Short Antenna for 40m: Reload!

Late last year, I threw up a shortened antenna for 40m using a coil in the lower 1/3 of a 5m-long elevated vertical. This allowed my 7m fishing pole, which is much more manageable in our regular, strong winds than a 10m version, to be used for all bands.

The idea is to make a multiband antenna that is easily carried down the beach and doesn't cost much.  I also would like to use it at home on lower bands, where it can tolerate very high winds.  Being able to get away from any home QTH is always a good idea to keep fresh, because you never know when someone will start spoiling your potentially huge investment with RFI.

The first coil worked pretty well, but I couldn't get the best match.  I think that was because I used short radials, rather than tuned, 1/4 wave units for a given band.  Even so, the match was reasonable, at about 1.7:1.

With better weather of late, I turned again to having a go at making a coil to allow a much better match on 40m, using tuned radials.

Even in summer, our winds can be strong!  Initial coil testing at 40m.

 
Initially, I had started making a copy of the PAC12-type antenna, made of alumimium rods.  I found this very slow going, not least because I had to cut my own threads and make connectors for the various components, made worse by Imperial measurements!

It also became clear, as I put the first bits together, that an aluminium rod antenna with a long telescopic whip on top was simply not going to survive on a North Wales beach, where we regularly suffer some of the strongest winds on the planet.

So, back to good old-fashioned, wind-resistant fishing poles!

I wound a coil of about 20 turns on a 43mm PVC pipe, with a split pipe of the same diameter slipped over the first.  This creates a slightly wider former, with a gap down the length, allowing a crocodile clip or similar to be easily connected at various coil positions.

The split second tube slipped over the first creates a gap for a matching clip. This is the second experimental coil.

The coil, being very light, simply attaches with a re-openable cable tie to the pole. It looks much less neat than a coil incorporated into the body of a PAC12-type antenna, but that's just unimportant!

My loosely wound coil was disappointing at first, as it showed a rather poor match.  I decided to push to turns much closer together, such that each was spaced by only about 4-5mm.  Immediately, this brought a perfect match with the whole length of the coil used.

The next step will be to make a set of tuned radials for more bands.  The photo above shows my new coil drying in the sun.  This has about 8m of wire - at least double the turns of the first, closely-spaced, so that I can hopefully reach at least 60m. Some hard-setting mastic was used to initially keep the coil spacing in place (few adhesives will stick for long to the PVC tube itself, especially if left outdoors).

I'll be running the antenna on 40m with the first coil from tonight onwards on WSPR, using just 200mW.  A few hours last night showed the system to be working very well.

UPDATE:

Here are the initial WSPR results at 200mW.  The following plot is on the first overnight run, where the Kp index was slightly high, at around 4.  The comparison station is my usual reference station, a full wave horizontal loop in England:

Doing will, compared with a full loop.

In particular, I was very pleased to be one of only two or three UK stations being heard in ZS that evening:

On the second evening, with quieter geomagnetic conditions, the results were even better, again showing the benefit of a clear environment and sloping ground to the sea:

 

Second 12h run.  Nothing wrong with this antenna!

3/8" 24tpi Antenna Connectors

If you like making antennas, especially portable vertical ones, it won't be long before you find a need to grab some (UNF) 3/8" 24 tpi stud connectors.

I really struggled to find a supplier in the UK.  So, if you're in the same position, have a look at:

http://www.a2stainless.co.uk/3-8-UNF-Studding-Connector-Nut_AZEE5.aspx

UK supplier found!

JTDX - An instant success!

Thanks to Bas, PE4BAS, I learned recently about JTDX, a derivative of the popular WSJT-X software.

I'm always interested in any new digital packages, but also always wary of having to spend hours looking at screens as the inevitable software conflicts, PTT/RTS/DTR options and the rest of those things make technology waste one's time.

Luckily, JTDX is much the same in terms of set-up as WSJT-X, so the settings are identical.  It worked straight out of the box, as it were.

Bas said that JTDX is a big improvement on WSJT-X, mainly because it decodes so much more than the original software.

