Portable Operations #4 – Pre Field Weekend Preparation

OK! Since the last field weekend I’ve managed to achieve the square root of nothing with regards to overcoming the few encountered hiccups and with the Bank Holiday Weekend and next Field Weekend fast approaching, the weather starting to score a cool 100% on the naff weather-o-meter; it was time to do something about it all.

The biggest problem was to be waterproof. As fun as it would be to get a “you can’t bend it 2 man tent” to use as my base of operations, it would be considered far more sociable to join the party in the club marquee so I invested a whole £4-50 in 10 meters of RG58U and set about building myself a feeder extension cable. With that easily squared away the next issue was to make that all so vulnerable metal of the plug to plug mating weatherproof.

Now this little trick, I can claim no credit for whatsoever. That goes to Mike Parkin G0JMI of Alton Antenna Arrays. Costing a whole £2-40 from Screwfix and providing enough hardware to waterproof countless future cables, you’ve got to admire the simplicity of this.


By creating a rubber bung using self-amalgamating tape above one PL259 plug a 25mm plastic conduit coupler is secured to the antenna feeder. A section of 25mm conduit is then cut and slid over the feeder extension. Plug your two PL259’s together using a back to back connector and slide the conduit into the coupler et voila, one weatherproof union! Just to stop any build up of water that drips down the antenna cable from working its way into the rubber bung I sealed the top end with a coating of epoxy resin. You’ve got to agree, simple is always best!


Portable Operations #3 – Field Weekend

At 0530 hr this morning, when the birds were giving their vocal chords a stretch it wasn’t looking too bad out there.

Strangely, in the time it took me to move from the horizontal to the vertical a few hours later it was very much a case that the days proceedings were going to be sponsored by our old friends precipitation and cloud. Having just spent the last couple of weeks having to deal with the stress and strains of weather like this –


I was hoping for something a bit better than this –


When it comes to the Great British weather, there’s nothing “Great” about it whatsoever. I’m assuming that it’s Brexited on a permanent basis along with our EU membership!!

Anyway, not to be defeatist I removed all my essentials like sunscreen, sunglasses and cap from my gear bag and replaced them with wet weather kit. We didn’t come all this way to quit so quickly! Somewhat annoyingly I’d been looking at offers on 2 man pop up tents online yesterday thinking “Nah, don’t need one, won’t need one, I’ll get one another day, it can wait, this weekend’s gonna be great”. Hmm, how wrong can you be?

So, with the rain clouds looming I set about deploying all my toys. Like everything first time out there was a bit of trial and error to get things just how they needed to be, but we got there.


My 728HFA sat perfectly aloft the trigpoint mount and with 100ft of paracord attached to the dogbone insulator, I ran it back to a tent peg pushed into the ground further along the battlements of the fort, which gave a 25-33 degree declination over the run.


The first snag arose when my feeder which was 8m in length and great for use in the garden or when you’re sat at the base of your mast, was just a bit too short to get me into the environmental safety of the club marquee. This was overcome by a bit of lateral thinking and a rummage around the boot of the car revealed the beach shelter which I set up literally at the marquee door, much to the amusement of the rest of the club. The colour scheme didn’t help matters greatly. I need something more manly and tactical!



And there we have it, M0XXF/P up and running. The next goof was realising I’d managed to unpack my ground sheet from the car while packing, so I spent the rest of the day in the prone position on top of an old Gortex soft shell jacket which had been in the car boot.

All I can say is what a great day. It just goes to show what 100m of elevation away from the electrical noise of the urban environment can do for antenna reception! I’ve never seen so many signals and with a marked increase in reception clarity.

At home my 728HFA runs east – west hidden beneath the facia board of the house and has to contend with the proximity of a brick building and the electrical pollution of the urban environment. Today it’s orientated north – south, so in effect side on to Europe with absolutely nothing of note near it. As such I was seeing PSK31 signals from countries and areas I’ve never seen before, Indonesia being one of note. All my QSO’s during the day were made on 20W, simply because my T1 ATU isn’t happy above that level and I couldn’t be bothered to keep adjusting the power settings within the rig. That said, I had packed my LDG YT-100, so could have upped my power if I’d wanted. I managed to bag a suitable number of QSO’s to make the day worthwhile, which was the primary objective.

