Monthly Archives: March 2008

GB1DSG hosts Thinking Day On The Air 2008 (TDOTA)

We put up a single feed fan dipole for 40m and 80m at 65 feet which certainly hammered out a signal creating quite a pile up in the UK, particularly Sunday afternoon on 80m. We had no shortage of stations to talk to, so thanks all who hung in there waiting for an opportunity.The evening before, James and I held court through the night picking up ZL, VK, S and N America which is excellent and James’s first copy to VK on 40 meter band – this was very thrilling. Being a Scout Station – and being spotted continuously meant that we were creating quite a stir across the globe.

 

petroleum-jellyThe day itself was excellent; we had a different Brownie pack through the door every half-hour. Each pack would have a fun chat outside by me before watching the “Hello” film from the ARRL. It’s very American but I can’t find anything short and to the point that can replace this wonderful little blast of interest for children. RSGB, if you have something – please let me know since I would love to show something a little more English.

After the film, they went to Chris and did a kind of “appreciation of morse code” where they could all send their names too. Morse bracelets were new this year – so thanks to the individual who thought this up, I can’t remember who you were now – a Pink bead for a DIT, a purple bead for a DAH and a white bead for a SPACE. They thoroughly enjoyed this activity. If only I could get Cubs to sit quietly and do these little crafts!

Finally they prepared their greetings message and Tim just maintained a pile up the whole afternoon so that when we had some girls ready, he would chose a strong station to get a greetings message through. If there was time, we had our own QSL design factory to top it all off!

That afternoon, we talked to many stations – many had been Guides or Scouts and some even claimed that their first ever radio experience themselves was doing JOTA and TDOTA – so it was wonderful not only to hear those stories but also to let the girls climb over their nerves to deliver a simple message on the radio. It didn’t help when I explained that only the WHOLE world was listening! I’m a rotter :)

Although we were gratefully thanked by the Guide District, I must say that it’s a pleasure to share our hobby with young people. We’re slowly building some budding M3s and I’m really proud of our achievements at Dorridge Scouts. If you are one of us and you are reading this, then be proud of what we do – and make sure that your local community understands that being a Radio Amateur is not a thing of the past, it’s bang up-to-date and happening now, on your door-step.

73 DE M0MCX

Kenwood TS-2000 Remote Mobile Controller RC-2000 Review

RC-2000If you’ve been keeping up to date then you’ll know that I have chosen the TS-2000 as the primary radio on board our new narrowboat, “Wherethehell-Rwe”. At the helm (which is a dead give-away for my yachting heritage) I have specified the RC-2000 which should be rather fun to muck about with as I swan along at 3mph across the countryside. In English then, the TS-2000 will sit at the front of the boat near the bow and 60 feet away at the stern (the back.. or in narrowboat terminology, the steering position), I’ll be running an RC-2000 remote controlled head, remote microphone and remote loud speaker. Clearly I’ll also need a switching system up near the front so that I can also use my toys in the evening in the comfort of the boat.

Isn’t this a bit over-the-top, I hear you ask? Oh yes. For those visitors to the site who haven’t seen a narrowboat, they are the long, thin steel boats that sail the inland waterways and canals of the British Isles (they used to be made of wood). The canal system was started literally hundreds of years ago and squeezes through the cities of England, Scotland, Wales and Ireland. Clearly running a bloody great big HF antenna is completely impractical, which is exactly why I’ll hinge my Shakespeare Marine HF SSB vertical over to rest when we’re motoring. However I have purchased a small 4-band 10/6/2/70 antenna that will allow me to play CB, 10m, 6, 2, 70 and PMR446 from my steering position. This antenna pulls-n-lays so that we can crouch under trees and bridges as required. Of interest, modelling my Shakespeare 5300 HF antenna whilst it’s actually lying flat to the deck, does demonstrate a small RF bubble of around -15dbi for the low bands. This will mean I can make some contacts on 40m and 80m as I travel along. Thank goodness for a high-power CG5000 ATU that has just arrived that will couple the HF antenna to my radio for an all-band experience (http://www.hamradio.co.uk/acatalog/Am_TunUnits_MyDEL.html)

RC-2000

I had seen pictures of the RC-2000 on the internet and I always thought it was about the size of three cigarette packets. I was about 40-50% too big. It’s more like one and a half packets sitting end-to-end (maybe a whisker more but I’ve stopped smoking so I can’t judge too accurately!). It’s smaller than you imagine because you don’t often see marketing literature or google images with the RC-2000 in situ with another item like a microphone or something.

