70cm UKAC with a simple set up

Last nights exploits on the UKAC on 70cms was a bit of a surprise for me. I trotted up to Sandwith water pumping station, noted for two things, a bit of height and a bit of noise (presumably from all the gubbins inside the station and from the mast nearby.

Needless to say I wasn’t expecting much and as the wind was getting all autumnal on me I took my trusty 5m decorators pole, 7 ele Sotabeam yagi and FT817 and these are the results. G4ODA took some doing but generally I was able to work pretty much all I could hear, a few got away but not too many and the GM stations were loud as anything and gave me equally good signal reports.

70cms

I don’t think I’ll ever win any prizes but I can’t fault the Sotabeam since swapping over from the 5 ele LFA on 2m, I see to get just as far, its light weight, robust and simple. As its also good for 70cm it makes the ideal companion to my simple set up.

I’ve also yet to find a simple rig to rival the FT817. It has a number of ‘diosyncrasies and a few faults but as an all rounder you can’t fault it.


Alex Hill, G7KSE, is a regular contributor to AmateurRadio.com and writes from Cumbria, UK. Contact him at [email protected].

Turkey

I had a qso with TA1GO on 20m (14076 KHz) with JT65A. Though poor propagation, I heard VK3FM and YV6BFE with JT65A.

WSPR tonight on 20m 5W


Paul Stam, PC4T, is a regular contributor to AmateurRadio.com and writes from the Netherlands. Contact him at [email protected].

The Sun is flipping out!

Every approximately eleven years, the Sun produces a “cycle” of sunspot activity. At the very lowest point in this cycle, there are few, if any, sunspots observed. Such a lack of sunspots can last for weeks. During the peak of the sunspot cycle, there can be a multitude of sunspots, ranging in size. This cycle is known as the sunspot cycle. It is caused, in part, by the magnetic activity within the Sun. Every eleven years, the Sun’s magnetic polarity flips–the north becomes south, the south becomes north. This is normal. Every twenty two years, then, the Sun goes through one full magnetic flip cycle. The flipping seems to coincide with the timing of solar cycle maxima. When it flips, we know about where we are in the eleven-year cycle. The magnetic polarity of the Sun appears to be in the process of reversing, over the next few months. If so, then we’ve pretty much reached the sunspot cycle maxima for Cycle 24. Observers note that this cycle is quite a bit less active than the last few eleven-year cycles.

A video that talks about this reversal is here:

The flipping of the Sun’s magnetic poles: Sunspot Cycle 24

More information on the Sun and the cycle, radio propagation, and related topics:

+ http://SunSpotWatch.com

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First 28MHz DX of the season from the mobile

Driving home this evening, 28MHz was in good form with some strong US and South American signals audible.

I was particularly pleased to work Ziggy KZ9DX from near Chicago. Although my signal was not huge, I was happy that 12W to the mobile antenna was doing ok.

Hopefully signals will continue to improve and there will be AM contacts to be made soon!


Tim Kirby, G4VXE, is a regular contributor to AmateurRadio.com and writes from Oxfordshire, England. Contact him at [email protected].

Tidbits From the QRP History Book

I've been reading, in small doses, "The History of QRP in the U.S., 1924 - 1960" by Adrian Weiss, W0RSP. So after reading about some of the beginnings of the QRP movement it is interesting to note in 1924, QST Technical Editor, Robert S. Kruse, 1XAM, went on the offensive in  promoting low power operation. His methods however were a little different than might be tried  today.

It seems that Kruse felt that American operators had become too enamored with high power operation and that the QRM and inefficiencies of high power operation were precluding the "grassroots" operator from even hearing DX stations. Weiss writes,

 "QST continually derided the abuse of power among American amateurs by coining a long list of derogatory epithets for the high power types. Such names as "watt-hog", "ether buster", "tribe of ampere hounds", "ampere chaser", "thunder factory', "watt burner" and "most miles per gallon" flowed across the pages of QST, leaving little doubt as to the attitude of the QST staff, and presumably the ARRL, to combat the developing dependence upon brute power by American amateurs in place of the ideals embodied in the QRP Operator...."