Eventually the sun came out to brighten up the day which was a bonus, that was promptly countered by an invasion of flying ants, motivated to take a flying lesson, by the spontaneous return of summer. Note to self, a blue and yellow beach shelter obviously looks like food to the critters and I think most of them decided to drop in to see what was going on. I’ve been picking the damn things out my kit bag for the past 2 days!


So come BBQ time and the end of the day, what had we learnt?

  1. Operating portable is great fun
  2. Get a longer feeder for my antenna
  3. A blue and yellow beach shelter really isn’t manly!
  4. I should have bought that pop up tent!



Portable Operations #2 – Field Weekend T-1 and counting

OK, we are now officially 15 hours away from FPARC’s July Field Weekend and the excitement is bubbling!

Not wishing to look a prize buffoon by rocking up with lots of stuff and finding it doesn’t work, I thought it prudent to actually see if my portable concept worked in the relative safety of the back garden. So, duly equipped with a pair of shorts and Oakley Half Jackets I gingerly transferred my rig to the patio table and started working out what I was going to take with me.

After considerable wrestling with the drivers for my rig-cat cable, reminiscent of my post Rig Cat Problems #3 and forgetting how to use my Elecraft T1 ATU, we finally got there! The next trick was to get this stuff packed down into a portable package.



Now this is a bit of a cheat as originally I was going to build a manpack based around M0PZT’s Porta-Frame which is a very cool idea.


The however comes in that when I priced up all the copper fittings, tubing, brazing torch, solder and flux I’d need to build one, it came in at about £4 cheaper than the FT-817/857 backpack I found on eBay. Don’t get me wrong I was all geared up to build one but here’s the thing. Expensive electrical items, by their very nature don’t take too kindly to moisture and being the UK, we have plenty of that. Just ask your 52″ LCD TV how it feels about standing out in the Great British weather for half an hour and I think you’ll get the idea. The backpack is fold and go, so when the heavens open, we’ve got some immediate protection. Also, the fact it has a ground sheet layer built into it means you can unfold and work without having to worry overly about the dampness of the ground. Everything folds down very cleverly and buckles tight. The storage pockets for cables and bits are a bonus and the rucksack straps make it instantly portable.



As this my first road trip, like any adventure, it’s worth overpacking! With a few elements of redundancy along for the ride my entire portable setup, minus my field mast, is packed in three small bags – an Aldi bag for life, a Bomber Barrel grip (best damn grip in the world!) and my FT-817/857 backpack.


All I need now is my BBQ contribution and we’re there!


Portable Operations #1 – Field mast

The objective for 2016 is to get out of the shack and into the wild with a radio. This has been on the agenda since day one, but like every idea there are teething problems, interuptions and cost implications!

That said we took one step closer today when I finalised my antenna mounting platform for use at field day events. This is a two pronged attack, giving me a mast I can mount an HF antenna on along with my BBHN node, which will give me Mesh access for WX, Cluster reporting and logging. While I mention WX have a look at this – blitzortung.org. It’s always useful to know how far away the serious trouble is!

So, on a bright and cheery Sunday morning I took a little trip to Fort Purbrook to see if my latest creation actually worked as it was based on a sketch and dimensions I was gifted and unfortunately I wasn’t able to actually get a hands on, prebuild examination of the trig point to get things straight in my head before I started hacking up my very limited supply of free plywood. Added to that, I have the woodworking finesse of dry rot, so the margin for error was slimmer than the shrinking exchange rate value of the pound!




In the words of Shrek, “That’ll do Donkey, that’ll do!”


When it drys out from the soaking with drizzle this morning I’ll give it a quick once over with yacht varnish to stop mould and the like setting in while in storage. The whole kit breaks down very nicely to a light weight bundle for transporting.

