Showing posts with label ham radio. Show all posts
Showing posts with label ham radio. Show all posts

Wednesday, 13 March 2013

A Quick RoIP Experiment


RoIP stands for Radio over the Internet Protocol and you can use this technology to connect remote radios over any distance, easily.

There are, of course, very complicated and elegant communications systems that do this already such as Echolink, D-STAR, Allstar, IRLP, Tetra and DMR/Mototrbo, but tonight I homebrewed my very own, modest private link in half an hour – and you can too!

If you have a rig with a packet data port and an external sound interface, such as a Signalink USB, then all you need is some software and a mobile phone, for example.

Signalink USB Interface with FT-817 set to 2m FM calling
Zello app with PTT



















I used a fantastic free app called Zello. Zello is a walkie talkie emulator for your smartphone but also has a PC programme counterpart. The clever bit is that it has a VOX function with several adjustments for sensitivity and delay. My project enabled me to talk remotely over 2m using my smartphone!

So, by pressing ‘PTT’ on my smartphone and making a direct call to my computer, the VOX switch was activated on my Signalink USB interface and my FT-817 transmitted. When the squelch was opened on my ‘817 by the station I was talking to (and this is the clever bit) the Zello programme on my computer used its VOX feature to transmit back to my smartphone.

Zello GUI on Windows XP
Zello VOX settings















Now I know that Ham Radio Deluxe can be established to give full remote control over my rig, but that’s for another day. This is one solution to automatically link two radios that anyone can do.

Friday, 23 November 2012

A WSPR in your ear.


Like many of us, I am still amazed by the amount of radio spectrum we have to freely play with. Shots are being fired and eyes are being gouged by companies for small slices of precious bandwidth. Multiply our many electric playgrounds by the number of games (or modes) available and the permutations are enough to overload your front end.

I’ve decided to catch up with WSPR, a mode well known to many but new to me. I’m going to give it a go – the difficult way. Julian, G4ILO has an excellent article on the system here.

WSPR stands for Weak Signal Propagation Reporting and is a computer programme that runs your VHF/HF transceiver automatically in order to receive others running the same system. Successful contacts, one or two-way, are reported automatically to a website. It’s like having a worldwide net of propagation beacons for every band available at your fingertips and the results appear quickly after automatic contact confirmation. What a great thing to leave your equipment running overnight or during the day when you’re otherwise occupied!
Screenshot of WSPR.net Map Page

The best thing is that WSPR works below the noise threshold and you can use very low power. I was staggered the other day to see that Tim, G4VXE had hit Australia on 40m with just 1W! One Watt! So I’m going to give it a go with 1W and just an indoor Miracle Whip antenna. I know many QRP CW experts may cracked this one before – but I’m new and excited. I’ll try 40m and work my way up to 2m and see what happens!

I’ll use my FT-817. A CAT lead arrived this week from Hong Kong but it seems I’ll also need an audio interface between the transceiver packet port and computer sound card to make it all work. Another option is to buy an external interface that has a sound card and interfaces to the computer with a USB. It’s not quite going to be a ‘plug and play’ job, I’m afraid to report.

In the meantime, I’ll be satisfying myself to regular chats on 2m with nearby stations on FM, SSB and even DV mode. So many ways of talking – and that’s just on 2m. I'll 'whisper' my progress here as soon as I'm up and running.

Friday, 19 October 2012

"Armchair Copy"


When I was last active on HF, in 2003, I hadn’t experienced the transient pleasures of a strong 10m opening. The solar cycle was way down on the current crescendo.

For the second day running, I’ve been receiving strong, clear, frequency modulated signals from far afield that sound as if they’re just down the road. Using my FT-817 (5W) and a small Miracle Whip antenna I had a fantastic QSO into Greece. Only a little QSB here and there presented any challenge. I tuned lower in the band to hear a W2 station calling CQ using AM – well I just had to try! I’m actually quite staggered he heard my signal, but obviously not strong enough to discriminate any speech. That would have been expecting too much.

Today on 29.620 the New York repeater, KQ2H, was booming in at 5/9+, of course. European stations a few hundred miles or less apart, were talking to each other via a lengthy transatlantic trip. The FM capture effect ensured that my QRP signal wasn’t fully heard, though I suspect I accessed the repeater more than once.

I’ll look forward to a little more 10m FM while it lasts. Congratulations if you’ve enjoyed a DX ‘armchair copy’ this week.

Monday, 24 September 2012

QRP v QRO – Blood on the Floor?


The mighty, omnipotent sun that our precious emerald and sapphire orb circulates is nearing the crescendo of its eleven year repeat-performance.

