AmateurRadio.com

Today I replaced the home made 2m Moxon Rectangle with a Vine Antennas SuperMoxon. As you can see from the picture of it installed in my attic it is a Moxon Rectangle with two directors that are also folded into a rectangle.

My attic, like my house, is very small. As is usual with modern British houses, the roof trusses are made of thin wood with cross-bracing for strength, so the attic area isn’t open to allow the free rotation of antennas. I have crammed rather a lot of antennas into this space to try to cover the maximum number of bands, so the VHF antennas have been forced into odd corners. Using a conventional small beam is not possible as there is insufficient space to allow rotation.

Vine Antennas claim that no other antenna gives so much gain in such a small turning circle, so it seemed like an ideal design for this situation. They claim that the directors add an extra 3dB of gain to the Moxon Rectangle design – about 9dBi which is more than a three element Yagi.

The antenna was quite expensive to buy. It is quite rugged and heavy but looks a bit home made. While the driven element and reflector made use of Jubilee clamps to tighten the main elements on to the smaller tubing used to form the corners, the directors used self tapping screws which had worked loose in transit (and probably would work loose in use due to wind vibration) and which stripped the inner hole when I tried to tighten them. You are left to your own devices to find a way to weather proof the feeder connection. Since my antenna is going to live a cosseted life away from the wind and rain I was not bothered by these issues.

The antenna presents a 50 ohm load but needs a balun to prevent feeder radiation. Vine Antennas offers a choke balun (apparently several turns of coaxial cable held in a loop using cable ties) for an extra £15. I decided to do without this, but I placed a clamp-on RFI ferrite over the cable close to the feed point which will hopefully achieve the same result.

The SWR is almost 1.0:1 at 144.0 MHz, as the plot from my AA-200 antenna analyzer shows, but it rises steeply to 1.4:1 at 144.4MHz and 2:1 at 144.8MHz. Clearly I had better not use this antenna to work satellites.

It’s a bit early to say how performance compares with my old Moxon Rectangle. The beam width does seem sharper and the front to back ratio seems quite noticeable. I heard the GB3VHF beacon for the first time since it moved to its new location, but it is in and out of the noise on slow fading as it always used to be. I can clearly hear the Northern Ireland beacon GB3NGI, which curiously is the same strength on the SuperMoxon as it is on the ribbon cable Slim Jim (which is also due for replacement with a commercial antenna.)

This antenna is probably as good as I am going to get given the restricted space available. The SuperMoxon design is copyright Vine Antennas and commercial reproduction is prohibited, which should be borne in mind if you try to make your own version.

I just got round to checking the Sport Radio page of the May RadCom so as to transfer to my wall calendar the dates and details of any contests I might be interested in making some contacts in this month. I happened to notice that the exchange for the 144MHz Contest on 15/16 May is RS(T), serial number, grid locator and post code.

Post Code??? What’s the point of that? And what if you are operating portable from a hill somewhere and don’t have a post code? Daft idea if ever I saw one.

I’m not paranoid, but I think everyone is out to get me!

I ordered some connectors from eBay seller m0jpm and, because I have been thinking about getting a radio that has N type connectors on it, I decided to order a couple of BNC to N-type adapters so I could use the much easier to obtain BNC plugs on my antenna cables. The listing I ordered from is shown below.

The package arrived this morning and when I opened it, to my dismay I found that the adapters were the reverse of what I wanted. As you can see, they are for attaching N-type plugs to BNC sockets.

It has sometimes happened that I ordered the wrong thing by mistake, so I was relieved when I checked the eBay listing and saw that this time it was the seller’s mistake not mine. But my relief turned to anger when I emailed the seller to inform him of the error and received the reply: Dear g4ilo, Hi we have send you what you have ordered, as this is the only n-type to bnc we have listed. but if you not happy send it back for a refund.

Is it really necessary to insult my intelligence by telling me “we have send (sic) you what you have ordered”? I will send the adapters back for a refund (and no doubt be out of pocket for the postage) because they are no use to me. But I shan’t be buying anything from m0jpm again.

