Monday, 28 July 2014

Back from Skye


It is back to the real world after a great week in the Isle of Skye with almost constant sunshine, temperatures topping 28°C (83 °F) and very humid conditions. Some great walks with the wife and the dogs to some new locations, the highlight was watching a school of porpoises playing in Loch Bharcasaig.


The cottage was booked last year primarily for our holiday requirements with no thought of radio operating as this has come later. As I feared in my previous post my unpreparedness meant disappointing operating as 2M0NRD/A

Located on the main tourist route up the Waternish peninsula I didn't want to have any unsightly aerials up at the front of the property. It is situated part way up a hill side and knew there was a wooden fence at the rear and to the right separating it from the neighbouring croft. I had taken a couple of 6 meter long fiberglass poles which I could bungee cord to the fence and then string the OCF dipole between them or alternatively use one of them to hoist the M0CVO Magitenna as a sloper. These poles and wires would be largely be obscured from view by the cottage.

The rear fence runs north to south, meaning the main lobes of the antennas would be to the west and east, not ideal for any ‘inter-g’ UK operating, so I had planned to use the side fence. What I hadn't spotted on the photographs was the overhead power line running on that side of the property. I could have put them up but opted for safety and used the rear fence.


I set up base in the spare bedroom at the back of the cottage but I really didn’t get to operate very much. We were out and about during the day and I did dabble on HF for an hour or so on some evenings. I could certainly hear a lot more than I do at home with very little noise and had some very strong signals coming in. I made a few QSOs but other than the contesting I am still finding my feet as an operator and being mike-shy I find the HF bands intimidating. I struggled to find a free frequency but did call CQ on 40m and 20m but with no response even after several minutes, eventually giving up as I was invariably swamped by another operator.

Last week was also the start of the 2014 Commonwealth Games in Glasgow, not only did I see some of the stadiums and venues while driving up to Skye but I also heard the special event station GA14CG operating out of Stirling on 40m some evenings. It was a huge S9+ signal and despite several sustained attempts I was unable to break the pile up. Seems they were beaming south and being north of them in Skye I stood little chance being at the back of their Cushcraft X-240 with just 50W and my OCF dipole being end on in their direction..!

Having holidayed in Skye before I was aware of the terrain but having surveyed the cottage using Google Streetview it seemed nicely situated. Upon arriving at the cottage it became apparent that the mountainous terrain was a bit more imposing than Streetview had shown, so not unexpectedly the 50MHz UKAC on the Tuesday evening was a disaster!

I spent the best part of an hour tuning around the band, occasionally hearing faint voices in the static but nothing legible. I vainly called out “CQ Contest” for a while but nothing was heard, even using the tuned dipole – even if I had managed to build the planned Quad beam it is unlikely I would have fared any better. 

The cottage was meant to have broadband and Wi-Fi facilities but a fault meant this wasn't working all week, coupled with no mobile phone signal left me feeling cut off, ironic really given the founding principle of amateur radio communication. I did do some digi-modes but without an NTP connection the error in the laptop clock (several seconds a day) meant I was initially too far out of synchronisation for JT65 or WSPR until I realised I could use the clock on my Garmin GPS which I use for geocaching. Doh!

It is likely we will be going back next year and hopefully will be a bit more experienced as an operator and will be more prepared. 

Oh and here are the porpoises I mentioned earlier

Wednesday, 16 July 2014

Skye Activations? Remember the 7 Ps!

As the military adage goes "Proper Planning and Preparation Prevents P*** Poor Performance" well I have fallen foul of this in getting ready for my imminent holiday to the Isle of Skye.

Last year we went back to the Isle of Skye after our first visit over a decade ago.  We rented a self catering cottage near Dunvegan and a great time. The scenery (and the whisky) is spectacular and the dogs loved it, so we decided to go back this year. 

The cottage
The view from the cottage
The tasting experience at the Talisker Whisky Distillery
The cottage is no longer available for holiday lets, but we have found another which promises even better facilities. Last year I wasn't licensed, so this time I planned to take the rig and operate from the island.
  
The holiday coincides with the 50MHz/6 Meter UKAC contest and the opportunity to operate from the rare IO67 locator square was something I was looking forward to, I was totally realistic as to my chances given my set up, the terrain and power restrictions.

IO67 Locator Square
I planned to build a quad beam, there are plenty of designs on the web and ordered some fibreglass pole to make the spreaders but over the past few weeks have got sidetracked and left the construction till the last minute and it has turned into a disaster!