In, December 1923, the very first QRP contest, The Station Efficiency Contest, was announced with this subtitle, "Miles Per Watt: An Argument For The Small Set and For Intelligence In Place of Brute Force" Weiss comments, "In other words, the use of low power was inextricably linked with intelligence and diametrically opposite to high power"

Further Kruse argued, "...what if his brute power does let him cover 4,000 miles, isn't he still inferior to the other man who handled his power correctly and went twice as far per watt?"

So there you have it, QRP operation = Intelligence.

Need we say more;-)

The book goes into much more detail about the attack on high power operation and rising credibility of the QRP operator in those early days. Interesting reading and entertaining as well.



Mike Crownover, AD5A, is a regular contributor to AmateurRadio.com and writes from Texas, USA. Contact him at [email protected].

20m WSPR

Tonight: 20 meter WSPR before all signals fade out.


Paul Stam, PC4T, is a regular contributor to AmateurRadio.com and writes from the Netherlands. Contact him at [email protected].

Digital Voice (DV) – the new FM?

Once upon a time FM swept away AM, but DV is taking its time despite some clear advantages.

I’ve had yet another stunning 5W mobile QSO on 2m this morning on my way to work. Several miles of clear, unbroken chat, without mobile flutter. DV mode delivers good quality voice against a noiseless background. It is sometimes claimed that coverage is roughly extended by 20% due to advantages of this mode, even. I doubt this is entirely true, but an excellent quality of communication is doggedly maintained before ‘falling off’ very quickly. It is quite robust and packed with extras. Ideal for V/UHF and it’s been around for several years.

Even the 2m band-plan in the UK lists all the simplex channels as dual FM/DV. I must admit that I and my friends keep traffic to the UK DV calling frequency (144.6125 MHz) to ensure anyone equipped with DV will hear us and join. If the current FM population heard our carriers on normal working channels, they would be quick to complain about the noise the noise as QRM.

This is what DV sounds like on your FM radio:


DV mode is famous for being the common mode that binds the larger DSTAR system (Digital Smart Technology for Amateur Radio), but excels as a simplex mode too. No analogue mode will embed your callsign for display, report your GPS position, over a low speed data link – all during a normal voice QSO, rounded off with an inoffensive little beep at the end of the over. (Because there is absolutely no background noise, it’s difficult to detect when someone has released their PTT). This is why DV is such a superb candidate to network via DSTAR. This is where radio marries the internet and we are its children.

The new Icom IC-7100 even has people quirkily chatting away on 4m with DV mode, which I gather works very well.

So what is DV mode made from? Well, your voice is encoded digitally using a vocoder optimised for voice communications in the same way your mobile phone does. The device that does this is called the AMBE chip (Advance MultiBand Excitation). Some people moan that this is unfair being a proprietary device, not being open source technology. However an AMBE chip can be freely bought for just a few dollars and uses proven, reliable technology. Inmarsat have been using it for years.

The digitised voice at 3600bps combines with an additional 1200bps (which you can do anything you want with! Think file transfer, photos, messaging etc.) before being modulated. The 3600bps voice data also includes 1200bps FEC (Forward Error Correction), which sends a little extra data in case any gets lost over the air. When bits are lost, the receiver uses this extra data the plug in the gaps. The modulation scheme is GMSK (Gaussian Mode Shift Keying), which is basically a form of phase modulation. You’ll also appreciate that all new modes often save bandwidth as well as improving quality and a DV carrier will happily fit into 12.5kHz channelised plans.



So, what are we waiting for? The manufacturers! The market is caught up in adoption stalemate, with Icom having settled for DV whilst others shun compatibility. But there are also homebrew DV options out there, with modulator/codec boards that will plug into your FM radio (via the packet port or tap into the discriminator) turning your analogue radio into a dual-mode digital delight.
My home DSTAR hotspot. Comprising 2m PMR radio (underneath), GMSK modem (top) and Raspberry Pi computer (bottom).
There are other digital modes out there too, all with different strengths and weaknesses – and they are interesting. But for the sake of everyday commonality and general take-up, I think DV has it.

So is it time to catch up with modern telecommunications techniques and move away from analogue FM? Maybe there’s something in the more ‘tactile’ feel of FM: The waxing and waning, the background hiss, the heterodyne-ing. You seem to know exactly what’s happening and what’s about to happen. So many modes – enjoy the hobby!

Rob Law, MW0DNK, is a regular contributor to AmateurRadio.com and writes from Anglesey, Wales. Contact him at [email protected].

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