For the first time since 2003, I have revisited the high frequencies: the short waves of equal delight and frustration that ebb and flow with the days, seasons and years. Back then, I worked the world with 10 Watts and a rather long wire antenna. I stayed up all night sometimes to listen to the magical waxing and waning of distant continents on 80m. It was like listening to a sublime symphony. Having moved to a new house with more limited prospects for creating a good HF antenna system, I turned my back on these noble frequencies to chase the excitement of VHF and UHF.

Ironically, the drive for portable operation at V/UHF has led me to flirt with HF again. It's the inevitable purchase of arguably one of the best amateur radios ever manufactured, the Yaesu FT-817. Five delightful Watts from top band, all the way to 70cm. MF to UHF. Sea level to mountain top. CW to FM, with all modes in between. What a gem of beautifully packaged, miniaturised happiness.

FT-817. 5W on 10m.
With 5W of HF readily to hand, I’ve hastily run 10m of vertical wire in the back garden to listen to a more contemporary performance of a classic favourite. Happily, 10m has truly sprung into life. This morning I’ve just completed a QSO from home (Wales) to Greece with 5W at both ends. Deep joy. A quick bargain has even brought a Miracle Whip into the ensemble – just experimenting for fun.

But scanning through the bands in general I’m noticing a tendency to transmit at powers of 1kW and above, whatever the band, whatever the conditions. Abrupt reports of 5/9+ are exchanged with a seemingly insatiable appetite to amass as many transient contacts as possible. Then there are the pile-ups. Those ungentlemanly bun-fights where the loudest (or largest bank account and electricity bill) wins. I’m sure that there are whole streets in Palermo where the lights actually dim when DX from Pago Pago is heard on 20m.

We’ll never know if was possible to work Pago Pago with QRP because we were never given the chance. This is on SSB at least. CW operators have a greater appreciation of low power. This is an old argument that will attract equal venom and praise from our electromagnetic community. But I do believe that as technology advances, there is a global drive for efficiency. Low power is in fashion and with solar conditions as they are, we should all be ‘turning the wick down’ a little bit, shouldn’t we?

I do believe that when the sun takes its rest, there is a place for high power, particularly on the more difficult bands. There – you see? I’m not anti-QRO at all. I’m just advocating using (as your exam tells you) the minimum amount of power necessary to maintain a comfortable QSO.

Wednesday, 2 May 2012

The Man Who Fishes For DX


I live on Anglesey, a mystical Celtic island steeped in the legends of the Druids and lapped by the misty waters of the Irish Sea. There was whispered talk amongst the old people of an elusive man who fished for DX and caught specimens from Borneo, Antarctica and other strange lands.

Actually, it’s only Dave.

Dave, GW4JKR, has an antenna system that you can’t buy from any supplier. He uses a carbon-fibre fishing pole on a metal spike and several acres of saltmarsh. The system is blindingly simple, takes minutes to erect and is devastatingly effective.

“I set up on the 20m band and all was quiet. I put out my first call (SSB) and you know what? I worked Borneo 5/9. Because he was an English ex-pat, I thought he was local until he gave his callsign for the second time! Other local stations here couldn’t even hear him.”

In a similar vein, Dave related how he’s had a 5/9 chat with a chap with a German accent. Only turned out he was on holiday in Guadalcanal. “You’re the only station in Europe I can hear,” he said from his sunny patio.

One of Dave's many QSL cards
The DX takes the bait each time. Reports come in from the Pacific islands, China, Japan, Korea, Antarctica and New Zealand. I think Dave’s witnessed more pile-ups than the M6 motorway.

The antenna system comprises two ultra-efficient parts, making it a genuine ‘killer’ setup. For the antenna, Dave uses a carbon-fibre fishing pole, also known as a ‘roach pole’. He specifies the better quality versions that use high modulus carbon for optimum conductivity. The pole is approximately 12m in length, coming in seven sections. It is featherweight at under a kilogram. The base of the pole mates to a large ‘agricultural’ steel earth spike, which is actually a brutal pummelling device for digging holes in rocky ground. A plastic sleeve insulates the two components. Coax is easily attached by jubilee and croc clips. The second part of the antenna system is the saltmarsh on the edge of an expansive tidal sandy bay. The saltwater saturation, even at low tide, is high. Ask the shellfish.

Red Wharf Bay, Anglesey
Like a latter day St. George, Dave holds the spike aloft and plunges it deep into the salty mud where it stands at the ready. If there’s a small pool of salty water nearby, all the better – in it goes. Wet, sandy beaches work, but not nearly as well as dark, oozing mud it seems. Lovely.

Clearly the vertical radiator, wide open aspect, perfect electrical ground and ultra-low angle of radiation give the best start a radio signal could ever want in in its sinusoidal life. It’s as electrically quiet as a library down on the beach which makes for reception most of us can only dream of.
Base section of carbon fibre
vertical in situ

Follow Dave’s simple formula and you too can become a fisher of men and the stuff of legend.