I abandoning the idea of a multi-element quad beam once I realised the sheer size it would be and the lack of space in the car and so opted to make a manageable two element quad.

I modelled up the antenna in MMANA-GAL to check the dimensions, made a nice short wooden boom, and cut the fibreglass pole for the spreaders, initially cutting them all to the wrong length! Cue expletives!

So I cut another set to the correct length and made the wire loop elements and tried to put it all together. Unfortunately the fibreglass spreaders are far too thin and bend and sag under the weight of the wire! Cue even more colourful expletives!

Plan-B is now just a simple tuned dipole and all I can hope for is some Sporadic-E on Tuesday evening!

I am packing the HF antennas a Magitenna and the HW-20HP from Nigel at M0CVO Antennas. I haven't done a great deal on HF finding the operating a little intimidating however I will endeavour to be on air during the week having realised in the last couple of days that I can 'activate' the island and some 'rare-ish' grid squares for the Worked All Britain (W.A.B) scheme, as well as 'activating' for the Island On The Air (IOTA) scheme. I might convince the wife to let me take the rig portable on a planned trip across to the Isle of Raasay for another activation.

With just 48 hours left I am rapidly reading up on what I need to do... as my wife pointed out I have had weeks/months to prepare for this... the 7Ps indeed!

If I do get on the air as 2M0NRD/A or 2M0NRD/P during the week please be patient and treat me gently! I will be on voice and maybe JT65 and PSK. The cottage has wi-fi so will post updates on my twitter feed @nerdsville.

Wednesday, 9 July 2014

Antenna Update

Tuesday night is RSGB UKAC contest night, this week on 432MHz. Following the frustrations of the weekend I spent a therapeutic Monday evening cutting various lengths of RG213 and fitting N-Type connectors.

I have now got a coax run through the wall into the shack, with another to follow soon. To facilitate 'switching' between multiple aerials I have fitted each aerial with a length of coax running down the pole, terminating in an in-line N-type socket near the base. It is a simple case of connecting the appropriate shack coax, fitted with a n-type plug, to the appropriate socket.

To keep everything water and weatherproof I have opted for a DRi-BOX. These are inexpensive plastic boxes sold as waterproof housings for outdoor electrical installations such as garden or Christmas lights.




The lid has a silicon seal and there are a number of cable entry points with a flexible seal. When the lid is firmly clamped securely in place the box is effectivly watertight.


It is a bit of a fiddle with the thick RG213 but it seems to work well. There was a vicious thunderstorm and downpour yesterday afternoon and the Dribox lived up to its claims after sitting in a few inches of water.

Still awaiting the X-50 collinear on the top!
The pole now has the 2M Yagi and the 70cm 7-element ZL-Special fitted. The 70cm aerial is far from optimal but I was looking forward to giving a go with some decent coax.

Tuning around prior to the start of the contest and the band seemed quiet, hearing just a strong local operator. The contest start time passed and I was met with a wall of static only hearing the occasional very weak signal. I tried unplugging and reconnecting plugs, new patch lead, took the VSWR/Power meter out with no effect after 20 minutes I gave up. I decided something was obviously wrong with my new installation at the top of the pole.

I went back into the house where the wife was watching some dreadful house/diy/makeover program on TV which I could only manage for about 15 minutes. Grumpily I went upstairs and fired up the FUNCube Dongle and twitter and realised I'd forgotten and completely missed the first pass of the newly launched UKube-1, unlike some lucky ones. Idly I tuned to 70cm using the discone in the loft and could see a waterfall of signals! Including that local operator with a lot of splatter considering he was running just 10W


Going back into the shack and things had improved, so perhaps it wasn't my setup! After missing nearly a hour I searched and pounced again, just making 14 contacts but achieved my highest score so far for a 432MHz UKAC contest, still operating as M6GTG in the low power section.



Various operators have commented on the weird/poor/flat conditions last night, so perhaps I shouldn't have been so dismissive of my ability to put up a decent antenna!

Monday, 7 July 2014

The best laid schemes o' Mice an' Men

To quote Robert Burns
The best laid schemes o' Mice an' Men, Gang aft agley,
An' lea'e us nought but grief an' pain, For promis'd joy!
That sums up my weekend perfectly.

After becoming licensed my eagerness got the better of me and in a moment of weakness I'd purchased a couple of 10m ready made cables from a major supplier only to discover quite quickly they were made from low grade RG58 coax (you can literally count the number of strands in the braid) and the connectors while serviceable were so poorly fitted they fell off!

