Monday, 19 May 2014

An Introduction to Antenna Modelling

Just a quick reminder that my new book "An Introduction to Antenna Modelling" is now available.

The book looks at the free MMANA-GAL antenna modelling program that lets you design and optimise a whole host of antennas – all on your PC.

It shows you step-by-step how to input antenna designs into MMANA-GAL, how to adapt designs you are given and how to optimise your designs for the best performance.

By the time you have finished you should be able to model a whole host of antennas including dipoles, the G5RV, the W3DZZ trapped dipole, verticals, off-centre fed dipoles (OCFD), magnetic loop antennas and many more.

The book also includes a CD-ROM that not only contains the MMANA-GAL software so you can get started immediately, but sample antenna files too. It also includes other antenna modelling software including EZNEC, MININEC Pro and 4nec2. Plus there are also more than 30 other amateur radio programmes included.

The RSGB has also managed to keep the price below £10.

See the RSGB shop.

Saturday, 22 March 2014

28MHz (10m) beacons still romping in

Predicted 10m propagation at 1600UTC March
Had an interesting hour or so listening for 28 MHz beacons this afternoon.

Despite the VOACAP prediction suggesting that there would not be much propagation into the USA from the UK on 10m, there were plenty to be copied.

I think 10m propagation to the States will start to disappear as we move towards summer.

I even heard two from California.

I like beacons. They are usually low powered, use single element antennas and the beacon owners appreciate a quick e-mail to show that their efforts are worthwhile.

You can find G3USF's list of 28 MHz beacons at http://www.keele.ac.uk/depts/por/28.htm

Anyway, here is what I heard, all with a dipole:

CALL COMMENT FREQ
N2PD/B New York, 5W 28.285
WA4ROX/B Florida 28.286
W3APL/B Maryland, 8W 28.296
K5TLL/B Mississippi, 25W 28.298
WI6J/B California 28.287
K5AB Texas, 20W 28.280
WF4HAM Florida, 10W 28.273
EA7JN/B 28.258
W6WTG California 28.287
WA2DVU New Jersey 28.257
SV2AHT/B KN10NO, Hortiatis 28.235
IQ8CZ/B Catanzo, Italy 28.230
SV2MCG/B Greece, KN10FC 28.222

Tuesday, 18 March 2014

International Marconi Day, Saturday 26th April 2014


Keith M0DZB operating at GB0CMS
Saturday 26th April 2014 is International Marconi Day (IMD) when stations around the world celebrate the birthday of Guglielmo Marconi.

It is also a good opportunity for you to gain a very nice certificate. All you have to do is work the requisite number of award stations and send in a log extract - you don't need QSL cards.

I gave a talk to a couple of clubs about the best way to win the award and you can download the presentation in PDF format (14Mb). It is aimed at UK operators.

I shall be helping to run GB0CMS again this year at Caister Lifeboat. There is short video that looks at the equipment the club used to make 165 contacts in 24 countries on Saturday 30 April 2011. And another for the 2012 event when we made more than 500 contacts.

See http://www.youtube.com/watch?v=JUXzJcaHThs and http://www.youtube.com/watch?v=C8ZRW0q6SyI

You can also view my propagation predictions online.

You can find out more at: http://www.gb4imd.org.uk/

Friday, 24 January 2014

New propagation predictions for first quarter 2014

I have now updated my HF propagation prediction charts for the first quarter of 2014 to take into account the latest predicted smoothed sunspot numbers. It is generally thought that we may now be at or past the second hump of this sunspot maximum, but the sun continues to throw some surprises. 

For example, the observed sunspot numbers for the last six months of 2013 were 57.0, 66.0, 36.9, 85.6, 77.6 and 90.3, which shows the great variation. 

The current predicted smoothed sunspot number (which is that recommended for VOACAP-based prediction programs) is about 61-62 for the next three months.

This equates to a 10.7cm solar flux index of about 110 (on 24th January it was 136 with an actual sunspot number of 121).

A flux over 100 suggests that 10m will continue to open on a fairly regular basis and the next few months should throw up some good opportunities for DX on the higher bands. However, the longer-term trend may be downwards.

On the downward side of the cycle we may also experience more unsettled conditions due to flares and coronal mass ejections. These may cause short-term D-layer absorption, poor or noisy conditions (especially on routes over the poles) or depletion of the F layer (with corresponding poor conditions on the upper HF bands). Looking on the bright side it may also give raise to aurorae.

The short-path HF predictions from the UK can be found via a link on the top right or by clicking here

If you want to produce more detailed point-to-point calculations (and don't have your own program) I recommend VOACAP online at http://www.voacap.com/prediction.html

You can keep track of the current state of the sun at www.solarham.com

Steve G0KYA

Chairman, RSGB Propagation Studies Committee

Sunday, 29 December 2013

Christmas Eve 2013 LF broadcast from SAQ, Grimeton, Sweden

The SAQ 17.2kHz transmitter at Grimeton, Sweden
I remembered to record the Christmas Eve Morse broadcast from the world heritage radio station SAQ at Grimeton, Sweden this year. It was broadcast on 17.2kHz using an Alexanderson alternator and about 100kW.

Last tranmission I forgot to turn my Wellbrook ALA1530S loop to point North East, so it was in the null and I received nothing - doh! I used a Perseus SDR and the loop, which worked well and all was copied.

The SDR broke the recording into two files and knocked off the "C" in "Merry Christmas", but I have put it back in using Audacity sound editing software.

If you don't read CW the message was:

-------------------------

VVV DE SAQ SAQ SAQ.

100KW ALTERNATOR ON 17.2KHZ.

WE AGAIN WISH YOU ALL A MERRY CHRISTMAS AND A HAPPY NEW YEAR. SIGNED: THE WORLD HERITAGE AT GRIMETON AND THE ALEXANDER-GRIMETON VETERANRADIOS VAENNER ASSOCIATION.