In a comment to my previous post Ricardo CT2GQV said that I should give up buying on the Internet. I wish I could, but if I did I would have to give up the hobby because it is not possible to buy radio stuff round here.

A few weeks ago I set up an experimental low power EchoLink node for use as a personal EchoLink “hot spot” using my FT-817 and a dummy load. I planned to make a a dedicated transceiver / computer interface for this. I thought I found the ideal basis for the project in this UHF Micro Transceiver Module from Elcom Research, a Greek company that makes packet radio and APRS products. The transceiver runs on 5V and can be powered by a computer USB port.

Perhaps I should have been warned off by the fact that an enquiry made through the web form on the Elcom site went unanswered, but I went ahead and ordered the module on 9th April, paying online using PayPal. After a couple of weeks nothing had been received, so I sent an email enquiry and received a reply that it had been sent by air mail and should be with me by the end of the week or the beginning of the next one. This was during the flying hiatus caused by the Icelandic volcano, so I gave it a bit longer. However it is now a week after the week that the module should have been received at the beginning of, and a further email received no answer at all. It looks unlikely that I will receive the module at all, so I guess my only option is to initiate the PayPal disputes procedure.

Not much happening today. I have been WSPRing on 10m with 5W but heard nothing and have been spotted just once – by OY1OF on the Faroe Islands.

Yesterday evening I was receiving EA4SG in Spain but he was running 20W. I upped my power to a similar level, and was spotted by G0HNW and M1AVV in the early evening. I left the system running all evening but after it was dark I noticed my neighbour’s security lights were coming on at the start of my WSPR transmissions. Not good when you are trying to maintain a “stealth” station!

Before I started with WSPR today I got out the old DOS laptop and the Motorola programming software to make a few changes to my GP300 configuration. I reduced the squelch threshold slightly, reduced the power from 6W to 5W which should help the battery endurance more than it will affect reception of my signals, and I programmed the radio for 16 channels.

Now there are 16 channels it’s difficult to remember what they all are so I made a paper scale to go under the tuning knob which shows the 2m channel numbers or repeater calls. I had to use the magnifying headset to do the very small lettering and I can only read the scale with my reading glasses on – which I don’t when I’m out and about. But I couldn’t read the channel numbers on the original dial scale either so I’m not actually any worse off. I used to have great eyesight – this is what happens after spending most of your life in front of a computer!

I spent the morning building this constant current charging circuit on to the circuit board of the junk Motorola charger I bought on eBay. I also made a power lead so that it is powered by my K2 power supply, eliminating the need for yet another wall-wart. The charger was supplied with a UK type switched mode power supply rated at 12V 1000mA. In view of the “quality” of the charger itself it is unlikely that I would want to use the wall-wart that came with it for anything, but surprisingly when I tested it I couldn’t find any obvious interference. As I have said before, the electrical noise level here is so high that something would have to be pretty bad for me to notice it, but that was a device which I expected to be pretty bad.

As I was checking the bands for new unwanted noises I heard a CW signal on the 6m band. That turned out to be EB1EHO, whom I worked for my first Sporadic-E contact of the year. I spent an hour or so on the band and worked several stations on the west coast of Spain and one in Portugal, CT1ANO.

As you can see from the DX Sherlock map, the reflective Sporadic-E cloud appeared to be located somewhere over South Wales. I did hear a Scottish station working EA6/M0DLL on the island of Menorca. The DX was right down in the noise and not copyable on my dipole but might have been workable if I had a beam. So clearly there was Sporadic-E about elsewhere.

This opening was a nice treat for a Bank Holiday and I hope is an indicator of things to come this year.

I’ve bought loads of radio and electronic stuff from Hong Kong and China on eBay and most of it has been okay. But I’ve had the occasional duff purchase, like the stubby dual band antenna allegedly made by Diamond which I’m pretty sure was a fake.

I bought a Motorola GP300 radio body at the Blackpool rally a couple of weeks ago but I needed accessories like a battery pack, charger and speaker mic. Ebay was the obvious place to look for them. The 1800mAH NiMH battery pack was fine, and a good price. The speaker mic is obviously a clone of the original Motorola design but a lot less solidly made, but I have received good audio reports using it so no complaints there. However I was a bit suspicious about the “overnight charger” purchased from RadioFactory because after 6 hours of charging the battery pack was really hot.