James that PL259 has fallen off again!

I had refitted the connectors using some solder this time and had managed to blag a 20m length of good quality RG58 (this actually has some braid) and I am ashamed to say these cables have been the weak link in my set up for far too long and needed to be upgraded.

I also needed to sort out the mounting for my aerials. Up till now I have been using a 5 meter telescopic painting pole that had cost around £16 from B&Q, it was okay when I was just clamping one aerial at a time to it but with the purchase of the rotator I has been chancing my luck with the loading, narrowly avoiding catastrophe when pushing the pole. I also couldn't fully extend the top section as the tube and joint were potentially weak. It was guyed quite well but was far from aesthetically pleasing, even in the summer sunshine!

6M Moxon up on temporary pole
I couldn't fit anything to outside of the house, not only for logistical reasons but also it wasn't sanctioned by the station manager. Anything on the side of the house would be highly visible from the road and the back wall of the house has too many large windows and an extension making it inconvenient to fit and access anything.

Never fear I had a plan, a 20ft (6m) scaffold pole bolted using swivel joints on to to an another pole concreted in the ground in the back garden. The garden was extensively landscaped a few years back but it was before I became licensed, so I hadn't planned ahead. With careful negotiations with the station manager I secured a location where I could put it.

Thanks to my local handy man I now have two 10ft scaffold poles, sunk to a depth of nearly 5ft and encased in concrete in the corner of the lawn. A few inches of soil was left on the top to allow the grass to grow. They have been left for over a fortnight to completely set.

Scaffold pole sunk in ground

I ordered a 100M reel of RG213 coax from Nevada Radio along with plenty of high quality N-Type connectors and various clamps and intended to sort out my antenna set up this weekend and banish the abysmal RG58 coax and PL259 connectors to some dark corner of the shack.

Before I took everything down on Saturday I managed to make contact with GB0TDF the special event station being run by the Denby Dale Radio Society from Cartworth Moor, Holmfirth for the Tour de France Grand D├ępart

A few months back I picked up a cheap rotator at the Dambusters Hamfest. It is designed for television aerials and isn't heavy duty but I was sure it would cope turning with the small 2M, 70cm Yagi and a 6M antenna on the same pole, with the X-50 collinear on the very top. However I was concerned by the potential lateral loading.

The rotator is a generic design and I spotted that an optional support bearing is available as an accessory. I chanced on one via Ham Radio Deals and had salvaged several good lengths of galvanised pole from a skip where I work. So the plan arrangement was as shown.. simple right? 

Planned arrangement

It turned it a frustrating morning after cutting the metal pole to length, bolting and clamping everything together I tested it at ground level with no antennas and the rotator refused to turn correctly and I narrowly avoided burning it out.

I checked poles and they were true, the rotator was free running as was the bearing. I unbolted, fettled and just couldn't make it work. I went away and had a beer while watching some of the Tour de France on the TV and in a moment of clarity realised what the issue was.

The problem was the diameter of the salvaged pole I was using. It was was slightly narrower (a couple of millimetres) than the hole in the bearing. I'd assumed it would line up with the rotator as it was similarly clamped, however when all clamped up top and bottom the pole wasn't perfectly perpendicular and wouldn't turn due to the eccentricity, Hopefully the drawing illustrates the problem.


Annoyed by this basic school-boy error I reverted to Plan-B for the short term, no support bearing! I was in bad mood now and so decided to leave the rewiring to another day. So I quickly put the 2M yagi on the existing coax as a test on the new scaffold pole to make a few contacts for the VHF NFD.

Temporary installation to test scaffold pole

Walking up the scaffold pole is straight forward, I have bolted a small cut off of scaffold across the top of support poles to act as a safety stop, lowering it likewise easy and I will certainly build up the muscles!

I managed to grab just 8 QSOs but was otherwise engaged for the rest of the weekend, however I was encouraged by the distances.
I hope to get the 70cm antenna up tonight on the RG513 ready for the 432MHz UKAC on Tuesday evening.
The birds like the new setup




Wednesday, 2 July 2014

Grantham ARC HAB Talk

Yesterday I gave my talk and demonstration at the Grantham Amateur Radio Club on High Altitude Ballooning and tracking.

This follows on from the South Kesteven ARS (SKARS) and the Spalding and District ARS (SDARS) talks I gave in May

It was very well attended with a large number of GARC members turning out. It was a case of everyone going in at the same time once the venues key holder turned up and I initially got a little stressed as I hurriedly tried to get everything set up while everyone sat patiently waiting.