FOR QSL INFO PLEASE READ OUR WEBSITE: WWW.ALEXANDER.N.SE.
DE SAQ SAQ SAQ SK.

---------------------

You can listen to the broadcast yourself using the controls below.

Friday, 22 November 2013

First FUNCube-1 telemetry successfully received

The telemetry frame showing the various parameters
Wa-hey! I have now managed to receive and decode my first telemetry frames from the FUNCube-1 satellite. This was on the pass starting at 09:10 on 22/11/13. There'll be another higher angle pass at 10:45 (22/11) over the UK.

I used a loft-mounted Slim Jim antenna for 2m and my Icom IC-7400 transceiver on 145.935MHz USB.

I fed the audio out of the back of the radio through my usual isolation interface, used for PSK and RTTY, into a Dell PC running the FUNCube-1 dashboard.  I only managed a few decent frames as the pass was low angle (about 9 degrees max) and my set up is not exactly optimal in terms of antenna and feeder (I don't do much VHF). But hey, it worked!

 The X- panel temperature rises during the orbit
You can quite clearly see the temperature of the spacecraft rise as it comes out of eclipse, plus the telemetry shows that all systems are working, the PA is putting out 287mW and the solar cells putting out about 4V.

The black panels are hotter than the silver, which makes sense.

If you are interested in collecting data form the satellite (which is then automatcailly uploaded to a data warehouse) all the details can be found at http://funcube.org.uk.

It isn't too difficult, but just follow the instructions carefully.

Steve G0KYA

Thursday, 21 November 2013

FUNCube-1 satellite launched successfully

The FUNcube-1 cubesat launched successfully this morning aboard a Dnepr rocket. It has already been heard in the UK and South Africa. Now the job of making sure everything checks out begins before it is fully ready for use by schools and amateurs.

In the meantime, see if you can hear it.

The frequencies are:

Radio Communications Payload
145.935 MHz BPSK Telemetry 30 or 300 mW

Inverting SSB/CW transponder 300 mW PEP
435.150 – 435.130 MHz Uplink
145.950 – 145.970 MHz Downlink

A program like Orbitron will tell you where the satellite is, although I imagine the Kepplerian elements to track it will be updated over the next few days. The raw ones I have are:

FUNCUBE-1
1 99991U 00000    13325.30956308  .00000106  00000-0  10000-3 0 00010
2 99991 097.7956 038.2570 0059925 198.5190 336.5388 14.77841394000015

Take a look at http://amsat-uk.org/ for up to date info.

Update: I just heard FUNcube-1 on the 21/11 19:52 pass, so the Keps look about right. I used USB on 145.935MHz +/- Doppler. It wasn't very strong, but I was only using a Slim Jim in the loft with some lossy RG58 coax. I think a beam is the way to go.

Here are some predicted passes for the next few days - no promises due to the raw element data that needs to be updated!
2013-11-21 19:52:44 FUNCUBE-1             80.4 10.0  ecl  2114 284.1 -35.7
2013-11-21 19:54:53 FUNCUBE-1             52.5 13.2  ecl  1896 284.6 -36.0
2013-11-21 19:57:01 FUNCUBE-1             24.7 10.0  ecl  2103 285.1 -36.3

2013-11-21 21:25:56 FUNCUBE-1            154.3 10.0  ecl  2118 308.3 -48.3
2013-11-21 21:30:33 FUNCUBE-1             71.7 68.9  ecl   722 309.8 -48.9
2013-11-21 21:35:07 FUNCUBE-1            349.9 10.0  ecl  2099 311.2 -49.4

2013-11-21 23:04:11 FUNCUBE-1            226.1 10.0  ecl  2119 344.2 -56.7
2013-11-21 23:07:27 FUNCUBE-1            271.0 18.6  ecl  1609 345.6 -56.8
2013-11-21 23:10:41 FUNCUBE-1            315.7 10.0  ecl  2107 346.9 -57.0

2013-11-22 10:46:06 FUNCUBE-1             19.3 10.0    ?  2036 166.6  16.2
2013-11-22 10:50:30 FUNCUBE-1            101.6 64.2    ?   691 167.7  16.4
2013-11-22 10:54:45 FUNCUBE-1            184.1 10.1    ?  1968 168.7  16.5

2013-11-22 12:23:19 FUNCUBE-1            348.5 10.0    ?  2037 190.4  16.6
2013-11-22 12:26:32 FUNCUBE-1            301.8 20.0    ?  1458 191.1  16.5
2013-11-22 12:29:41 FUNCUBE-1            254.9 10.0    ?  1991 191.9  16.4

2013-11-22 20:13:39 FUNCUBE-1            101.0 10.0  ecl  2112 288.7 -38.8
2013-11-22 20:16:50 FUNCUBE-1             57.3 18.8  ecl  1596 289.5 -39.3
2013-11-22 20:20:00 FUNCUBE-1             13.4 10.0  ecl  2096 290.2 -39.8

2013-11-22 21:48:09 FUNCUBE-1            169.4 10.1  ecl  2111 315.2 -51.0
2013-11-22 21:52:47 FUNCUBE-1            256.3 77.8  ecl   691 316.7 -51.5
2013-11-22 21:57:23 FUNCUBE-1            343.5 10.0  ecl  2095 318.3 -52.0

2013-11-22 23:28:12 FUNCUBE-1            252.5 10.0  ecl  2114 354.3 -57.6
2013-11-22 23:29:59 FUNCUBE-1            275.4 12.0  ecl  1976 355.1 -57.6
2013-11-22 23:31:46 FUNCUBE-1            298.3 10.0  ecl  2109 355.9 -57.6

Steve G0KYA