Category Archives: DX

Sporadic E Season

It’s the Sporadic E (http://en.wikipedia.org/wiki/Sporadic_E_propagation) season at the moment. The season in the northern hemisphere is generally accepted to start 1 May and finish 31 August. However it possible to hear Sp E in April and (more rarely) other months. However this four-month summer season is generally accepted to be “The” season.

This year in the UK it started quite slowly and you had the usual culprits on Skywaves bemoaning the awful season – some people just don’t understand the meaning of sporadic I guess. However that all changed the last couple of days with a sustained opening to Eastern Europe Monday 2 June and a smaller Scandinavian focused opening 3 June.  The previous 3-4 years I have wasted too much time doing Band I Tv dxing. My urban location in the London ‘burbs mean that there’s an awful load of muck in the video passband and getting good video is practically impossible (i.e. I have a S9 baby monitor on 49.850 Mhz and various carriers, data signals etc).

So this year I decided to focus on getting my 6m scores up. I like to set targets in my dxing and this season I determined I should reach 50 DXCC on 6m and 200 locator squares. Thanks to this superb opening I am now at 54 DXCC and 199 squares – new countries worked on 6m include SV9 Crete, EA8 Canary islands and ZA Albania.

Given the complete lack of F2 propagation on 6m this sunspot cycle high (sic) I think a final target of 60 DXCC and 250 squares on 6m should be achievable with 3-4 years.  For 6m I use my Icom 7600 into a Sandpiper 3 element up at about 10m on the Tennamast or the Diamond V2000 triband co-linear- the beam being far superior of course.

I could not quite resist doing a bit of TV and OIRT dxing. The morning of 3 June saw some very strong Band I TV carriers – I view the audio output from my AOR AR5000 into Spectrum Lab on the PC. So i fired up the separate PC I use for TX dxing – this has a flyvideo 3000 card inside with the saa7134 chip. I feed my HS Pubs  VF1004 4 element (45-70 MHz) into a 4-way tv distribution amplifier from Maplin (brand NIKKAI). One output goes to the AR5000, another to the Sony XDR (see below), the third to my JVC 610 tv and the fourth to the HS Pubs D100 narrow bandwidth converter whose output is fed into the Flyvideo TV card. I then use dscaler and freerun to view on the PC.  So this morning I was watching Ukrainian 1+1 TV on channel R1 on the JVC, 1+1 on channel R2 on the PC, listening to OIRT stations on the Sony XDR and monitoring TV carriers in Spectrum Lab.

After doing the Konrad GTK mod on the Sony XDR it can now tune the OIRT frequencies where its performance is not too bad at all though I do get images from the strong BBC Band II stations. You can see my OIRT loggings at http://www.fmlist.org/fm_logmap.php?datum=2014-06-03&omid=2121

As I mentioned it’s very hard to get decent TV DX video here – despite the S9 signals. However i did make three small videos:

Ukraine 1+1 R1

Ukraine 1+1 R2

 

New Baluns for Flag Antenna

I recently revamped my Flag antenna which has served me so well for MF dxing in this very suburban London location. It was around 8m by 3m but I made the vertical sections longer and the horizontal section slightly longer as well so it is now 9m x 4m.

The major change was that I constructed a balun. I had been using a balun made for the Flag antenna by eBay seller kafa2500 which was well made, waterproof and reasonably priced – however i thought I would have a go myself. In the end I ended up making two baluns which i’ll describe and show here.

Remember the purpose of the balun is two fold – primarily to transfer the wave energy of the desired signal from the antenna to the feeder cable – RG58 in my case. The second purpose is to prevent common-mode currents flowing along the balun which could cause RF problems in the shack. The latter is not an important consideration for the receive only paradigm. The balun will not help with directivity or nulling. The energy is transferred by the balun using magnetic induction which is a manifestation of the Work form of energy transfer  – http://en.wikipedia.org/wiki/Energy_transfer

The first balun was constructed using a pair of largish monocular toroids picked up a the Kempton ham rally, bound together in a box picked up for £1 at the same rally. The windings ratio is 11:3 using 24 swg magnet wire from Maplins. I was intending for 12:3  following advice from N2VV but could not get the 12th turn through! Believe me it’s not critical.  The SO239 and phono antenna sockets I had in stock.  Here’s a close-up picture of the beast: 

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and here is how it looks with the box top screwed down- all connections are wrapped with self-amalgamating tape with black electrical tape on top and liberally smeared with vasoline to further combat water ingress, especially the box top screw holes.