SAFETY: Dave would like to warn all readers to exercise care when handling a carbon fibre pole in the open. Do NOT venture anywhere near power lines. You may render yourself permanently QRT.

More photos available on Dave’s Flickr site.

Thursday, 26 April 2012

DCS: Also Reflecting Our National Traits

Sometimes I find how we use new technology is as interesting as the technology itself. You may not know or care what DCS reflectors are, but the way they’re developing tells us a little about ourselves, I think.

DCS reflectors are basically a new generation of servers or chat rooms we use with digital amateur radio to link repeaters, nodes and individuals together. They were developed recently by some very clever enthusiasts in Germany and are growing in an organic way. A bit like dandelions.

Each DCS reflector has modules from A to Z, which are a blank canvas. The way in which these are being filled is like a group of sugar drink-fuelled children scrambling to choose their bunk-beds in a large dormitory at summer camp.

Let me explain: The first two DCS reflectors, DCS001 and DCS002 were hosted by the Germans. They had neatly and orderly divided up the entire globe into modules. It was a good start. For their own country they had a national module of course, with additional modules for north, south, east and west Germany respectively. But anyone who knows a little about Germany should not be surprised to see that Bavaria has broken away and formed its own module. The states of Hessen and Baden-Wuettenberg followed suit, of course. The states of the former East remain quiet for the moment, it seems.

There are now nine DCS reflectors at the time of writing, all now hosted by different countries who wanted their own national servers. The Dutch are fastidious in their egalitarianism. They’ve gone and divided their reflector into nation-wide, north, mid and south Netherlands as well as – wait for it - thirteen different regions including the colonies of the Dutch Antilles. The inhabitants of Flevoland must be ecstatic.

The Swiss, however, have no national module at all. No, they’ve divided their piece of DCS cake in language-slices: German, French and Italian. I’m also sure it will be the most reliable DCS reflector ever known to man.

The Italians seem a little less self-assured. They have a record number of four test channels, just in case.

The US reflector is well-ordered, with a couple of the noisier states, like Texas, having their own module. Even the Canadians are accommodated.

And as for my lot, the Brits? Well, we would have to be a little bit different, wouldn’t we? At the time of writing there is a national UK module, with a Northern Ireland, Wales & West, Midlands and South module. No Scotland so far. Maybe it’s the expense. And uniquely in the new DCS community, the city of London has decided that it is elevated enough among the great and good capitals of the world to merit its very own module.

I think we can rightly take most pride in the four inconspicuous modules simply labelled as ‘chat’. You can transfer to these modules for your one-to-one conversation without tying up the repeaters of an entire small country. I have heard less-than-scintillating conversations occupy worldwide reflectors for some considerable periods.

The pace of development is astonishing. An idea whispered in the ear of a developer is often embodied overnight. And we’re just one month into the story…..

UK DCS005 shown on he excellent (German) DV-RPTR
Control Centre software

Wednesday, 25 April 2012

FT-790R, 1W of Forlorn Hope?

“One Watt! One Watt! What on earth bl***y use is that to you?! I don’t know… (sigh)” exclaimed one local straight-talking OM on 2m FM yesterday.

His response to my acquisition of a rather dated Yaesu FT-790R ‘portable’ transceiver was less than encouraging. It’s just as well I’m an optimist then. With a maximum output of one Watt on one band (70cm) I think I’ll need to maintain an upward outlook.

But here’s the thing – I always find myself drawn to obtaining the more elusive QSO. You need a certain amount of eccentricity and tendency to self-harm to stand on a hilltop for hours calling out on 23cm FM QRP, for example. I was the first in the area to start calling CQ on DV mode on 2m. It took months before my first simplex QSO and then very little since.

The higher bands and modes have their rewards in spades, however. The rush of excitement when you finally make that new or distant contact. The perceived camaraderie knowing someone has gone to the same quirky lengths as you to operate on a lesser used band/mode or from an unusual location. You feel you have made a meaningful and personal connection, at least for the duration of the QSO. Oh, it’s such a far cry from exchanging reports of 5/9 with the fiftieth Italian station running 1kW on 20m you’ve spoken to in one morning. Better still, no QSL cards.

Any why the FT-790? Well, at just over £100 it’s one of the few portable internal battery-powered transceivers you come across before taking the small fiscal leap to an FT-817, for example. Either way, it will hold its value if my 2m friend’s prophecy becomes true.

Anyway, so far so good. It’s powered up and seems to be fully serviceable. I’ve even managed a short-distance QSO with John GW4ZPL over the Menai Strait in the Caernarfon direction, just a few miles away.

I’ll be out and about when the weather improves and will post my experiences here. Will it be too futile, or with a bit of luck will I make that elusive QSO I’m after? Will my single sidebanded plaintive cries of CQ reach a caring ear?