The GP300 battery ran out while I was on Watch Hill this afternoon so I need to charge it back up, but before I do I thought I would take a look inside. The case is conveniently designed so that you can pull it apart after pushing back four flexible plastic clips. The circuit board then just lifts out. I got quite a surprise after I did!

The top of the circuit board is printed with component outlines but most of the components marked are not present, and many of the components that are there don’t correspond with the outlines. In the middle of the board is an unidentified component that looks as if it has overheated.

On the underside of the board, again, most of the components that are supposed to be there are missing. Some of the tracks are bridged together with solder blobs or a wire link. I haven’t got the time or, more importantly, the clarity of mind to work out exactly what the circuit on the board actually is, but it doesn’t look much like something capable of charging a 7.2V battery pack from a 12V wall wart.

I’m not quite sure what to do about this. I have the plastic case and the charger contacts, which as I know from the charger I made for the TH-205E are the hardest parts of a battery charger to make. So I could simply make up another constant current charger circuit on Veroboard and put it into the existing case. Or I could simply cut my losses and buy another Motorola charger from a reputable source. I’m sure that one of my readers will know of one.

It was a fine sunny morning. I remembered – having worked a couple of activators yesterday – that it was the Summits On The Air (SOTA) Activity Weekend, so I thought we would go to Watch Hill, G/LD-054, and see what I could work from there.

Compared to all the people who have slogged up thousands of feet to get to their summits Watch Hill is a bit of a cheat. It’s a 15 minute stroll from the nearest car park, with only the last couple of hundred metres being a bit steep. But as it is a less than 10 minute drive from home it’s a popular walk for Olga and I and we often take a picnic lunch up there.

I took with me the Motorola GP300 and the Kenwood TH-205E with the 5/8 telescopic whip. Getting the 4 contacts required for a SOTA activation can be a challenge from there, as it is a fairly low hill and there isn’t a huge amount of 2m FM activity round here. Many have tried and gone away disappointed. However on Sunday morning the Workington Radio Club has a 2m FM net. I broke into that and soon had 5 contacts logged. Future would-be activators of Watch Hill please note.

I also made a summit to summit with 2M0NCM/P on Lamachan Hill SS-061 in Dumfries and Galloway, and then caught Geoff G4WHA/P who was just stopping for lunch on Wether Hill, WOTA summit LDW-103. I wouldn’t have heard him from home, so that was a nice WOTA chaser point for me.

The Motorola produced great, loud audio which is ideal for listening on a windy hill-top, and I got an unsolicited report of “BBC quality” audio on my transmissions, so it seems to be working well. However I noticed that some stations seemed to chop up a bit. I’m not sure if they were weak and the squelch is very sharp or whether their deviation is a bit wide for the Motorola IF filters. I will need to investigate this further.

The TH-205E came in handy after the Motorola gave a few beeps to warn, I think, that the battery was exhausted. There is no visual indication of battery state on the Motorola so I had no advance warning. The station I was working said that he could hear a carrier but no audio after the battery went. Still, it does seem to be a nice radio and rugged enough for this type of use.

I finally completed phase 1 of the shack renovation. G4ILO is back on the air!

The floor is now covered in wood laminate, and there is a shelf unit on the desk that displays all my radio equipment “ready to go”.

On the “ground floor” is the VHF antenna rotator, the MFJ noise canceling unit, the tuner for the MFJ magnetic loop and my two Morse keys.

On the next level is my Diamond GSV3000 power supply and my Elecraft K3. There is space for a new addition to the right of the K3. This will not be a P3 panadapter, the pictures of which haven’t excited me at all, nor will it be the recently announced Elecraft 500W linear amplifier – as if I could use one with my attic antennas!