What’s in the box? You get the head itself and a pretty external speaker that matches the size of the RC-2000. The speaker is very well made and the sound is good, peaking strongly in the 300-3000Hz band for clear voice comms. Three main cables come with the box, a large microphone extender that has a CAT5 joiner near one end connecting a female and a male 8 pin mic extension together. I don’t know why they’ve done this? Maybe so you can squeeze the CAT5 plug through little holes in your vehicle? Frankly I’ll be cutting this part off and replacing with something properly grounded. You also get an external speaker lead and a 4 way control lead. It says in the manual that one end is a 4 pin RJ45 style socket and one end is a 6 pin, in fact this is slightly misleading. The 6 pin doesn’t have 6 pins – it has 4. However the confusion reigns because it’s the size of a regular 6 pin version but the two outside slide connections / pins are removed completely. The pin-to-pin layout essentially transfers all pins on the 4 pin plug to pins 2, 3, 4 and 5 of the “6 pin plug”. If you have come here from a google search, I trust you can work this out! You also get a bag of screws, three clip-on ferrites and a large beefy TS-2000 Mobile bracket. Lastly, don’t forget a neat mounting bracket for the RC-2000 and the remote speaker.

RC-2000

The initial fears of the size issue soon disappear when you plug everything in and switch it on. Menu 00 (Brightness) and menu 59 (Contrast) work here for both the head and the TS-2000 at the same time, so you may have to enter a compromise situation, particularly on the brightness – however you can program different “users” and each user can have a different requirement so whilst using the main unit, you can select user 1 and when using the remote, you can select user 2 (for instance). I was initially extremely disappointed to start with because I couldn’t fathom out how to increase the contrast until I hit upon the idea of menu 59. Working these two menus mean that you can get a really clear and cute display on the go.

Using the RC-2000 itself is very intuitive with lots of neat stuff tucked away. I won’t give you a complete run-down because that would be extremely tedious however be assured that I was up and running in seconds. Apart from the soft switches down each side and across the bottom, you are left with three control knobs; the main VFO which doubles up as a finer VFO by pressing once, then the twin squelch and volume controls which mirror exactly what the main TS-2000 does.

The soft switches work well. Bottom left is initially called A-1. Pressing it repeatedly changes the functions of the bottom buttons via deeper menus, A-2, A-3, and A-4. Holding it down for about a second gives you the B series of menus as described and finally holding it down again gives you the C series of menus. Inside all these, you are mirroring the functions on the TS-2000 in various ways.

Essentially, everything that you can do with the TS-2000, you can do with the RC-2000. I’ve had mine sitting beside me for 24 hours now, forcing myself to use it for everything from changing power settings through to recalling memories. It works well – and just for fun, I called QRP into Russia on 10w and scored a hit. Why QRP? I just thought it might be an idea. Don’t worry, I’ve gone off the idea already!

RC-2000

My only concern is the main remote head VFO and this worries me for two reasons. Firstly, in terms of pure usability: You can tune in 1KHz steps, so let’s take the 40m band.. One clockwise mini-click on the remote VFO takes you from 7.050 to 7.051 (there’s about 30 clicks per rotation). However, you can hear a station in between these two frequencies, so you need to tune to say 7.050.50. To do this, you need to hit the VFO like a switch and a small “TUN” legend comes up on the display. You then rotate and mini-click your way from 7.050.00 up the required frequency in steps of 10Hz, so that to get from 7.050.00 to 7.050.50. You’ll need to rotate the knob around about one and a half rotations (50 clicks) to get to 7.050.50.

However, the UP/DOWN keys on the microphone is a heck of a lot faster so if you’ll be running the stock mic, you can NET someone in perhaps better by using that.

The second concern is the quality of the remote VFO knob. It feels a bit cheap, perhaps fiddly but I’m spoiled with a number of FT1000 variants in the shack here and of course the TS2000. To be fair, there’s an element of chalk and cheese here – after all this is a remote head is extremely economical, attractive and functional – and fairly unique in the amateur radio market, it’s not a snap-off, it’s an additional piece of equipment that will either extend your shack in your home to perhaps a different room or to another wall in your shack. Of course, most will buy it for mobile work, and what a beast that would be? You only need to add SGC’s 500 watt amplifier and a CG5000 800 watt PEP auto coupler and you’ll be mobile QRO all-band for under £5k! Oh! You’ll need an 8 foot stainless whip :)

Marks out of 10? Well I was expecting to give this an 8. I really was. I thought it would be too big – and a display that needed some “imagination” to make the best out of it. However now that I’ve had it on test for 24 hours, I can honestly say that it’s now giving it a 9, only losing points on the VFO issue that I’ll probably get over in time anyway.

Go on, treat yourself – they’re great fun.

Callum.