Maybe I’ll be happily shouting “One Watt! One Watt!” from a heathery Welsh hilltop.

FT-790, forlorn hope?

Tuesday, 24 April 2012

Loving My Alinco DJ-G7


Alinco DJ-G7
There are many reviews on the internet already about this cracking little 23cm-capable transceiver. In fact, it's the only 23cm handheld currently manufactured, which begs the question when will the Chinese fill the obvious gap in demand?

I'd like to add a couple of comments to help G7 owners get the most out of their cherished handsets:

Firstly, you'll find that programming the frequency offsets for 23cm repeaters may involve two minutes rotating one of the knobs. So, before you do this, set the tuning steps to 1MHz and not 25kHz, for example. You'll be able to dial a 20MHz offset in no time.

Secondly, make full use of the large alphanumeric display. This is the only radio I have where there are enough characters to enter a repeater call sign AND its location as shown to the right.

Alphanumeric display
If you're thinking of trying 23cm FM with one of these, I'd urge you to go ahead! I've had so much fun working good distances with just 300mW from a local hilltop. The top power on 23cm is 1W with 5W on 2m and 70cm, of course. The audio quality is crisp and clear and QSO's are very rewarding. Is there activity? Well, not a prodigious amount, of course. Try monitoring the SOTAwatch website for hilltop activity or put out a call on 2m or 70cm asking for stations QRV on 23cm to respond. Note that some stations may have horizontal beams for SSB - simply turn your antenna on its side when needed. Do some research on homebrew bi-quad antennas as they're really easy to construct and will give you immediate gain without sacrificing portability. Again, there is plenty of excellent information on the net. I used this design here: Hybrid Quad Directional Antenna

Check your licence terms, though, as Foundation holders don't have access to this band. Otherwise I look forward to working you soon!

Read Ross G6GVI's excellent review here: G6GVI Alinco DJ-G7


Update - here's a list of stations worked in my first week QRV on 23cm:


GW4ZPLJohnCaernarfon
G7IEIShaunBolton
G6AOSSteveBlackpool
G6ODUBobOrmskirk
2E0DDDRobStoke
2E0XYLKarenWirral

D-STAR Makeover

I had a surprising and slightly emotional experience on DV mode last week. I was in QSO with a mobile station who temporarily lost the repeater for a couple of seconds. Not unusual, but get this - instead of vanishing permanently in to vast digital abyss, he came right back as the system re-synced and locked-up. This happened again and he was re-acquired and all was well. Remarkable.

No longer will your beautiful, eloquent, flowing QSO be 'bumped' abruptly and permanently off the air by a random mobile station the other side of the world 'pinging' his local repeater for a few milliseconds. You can now even QSY to a 'chat' module and not hog the repeaters of an entire nation while you discuss your passion for North Korean tractor parts for three hours.

The advent of DCS reflectors, hand-in-hand with the German DV-RPTR boards shipped all over the world, is going to save the mode from extinction, no less. Witness the used D-STAR radios in the graveyard of Ebay as testament to the disillusioned DPlus users.

If only they'd have waited.

The DV-RPTR unit in its housing












*UPDATE 24th April 2012: Looks like the Dplus system has been suddenly revamped to include the routing information with the voice packets in the same way as DCS. Shame it took seven years of dysfunctional communications and a rival system to prompt this. I'll be staying on the DCS system - but enjoy whichever system you use and enjoy the mode!

Sandpiper 23cm 19 Element Yagi

My relatively new Sandpiper beam is now performing well after a shaky start. It's a misnomer to sell it as anything else other than an antenna kit, to be truthful. It really does arrive as a bag of bits and two rough photocopied pages of sketchy instructions.

It didn't help that the elements were supplied in the wrong sequence with a couple of 'wild card' elements from another antenna design altogether. Marc, the manufacturer, was extremely apologetic and helpful in sending me the antenna measurements straight away by email. However, it meant the additional purchase of a metal rule and measuring callipers from our local excellent ironmonger to get cracking.

After what seemed an afternoon of measuring and re-measuring, the beam started to take form. This involved discarding one element and chopping down another to size. In the initial construction the reflector ended up as the first director. What was supposed as a reflector must have come from a 70cm design. No wonder the thing worked better sideways.

But now, all is well. Coupled with my 1W Alinco DJ-G7 I worked Stoke on Trent (2E0DDD) simplex from a local Anglesey hilltop thanks to a slight tropospheric enhancement. It seems to offer the best combination of gain and beam width. This means your calls will be heard reasonably widely with enough gain (17.1dBi). You won't be losing out too much due to de-pointing either. Its size also means that it can be supported by a modest pole/guys or tripod without offering too much windage.

I think it's possibly the most optimal solution for hilltop and portable operating.

The completed 19 element 23cm Sandpiper yagi