I’ve got my Special Contest Callsign back

In 2013 I was issued a Special Contest Callsign (SCC) and used it very successfully for a number of contests which you can see on my Contest results page.  Because I wasn’t active in the qualifying contests very much after that, I couldn’t renew it when it expired at the end of 2016.  Part of my inactivity was due to the problems I had with interfacing the radio to the computer which I resolved last year.

After entering a few contests in 2017 I realised that I’d probably got enough points to be able to renew my SCC.  It took some scrabbling around and looking up my old results to confirm that I was just one point away from being able to renew.  Towards the end of December the results from the WAE RTTY contest were posted and my result gave me two points towards my callsign.

I submitted my application at 20:38 on the 21st December and at 14:38 on the 22nd December I received the NoV for M7P.

Notice of Variation for M7P

Notice of Variation for M7P

There are some good reasons to have a Special Contest Callsign – Being only three characters, they’re quicker to use in all modes and are far more distinctive.  A very nice bonus is that if you pick one of the more unusual prefixes then they’re quite rare.  Some contests use prefixes as multipliers and people will generally be looking to work as many multipliers as they can.  It’s nice to have a relatively rare prefix.

I’ve given it a quick airing this year and just made around a hundred or so QSOs in various contests, giving away a few points.  It’s nice to have it back again.

You can find out more about Special Contest Callsigns and how to apply for one (if you qualify) here.

As an unrelated footnote, I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

Posted in Amateur radio, Contesting | Leave a comment

QSO statistics for 2017

I’d just like to record my annual stats as extracted from ClubLog for 2017

As is normal for me, most of my QSOs were data.  The majority of those were RTTY although a fair few were using the new FT8 mode.

I’m not unhappy with those figures, especially when you consider how poor the HF bands have been for the year.  Remember, we’re still the best part of two years away from solar minimum (cycle 24 started in December 2008) so in all reality, I think that we’re probably four years away from when we’ll notice any improvement in HF conditions.

As an unrelated footnote, I’ve been told that somehow these blog posts are being cross posted to a couple of amateur radio newsgroups automatically.  I’m not responsible for this and I have no control over it.  I wouldn’t choose to have my entries replicated there but I can’t do anything about it.  If you’re reading this on a newsgroup then please be aware that I won’t see any replies or comments.

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OK DX RTTY contest 2017

What a difference five years and nearly half of a solar cycle makes.  Last weekend I entered the OK DX RTTY contest and upon checking my log, I realised it’s been five years since I last operated in this contest.

In December 2012 we were approaching solar maximum and conditions were excellent.  Five years later, we’re approaching solar minimum (although we’re still a couple of years away) and conditions were, to be blunt, bloody awful last weekend.

I had things to do in the shack so luckily I wasn’t tied to the wireless all day Saturday and was able to do other stuff.  It’s just as well.  In 2012 I managed nearly 350 QSOs on 15m but last weekend, all I could rake out was 32 contacts.  I tuned around a few times and I simply didn’t hear any other stations calling CQ on 15m at all at any point.

Conditions would have been the same everywhere so it would have been rubbish for everyone else making a single band 15m entry.  The results for this contest are normally out very quickly so it won’t be long before I find out how well (or how badly) I did.

** update – 25/12/2017**
The results are out, just two weeks after the contest.  I was 4th out of 9 entries in the section.  How different this is to 2012 when there were 58 entries in the 15m category.

You can see the SH5 log analysis via my contest results page.

Map of stations worked by G6NHU on 15m in the OK DX RTTY contest 2017

Map of stations worked by G6NHU on 15m in the OK DX RTTY contest 2017

Posted in Amateur radio, Contesting, HF, RTTY | Tagged | Leave a comment

Building a Hendricks 41dB Step RF Attenuator

Two or three years ago I had a browser tab sitting open on the Hendricks 41dB Step RF Attenuator from Pacific Antenna/QRP Kits in California.  For some reason I never ordered one and when I finally remembered that I was going to get one, they were out of stock.