I can testify that Bas's assertion is absolutely correct!  One is faced with 25 or more stations upon decode, and even having several stations responding to my 'CQ' being decoded quickly.  That is very rare for WSJT-X, but common on JTDX.

I did wonder whether, though capable of decoding so much more, many of those stations might be too weak to contact in practice.  This doesn't seem to be the case.  Looking early this morning at JTDX, it's like there's a whole world of stations out there that WSJT-X might not let you realise exists.  I had quite rare stations like Egypt and Peru coming through nicely, although it could have been coincidence.

It's a bit irritating, though, that the waterfall for JTDX seems to cover a wide frequency span, such that the whole thing is too compressed, especially with JT9, for it to be ideal. 

So, like Bas, it's unlikely I'll be reverting to WSJT-X, and look forward to seeing if I can grab a new DX entity out of the noise with JTDX!

Welcome to Amateur Radio! You'll need £5099, though...

This week, my eleven year-old daughter received her much-awaited Foundation Licence certificate from the RSGB.

The certificate is nicely done, and one has then to apply for a callsign via the much-criticised UK regulator, OFCOM.

Sadly for my daughter, and the ham radio contigent in general, OFCOM's online licensing system flatly refused to work properly.  A swift phone call revealed other complaints about the same problem.  A day later, it's still not working.  Big disappointment for anyone, let alone a child.

Alongside the certificate from the RSGB comes a 15-page leaflet - 'Radio Today' (bizarrely, priced at £1.95, even though, like RadCom, it doesn't appear to actually be on sale anywhere) - that aims to help newcomers set up their first station.  It's a dismally dull read, lost the interest of my daughter in seconds (I didn't last much longer), and is full of the usual adverts for wildly expensive equipment.

Indeed, it seems to be mainly driven by adverts, as all magazines are.  The front and back cover feature a rig costing over £5000.  For just an extra £995, you can currently buy a brand new Dacia car!

Why does the RSGB choose this £5100 rig for an introductory text for new hams?  Image: AB4BJ.

The leaflet's 'how to set up' article uses not a second hand unit from e-bay as an example station, but a £1200-odd rig, together with a £250 desk mic and proprietary PSU and speaker.  At least three of those things can be aquired for a fraction of the proprietary vendor's prices, and the rig could be at least half the price for any normal user.  My own boom microphone set-up cost me £11 for the Behringer mike, and £10 for the boom.  Spending £500 more would not make any practical difference.

So, an adverts-driven leaflet that makes ham radio look utterly elitist and unaffordable, especially to those youngsters who haven't a cat's chance in hell of affording an education, house or pension, let alone finding the spare cash for a 'flagship' transceiver.

The RSGB, dominated by ageing middle class, white men, needs to quickly drag itself into the real world of operators flooded by electronics-generated QRM, postage stamp-sized gardens, a regulator that doesn't regulate, and an overwhelming antagonsim towards our hobby.

HF Manpack Success!

I like the convenience of operating from home, where I have a modest, 'kitchen-top' station.

But, using one's home as a radio sation can be intrusive on other members of the family.  It can also be far too much like putting all your eggs in one basket if EMC issues develop in the neighbourhood.

So, I've always kept my hand in simple, rapid deployment of HF radio away from the home, so that, whatever comes to blight me there can be avoided simply by getting in the car and visiting a hill or beach.

My most recent incentive to go portable in earnest came a couple of weeks ago, when a neighbour installed an electric fence right up to my boundary.  Whilst noise blanking gets rid of the ticking almost all the time, and the fence is not that noisy anyway, it does show how easily and quickly neighbour EMC problems can come to influence and possibly spoil your home station.  (Update: three years later, the electric fence was such a maintenance headache that they gave up on it - hurrah!)

So, I took some inspiration from a few images under a Google search for 'HF manpack'. These were all much the same, copper tube constructions that contain all the equipment and are either backpacks in their own right, or otherwise slip into a fabric rucksack.

WSPRlite testing of the copper tube manpack.

