AmateurRadio.com

A new narrow band digital mode optimized for MF and LF (160m and down) has just been released. Developed by Con, ZL2AFP the new mode is called CMSK.

CMSK uses Minimum Shift Keying (MSK). This is similar to Phase Shift Keying (PSK) but the frequency is shifted smoothly, achieving a 180 degree phase shift within one bit period, with the result that no amplitude variations occur, so the transmit amplifier need not be linear.

The mode has been designed specifically for use on the lower frequencies which provide good phase stability on received signals and low Doppler shift but can suffer from a high level of impulse interference. Four variants are available, ranging from CMSK8 which has a 12.5Hz bandwidth and supports a typing speed of 3.75wpm to CMSK125 which requires 200Hz and gives a typing speed of 60wpm. The default mode is CMSK63 which uses a 100Hz bandwidth and supports typing at up to 30wpm.

The software can be downloaded from Murray Greenman ZL1BPU’s website.

If you are frustrated by the inability to put up as good an antenna as you would like, take a look at the experiments being conducted by Roger, G3XBM, using an antenna made in the ground using 20m spaced earth electrodes. The results are quite amazing.

Unfortunately many of us in the UK cursed with antenna restrictions also have postage stamp sized plots where achieving 20m separation would involve having one electrode in next-door-but-one’s garden. But if your only problem is awkward neighbours, not the size of your plot, this might be something to try.

I still think the tin foil does the magic!

After years of neglect, this analog era ham is willing to admit I only understand a bit about digital electronics. (Yep! Pun intended.) Well into the second week of my sabbatical leave, I have begun to plot out a course of study to get up to speed on the state of the art that I have so long neglected. Should be fun. There seems to be a good bit of open source help online these days and I have my trusty ARRL Handbook, Extra Class study guide, Antenna Handbook and assortment of other aids.

Any suggestions from the veteran techies out there will be greatly appreciated.

I am a learn by doing/hands-on sort of guy and find deep theory puts me into a semi-catatonic state after a few minutes.  For me, it’s a whole lot more fun to take a stab at things and find out if they smoke, and it also makes a lot more sense when I can dink and tweak and see what that actually does. But since that is a bit expensive, perhaps I should learn how to use software like spice to do simulations? Any recommendations for how to learn this software?

Another area of toe dipping will be learning to do antenna modeling. For years I’ve looked at those charts and made little sense out of them. HA… I like to throw wire out and see what happens, but in the summer heat, maybe it is wiser to do a bit of modeling from my air conditioned den?

Thanks WX7S– Your site looks AWESOME for learning this stuff!

I’ll try to share some of the learning curve, but would love to hear from some of you that have gone before. Shortcuts are nice. WX7S your site looks like a great place for me to start! Thanks for the effort it takes to do that.

This weekend (Sat 14 Aug 2010) the Central Florida QRP Group will gather for breakfast at 0730 (Denny’s in Sanford, FL) and off to Sylvan Lake Park in Sanford, FL at 0900 EDT to operate. If you like cw and qrp or are just plain curious… come join us!

A couple of times I have been told by a station I was in contact with that my signal was “Radio Five”. I was a bit offended. As a classical music lover I would have preferred to have been “Radio 3”, or at least “Radio 4” which is the BBC’s highbrow channel with news, arts and current affairs programming. But joking apart, what were they trying to tell me?

I don’t want to sound like one of those curmudgeonly old farts who believe that it would have been better if newly licensed hams had never been born in the first place. I’m well aware of how such an attitude can, and has, put off newcomers to the hobby, and don’t wish to discourage someone who might just have plucked up the courage to make their first QSOs by telling them they are doing it wrong. At the same time, I’m afraid that if one does nothing, says nothing, these nonsensical phrases will slip into common usage like a virus as others hear them on the air and think that’s what they are supposed to say too.

So let’s set things straight. The only “Radio” you need to mention during a contact is the make and model of the box you are talking to me with. If you are giving me a report on how well you are receiving my signal then the term is READABILITY.

Radio amateurs have long enjoyed the Perseids meteor shower as being a good one for making VHF Meteor Scatter (MS) contacts. Back in the 1980s, I was part of the Square Bashers Dxpedition group which made many MS QSOs on 144MHz from ‘rare’ locator squares. My first MS expedition was GB2XJ from the Lizard in Cornwall (IN89 these days).

Primarily, we used high speed CW, around 600-800 lpm (120-160wpm) generated by memory keyers and tape recorders to slow the morse down. By todays standards this probably seems agricultural and it worked well. We made contacts over 2000 kms.

