SELF-BUILD RADIO KIT

 TECSUN 2P3 AM TRANSISTOR RADIO KIT

Since it's approaching Xmas time, I thought it might be an idea to repost this little gem which is a nice stocking filler. 

My lovely wife bought me a little transistor radio kit for my birthday and I was really chuffed with it. It's the sort of gift I would have treasured when I was a child, but back then all I got was a couple of tin cans and a piece of string 😂

Back in the 60's I was a little 

obsessed with transistor radios and I still have a great fondness for them when I see them on the internet. There were some fantastic designs (I'm talking aesthetics now) and I'd love to collect some of them, but the price of them is just plain ridiculous!

So, some 50 years later, here I am with my dream boyhood birthday present. The kit is well packed and hopefully contains everything needed to complete the build. The instruction sheet was in Chinese 😦 so that would have been fun 😂. Fortunately, I found a PDF file which contains an English translation. It can be downloaded HERE.

I started the kit in the morning and expected to complete it by lunchtime but it actually took me all day, lol. It was very pleasurable and I would love to do something similar again. The kit only cost £27 - you can't complain at that!

The build requires very little in the way of tools - a soldering iron, multi-meter, pliers, cutters, a blade and small screwdrivers. I also found it beneficial to have a pair of tweezers and a round file. 

The first thing I did was lay it all out and then put the relevant bits together, like resistors, capacitors, etc, to aid identification and determine values.

Identifying the resistors was a simple case of measuring them with the multi-meter. You could of course use a colour-wheel or an app like the one on Digikey.co.uk

After sorting out all the components, I cut off a part of the PCB which is later used for the Volume control...

Then it's a case of installing the AUDIO SECTION components - a few resistors, capacitors, an IC and a headphone socket.

Following that simple job, it's onto the DETECTOR SECTION which involves fitting some diodes - and this apparently, is where mistakes can easily be made. Personally, I thought it was pretty straight forward. You just have to take your time and double-check the orientation of the diodes.

With that bit done, it was time to fit more capacitors, resistors, transformers and transistors...

When that job's done, it's time to fit the volume control, complete with its 90 degree PCB section. Once it's slotted in properly, it's a simple case of soldering all the contacts and making doubly sure that the unit is perfectly square.

With the IF SECTIONS complete, it was time to install the Capacitor Gang. Quite a simple task but care had to be taken not to cause any heat damage during soldering.

The most awkward bit of the whole project was installing the ferrite bar and soldering those (6) TINY antenna wires to the PCB. After I'd finished the job, I used a hot-glue gun to stop the coils sliding up and down the bar. 

That's the end of the hard bit - now it's just a case of putting the case together. Needless to say, it's best to see if it actually works before putting it all together, so I fitted some batteries, connected the speaker and switched it on. It was fine!!

After a little "fine tuning" of the transformers and gang-capacitor, I was happy with the radio and then tried it with my TECSUN AN200 loop. That made a big difference to weaker stations, but overall, the radio worked very well without.

VIDEO - Internal Antenna

VIDEO - External AN200 Antenna

For £27, I got a great day's entertainment and a great little transistor radio. Absolutely recommended. It's incredibly easy to build and despite me having very little experience, I got through it with no hiccups and no problems. 

There were no missing components and everything seemed to be of good quality. I found that I had to file part of the case to make sure the tuning dial turned smoothly, but that was the one and only departure from standard.

You are recommended to run tests and take measurements throughout the build but I did none! I just didn't feel that I'd done anything wrong and it turns out I was right, lol.

Good fun!!

HERE'S A COPY OF THE INSTRUCTIONS...

Thanks for visiting - please take a minute to leave a comment below 

73, Tom, M7MCQ.

HANDY BATTERY CASE

 I recently purchased a light, tough little case to carry a radio around in, but then found another use for it.  Like many hams, I’m a little addicted to cases and boxes 😂 so when I saw this one for £17, I just had to have it.

It looked like it was tailor-made for my Zippy FlightMax batteries! Both the 4200 & 8400mAh LifePO’s sat side by side inside the mesh covered base, leaving ample space in the lid for my Accucell 6 Balance Charger (complete with leads and even a battery tester). 