I dropped them an email back in March this year and James told me that they were hoping to either redesign or restock and then in September he emailed me to tell me that they were restocking.  As soon as the kit appeared back in the shop, I ordered one straight away and it arrived just a few days later.

There’s not really much in the attenuator but here’s everything that came in the kit followed by a picture of the circuit board and all the components ready to go.

Hendricks 41dB Step RF Attenuator kit

Hendricks 41dB Step RF Attenuator kit

Hendricks 41dB Step RF Attenuator kit - All the components

Hendricks 41dB Step RF Attenuator kit – All the components

I was struck by the quality of the circuit board.  Very solid, good through hole plating and very decent sized pads on each side.

It didn’t take me long to fire up the soldering iron and get to work.

The first two resistors soldered into the Pacific Antennas QRP Kits attenuator

The first two resistors soldered into the Pacific Antennas QRP Kits attenuator

Back of the first two resistors fitted to the attenuator

Back of the first two resistors fitted to the attenuator

Because the solder pads are so large on each side, rather than rely on solder to flow from one side to the other, I made a point of soldering on both sides.

All the 'vertical' resistors in position

All the ‘vertical’ resistors in position

I fitted all these resistors and then moved on to the ones below the switches.  I worked from left to right and when I’d fitted R3, I realised that I had no more left.  There was no R16 in my pile of components.


I looked around, I checked the bench, I checked the packaging, I checked the floor but there was no sign of the missing resistor.  I checked my component rack but I didn’t have any 270R 2W 5% resistors in there.

I quickly realised I was going to have to find a spare resistor from somewhere.  I can’t remember exactly how it happened but I got into a conversation on a local repeater where I happened to mention that I was a resistor short and a good friend popped up a few minutes later to tell me that they would drop one over to me later that afternoon.  I asked where they’d got it from and they told me it was a local shop.  I was planning to head over to town later anyway so I said “thank you very much, I’ll pick it up myself”.

When I collected the resistor, I looked at it with disappointment.  It was the correct size and value but the style was very different to the resistors already on the board.  Even though the board was going to be mounted in a box, I wasn’t happy with how it was going to look.

The non standard 270R resistor in the attenuator

The non standard 270R resistor in the attenuator

You can see that it’s totally and utterly different.  You can also see that it’s not soldered in, I just couldn’t bring myself to solder it.

eBay called and I found these.

They looked perfect, correct value, correct power rating and correct tolerance.  They came as a pack of five and I ordered them, paying the extra 20p for next day delivery.

About an hour after ordering these, I rolled my chair back and it stalled on something.  I looked on the floor and there was the missing resistor.  If resistors could smile, I’d swear it was smirking at me.

Within thirty seconds it was soldered in place.

All the resistors fitted to the 41dB step RF attenuator

All the resistors fitted to the 41dB step RF attenuator

The next thing to fit was the large slide switches.  These are big and chunky and feel very positive when chunked backwards and forwards.  I fitted them all with no problems at all except somehow (and I genuinely have no idea how) this happened.

The broken switch

The broken switch

I tried to find a replacement switch locally of the same style with no joy so I emailed James to ask about getting a spare.  James was very helpful and just a few days later a care pack arrived from California.

Two spare switches

Two spare switches

Because I’d done such a good job of soldering everything in, getting the broken switch out was a nightmare.  It took me a good half an hour of working with both a solder sucker and some desolder braid.  It goes to show the quality of the board that I was able to spend so much time on it with a hot soldering iron and not damage it at all.  I’ve never used desolder braid before but that and the solder sucker eventually did the job.

The circuit board showing where the switch was removed (click for a full size version)

The circuit board showing where the switch was removed (click for a full size version)

With the broken switch removed, I fitted one of the replacements which left me all ready for the next stage.

