AmateurRadio.com

Sorry for the delay….. the hazy days of summer yield to a LOT of amateur radio and public service events!!!!

Today, we take a trip back in history to the American Signal Corps.  Here is a series I recently stumbled upon with training for the SCR-694.  Interesting radio (kinda like one of the early “go-boxes”.  I am amazed when I see these or similar at hamfests and people just pass them by – they’re interesting.  Maybe I love the history behind our beloved hobby to much…… so I couldn’t resist.

When you are out in the field, especially on a windy hilltop, logging the contacts you make can be a bit difficult. One hand holding the radio or microphone leaves only one hand free to hold down the log book and write in it. If you’re using a hand-held and standing up to get the maximum height gain, it’s even more awkward.

A few weeks ago I hit on the idea of using a personal digital voice recorder. Initial researches suggested that they were a bit expensive – many models sell for around £70 or more. But diligent searching on eBay revealed that it was possible to buy them for much less than this.

The one I got is an Olympus VN-100 Digital Voice Recorder and cost £15.99 including free postage. It was described as “refurbished to new condition by Olympus.” This might be an indicator of a product that tends to fail and has a high number of warranty returns. However, this particular one was indistinguishable from new, works fine and is simple to use. It isn’t the colour I’d have picked if I had a choice, but price and functionality were the principal considerations.

I don’t know what the differences are between the VN-100 and the more expensive models apart from colour, probably storage capacity. However this model has capacity for more than 13 hours of recording – more than adequate for my purposes.

I find the VN-100 easy to operate with the hand that isn’t holding the radio. You just press one button to start recording and another to stop. A bar meter shows the level of the audio input. You can either say the callsign, time and whatever else you are interested in logging, or just point the device at the radio and make an off-air recording. At home it could be a handy shack tool for recording unusual DX contacts.

The only problem I found is that the voice recorder is just as sensitive to wind noise as the microphone in the radio. More than once I have returned home to find a recording was unintelligible. However, mishaps like this can probably be avoided with practise.

I’m finding my digital voice recorder to be an indispensable companion on portable outings. It’s also handy for jotting down ideas for blog posts that occur whilst you’re out and about!

We are very pleased to announce the winner of
1,000 full-color photo QSL cards
from KB3IFH QSL Cards!

Thanks to Randy at KB3IFH QSL Cards for sponsoring this month’s drawing.
We had over 750 entries!

We’re giving away another great prize in September.
Stay tuned and get ready to enter.

OK, on to what you’ve all been waiting for!

The winner of our August 2010 prize giveaway is…

Read the rest of this entry »

I picked up an iPhone4 when I got back from Madrid. I’ve been pleased with it. The much mentioned ‘antenna issue’ can be reproduced easily, but a case solves it easily and it doesn’t cause me any issues in day to day operation.

If you’ve been reading this blog for a while, you’ll have seen me mention iBCNU an APRS client for the iPhone. I hadn’t really tried it on the iPhone4 before today, other than swapping some quick messages at home.

The GPS in the iPhone4 seems to lock up on a position much quicker and I found that in conjunction with iBCNU it worked really well from the train in tracking my position and displaying the speed. Top speed on the way in this morning was 125MPH (200KPH), just to the east of Slough. You can see the track on http://aprs.fi – just search for G4VXE-6 – or I did a screengrab a bit earlier.

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.

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!