I was interested to see whether I could reach any sort of workable match of the tube frame when I mounted a 20m mobile whip on top of it, using a gutter mount, but no ATU.  A quick connection to my SARK-110 antenna analyser showed that, indeed, a perfect and relatively broad match could be achieved quite easily, simply by adjusting the whip length as normal.

Armed with quite a positive first indication from the analyser, I set the frame out in the garden and hooked-up my WSPRlite QRP transmitter, running 200mW.

I left the unit running all day whilst I was out, but conditions were so poor in an R2 blackout that I had no spots at all!  That changed the following day, when conditions relented somewhat, and good distances out to Finland during the day were being achieved.  Later, a few spots out to Russia and the US were reported.

I can tell the bakcpack is working well because, thanks to DXPlorer, the software that comes with WSPRlite, I can compare with known, efficient stations elsewhere in the UK and see that it is as good as, for example, a full wave horizontal loop.  More time is needed for a full assessment.

Clearly, this frame is a workable and efficient solution to not only going mobile but backpack (or pedestrian) mobile, all at very little cost.  Those who operate /PM from the beaches of the UK on a regular basis know how they can manage QRP contacts with VK and ZL very easily, whilst folks at home can't even hear the antipodes!

I'm looking forward to grabbing an FT857 or similar rig, and enjoying morning and evening sessions down the beaches.  Imagine, no noisy solar PV, plasma screens, LCD lights or electric fences anywhere in sight!

UPDATE!

Here are some results from WSPRlite testing.

First, a comparison with a horizontal, large loop antenna:

Next, a comparison with a doublet:

And, finally, against a trapped dipole:

Update 2:

I've now assembled my TS-480 and a 12Ah battery onto the frame.  It's comfortably backpackable, having bought some shoulder straps for it.  The overall experience of using the system on SSB is pretty much identical to operating from a car with a magmount, so I'm pretty happy with that.

The battery is small, but provides enough duration to enable me to cover plenty of overs during the 20-30 minutes of peak long path propagation.  On about 15-20W peak output, I've managed Russia and the mid-west US so far, as well as the usual lot of easy EU stations.  Overall, it is working as well as such a system can be expected to.

An obvious improvement in terms of power duration and ease of transport would be to install the system around a decent, large-wheeled all-terrain pushchair.  Sadly, I sold ours years ago, and that model, which was perfect, is either difficult to find and/or very expensive now.If you go down this route, avoid, at all costs, those buggies with front wheels that swivel, and wheels that are either too narrow, too small, or both!  Wheels needs to be at least 12" in diameter to cope with sand and rough surfaces well.

RadCom asks - me? - to help them out!

Last month, RadCom ran a second article about earthing an amateur radio station.

None of the following constitutes advice.  It is for you to engage qualified people to examine and install your system.

In this latest contribution, there was text, supported by a graphic, that showed, in essence, each piece of radio equipment attached to an earthing bus, connected to a stake/rod stuck in the ground outside.

Now, all amateurs are meant to have passed an examination which should mean they understand earthing to a reasonable level.  But, visit many shacks or listen to on-air QSOs, and you will quickly realise there are an awful lot of people who have absolutely no idea why they are earthing their equipment, or how to do it properly (i.e. safely.)

Unfortunately for RadCom and its author, who seem not to have thought an awful lot before publishing, they failed to include instructions on how to properly earth a shack that is served by what is actually a pretty common system in the UK - Protective Multiple Earth (PME).

The PME earthing layout, very common in the UK.

Setting up a shack with a ground rod attached to equipment in a PME-served household is potentially extremely dangerous.  The earth wire at the incoming mains is not a separate connection back to some remote earthing point, but one that is completed via a connection to the neutral wire.  If the neutral breaks during a storm or other failure, you could end up with a whole neighbourhood's supply trying to use your equipment and its questionable earthing to complete a ciruit.  Fire is the most likely outcome.

Solving this problem is not difficult.  You do the same as RadCom published - i.e. connect each equipment to a ground stake, but also add a separate wire that is connected directly to the stake, and runs back on its little own to the consumer unit. The wire needs to be a minimum of 10 square mm to handle the potentially high current that might try to use it, down to your earth stake.

