testing the magnetic loop
09 Mar '10, 20:19
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.
magnetic loop aerial
08 Mar '10, 19:17
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.
the end for 6music?
02 Mar '10, 18:55
The BBC has today announced cutbacks to it's services intended to save £600m which will be re-invested into programming and original content.
The victims of these cutbacks are the radio stations 6 Music and the Asian Network along with a significant proportion of the BBC's website.
Initially this was reported in the newspapers a number of days ago so the announcement is in no way a surprise but I wanted to wait until it was official before commenting.
I'm disappointed that the BBC deems it necessary to wield the axe over 6music. The station is exactly what a publicly funded broadcaster should be providing - a station that would not exist in the commercial sector. Absolute Radio and XFM are probably the nearest big commercial stations but these do not have the diversity offered by 6music. Losing this station will leave a gap that will not be filled.
Part of the problem of the station has been the number of listeners it attracts. I wonder if this problem is down to it's broadcast medium though. Personally speaking I listen to the vast majority of radio whilst in the car. I do not have digital radio in the car. I therefore cannot listen to 6music. I'd be surprised if this is not the case for many people, and therefore I do proportion some of the blame on to the fact that in-car digital radio equipment is not easy to come by (I've checked Halfords and they have precisely none). Most cars do not have digital radio fitted as standard. Until this changes, digital-only stations may well suffer from lack of audience.
The BBC's proposals have now been submitted to the BBC Trust and will be subject to a 12 week consultation period, so there is still hope for the station. If things go the wrong way though, 6music could disappear by the end of 2011.
The BBC Trust are accepting views on this consultation, so to petition the broadcaster to save the station visit:
https://consultations.external.bbc.co.uk/departments/bbc/bbc-strategy-review/consultation/consult_view
new digital mode
25 Feb '10, 20:34
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.
psk31 - a day at the keyboard
17 Oct '09, 18:39
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?
psk31 - first experiences
11 Oct '09, 18:34
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.
national hamfest
04 Oct '09, 12:07
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!
clusterclient in linux
17 Sep '09, 20:04
My friend Charlie, M0PZT has taken the time to write a piece of software which provides quick and easy access to the DX Cluster via the internet (telnet). ClusterClient, as it's known, recently received some good comments on the ICQPodcast and I decided to give it a try myself. The only issue being, I run Linux and the software is written for Windows.
Not to worry though. I spent some time last night figuring out if I could make it run and the short answer is yes I can. Thanks to this guide, now so can you!
It's actually very straight forward to get the software going in Linux, and it may well be much simpler than the guide tells you. I'm assuming that the computer being used does not have a copy of WINE installed, nor the appropriate DLL files. I should also mention that I have tested this in Ubuntu 8.04 (Hardy Heron) and Ubuntu 9.04 (Jaunty Jackelope).
First we need to get a copy of the software. This is available from Charlie's site (see ClusterClient link, in Related Links below) - just scroll down the page until the Download link is visible. Download ZIP file and open it.
Extract the contents of the ZIP file to a suitable place on your computer. I've put it in /home/ben/ClusterClient/ but it doesn't really matter as long as you have full permissions to the folder.
Use the Applications > Accessories menu to access the terminal. Don't be scared of the terminal if you haven't used it before. It really is quite straight-forward.
In the terminal window, change to the directory containing ClusterClient. In my case I'd type the following code. Replace the directory structure with wherever you saved your copy of ClusterClient (remember it is case sensitive):
cd /home/ben/ClusterClient
Again in the terminal window, type (or copy) this command to install WINE (the Microsoft Windows compatability layer) and cabextract:
sudo apt-get install wine cabextract
You will probably be asked for your password. This is normal and is required to confirm that you wish to make changes to your system i.e., install an application. After entering your password, if you are prompted to confirm installation, press Y
Once WINE is installed, we need to get a couple more files required by ClusterClient. These aren't available through the repository.
Still within the terminal window, type (or copy) the following command:
wget http://www.kegel.com/wine/winetricks
A few additional files will be placed in the currently selected folder; the ClusterClient folder if you followed Step 2 above.
The package downloaded will enable us to get those missing files, so type in the following command:
sh winetricks comctl32.ocx vb6run
When asked to confirm if you would like to the Visual Basic 6.0 Run Time files, click on Yes.
With any luck, that should now be it. Attempt to run ClusterClient from the terminal with this command:
wine ClusterClient.exe
After a few moments, the window should appear.