Hendricks 41dB Step RF Attenuator PCB all built and ready to go

Hendricks 41dB Step RF Attenuator PCB all built and ready to go

The next stage was testing so I hooked up my DVM and checked the resistances were all correct with the associated switches.  All looked good.

After this, it was time to prepare the box.  The supplied box has a nice brushed finish and  decided I was happy to leave it like that rather than paint it.  There are some nice decals provided for labelling and the instructions recommend spraying the box with “Krylon clear” first.  This is a USA brand of lacquer spray and not available in the UK so I sourced this alternative from Wilko.

Wilko clear lacquer spray

Wilko clear lacquer spray

After a couple of minutes shaking and spraying, the box was left to dry for 24 hours.

The box, freshly sprayed and drying before applying the decals

The box, freshly sprayed and drying before applying the decals

This looks fine but once the lacquer dried, it didn’t really look very attractive.  I mentioned this to a friend who very kindly offered to hydro dip the box and lacquer it for me.

Once it was all done, I assembled everything into the box for testing.

The finished attenuator

The finished attenuator

It’s quite a dark finish but I think it looks good.  I used my analyser to test the actual attenuation and on 40m, it’s within half a dB or so of specifications and so this will be a useful addition to the shack as it’ll allow me to match the output of my two WSPR transmitters for proper aerial comparisons.

Considering the complexity of some things I’ve built over the years, this should have been a simple build.  It just goes to show that the gremlins can creep into anything and everything seemed to go wrong with this one. I’m just glad it’s finally completed and working as intended.

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Shack wallpaper

Back in 2011 while I was working my QSO365 project (the reason why this blog started), I reached 100 DXCC entities worked and although I applied for the award, I don’t think I ever actually posted the certificate on here.

The general DXCC award is for the “mixed” category which means that you’ve worked and confirmed contact with one hundred different DXCC countries (known as entities) using any mode or band.  There are also certificates available for individual modes (phone, cw, digital) and bands.

Naturally, the first award I applied for was mixed and since then, I’ve added some extra certificates to my collection.  Stickers (or endorsements) are also available for additional entities worked and confirmed.

When I got my first certificates, I put two of them in frames but the frames really weren’t very pretty and I didn’t bother hanging them on the shack wall.

Earlier this year I decided I really ought to update my award account on Logbook of The World and applied for some additional certificates and endorsements.  I also found some much nicer frames and ordered those as well.

So here are three of my DXCC certificates in the new frames.

G6NHU DXCC certificate - Mixed

G6NHU DXCC certificate – Mixed

G6NHU DXCC certificate - Phone

G6NHU DXCC certificate – Phone

G6NHU DXCC certificate - CW

G6NHU DXCC certificate – CW

I’ve actually got eight certificates for different combinations  but I’m not going to frame all of them as I simply don’t have enough space to hang them all.

At time of writing, I’ve got the following number of entities confirmed:

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Working duplicates in a contest

When I work a contest, most of the time I’m calling CQ and I always work duplicates.  If someone calls me and my log flags that they’re a duplicate, it doesn’t bother me in the slightest, I work them again.

Some operators flatly refuse to work duplicates but I think that’s a mistake and I’d like to explain why, from both the running (CQ) side and when operating S&P.

In a contest earlier this year, one station called me four times.  Each time I worked him.

When the scores were published, the contest also published the UBN log checking report (UBN stands for Unique, Busted, Not in log).

I decided to download the UBN for this particular station and see why he worked me four times.

Here are the four logged QSOs.

0014 21000 G6NHVP G – 0 Busted call, should be G6NHU
0018 21080 G6NHU G + 2 *
0128 21080 G6NHV G – 0 Busted call, should be G6NHU
0197 21080 G6NVT G – 0 Busted call, should be G6NHU

He logged my callsign incorrectly three times (in fact his log was absolutely full of errors) but if I’d refused to work him after our first contact, I wouldn’t have got the points for the QSO.  It’s generally quicker and easier to work someone again than it does to reject them as a duplicate.  The contest adjudication software will pick up on any duplicates and I don’t know any contest where dupes are penalised in any other way than not counting for points.