These days, meteor scatter contacts on VHF very often use the WSJT software which is very effective. But you don’t need specialised equipment to make QSOs. At the peak of the shower, you will easily be able to make contacts on SSB – as reflections are quite long. Listen to 144.300, 50.150 or 70.200 and see what you hear.

The shower should peak on the 12th August, but you should be able to hear decent reflections for a day or two before the peak.

On Twitter, there’s been a great deal of interest generated in the whole subject of observing meteors. People all over the would are being encouraged to ‘tweet’ when they see a meteor and use the #meteorwatch hashtag. Adrian West (@virtualastro) has put together a brilliant website devoted to Meteorwarch which will run from Wednesday 11th August to Saturday 14th August. There’s a page devoted to detecting meteors by radio which provides plenty of information to get started.

Whether your a radio observer or a visual observer – enjoy the Perseids!

Someone – ‘G7 in Northampton’ – just posted a comment to an old post asking where I got my DVAP. I can’t see where your comment has gone! Anyway…

I got my DVAP through HRO in Atlanta in the US. However, they are now available in the UK and I have heard that Waters and Stanton, Martin Lynch and RadioWorld have all had stocks – quite likely other stockists too.

Hope that helps…

The hills are alive with the sound of “CQ SOTA” and “CQ WOTA”. These two adventure radio programmes are becoming so popular that anyone trying to make contacts from a hilltop this last weekend on 2m FM had trouble finding a clear frequency. The sight of radio amateurs on mountain summits is becoming so commonplace that soon it will be the ones without radios getting the funny looks.

On Sunday morning Olga said to me “You should go for a walk”. Needing no further encouragement, I tossed the VX-8GR and a few bits and pieces into my rucksack and off I went. I parked at Thornthwaite near the old Swan Hotel and made my way up through the forestry roads to the minor summit of Barf. I didn’t go up by the direct path from opposite the Swan as it is very steep and slippery – I came down that way once a few years ago and it was enough for me.

On the way up I had a contact with top Wainwrights activator Phil, G4OBK/P on the summit of Brandreth. Phil is well on his way to completing the challenge of activating all 214 Wainwright summits in the English Lake District within two years and reached the half way mark this weekend. Visit Phil’s Wainwrights blog if you get a chance.

Shortly after contacting Phil I saw two ospreys circling over Bassenthwaite Lake and calling to each other with their high-pitched cry. I stopped and took the picture shown above of the view towards Keswick. About ten minutes later a small red deer came out of the forest about 100m ahead of me and trotted into the distance. Perfect!

It was cool but humid, but the misty weather creates a special atmosphere in the forest that is very pleasant. However once on the top of Barf a drying breeze was experienced. I made another contact with Phil, who was now en route for Great Gable, so he could tick Barf off on his “worked” list, and made another contact with Geoff GM4WHA. I also received an APRS message from Colin 2E0XSD, who unfortunately couldn’t hear me direct due to the amount of rock between us.

I then set off for the higher summit of Lords Seat, which I reached in about half an hour, where I stopped and had my lunch. By then Phil had reached Great Gable so we had a summit-to-summit contact. I made numerous other contacts, including Geoff and Colin and a couple people on SOTA summits outside the Lake District. I received a lot of comments about wind noise in the microphone, despite trying to shield the radio with both hands. The VX-8GR is the only one of my 2m hand-helds not to have a speaker mic, due to the fact that the only option is the expensive original Yaesu version. I should probably carry the VX-8GR just for the APRS and take the Motorola GP300 for voice contacts.

Simon, M3IWN/P called CQ from the top of Scafell Pike in the Lake District, which is England’s highest mountain. He was doing a SOTA activation and had a beam antenna with him. On a clear day I could probably see his summit from where I was, but he had so many callers that after 10 minutes of trying he still hadn’t heard me. I decided to move to another frequency and make some contacts of my own, checking back on Simon’s frequency now and again until eventually he got my call and we had a contact. At the time I worked him Simon had filled two and a half log pages with contacts including several summit to summits.

The QRM up there had to be heard to be believed. I was only using a 2m helical. The VX-8GR receiver tends to die in the presence of strong signals and I have heard strange things when using anything better than the stock antenna. Another reason for taking the Motorola, which has a better receiver. First, though, I will need to reprogram it to cover 145.300MHz, the frequency Phil likes to use on his activations.

Over the weekend I think something like 20 Wainwright summits were activated by around half a dozen different operators. Scafell Pike was actually activated twice on Sunday! Later in the afternoon after Simon had left I saw a spot had been posted for another station on the same summit.

I returned to the car via the forestry roads for a very pleasant walk with a lot of radio fun as well. If you want to join in, come to the English Lake District on a summer weekend – you won’t regret it!