101 uses for a DVB-T dongle

I only got into Amatuer Radio proper in 2014 as a byproduct of something else I was playing with at the time. Some kit I was looking to buy carried the caveat of “may require an Amatuer Radio licence to operate on certain frequencies” and not wishing to end up on the wrong end of some draconian individual I decided to sort the licence side out first before shelling out my hard earned on my new toys. Somewhat naively I assumed obtaining a licence to operate radio equipment was similar to obtaining a licence to fish in common waterways. You know? Rock up at the local council office, flash your cash and walk away with a small square of paper saying you’re hot to trot. How wrong can you be?

Two years on and I’m slightly more educated and definitely finding radio more rewarding than previous ventures. Now when I landed in the world of the Foundation Licence learning it all seemed a bit abstract. I’m very much a learner by application rather than just being able to read and comprehend, so I wanted/needed a very cheap setup to play with to cement the theory. I wasn’t planning on being in radio land for very long (originally) so the cheapest way to do this seemed more appealing than ever.

I had a dabble with WebSDR to start with, especially Hack Green. Lets face it anything that says it’s based at the site of a previous secret nuclear bunker is going to draw the crowds! From there I fell for the idea of software defined radio and started reading, stumbling across RTL-SDR. What a resource that site is! Now I loved the idea of actually having a tangible SDR radio for the princely sum of 10 quid and invested.


Meet my first radio! So after working out how to use it and listening to the limited range of content, mostly commercial wideband FM broadcast stations I needed something slightly more challenging to have a play with.

RTL-SDR offers a whole host of projects for the humble DVB-T stick and the whole idea of ADS-B radar fired my imagination. Living on the south coast with a host of commercial and private airfields in the county, plus a multitude of shipping traffic bobbing past in the Solent, this whole thing definitely had legs.

Next thing you know I was making antennas for the sole purpose of receiving aircraft ADS-B beacon transmissions.


This is my massively successful quarter wave ground plane antenna built using the guide at ATOUK’s site. A copy is attached here for easy reference


Bearing in mind I didn’t have a Scooby what I was doing I was gob smacked by the increase in reception of my little receiver when compared to the supplied stock antenna. I was on a mission from then on! I took myself off to Nevada and bought myself some lengths of coax and spent some time fashioning various collinear coax and wire antennas and testing them using various software tools to plot their reception characteristics. Nothing I made beat the tiny quarter wave ground plane, it reigns supreme to this day in the ADS-B stakes! Unfortunately I don’t have any of my original work to share with you as I dumped it when I upgraded my PC, but it was good fun.

From there I added a Raspberry Pi to the equation to make a dedicated ADS-B server



followed by an ADS-B SAW filter to improve reception. I scoured eBay for the EPCOS 1090 MHz SMD device and fashioned myself a PCB.




Again, the improvement in reception was dramatic.

Next came the addition of a LN4ALL low noise amplifier



And all this to watch aircraft on a PC screen in a manner similar to an air traffic controller!


It’s a project I really need to resurrect when I get 5 minutes.

Since then my trusty RTL-SDR dongle has found itself playing a key role in a few side projects alongside other SDR and conventional radios. It’s a piece of kit everyone should own in my opinion!

So how about turning your phone into an SDR radio? SDRTouch for Android does just that. There are apps such as glSDR which give you WebSDR, but if you’re not on WiFi or 4G it’s a bit limited. SDRTouch takes your phone and allows you to plug your RTL-SDR dongle into it and gives you your own portable SDR receiver for the cost of 99p for the OTG cable from eBay.


And proof that it’s not just a fancy screen saver –

SDRTouch RTL-SDR test



Broadband HamNet (BBHN)

A couple of months ago FPARC circulated an invite to attend a conference hosted by Crawley Amatuer Radio Club (CARC) on the subject of Broadband Hamnet or HSMM-MESH as it was previously known. Now, always keen to experiment and learn I started doing some digging to find out what it was all about. To avoid regurgitating the Internet the origins of BBHN or HSMM-MESH can be found here and are explained better than I ever could.