It works the other way round as well – When operating S&P, I try not to call people twice but occasionally it might happen if I misread their callsign or make a mistake logging it.

In the CQ WW SSB contest a couple of weekends ago, I tried breaking a pileup to work one of the rarer stations and as far as I was aware, I didn’t manage to beat the pileup and I gave up.  A few hours later, I tried again and this time got through only to be told “we’ve worked before”.  I can only imagine that he picked my callsign out but due to QRM, I didn’t hear him reply.  Of course, I didn’t give the exchange so it must have been automatically filled in by their database (it’s fairly obvious that a G station is in zone 14).  In this case, I was lucky enough to be able to get back and say “you’re not in my log, can we work again please” and we did complete the QSO.  It would have been quicker for him in the first place to simply work me again and not try and bounce me as a duplicate.

It’s quicker to work a dupe than to faff about rejecting it and by not working a dupe, you could be doing yourself out of the points for that QSO.

Please work duplicates.  They might be in your log but there’s a good chance you might not be in theirs.

Posted in Amateur radio, Contesting, Operating tips | Tagged | Leave a comment

DMR – My thoughts about Digital Mobile Radio

I’ve written a couple of times in the past about various digital voice modes and if I’m honest, I’ve been quite scathing of them.  I make no secret of the fact that I’m very happy to use repeaters for local natter but don’t like the idea of linking remote repeaters together via the internet to work “DX”.

When I use D-STAR, I tend to unlink the local repeater from the reflector and call through it to see if any locals are listening.

I’m a founder member of the Martello Tower Group and we run a number of analogue and digital repeaters.  We recently moved GB7CL, our DMR repeater to a site just a couple of miles away from where I live and I’d openly said that once that happened, I’d get myself a DMR wireless.

I’ve now had a DMR radio for about a month and have spent a lot of time sorting out the configuration and learning how to use it – It’s quite a steep learning curve but I found a base “code plug” and tweaked it slightly to suit my requirements.

The obvious comparison is with D-STAR.  The first thing to notice about DMR is that the audio is significantly better than D-STAR which is down to higher bandwidth and a better audio CODEC.  It’s not uncommon for me to hear someone I know working D-STAR and barely be able to recognise their voice.  That’s not the situation with DMR, everyone sounds as I’d expect them to do.

What I like very much about DMR is how the Regional “Talk Groups” work.  DMR repeaters are centrally controlled and certain talk groups are linked together by region.  For example, Talk Group 840 links together repeaters in Ipswich (GB7AL and GB7MK), Clacton-on-Sea (GB7CL), Tring (GB7CT), Norwich (GB7DS), Pointon (GB7FU), Halstead GB7HA), Attleborough (GB7ND), Peterborough (GB7PE), Cambridge (GB7PY), Leicester (GB7SK) and Bury St. Edmunds (GB7WS).

In practise, if you transmit on the East England Talk Group 840, you’ll be relayed through all the above repeaters simultaneously.  This is very much how we used to have the analogue repeaters GB3CE and GB3CL in Clacton-on-Sea and Colchester configured except we were linking via RF and not an internet backbone.

I have no problems with this form of linking, in fact I think it’s fantastic to have multiple local/regional repeaters joined together like this.

In addition to this, there’s a larger Talk Group (801) covering the whole of the South East which consists of twenty repeaters all linked in the same way.

There are other regional Talk Groups configured and the best way to demonstrate this is to have a look at the link on the DMR-UK web site here where you can sort the list by regional talk group to see exactly what’s in each one.

In addition there are other talk groups designated as World Wide, UK Wide and Europe where. as the name suggests, anyone calling through them will be relayed through every repeater in the group.

However you don’t have to access multiple repeaters at the same time.  Each repeater has two local talk groups which are entirely self contained so they can be used in exactly the same way as a traditional stand-alone repeater.

This page gives a list of all the talk groups which are available on each repeater.