Picture by Kevin Burton

The first issue I had was the projector seemed to be limited to just 800x600 pixels, which was fine for the PowerPoint presentation but for demonstrating reception using a RTL-SDR with SDRSharp and decoding using DL-FLDIGI and the UKHAS Habitat tracking system spacenear.us/tracker the lack of screen space was a problem, DL-FLDIGI couldn't be shrunk down to fit, so there was a lot of scrolling about!  

The second issue was the venues wi-fi connection, my laptop stubbornly refused to connect to it (I wished I'd taken a ThinkPad laptop I have instead of the one I did as it has a better wi-fi adapter) so was forced to use my mobile phone as a tethered hotspot - while it worked the connection was painfully slow.

Despite these issues I was able to give the presentation about the HAB community and the technology. It contains a lot of information to digest but there is some light relief with its videos of Felix Baumgartner, Dave Akerman’s Babbage Teddy Bear free fall and wacky chef Heston Blumenthal's ‘Spud-in-space’ feature from his recent television program.

I demonstrated Project Hab's VAYU-NTX tracker and thanks again to Steve Smith  (G0TDJ) for its loan.


I ran my own prototype tracker (NERDTEST) which I had updated to simulate a local flight, the transmission, reception, decoding and uploading to the UKHAS Habitat system was completely genuine, both using SDR and a traditional radio (Alinco DX-10) hooked up to the sound card. The only thing fictitious were the GPS coordinates and altitude.  (A programming error in the first version of this simulator had the balloon travelling at near 10km/s, thankfully I had corrected it to something more realistic)  

The poor internet connection cause issues with spacenear.us/tracker but was able to use Phil Crump's (M0DNY) version at at habmap.philcrump.co.uk to demonstrate the real time map tracking.

Checking the spacenear.us map this morning and the receiver station at the club house and the demo flight could still be seen - it was programmed to take off from a nearby high point!



By lucky coincidence Chris Stubbs (M6EDF) had launched a balloon CARS-1 from the Chelmsford Amateur Radio Society meeting at Oaklands Museum where he was giving a talk and demonstration at the same time as my talk, so I was able to show how multiple receiver stations were tracking a real flight.

I was also able to demonstrate SSDV image decoding using some recorded SDR files of the HiPi flight

I thought I had overloaded the attendees with too much information, lots of references to Arduino, Raspberry PIs, SDR, dongles, GPS could be quite daunting to the uninitiated but again feedback has been very positive. Grantham Amateur Radio Club on Facebook

Now I just to sort out doing a proper flight!

Wednesday, 25 June 2014

Noises Off!

Radio frequency interference (RFI) is the bane of a lot of amateur radio operators. Sadly it is becoming a real issue at my QTH.

RFI is referred to as QRM or QRN and I am learning the difference.

QRM means "I being interfered with" and is interference coming from someone using radio equipment. This covers deliberate jamming, people tuning up or just normal operations on a crowded band that causes QRM.

QRN means "I am troubled by static" and technically means interference from a natural noises but has come to refer to interference coming from anything that is not an intentional radio emission and interferes with reception of transmissions. So now covers atmospheric noise, static or the noise generated by electronic devices.

Noise isn't a new issue here as I have posted before. It has tended to be sporadic and bearable but since becoming licensed I have become more sensitised to it. Until now I have tended to focus on the VHF/UHF side mainly contesting venturing only briefly onto HF.

My HF set up is limited at the moment with just a single antenna which isn't optimal for the lower bands. Due to the day job I am largely restricted to evening/night time operation when the upper bands have largely been closed anyway so haven't really attacked HF with much enthusiasm apart from data modes such as JT65 and WSPR which have immunity to noise.

When I have got the chance for some early morning daytime operation or at the weekend I have struggled with noise.  Recent weekends have seen some special event stations operating for the Museums On The Air and the GB1JSS Summer Solstice which have been predominately on the 40M band but I just cannot hear anything on that band due to noise.

I am aware the Sun has been particular active recently producing a number of large flares and CMEs that have caused a number of radio blackouts, but this noise isn't due to atmospherics I am certain it is man made by one of neighbours.

I made this video last weekend


and this video was from the weekend before that


This weekend was the 50MHz Trophy Contest which I was looking forward to, sadly it was also to become a victim of the QRN as this screenshot from my SDR will confirm, for much of the time I was operating I was just listening to noise.