In short BBHN takes a standard wireless router that you’d use in your home and re purposes it for more interesting stuff in the hands of a licenced HAM, who can use high gain antennas to achieve much greater distances. A 2.4GHz wireless router is utilising microwave frequencies (13cm) to achieve connectivity. As such we are venturing into the world of microwave networking.

A BBHN mesh is a clever thing. The routers or nodes are self discovering, self configuring and if a link breaks self healing, looking for other routes to get from A to B.


Now the fun really starts in that apart from using microwave, the mesh can be built up by conventional HF links and tunnel (VPN) connections.

There is a large following in America where this technology is utilised in disaster recovery situations. Having suffered tornadoes, floods and storms the BBHN or AREDN nets run alongside the emergency services and provide communication resources in areas where all the conventional networks are down due to disaster.

Now you can’t do this with any old router, the software is restricted to certain iterations of the Linksys WRT54G and Ubiquiti family, due to the open source nature of the project.


Not wishing to miss the fun I found an old Linksys WRT54G laying in the back of the garage which had previously been my ISP router, dusted it off and took the plunge. Configuring it as a node was as simple as flashing it with a new firmware. On rebooting I was rewarded with a simple config screen requiring a callsign and that was about it, we were officially MESHing.

Screenshot 2016-03-26 12.29.57

OK, now what? Good question. A MESH network isn’t a network until it can talk to something else, so having a solitary node sat there meant we weren’t going to see or learn a lot in a hurry.

A few weeks later, the CARC presentation came and went and boy what a learning curve! There are some seriously clever people playing with this stuff and when attending delegates fly in from Europe for the few hours of the presentation and fly out, you know you’ve got some serious enthusiasts out there.

Armed with my new found knowledge, I set myself a little project.

BBHN MESH networking in the UK isn’t as popular in the USA. That said, there is a hub of interest on the south coast, especially having had cold call emails from people asking if I was still playing around with BBHN! I’ve got people with nodes both east and west of me, plus on the Isle of Wight, but they are too far away for RF connections without a bit of ingenuity. Also, if you want to grow an idea, there’s nothing better than getting a radio club interested.

FPARC have their club house at Fort Purbrook perched on Portsdown Hill with a commanding view of the south coast, Solent and Isle of Wight. There’s a trig point within the fort with an elevation of 96.624 meters. Bearing in mind Portsmouth is at sea level, you’re not going to get any higher than that, plus I’ve got access!


I know I’ve used this photo before but I absolutely love the view from up there and on a sunny day you can loose yourself in it quite easily.

So, the initial plan is to establish an RF link from the apex of my roof at home to that trig point where FPARC pitch their marquee and antenna farm on field weekends. I’ve got an unobstructed line of site to the fort so this really has potential. Admittedly this will only be available on certain weekends during the year but it’s a start. I’m sure with some diplomacy and correctly worded application I may be able to site something more permanent at a later stage, but first things first!

The trick has been to find suitable hardware to build this project with. Linksys units are end of life, but with a bit of tenacity and the power of eBay I managed to bagsy a few from America, along with a Ubiquiti Nanostation LocoM2 which will be my roof mounted antenna and node.

So the other weekend, having been given permission to play I threw everything in the boot of the car and spent a day at the FPARC field weekend playing with a couple of nodes and testing the water about sighting an antenna at the fort.


There’s my trig point, nestled in among the other antennas in play.


And there’s the view from the point. You can see where this is going! With minimal effort there could easily be an RF MESH connection which could push out to the other nodes sat in isolation in the local area as well as providing Internet connectivity to those at a Field Weekend for logging, weather predictions etc.


Anyway, moving on. After a successful day in the sun I did a bit of computer modeling regarding the elevation and line of site issues, which is even more encouraging.


After a few more days generally playing with things I managed to get the Ubiquiti node functioning as a server and I have VTUN connections to the wider word! I’ve got to say a big thank you to Ruud (PE1BTV) in Holland and Rob (2E0RPT) for their help with this as strange things were happening with the VTUN client which still hasn’t been resolved, but by setting up a server and hosting connections rather than being a client user, we have connectivity.

Screenshot 2016-06-11 10.52.52

Here you can see the connected nodes on the MESH.