Station Ground

Station GroundFive years after becoming licensed, I’ve finally got around to putting a formal station earth / ground in situ comprising 2 x four foot copper rods and a liberal amount of copper wire into the ground on the front lawn. Instead of cutting the last 8 foot off, I used a lawn edger and shoved the copper about 4 inches into the lawn until there was two foot left. Looking around wondering what to do with this, I spotted my massive hammer drill with 24 inch 20mm drill bit. Clearly, it was asking me to drill a hole into the lawn and shove the remainer into it! I did. So I now have 2 x four foot and 1 x 24 inch ground. No idea if this remainder will do any use at all. You never know.

They say one has to reduce the run of copper cable connecting the station to the ground as short as possible – and in this case, I’m running at about 8 feet prior to the first copper rod.

The bad news is that I managed to crack one of the 3 x 2 slabs outside the front door. Wendy is delighted because it means, to use the US expressions, we’ll have to re-model the front! Grrr.

Technically, I have no idea why this new ground will make a difference however my good friend Terry (G4MKP) put a load of copper in the ground a couple of years ago, connected everything to it and all his interference went away. Finger crossed, I might experience the same. I’ll connect up tonight and let you know.

Station Ground

[Later] Terry says that instead of connecting the earth to each grounding post, I should probably connect the earth to just one of the lugs. The thinking it’s unliikely for a single ground to induce a ground loop and in the case of a station “funny” it’s easy to disconnect the earth for problem solving.

The other thing he pointed out is that my bus-bar should be ideally gold :)

Yaesu FT-8800 TX mod for PMR446

I needed to mod my Yaesu FT-8800 recently. Be aware that the FT-8800 does not have have 6.25 kHz channel selection, the true PMR446 frequencies START the sequence at 446.062.50, which is channel 1 as in this table:

PMR 446 Channel Frequencies

  1. 446.00625 MHz
  2. 446.01875 MHz
  3. 446.03125 MHz
  4. 446.04375 MHz
  5. 446.05625 MHz
  6. 446.06875 MHz
  7. 446.08125 MHz
  8. 446.09375 MHz

So to listen for channel 1, you need to dial to the nearest you can get to, which would be 446.005.00. Channel 2 will be 446.020.00 etc. Obviously, set your rig to 5kHz channel selection (Menu #38).

FT8800 TX/RX modIdeally, you need 12.5 kHz channel selection starting from 446.006.25 which all Kenwood’s do (eg TS-2000 and Kenwood handies) however I don’t believe there’s a way to do this with FM only Yaesu Ham rigs.

Anyway, you want to mod yours? Here we go: Remove the screws on the top of the unit and lift it off, careful not to pull the loud speaker wires off.

Find the bottom right Resistor/Diode I took this picture, because I couldn’t find one on the net that was the detailed enough for my poor eyes! Remove the component on the bottom left, as shown in the red circle. Unsoldering this is lots more difficult than you can imagine when your eyes are having an off-day. In fact, I got it off by scratching the soldering iron around tying to find the blasted thing. All of a sudden it was gone. You can tell I’m no hardware engineer! I have no idea where it went – it just dissapeared. Could it have melted? Dunno.

Anyway, re-assemble the radio and power it up. It goes through a factory reset power-up procedure and away you go with a brand new radio. Well, it worked for me!

Tips from others: Use a low wattage soldering iron and a ground strap. I didn’t do either!

73

Callum.

How to build a proper Skyloop (Delta loop construction)

Well folks, I’ve been continuing my experiments with my two sky loops (closed loops of wire held above the ground at three or more points) and comparing them against various verticals. Sometimes the verticals win, other times the loops do. I’ve had 8m verticals and longer too. Today, I’ve put the 12m vertical back up (http://www.m0mcx.co.uk/?p=102) fed with my trusty SG230 coupler. I may add that anyone interested in fast antenna experiments should get one of these. A tremendous piece of kit. Matches anything.

SkyloopApart from the noise factor (loops are quiet), the vertical seems to make a better impact on transmit more often than not for DX, unless I’m into NVIS or near NVIS (500 miles or so). Even then, up to 1,500 miles, the jury is out – either antenna can win. Beyond 1,500 miles the vertical seems to do a better job most of the time – not always, however my loops are very low to the ground, maximum height of 7 meters. On 40m, I would say the vertical is a better antenna to have almost all of the time unless you need NVIS for local copying – and with the sun spot cycle as it is, you won’t get this for a while yet!

I used to have the opinion that loops were more often than not, cloud warmers. However let’s face it, so are almost all low-to-the-ground HF antennas. My interest was tickled recently when VE7HA mailed me an MMANA file of a very high (80- foot) 300 foot circumference skyloop that he had built with three very large trees. He claimed great contest results with this loop. I had a look at the plots. Yes, he was right.. Check this out, 10.4 dbi gain at 5 degrees to the horizon on 10m? On 15m band, we’re looking at 12.5 dbi at 7 degrees to horizon! On 20, it’s as good with 10.5 dbi gain at less than 10 degrees.