That's all there is to it. ClusterClient can now be run from the terminal at any time by opening the terminal window, changing to the ClusterClient directory and running the command above.
But that's not the easiest way to launch it. Follow these additional steps to add a launcher to the desktop:
Right-click on a blank area of the desktop to display the context menu
Choose 'Create Launcher...'
A window will appear. Complete the following details (remember, the directory in Command will need to be whatever is applicable in your case):
Type: Application
Name: ClusterClient
Command: wine /home/ben/ClusterClient/ClusterClient.exe
Comment: ClusterClient by Charlie, M0PZT
Click OK
An icon will now be on your desktop. Just double-click to launch ClusterClient
Simples!
shack developments
09 Sep '09, 19:30
Over the last couple of weeks, I have been racing along with the development of my amateur radio station. Starting off with the purchase of a HF/6m whip aerial, through to buying my first HF transceiver (Yaesu FT-450) to setting up the IT side of things. It is here that I have hit a snag.
The modern radio shack isn't complete without a computer. Whether it is used for logging, decoding digital signals or just looking up callsigns; it must be said that it is a pretty indispensable piece of equipment. Because my setup is in the living room of my flat, I needed a solution that was low profile and quiet.
Fortunately, I had access to an old laptop (IBM Thinkpad R50e) which has a broken LCD screen. Perfect I thought. Connect up an LCD monitor, keyboard and mouse and there's my solution. I've attached some brackets to my desk so that the machine is out of the way and today I connected up the peripherals.
Being quite sure the machine worked, I wasn't to worried about the big switch on but I do have a record of things dieing at this point so I was pleased to see it all spring to life even just running off the battery which hadn't been charged for a while. I did of course connect the mains adaptor too.
And it is this that is the problem. When connecting the mains adaptor to the laptop, it wipes out my radio with +20dB of noise making most (if not all) signals unreadable. To confirm it was the power supply; I unplugged it (after which the signal meter fell to a much more reasonable S3), tuned about on 20m until I found a signal and then plugged it back in again. Lo-and-behold, the noise floor rose and the signal dissappeared.
So now I'm on the search for a solution that doesn't involve me giving up on the laptop and putting in a desktop computer. I can charge the laptop battery when not using the radio and then unplug it when I'm operating but that's a little inconvenient.
I did get to wondering whether the laptop would run from my DC power supply at 13.8V. I checked the laptop's power block which is rated at 16V 4.5A. No problem providing the amps, but I'm a little short on the volts. However, the battery is rated at 10v. I'm thinking that perhaps running without a battery, I could get away with it. However, I'm also wondering if there is a chance of damage to the laptop or power supply.
I'm going to have to do some more research.
further deterioration of local radio - the end of essex fm
21 Jun '09, 23:10
Tomorrow morning at 6am marks the official start of Heart Essex - the new name for the station formerly known as Essex FM, and Essex Radio before it.
It's not just Essex FM that is disappearing. Local stations up and down the country are receiving the re-brand treatment. For many, it's already happened. For the remaining few, the transition is completed tomorrow morning. As an example, other stations include Invicta FM, Ocean FM, Southern FM, 2CR, Buzz 97.1, Champion 103, Coast 96.3 and Marcher Sound.
This means that 33 stations now carry the well known brand. 33 stations will carry more networked programming and have decreased local output. According to The Guardian there will be 14 hours per day of networked content.
I will mourn the loss of the once local brands, but not too much. It's been a long time since Essex FM at least was a truly local station. Many times, when driving around England, have I tuned through the car radio and received the same programmes throughout the journey. Now, thanks to this re-brand, it will feel almost like one of the national stations.
The saving grace for localness comes in the form of breakfast shows and local programming between 1pm and 7pm. News is suffering though, with local opt-outs only between the hours of 6am-9am and 4pm-6pm.
I hope that local radio will be revived in the coming years as the switch to digital radio gathers pace. With the plan for major FM stations to broadcast solely on DAB around 2015, the vacated FM space will hopefully encourage new local and community stations.
So, although the brand Essex FM has already disappeared from the airwaves* I say now goodbye to the station that captured my interest in broadcast radio.
* There is now no official name - just a mention that Heart is coming. Tomorrow morning, from 6.
older
Last.fm: Last played:
06 Mar '10, 19:04
The Bluetones – A Parting Gesture
Last Microblog Post:
07 Mar '10, 19:24 via Identi.ca
CQ on 40m PSK31 #hamr