I’m slowly taking over the dining room table with this lot but at the moment this is just the beta stage. Once everything is working properly, the Ubiquiti will be up on the roof and everything else will be in the rack with the other IT kit.

I had a look at getting my Ubiquiti node (the white one on the right) up on the roof of my house yesterday to progress the RF linking ready for the next field weekend. When I got to the top of the ladder, still 6 foot below the apex of the roof I discovered it wasn’t such a good idea to be up there and will be getting a company in to do that for me. I have no fear of heights, just a lot of respect for gravity when you’re on the top 3 rungs of a ladder which is flexing under your body weight and the concrete 25 foot beneath me!
That can go on the back burner for a while. In the meantime, I’m working on getting a server attached to my node so I can get some useful services available.

A Raspberry Pi is a useful tool for this application and having several laying around it didn’t take long to have one configured and serving a webpage of general information.

Screenshot 2016-06-11 17.58.22

A note for future reference, once again the Jessie distro of Raspbian played havoc and corrupted the SD card on several occasions before I reverted back to Wheezy and all was good. I’ve got recollections of similar grief with my NTP server!

As the device is running in a headless configuration I decided to have a play with Webmin to manage the Pi via a web interface. Initial indications are good.

Screenshot 2016-06-11 12.53.06

This project is slightly longer term and I’ve been promised a few WRT54G nodes from a friend along with an old Via Mini ITX motherboard which I can resurrect in a server capacity to replace the Pi, which at this precise moment in time is running pretty warm despite the low load on it which is a little concerning!

If you want to learn more about the whole BBHN/ARDEN mesh network a good place to start is Andy’s site where he explains his portable node build and potential applications. The ARRL publication High Speed Multimedia for Amatuer Radio is also worth a read. At £25 plus international postage it’s a bit steep. The £7 Kindle edition offers much better value for money!

QSB-01 (qrp-tech synchronous buildathon) #7 – Final Details – Custom Case Decals

Having spent a lot of time building my 1 Watter I wanted it to look half decent in its enclosure and had a good look around at my options for labeling up the case with something funky to do it justice.
As big a fan of the old Dymo labeller as I am, I’ve never been 100% happy with the finish I’ve achieved when I’ve used them. Although functional they’ll never win any prizes.

A bit of research unearthed the idea of custom decal printing. This is something I’d never even considered. Bearing in mind the number of Airfix models I built as a kid, it never crossed my mind that things in that department had evolved with the whole IT concept of “print your own”.

My favoured option would have been to use the media which you run through a laser printer to give the most crisp output, but not owning one and in a similar vane to the Dremel bench saw project, I wasn’t about to go and buy one for a single job, so left it in the hands of my Epson Stylus Photo R360 to see what it would do with the ink jet media.


Mr Decal Paper (real name not me being flippant) on eBay supplied the decal sheets and the instructions which made life a bit easier. You need to seal your printed sheet with spray varnish to prevent the immersion in water stage from causing everything to run off the page. A trip around the art section of The Range provided a solvent based product rather than a water based one which would have defeated the whole object.

I designed the decals in a combination of PaintShop Pro, MS Paint and MS Word. The dry run on plain paper was spot on but the actual print on the decal paper was less than polished. I’ve had this before with ink jet inks not wishing to play ball with media other than the massively overpriced product from the manufacturer. As Epson don’t produce a decal paper I’ve got to live with it.

Now despite my anticipation of thunder storms on a Bank Holiday weekend, the weather proved me wrong and in effect was perfect for turning the garden washing line into an impromptu spray bay.


My three coats took seconds to dry in the heat but I still gave it ample drying time between applications to prevent any mishaps.

The next morning brought judgement day along with an assessment of my ability to accurately cut things out with a slide cutter and pair of scissors.
Like the Airfix kits of the 70’s a quick soak in water releases the decal from its backing sheet allowing them to be applied.



Not bad for a first attempt! The instructions suggest a drying time of 24 hours or a spell in a low temperature oven to harden the decals dependent on the surface they’re applied to. I’m not sure my 1Watter would see the funny side of that!