Skyloop Far Field PlotNow.. This is a very different animal to the Skyloops that most people build. If you want a pile-up generator, this is the animal to have. It fundamentally, takes all your RF energy and pancakes it low to the ground in various star shapes. Very Of course, you will sometimes null out the station you want but you could get really clever and change feedpoints with relays. But ignoring the clever engineering, this has changed my mind as to the effectiveness of a high skyloop.

Be prepared to get into some matching territory though, ideally an automatic coupler at the fedpoint with open wire feeder, or perhaps an olde-fashioned tuner in the shack!

Some day I will build one, I just don’t have the trees :(

(Years later: I did build one. They’re amazing).

73

Callum.

Antenna -v- High Wind

Movie IconWas I QSB this afternoon on PSK31? Probably!

(Can’t get video to play? Right-click and save it to disk first! Don’t ask :)

In the main, we’ve all heard that wind normally beats antennas when it comes to staying up. In case you haven’t ever seen a cheap fishing rod blank in high winds, have a look at this. I call it a 10m vertical, in fact this one is only 8m. The matching is done at the feedpoint with an SG230 and 9 raised radials. It’s a temporary antenna. I’m just testing it out for fun. The 12m beats this by a fair margin on the 40m band.Anyway, enjoy the little film!

By the way, don’t be fooled by the helically wound look. It is hardly that. Here’s a real helically wound vertical from a couple of years ago – and this one does tune on the 40m band without help from an SG230. It is directly fed with coax:

73

Callum.

Andrew Grid Dish 2.4 GHz

Last year, I became inquisitive and managed to take apart one of my Andrew Grid Dishes. They’re rather well made so it takes some patience and some sharp Stanley blades - along with an excellent first aid box! I nearly cut my finger off. Not the first time. My original intention was to replace the feeder directly with heliax to trim down the losses but looking at how they assemble these in the factory, I needn’t have worried.

You will see from the pictures (see link below) that these dishes are well made. I wonder what the goo that completely blocks up the tube that supports the dipole centre? It’s clearly some sort of water seal and I must say it’s completely over the top. It took a heck of a struggle to get the coax out.

These dishes are shipped in two halves along with the coaxial dipole mounting centre that bolts to the grid from behind. It’s possible to get the polarisation incorrect from the beginning. Notice in the picture that this one is vertically polarised. To change polarisation, you DO NOT change the plane of the dipole feepoint, instead you must rotate the dish through 90 degrees. Note that all fasteners are imperial dimensions, not metric. Don’t start losing nuts and bolts if you live in a metric country.

With a 23dbi gain and an 8 degree lobe of RF pointing in the appropriate direction, this is a serious bit of kit but please use low-loss coax; LMR-400, Westflex or if you must, RG213. Don’t use RG58, this is actually very HIGH-loss coax and shouldn’t be sold as low-loss at all. The losses at 2.4GHz are tremendous and you could easily see most of your signal wasted in the coax. The dish is terminated in an N-Type connector on a flying lead with RG-213 type coax. Point-to-point, you probably can’t do better unless you start to spend astonishing amounts of cash.

James and I will try and give a pair of these a test in the summer from Monument hill to the Scout hut – about 10 miles. Apparently a breeze. The world record is for an un-amplified signal is something like 150 miles!

Callum.

Shakespeare Marine 5300 HF SSB Antenna update

I was very excited about taking delivery of my 2-piece 5300 Shakespeare Marine SSB HF Antenna for my narrowboat this week.

IMG_8483Close inspection showed that the antenna is a 2-piece 28’6″ (8.5 meter or thereabouts) white fibreglass hollow pole with a 2 foot aluminium heavy-duty sleeve at the base for mounting purposes. This main lower section (of around 17 feet or so) has three elements running the full length embedded inside the fibreglass at time of manufacture from the side feed to the top, in 120 degree arc segments. A heavy-duty male screw fitting at the top, electrically connects to the top section’s female thread.

Since the wind had died down this morning, it was an ideal opportunity to take down the 40 foot vertical and replace it with the 5300 as a test. I inserted one of my light duty aluminium poles up inside the aluminium housing approximately 12 inches in depth to where the fibreglass stopped inside the sleeve (from the other end) and I raised it to the vertical by walking up the antenna from the pointy end until it was raised vertical. I then lowered it using the same technique.

 

Lowering it at around 45 degrees, the fibreglass groaned, cracked at the sleeve point and fell to the ground.

Clearly, there’s a flaw just above the aluminium sleeve. A one-in-a-million manufacturing defect.

I’ve written to shakespeare and await their reply.

[Later] On Monday morning, I was emailed by their UK sales department explaining that another 5300 would be shipped immediately. This is the first time one of these has ever broken in the history of the 5300 antenna production and clearly this is a freak. Good news Shakespeare, thanks.

Callum.