The shelves above the K3 lift out to make it easier to access the back of the radio for changing cables. On the second storey is my QRP K2 with its matching power supply. The K2 is really there just for display, as it isn’t actually connected to any antennas, though I could easily swap an antenna from the K3 to the K2 if I wanted to. The K2 power supply runs a few other items including the FT-817ND, seen on the right with the Microset R50 144MHz amplifier. The 817 is doing duty as my 2m rig at the moment – I have given up the transverter due to a number of issues including poor memory ergonomics of the K3 and the fact that it is convenient to be able to monitor or even operate on 2m while the K3 is otherwise occupied.

The top shelf holds the Medion computer speakers that deliver decent-sounding audio out of the K3, my KK7UQ PSK IMD Meter and my collection of VHF/UHF hand-held radios and their chargers.

The opposite wall is still a hodge-podge of shelves screwed to the wall. Phase 2 is to install a custom designed system of shelves and cupboards so the boxes of “junk” can be hidden away behind closed doors. There is a firm that has a web site where you can design your own unit from standard modules and it arrives as a giant flat pack which you assemble. Olga is designing it as she is much better at that sort of thing than me.

I’m not very skilled at joinery and my home made shelf unit doesn’t look all that professional but it’s better than what I had. Having all (well, most of) my radios at my fingertips I feel for the first time in my life like I have an actual radio station. I made a few contacts today including a PSK31 QSO with Greece on 12m, two SOTA stations on VHF and a nice slow morse contact with Helge, LA1PRA on 80m.

Two more items for the Motorola GP300 arrived from Hong Kong today, an 1800mAH NiMH battery pack and a charger. I’m a bit dubious about the charger. I put the battery pack on the radio and started charging it, and when I checked six hours or so later the battery pack and radio were really hot. I would have thought the charger should have shut off by that point. So I’ll have to watch the charge times.

I wanted to have another try at programming the radio using a newer version of the software from the hampedia site but when I started up the Toshiba Satellite 1800 and tried to go into the Bios to re-enable the cache (which I disabled yesterday to slow the computer in the hope of overcoming the programming problem) it asked for a password. Somehow when I disabled the cache I must have accidentally enabled a Bios password, but of course as I didn’t do it intentionally I have no idea what the password is. I tried to start Windows 98SE but it took 20 minutes to load and was unusable once it eventually did. So that’s that.

But in the end another solution was found. I registered with the forum at the curiously named Batwing Laboratories website, which apparently is the fount of all knowledge for all things Motorola, and posted about my problem there. Tom in D.C. (W2NJS) replied that the DOS in Windows 98SE wouldn’t do, I must use MS-DOS 6.22.

Now I was programming micros since before IBM invented the PC. I’ve read Ray Duncan’s “Programming MS-DOS” from cover to cover several times so I was pretty much an expert on the subject at one time (though I’ve forgotten just about all of it now) and I would never have thought that there were any differences between the two versions affecting the use of the serial port. But Tom was firm enough in his advice that I downloaded an MS-DOS 6.22 boot CD image and made myself a boot disk. It wouldn’t recognize my Windows 98SE partition so I had to vape that, reformat under MS-DOS 6.22 and set everything up from scratch. Fortunately I still remembered enough about things like config.sys and autoexec.bat to get it to work.

I reinstalled the programming software, connected the interface, and this time I got “Radio Communication OK!” Tom in D.C. probably heard my cheers from there. So I was finally able to program eight 2m frequencies into the radio – five simplex channels plus the three local repeaters – and have just completed two QSOs on the GB3LA repeater from inside the house using a quarter wave telescopic whip, so it works!

The Motorola GP300 seems to work a bit differently to ham radios. For example, there are three power levels but the power level is fixed for each channel, so if I set High power in order to access a repeater from home I can’t reduce the power to Low to save batteries when I’m in line of sight of it from a hilltop. And if you want a Scan function you have to dedicate a channel to that.

Possibly there are some tips for setting up these radios for ham band use that I’m not aware of yet. But even if there aren’t, it’s still a nice radio for £1. Even if by the time you add in the cost of the programming interface, the battery pack, the charger and the adapter that converts the Motorola proprietary antenna socket into a BNC it ended up costing more like £40.