AmateurRadio.com

It’s probably a character weakness, but I have always had a tendency to push my luck a bit too far and end up regretting it. That thought was in my mind when thinking about what to do with the Trio / Kenwood TH-205E that I got for a song on eBay. The rig worked well enough already to do what I thought I would do with it if it worked. But I was finding it hard to resist the temptation to see if I could restore it to full working order even though there was a risk that I might end up breaking it completely.

In the end, the temptation to try to restore it won. The radio came apart quite easily – it is a big radio, and fairly easy to work on, though surprisingly for 1986 vintage equipment it uses a lot of SMT parts. The back half is a solid cast metal chassis containing the IF and RF boards, and the front half is plastic and contains the front panel with the control logic. The two halves are linked by two ribbon cables and one had been inserted a bit crooked, which led me to hope that repositioning it might solve the problem of the inoperable buttons, but that proved not to be the case, so the front panel board had to come out.

The front panel board is secured to the front panel itself with a large number of small self-tapping screws. Once they were removed and the wires to the speaker and mic unsoldered, the board came out to reveal the sight shown above. The front panel buttons were not sealed units but capacitive switches operated by contact with the rubber buttons, and they were covered by a sticky mess of gunk – presumably the same stuff I had found on the outside of the case which a couple of readers informed me was a cleaning agent used to spruce plastic items up prior to sale. This hadn’t just distributed itself over the switch area, it had even penetrated through some of the vias to reach the other side of the board. What a mess!

Olga found me a few small pieces of rag and I went to work with some white spirit from the garage. I eventually managed to clean most of it off. My fears about causing even worse damage were raised when the LCD display fell off. It didn’t seem to be attached to the board and had perhaps become stuck to it with some of the gunk. However when I reassembled the radio I just rested it in place while I fixed the PCB in place and it still worked.

There was no way I could test if the switch contacts were clean enough without reassembling so eventually I decided that it looked good enough and back it all went. I applied power with trepidation. The display lit up and I could hear hiss in the speaker. I then pressed the Offset button and was able to select repeater shift! The Scan function set the receiver scrolling slowly through the entire 2m band in 5KHz steps – very useful that! I was also able to program and recall frequencies in the three memories, although the memory buttons still need a bit of persistence to get them to work. It isn’t worth taking it all apart again just to try to improve that.

While I had the rig apart I took the opportunity to reset the power levels to give 5W on High power with a 13.8V supply and 0.5W on low power. Some previous owner had probably tweaked the power controls to give 7W out. No point in stressing the probably irreplaceable power transistor for a barely detectable 1dB or so of extra power. Then I put it all back together. Job done, and the TH-205E restored to full working order. I was feeling pretty chuffed.

As usual, there was no-one around on any of the simplex channels to do a test with but I was able to access the GB3DG repeater and even GB3LA on 145.7125 (a 12.5kHz channel) by tuning to 145.715.

I’m starting to feel a bit of affection for this big old radio now that I’ve made it as good as new. I’m thinking that it would be worth trying to resurrect the NiCad battery pack, which at the moment is showing a dead short. But there I’m really stumped, as I can’t see a way in. Clearly the plastic case is made in two halves, but sticking a screwdriver in the crack and twisting is just going to chew up the plastic. Anyone know if it’s possible?

Whilst buying on eBay can sometimes result in a piece of junk, it can also produce the occasional lucky find. The radio pictured on the right is my latest auction success which arrived this morning. It is a Trio / Kenwood TH-205E of 1986 vintage which was being sold as for spares or repair. It cost me all of ten quid ($15 for my US readers), four of which were for postage.

When it arrived it was a bit oily, for some reason, but a wipe over with some tissues took care of that. From the front it looks almost like new – no scratches or signs of wear on the markings or buttons. The rig has obviously had an active life though as on the back the paint has worn away and the serial number plate and the warning notice on the battery pack have been polished almost clean of lettering.

The seller stated that they could not get the radio to charge up, which is no surprise, as for 24 year old NiCads to still retain a charge would be nothing short of a miracle. I applied 9V of external power, switched on, and was pleased to see “144.000” appear on the display and hear the hiss of an unsquelched receiver from the speaker. My initial delight at having acquired a worker was short-lived, however, as the frequency display failed to respond to the up/down buttons and the squelch did not seem to work either.