I wasn't operating constantly, just grabbing a few minutes here and there and I did manage to make some decent contacts when the QRN subsided even catching some of the sporadic E opening to get EF7X in Spain.



I have ruled out any noise being generated by myself by powering everything off and running on battery. This leaves me in a bit of a quandary I could go around and locate and confront the culprit or even contact OFCOM but at the same time I don't want to antagonise anyone who could then object to any antennas I might want to put up in the garden.

Rotating the 6M Moxon around at the weekend during the contest as at least pointed me in the direction of one strong noise source. I am also convince that much of my problem is due to an evil PLT device in an adjacent property.

Following on from the weekend last night was the UKAC 50MHz contest and yet again I was troubled with noise leading to mostly local contacts.



I have been looking at some of the noise cancellers that are available from MFJ and others. I have heard conflicting options on their effectiveness but I am willing to try one if I can obtain one cheaply, or even home-brew one from the numerous designs available.

These devices work by using a second antenna which receives just the noise which is then mixed out of phase with the main antenna signal hence nullifying the noise. By all accounts they are tricky to use and often  need constant adjustment but may be my only viable solution at present.

Monday, 23 June 2014

Using the Ultimate3

I have dusted off the Ultimate3 QRSS beacon kit that I built earlier in the year while a foundation licensee. Having progressed to a intermediate licence I can now operate something I've constructed.



Until now it has been attached it to a dummy load with the FUNCube Dongle Pro+ SDR in close proximity as a receiver for experimental purposes.

One unresolved issue was it being consistently off frequency. The DDS modules used are prone to temperature fluctuations and component variances so the Ultimate 3 has the option of using a GPS module to provide both an accurate time source and an accurate 1PPS input which can be used to self calibrate. Except in my case it had proved to be unreliable.

I am using one of the inexpensive GY-GPS6MV2 modules containing the U-Blox chipset I posted about previously with the additional tap off to provide the 1PPS TTL signal.

Initially the GPS module was connected in close proximity to the Ultimate3 but struggled to maintain lock probably due to interference from the DDS module. Even when lock was achieved the calibration never seemed to work. I posted a question on the yahoo support group and from the answers I verified the calibration setting were correct so the only likely culprit was the quality of the 1PPS signal.

The serial NMEA sentences and the 1PPS signal from the GPS are likely to be required in other planned projects, such as an 'shack clock' and a GPS disciplined frequency standard. So I decided to put the GPS module  into a waterproof housing that can fitted on the shack roof in clear view of the sky and away from any potential interference. A multi-cored cable supplies power and the TTL RX/1PPS signals being fed back to the bench.

Sourcing an inexpensive weatherproof enclosure (£2) and waterproof cable gland were straightforward enough. I mounted the GPS module on a piece of strip board and replaced the on board LED with one mounted in the enclosure so I easily determine if the GPS had achieved lock, since it only flashes when it has. The LED is sealed with epoxy resin. It should be noted that the outputs of the U-BLOX chip are only rated at 10mA so bear it mind when selecting an LED and calculating the current limiting resistor. The connecting cable is some surplus unscreened alarm cable fitted with a couple of ferrite clamps.


The GPS now has no trouble achieving lock and quickly sets the Ultimate3 clock. Researching the 1PPS problem I hadn't come up with anything definite, as the signal looked okay on the oscilloscope. But I decided to fit a 10K resistor pull up resistor between the 1PPS output and the 3.3V supply on the GPS module. If this actually made the difference I have no idea but the Ulimate3 now successfully calibrates the DDS using the GPS.

At the moment I have configured the beacon to run WSPR and I have been spotted by other operators. Initially I wasn't getting much RF out of the device and it turned out to be a combination of poor connection caused by me not removing the enamel properly on a toroid winding and an iffy antenna connector. Both have been corrected and now get a measurable deflection on the SWR/Power meter. With the additional of a second power amplifier FET it is around 200-250mW.



I purchased the Ultimate3 with a low pass filter for the 40M band and while I have had some European spots the results have been a little disappointing. 40M has turned out to be almost unusable at my QTH due to QRN/M so not sure if that is having an effect, also the antenna I have isn't naturally resonant on 40M so is going through a tuner which will certainly be introducing some losses, without the tuner the FETs get very warm!

With this in mind I have purchased some additional LPFs for the 30M and 20M bands and the LPF relay switching board for the Ultimate 3 so can try/run multiple bands.