So I now have everything neatly stored in one convenient location. The case can be left in the back of my truck, always ready for action. I just hope the batteries never go rogue or it could be a very expensive storage decision 😂

ELECRAFT AX1 & XIEGU X6100

There seems to be some interest (or curiosity) about pairing the Xiegu X6100 with the Elecraft AX1 multi-band telescopic antenna, so I thought I'd give it a go, since I own both items.

The AX1 is a fabulous little telescopic antenna with a loading coil at its base and a BNC connector so that it can sit directly onto a radio's side-mounted antenna socket with a 90 degree elbow. It was obviously designed to fit onto an Elecraft KX2/3 and there's a small accessory available to support it in the form of two adjustable legs. Use of the AX1 does require an ATU.

From the box, the antenna will cover 17M and 20M but with a wide-ranging ATU (which is built into the X6100), you should be able to get a usable match on 15, 12 and 10M! With the optional 40M coil, you can get on the 40 and 30M bands too.

Needless to say, this is very much a compromise antenna and you shouldn't expect too much from it - that would be silly. But there's nothing else out there quite as versatile as this little package which breaks down into 6" sections for storage. There are plenty of closed-minded keyboard warriors out there who will tell you that it's just a dummy load, but those same people have never actually put their hand in their wallet and tried one - it's so annoying, but I guess that's social media for you.

Despite the compromised nature of this tiny antenna, you will be delighted at how well it can work, given the chance. If the band conditions are right and you put a little extra effort into it, it will surprise you. You should bear in mind that this antenna (without or without the 40M extender) is very narrow banded, so you will need to retune more often than usual, especially as you move from one end of a band to the other.

The first and most important thing to do to improve your chances of success is to choose a good take-off location. This isn't a base-station antenna - it's designed for portable ops.

The next best thing is to add some radials. You get a single radial with each coil, but there's nothing stopping you from adding more - and you should!! Grounding the radio using a spike into the soil can help too.

If you don't want the antenna to be connected directly to the radio, you can buy a tripod accessory called an AXT1 and this will give you more options in terms of placement. You can move the antenna to the side of your table-top or you can move it further away on top of a full-size tripod.

AX1 with IC-705

Using the aforementioned legs, the AX1 will sit comfortably on the X6100 although normally I prefer to use a mini tripod myself, to get some physical separation between me and the antenna to avoid any body capacitance issues. I also have an aversion to placing loads on bnc connectors. But for this test I wanted ‘worse case scenario’.

The AX1 can manage up to 20W using SSB, but I've only ever used it at 10W max and never tried it in any digital modes (and probably wouldn't unless it was at 5W or less (which would be fine for FT8)). 

So, with the antenna connected to the X6100 I started looking for contacts on 20M. I was working from my porch at my static caravan in the Forest Of Bowland with the little AX1 perched on the side of the radio - so the antenna didn’t have any height or placement advantages - quite the opposite - it was very poorly sited.

Within a few minutes of setting up, I managed to get the first contact : OH5TS from Finland, almost 2,000 kilometres away 😮 and received a ‘contest’ 59 from him. I pushed on for a while with 20M and bagged a few more contacts (but none further away) before moving onto 40M. Who’s the dummy now??

If video doesn’t show, CLICK HERE

Then I tried 17, 15 and 10M before calling it a day. I was pretty pleased with my success and it proves that these so called 'Dummy Loads' are absolutely capable of producing good results.

Yes, I would probably have made more contacts with a dipole or a wire thrown up into a tree, but that's not always an option. Sometimes you just want to carry something light and trouble-free. Something that will sit in a small bag, ready for quick deployment at a moments notice.

My AX1 with KX2 in tiny case.

The Elecraft AX1 is not a cheap antenna - it costs around £120 in the UK (if you can get one). And then you have to pay more if you want the 40M coil and the tripod adapter. But with it, you can get some pretty amazing contacts using low, low power and a super compact, super portable kit, easily capable of around 400km/Watt. Below shows a previous 1000km contact which I made using an FT-818 and 2.5W from a terrible take off point.  

So would I recommend the Elecraft AX1? Absolutely!! It can form part of a supremely compact go-bag which doesn't weigh you down as you climb up a hill to bag some new contacts. 

FINALLY, if you're a bit of an experimenter, you could always look at modifying the basic AX1 like Rob Ramsey did in this post.

73, Tom, M7MCQ