After a while spent pressing buttons in the faint hope of getting the frequency to change, it suddenly did increment a few steps and the squelch also operated. Then the radio gradually became more responsive to the buttons and I was eventually able to persuade it up into the 145.500 region. I connected my QRP power meter and was delighted to observe that the TH-205E was putting out a good 5W in the high power position and 1W in low power. I could also receive the signal on the TH-F7E standing nearby, which was somewhat dwarfed by its older sibling. I’d forgotten hand-helds were still this chunky in 1986!

I connected an antenna and found that I could receive all the local repeaters, so sensitivity is acceptable. The TH-205E will only do 5kHz steps so it isn’t suitable for 12.5KHz channeling, but the receiver is broad enough to receive the GB3LA repeater on 145.7125 when tuned to 145.710 with perfect audio. There is no CTCSS, though there is a tone-burst switch (which I haven’t tested.)

Apart from the up/down frequency selectors the only other front panel button that appears to work is the Lamp button which backlights the LCD display. I can’t activate the repeater offset or program or recall any of the three frequency memories. Possibly these buttons will eventually spring to life after repeated pressing. Otherwise it may require a look inside to see if it is possible to clean the switch contacts. But to be honest I’m not all that bothered, as I’m unlikely to be using the TH-205E on any repeaters.

The most I hoped for when bidding for this was a radio that could easily be got working and could then be put to use as a dedicated rig for APRS on 144.800 or something similar. The least I expected was something I could cannibalize for £10 worth of useful parts. So already I have got more than I hoped for!

Several months ago I had a plan to build a project using Manhattan style construction so I decided to get a tool to make myself some Manhattan pads. Constructors in the US can buy a nice hand punch from Harbor Freight for $25 – that’s less than £18. Over here the nearest equivalent cost around £90 from a tool supplier, except on eBay. I bought the eBay one, but even that cost over £30 including postage.

In the end, apart from punching a couple of test pads using the 7mm punch that was already fitted when I opened the box, I didn’t use it. Until this afternoon, when I wanted to make some smaller pads. That was when I discovered what a shoddy piece of manufacturing this eBay hole punch is.

The 7mm die was a bit stiff to remove but came out with the aid of a screwdriver in the slots provided. The 4.5mm one I put in would bind at each turn and got more and more stiff. Eventually it wouldn’t budge, so I put the screwdriver blade in sideways to get a bit of leverage. There was a crack and a whole piece of the die broke off! I guess it was made by the same firm that makes K3 knobs for Elecraft!

It’s far enough in that I can make 4.5mm pads, but not only does it not want to go in any further but it also doesn’t want to come out. I might be able to get it out with some Mole grips but this is probably the most useful size and I might never be able to get it back in again next time I need it. Crap!

A new posting by Dan KB6NU alerted me to the fact that eHam.net is now allowing users to rate ham radio blogs. I followed his link, selected the Blogs category and found that of all the blogs currently rated, G4ILO’s Blog is (or was, when I went there just now) the only blog that had a rating of five stars! I am amazed, humbled and proud, even if only two people had actually contributed to the rating. 🙂

If you would like to help keep my blog at the top of the table, please pop over to eHam, click on the stars next to G4ILO’s blog and add your rating and comment. Thanks!

With the growing popularity of ham radio simulations like QSONet and HamSphere, I guess it had to happen sooner or later. According to an announcement just out on the IARU website, from today contacts made using these VOIP systems are now officially amateur radio contacts and can count towards amateur radio awards.

The announcement says: “There is an ever increasing use of computer and internet technology to facilitate the making of contacts between amateur radio operators. For many years use of the DX Cluster has been permitted to locate DX contacts to work and many operators now use internet sites to arrange skeds for needed contacts. We also see the development of new digital modes that can make possible contacts between stations that neither side can even hear. Permitting the use of VOIP modes to make contacts is simply an extension of the use of this facilitating technology, by removing the unreliability caused by the behaviour of the ionosphere. This move will also be welcomed by the many radio amateurs living in antenna-restricted locations who are no longer able to be active on what have traditionally been regarded as ‘the airwaves’.”