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For context a picture of the garden showing part of the Flag antenna wires and balun box:

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This new Flag antenna works very well with excellent signal/noise characteristics from LF up to 26 Mhz and beyond. It also delivers a decent signal strength hence not necessitating the use of a pre-amp.

I also made a similar balun with an Amidon binocular toroid BN-73-202 kindly sent to me by N2VV. The BN-73-202 is very highly thought of by serious low band dxers. I aimed for  the same turn ratio but think I ended up with 10:3 – again it works very well but for the moment I am long-term testing the larger toroid model. Here’s a picture:

 

 

 

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I think the reason people complain about low signal strengths from Flags and lack of coverage above 4-6 MHz is purely down to the choice of toroid and the turns ratio used. You can’t just use any old toroid and a random turns ratio – source a proper high quality toroid and use an appropriate turns ratio.

 

How to be a Successful HF Dxer Part II

Welcome to the second of an irreverent and not too serious look at how to be a successful HF DXer.  Last time we look at how we defined DXing, what is a DXCC entity, band slot and the fundamental steps you need to take to start DXing. Today we’ll look at how you cam maximise your chances of filling bands slots.

The DX Cluster is a much abused but very useful tool to see what DX is on the bands at any moment. The Cluster is simply a list of DX stations, their frequency, time spotted (you always “spot” to the cluster), the spotting station and a comments field. Originally this list was propagated by packet radio on 2m – however this method has now gone the way of DR-DOS (i.e. obsolete but one of two people still run it and consider it to be the future). 99.9% of people now access the Cluster using an Internet connection. Technically the Cluster program is a telnet application (you what?) and it really comes into its own when you have an always-on broadband connection. Run the cluster 24/7 and you will have a record of what has happened and what is happening at the moment on the bands.

I’ll not explain the details of how you set up the Cluster program here but googling DX Cluster will give you loads to read and going to www.bcdxc.org/ve7cc will fast track you. The ve7cc program is the one I use so help is available if you go that route.

You will need to “filter” the spotting stations or else there will simply be too many station spots on the screen to comprehend. I always set my filters so that US and Canadian spotters are excluded (too many of them, I’m not interested that Japan can be heard in Iowa,…) along with Italian spotters (too excited, always spotting that North Korea is 59+60 on top band at noon). You may think it is a wise move to only allow UK spotting stations – it is if you want one spot every 10 hours.

The Reverse Beacon network (skimmer) has really taken off in the last two years. These are automated programs that decode stations sending CQ using CW, RTTY or other digital modes and report them. ve7cc contains an option to turn on these skimmer spots so you can get an immediate indication that a station is on the air even before it is spotted by a human. Some people don’t like this degree of automation – however it can give you 30 seconds advantage to try for a station before the EU pack descends and chaos reigns in the dx zoo.

Let’s move on to Contests. Yep, those guys shouting 59 569 all over the bands when you just want to chat with your mate in the North about your latest hospital appointment (you have heard about telephones?).

Contests are very useful to the DXer as the good contests mean that a lot of stations will enter including rare DX stations. The QSOs are quick and especially on the 2nd day of a 48 hour event you can often work the DX station on 1st or 2nd call as the big boys will have bagged him by then. Contests take place on all the HF bands except 30m, 17m and 12m (so-called WARC bands – google it Joe).

You can safely ignore all the RSGB contests (working loads of G3s will not improve your DXCC count) with a couple of notable exceptions. The Commonwealth CW contest in March is your best chance to work VK, ZL etc with NO EU QRM. The contest is limited to Commonwealth countries and try as they may to persuade the DX station otherwise Italy and Ukraine are not in the Commonwealth. Hence Luigi and Vlad have to sit and weep at their 10KW stacked yagis station while you work ZL3 with a Yaesu 817 and a miracle whip (ha ha!). Even if you don’t do morse you can use programs like cwget and cwtype to decode and make the exchange (again google them Joe).

The other useful RSGB contest is the IOTA in July which normally has a big turnout of stations on islands – some from exotic locations like Anglesey. Oh no, wait the IOTA committee in its infinite wisdom don’t consider Anglesay to be an island while the UK is…

Good places to see what contests are on are http://www.hornucopia.com/contestcal/index.html and http://www.sk3bg.se/contest/index.htm.

Well if the Cluster and Contests don’t improve your DXCC score there’s always your local 2m/70cm  to play with. Bip Bip!