look forward to.

On the plus side, as these TV services close down across Europe, it appears that more countries are acquiring Amateur allocations in the 70MHz region. As I will hopefully be joining the ranks of 70MHz users in the future, once my homebrew 70MHz "Eden9" transceiver is up and running, that is a bonus.

R.I.P. RTBF-1 Liege, E3

Sunday, 10 January 2010

Another anti-Linux rant, I'm afraid.

Today, for reasons I won't bore you with, I had to move my "Linux box" to a different location, and the new location demanded a different mouse to the one I was using previously. Naturally I planned to use the Linux GUI rather than the command console.

The first mouse which came to hand happened to be an old but nice Microsoft serial mouse (remember those?).

Well you would think setting up Linux to work with a serial mouse would be easy, wouldn't you?


I did a fair bit of research on the internet, noting from that others had had similar problems.

None of the suggested remedies I tried worked. I gave up in the end and located a spare USB mouse which worked straight away.

OK, so serial mice are definitely "old school", but I would have thought that there were a fair few in use around the world.

Linux really is PANTS!

The Noble Art of Blogging

I suppose psychologists have a number of theories about why people "blog", and I have often wondered myself. This morning I was following a train of thought in my head as a result of which I looked up something on Wikipedia (I don't think I need to elaborate about what and why ...). It happened to be about a well-known person of whom I knew a fact that the average person would not know, owing to the fact that the "celebrity" in question had a descendant with whom I was acquainted in my school days.

As one does I followed a "web trail" of links and cross-references, and ended up reading someone's "Blog" where quite detailed and intimate (not in any way in the salacious sense of the word) references were made about my former school-mate. At this point I should say that I wasn't a close acquaintance but, an at least we would have been on "first name terms".

Now it so happens that my former school mate deceased prematurely in her forties, a few years ago. I was already aware of this fact, but the "blogger" in his column made me aware to a certain extent of some of the reasons why this person's life came to a premature end. Part of that story actually had its roots in our mutual school-days and, naturally, it struck a nerve.

As you can imagine, this was quite a harrowing experience, but it did make me wonder about why I find some blogs so interesting.

I now think it is something to do with one person articulating in the form of the written word (unlike in the printed or officially published press, there is no financial or career motive for writing down what one thinks) their thoughts, observations, etc, and the reader reading those thoughts and observations and thereby giving their own thoughts and observations a context. Possibly rather like having a conversation with someone you have never met before, but whose point of view you find rather interesting, even if you don't necessarily agree with it.

One of my personal philosophies is that I don't mind too much being wrong about something.  I will admit to prefer being right to being wrong, but accept that that one cannot be right all of the time.   However, I usually enjoy the argument, and if the argument proves that I am wrong, then so be it!

Just a thought ...

Saturday, 9 January 2010

Classic Hybrids and WSPR and ...

A very interesting thread has sprung up on the "Fox Tango" Yahoo group prompted by an Italian amateur with an interest like mine in classic hybrid radios - in his case a Yaesu FT-901.

Apparently his radio developed a couple of faults, in particular the failure of the 6V regulator which feeds (inter alia) the DC supply to the VFO circuit.

Not surprisingly the original IC regulator is obsolete, and having nothing else to hand he replaced the faulty one with a bog-standard 7805 unit, and even though the previous 6V supply is now only 5V he claims that the VFO is now "rock solid".

You will realise from my web site that old radios are also an interest in mine, and it so happens that over the last couple of days I have been looking at the performance of my own FT-902DM and in particular the VFO stability (or rather the LACK of VFO stability) of this particular set.

I had been musing upon the supply regulation to the VFO as it appears that the real problem is that the VFO drifts as the set warms up, and as it is a bulky, heavy radio it really NEVER warms up properly (not in a reasonable operating period anyway), consequently it NEVER stops drifting.

It drifts so much that you couldn't use it sensibly for a mode such as WSPR.

I had come up with a theory that the original regulator, which claims to be a "low drop-out" device (ie it will work with the input and output voltages relatively close together, really was working just TOO close to the wire with only a theoretical 8V input being regulated to 6V out, such that the thermal changes in the environment were affecting the output volage to a significant extent.

Having a bunch of 7805s kicking around in my junk box, I just might give this a try. OK the output voltage may be significantly lower, but assuming any static frequency change can be trimmed out, the extra volt of dropout voltage, coupled with a more modern device may well make a noticeable difference to the performance.

Another contributor to the same thread suggested putting a diode in the common lead of the 7805 to lift the output voltage, but I would be tempted to try it without as (a) it would reduce the dropout voltage and (b) I suspect that the temperature coefficient of the diode would exacerbate the drift problem. Having said that, it would be very interesting to find out!

Another alternative would be to fit a 7806, and possibly take the input voltage from somewhere else, eg a 12V or similar rail in the radio.

Another item added to my "to do" list, so watch this space!