Addressing the criticism that no radio is actually used when making contacts via QSONet or HamSphere, the statement says: “Many amateur operators nowadays use laptop computers which are connected to the internet via a wi-fi router. This does, of course, involve the use of radio. Initially, therefore, only contacts made using a laptop with a wireless connection will be allowed to count under this new ruling. The frequency should be logged as 2.4GHz. This restriction will be reviewed at a later date.”

More information on this development will apparently be posted on the site at midday today.

Martin, G8JNJ, sent me an email with some suggestions for getting the super-regenerative Fredbox receiver to work. He also sent me a link to the blog of Steve, G4AQB, which mentions the Practical Wireless CQ2 receiver design on which the Fredbox receiver is supposed to be based. I remember the name “CQ2” and the picture on the magazine front cover and circuit diagram shown on Steve’s site look similar to the receiver I built in the early 70s to listen to the 2 metre band which finally gave me the interest to get my Class B (144MHz and up) amateur radio license. I seem to recall that the article also had detailed drawings of how the components in the receiver were to be laid out.

Steve writes that he mounted the receiver on an aluminium front panel but that this played havoc with the tuned circuit so he rebuilt it on a piece of plywood! My memory is pretty poor these days but my recollection is that I built it into an aluminium box of the sort that you could readily buy from the local radio parts shop (those were the days when there were local radio parts shops!), like a box with a lid secured with two self tapping screws. The box stood on its side so the lid was the front panel of the receiver.

Steve writes that he built a quad antenna to use with the receiver. My antenna was a dipole mounted on a wooden stand in my bedroom and fed with a few feet of audio co-ax, since at the time I was ignorant of coaxial cable properties like impedance or loss! In those days I lived with my parents in Rayleigh, Essex. I was able to receive the local police on the CQ2 receiver, as well as amateurs in the Southend area such as Barry G8HNX, John G8IDI and Chas G8HVS. I could receive the GB3VHF beacon from Wrotham, Kent, and also a couple of old-timers who had a regular sked: G6LL whom I think was in Hertfordshire and G5OX who may have been in Ashford, Kent (or perhaps it was the other way round.) This was nearly 40 years ago and I’m surprised I can still remember any of it!

Steve also writes that the radiation from the super-regenerative receiver wiped out the local TVs. I don’t remember that, fortunately, or an end may have been put to my aspirations to be a radio ham before they even started!

But my first proper transceiver – a Hudson AM108 ex-taxi radio that I bought for £5 at the RSGB Woburn Rally in 1973 (which was actually before I was licensed) caused patterning on my parents’ TV on receive! After I got my license I soon found that it caused serious breakthrough on my father’s stereo hi-fi on transmit as well, so my operating was done mobile /M from the car after that.

Later I built my own 4-channel 2m FM transmitter (using tubes, to another PW design) which I used in conjunction with a Microwave Modules receive converter and my short wave receiver (also home built, using tubes, from a PW design.)

So much fun with such primitive equipment! I often wonder if all the technological advances we have today have really added to the enjoyment of the hobby.

One of the things that annoys me about Microsoft is that it has created an operating system that behaves as if it is your job to service its needs rather than a tool that is supposed to serve yours.

I’m thinking specifically about updates. Windows constantly nags you to install updates (which wouldn’t be necessary if they’d designed the thing properly in the first place) and then it expects you to interrupt what you’re doing while it does. After you have downloaded updates it nags you to restart the computer in order to install them. Perhaps they could have designed it so you didn’t have to restart the entire OS after every change? When you do shut down it won’t let you switch off while it is installing updates, so you have to wait around twiddling your thumbs until it is finished.

Hey, Microsoft, it’s MY computer, okay?

I just received an update to Internet Explorer 8 (which I don’t even use) today. After it was downloaded, Windows nagged me twice to restart the system by popping up a window in front of what I was doing, even though I was in the middle of writing something and did not want these interruptions to my train of thought.

Fortunately there is a magic incantation you can remember to show Microsoft who’s boss. It’s:

net stop wuauserv

Just click Start, Run, type the magic words into the box and hit the Enter key. What it does is kill the Windows update service for the remainder of that session. Windows will nag you no longer, and your updates will be installed the next time YOU decide to restart.