Another nice feature of DMR is the ability to automatically ‘roam’ across the network so if one goes out of range of one repeater, the radio will automatically switch to another one.  As I don’t have a DMR wireless in my car, I’ve had no experience of this but I have listened to stations driving around who have commented that they’ve just roamed to another repeater.

Each repeater has two “Time Slots” (TS).  Effectively this means that two QSOs can happen at the same time, doubling the capacity of the repeater.  TS1 is used for national and international talk groups and TS2 is used for local and regional talk groups.

The above probably sounds incredibly complicated and when I first switched on my DMR radio, I was totally overwhelmed.  I spent a lot of time reading the DMR-UK site and along with listening around the network, I’ve quickly picked it all up and I’ve got my head around most of it.

Whereas D-STAR radios are almost exclusively manufactured by Icom (except the recent Kenwood TH-D74E), there are a few different DMR manufacturers.  In the UK the most common seems to be the Tytera (TYT) UHF MD-380, available from China for as little as £70 via eBay or a little more if you buy from a supplier based in the UK.  There is also a recent mobile dual band radio, the TYT-9600 although I understand that’s going through some teething problems because it’s so new.  At time of writing this is only available from one UK supplier.

I’ve often heard DMR described as “The poor man’s D-STAR”.  Although it’s significantly cheaper to buy a DMR wireless than a D-STAR one, I don’t think that’s a good comparison.  Compared to D-STAR with the random linking of reflectors and the relatively poor audio quality, I think I prefer DMR.

I like the way the network is configured centrally into regional talk groups, I like the roaming feature, I really like that by selecting the local channels, it can just be used as an unconnected repeater.

With all these positives, is there anything I don’t like about DMR?  I’m not a great fan of the huge learning curve.  I can see that it can be quite complicated and can understand why some people aren’t able to get their head around it.  I think that by forcing myself to be a DMR SWL for a good few weeks, I’ve been able to get a decent grounding in how it works and how to operate it.  I don’t like using things I don’t understand.

A few days ago, I visited an area which I don’t have programmed into my DMR radio.  Because of the complexities of setting these things up, I couldn’t use it.  Unlike an analogue radio, I couldn’t simply tune my wireless to the local repeater, set up the CTCSS tone (or whistle at 1,750Hz) and speak through it.  It was effectively useless.  This is the same for D-STAR as well though, it’s not just a limitation of DMR.  At least with D-STAR I have the entire UK repeater network configured and using the built in GPS, it can always find the closest repeater to me.  I don’t think this feature is available on any DMR wirelesses yet.

I’m also quite frustrated by the terminology that seems to be coming into amateur radio from the commercial side.  Everyone talks about a “code plug” which is really just a list of frequencies, offsets and memories and links them together.  We’ve been doing this for years, programming memories and setting up radios but for some reason we’ve now adopted a commercial term.   Also, there’s a “colour” linked to each channel which is the CTCSS tone.  Why not just say that you’re programming the radio and using (103.5 or whatever) CTCSS?

The World Wide and Europe Wide talk groups don’t interest me in the slightest.

What radio did I buy?

Despite saying that I don’t like handhelds, I bought one.  I didn’t go with a very cheap Chinese import because I’ve heard too many horror stories about them arriving broken or failing after just a few weeks and being impossible (or prohibitively expensive) to return them.  I bought mine from a UK supplier via Amazon because I figured that I’d have a better chance of any returns if it arrived faulty or stopped working within the warranty period.  I also had some credit on Amazon so the actual cash I had to spend made it a very reasonable price.
I wasn’t prepared to pay £280 for a dual band mobile radio for a mode I may have hated and I’d also read too many bad things about the MD-9600 and the poor firmware to consider one just yet.

This is what I bought.

TYT MD-380 DMR UHF handheld

TYT MD-380 DMR UHF handheld

Posted in Amateur radio, D-STAR, DMR, FM, UHF | Tagged , | Leave a comment