MKARS 80 QRP TCVR (purely user description)
How I got to my own radio on 80m
It is the dream of every radio amateur (among other things) own a quality walkie-talkie. I had one borrowed from Vasil for some time – OM7TX. It was UW3DI. However, it had one irreparable flaw. It wasn't mine. Since there was a bit of a shortage of funds for new ones, I was looking for something second hand. The requirements were simple: low price, small size for portability and minimum 80m band. There was relatively enough equipment - but the PRICE parameter did not fit.
Colleagues from the area therefore began to involve me in various schemes and the construction of the QRP KV TCVR. There were also quite a few. From the simplest sparklers, to decently complex machines. Among them was a link to one page, where, in addition to detailed construction instructions with a list of parts, there was also the possibility to order this device in the form of a semi-finished product. A bagged version of TRX with everything, I was interested mainly because of the construction, that there was no need to further order something and laboriously search online stores. dB and dynamic range at a distance? Without buttons and connectors 50 pounds. Nice price. I contacted a colleague who "fixed" it for me, that I'm going to order it. Supposedly, to order him too, that what are the terms of delivery and payment.... We ordered the device on Friday evening, the payment via PAYPAL went through just after 22:00 and we were left in shock, when it arrived at our post office from GB by lunchtime on Tuesday. Bleskovka!! (Final price for 2x complete packaging!! with fees it was 140, something EUR.)
As for the construction, due to my extreme "skill", I turned to an acquaintance with a request, would he put it together for me?, that I would be happy, if it would still work after putting it together, which is not guaranteed for me. He was willing. In the evenings, it was finished in three days. It went on the first connection. Of course, the details around the end had to be fine-tuned, but basically, after turning it on and setting it up according to the manual, it worked right away. I was already putting it in the tin box. That's why it looks the way it does - I'd rather not publish the photo 🙂 (But it remained functional.)
Controlling:
Debugging it is quite hard, but you can get used to it. When you get your hands on it, it's cool. Tunes with two "sensors" – one is coarse and the other fine-tunes it. The third "sensor" is the input sensitivity control.
Since it doesn't have a volume control, I recommend buying headphones with volume control.
MODULATION INDICATOR – it's the one between TUNING and INPUT SENSITIVITY CONTROL. After pressing the PTT, it lights up permanently and goes out in the rhythm of the modulation during modulation. It happened to me that this warning light reminded me, that I don't have a microphone plugged in. 🙂
PTT – you have to finish according to your own ideas.
Display – clear and simple. The frequency is displayed on 3 decimal places, debugging has a step 5 Hz. The AKU status is also displayed here - the current voltage - which is a nice data if it is transmitted from a small flashlight.
After approx 300 I can't say anything bad about QSOs with this device! He listens fantastically, broadcasts very satisfactorily - but here's one thing, which I would recommend: Cutting the lower frequencies from the microphone. Modulation is a faj from production, but it's more listenable if it "doesn't sound". Since it is a drop-in device, out here - the same goes for nearby stations (circuit of approx. 5 km) it appears wide and tangled. It's a fact, but since I'm not that skilled an electrical engineer, so I don't solve it. (Colleagues around me agreed, that they will forgive me.) Remote stations haven't had a problem with this yet - or no one has pointed it out to me yet.
Pile-Up: no, here's a bit of a problem - while equally powerful stations are pushing me, so it's quite OK. I can filter it out with my ears, what I need. However, if one makes noise, or several stations with significantly greater strength than the current average, so it creates one "sound" from which nothing can be understood. This is how I use the device, that the input sensitivity is at max. Weak signals come through just fine, but a strong signal is deafening. But it doesn't happen often - it's more of an exception, if a station appears on the air "from over the hill" and with full power. 🙂
The reports are nice - but a lot depends on the antenna used. I have an INVERTED V. Both at home and on laptops. How to hear me? One of you recorded an ISS crew, that is enough for 5W. Actually, that one, those who have already connected with me know… I'm happy with it - extremely happy - for the price!
Who wants to play with parts and make something simple, portable, but mainly functional - whatever you like. This is the right toy 🙂
For now, then 73! and after-hearing on 80m.
OM7AQA – Thomas