Even then, the job may not be good enough.  I found that the very short earth wire between the incoming mains and the consumer unit was very thin - probably way below what modern regulations stipulate.  That was installed by the supply company about 40 years ago, so it's entirely their fault.  If your wire is similarly inadequate, you will need to ask the supply company to inspect and change the wire, hopefully without charge because it doesn't conform to their own regulations.

I pointed all this out to RadCom and the author of the article.  After a month, I received a sheepish e-mail from the editor of the magazine that said many people had been in touch about this issue, and would I consider writing an article to set the record straight?  I politely declined the offer, saying that they had better get someone with current electrical engineering qualifications to do so, and maybe pay more attention to proof reading and quality control in future.

So, if you have PME, do consult the document that RadCom and its author seemingly didn't, freely available here:  http://rsgb.org/main/files/2012/06/emc-leaflet-07.pdf

None of the foregoing constitutes advice.  It is for you to engage qualified people to examine and install your system.

RSGB Expenses Hike Prompts Departure

It's that time of year again when the finer details of the RSGB's accounts are slowly sinking in.


I'm always interested in the non-remuneration of the board members which, the Articles of the company say, is to cover legitimate expenses.  It is not, therefore, pay.

So, let's look at this latest accounting period.

In 2015, eight board members collectively claimed £15,000.  That's the equivalent of £1875 each.

In 2016, seven board members - one less than in 2015 - claimed £17,000.  A new equivalent of £2428 each.  Note that some members may have claimed more than others.  That's why I use the term "equivalent".

Now, these are not huge sums, and there is no suggestion that the claims are not legitimate and properly due.

What is surprising is that, despite the number of board members claiming dropping by 12.5%, the total claimed has nevertheless gone up by 13%.  Inflation is essentially flatlining, so that doesn't explain much of anything.

I find myself again questioning why I have joined the RSGB when, in practice, all I get is a magazine that I don't actually ever enjoy reading.  This is very different from the experience of being a member of the ARRL, where everything in QST and beyond is so much more practical and approachable, albeit with no influence in the UK.

I think the basic problem I have with the RSGB is (a) that it is a limited company where the directors each shoulder the non-responsibility of a £1 liability if it all goes belly-up.  That doesn't foster a sense of ownership and responsibility, as this event, or this one have fairly recently proven.  I think an alternative structure like a not-for-profit or community benefit organsiation might better match what we actually expect a hobby society to be.

And, (b) there is a very strange culture surrounding the RSGB.  I found this out with some amazement a few years ago when Len Paget, still an RSGB bigwig, decided to send his views of me (based on exchanging a couple of emails about planning matters) to 11 members of a non-radio organisation, questioning my suitability to be a representative of that organisation.  He used his personal e-mail address to do so, but was in practice representing the RSGB, because that was the only route through which I had ever approached him, via the 'haveyoursay@RSGB... address', and the RSGB (and ICO) accepted the breach was their responsibility, not a personal matter between myself and Paget. Paget was very lucky he didn't end up with a libel writ.  Sadly for him, I wasn't even a member of the society he contacted.  The ICO carpeted the RSGB for its poor data control.

With many of the same old people in charge, it's hardly surprising that I find the RSGB hasn't really changed very much with some new faces over the  past three or four years.  I can't even say I've been very impressed by the quality of advice offered by those volunteers I've approached for help; I could have done as well or better under my own steam.

For example, the RSGB continues to claim that a member using its planning advice service is more likely to gain planning approval than someone who doesn't use those services.  This is a big claim.  It's also a claim that, without a very extensive, expensive and, so far as I know, not actually undertaken exercise, one the RSGB is not in a position to make.

So, for the second time in about six years, I've decided this is not a society that represents my values, wishes and interests.

I thought I was clever in joining the GQRP Club, until I received a very unwelcoming email from someone there, who clearly showed this was not the place for me.  I demanded a refund - and was as relieved to receive it as they were to issue it.