AmateurRadio.com

There are dozens of QRP rig designs and new kits that pop up each year, the majority of which are reiterations of previous designs.  For the past ten years it seems we’ve been in a bit of a rut building NE602 based direct conversion and superhet rigs.  But once in awhile a groundbreaking design is released, and everyone follows.  Rigs like this are truly memorable, like the W7ZOI Ugly Weekender, the NEophyte, the Norcal 40, the 2N2/40, and the K2.  I think the Minima, a new transceiver designed by Ashhar Farhan is one such design.  The design has really impressive and innovative features:

• 1 to 30 Mhz coverage
• CW and SSB operation
• Si570 DDS local oscillator
• 20 Mhz IF
• KISS Mixer
• Arduino controlled, with open source software
• Other than a few ICs, most of the active components are general purpose NPN and PNP transistors
• A relatively simple and reproducible design

Looking at the schematic, you can see immediately how unique it is starting at the front end.  From the antenna jack, you go into a high pass or low pass filter and then hit a mixer with two FETs.  After that is an IF amplifier constructed from bipolar transistors, a BFO mixer and then the audio chain, again built from bipolar transistors.  The transmitter chain works essentially the same, in reverse, with the mixer as the final active stage and providing a one watt output.

I’ve been eager to build something ugly style on a sheet of copper clad PC board, and this is just the ticket.  And it’s Arduino controlled which is icing on the cake!

Anthony, K3NG, is a regular contributor to AmateurRadio.com.

Norway has had its fair share of precipitation this winter. Along the coast most of it has been in the form of rain. But that is different in the mountains. Our cabin at 800 m above sea level is now about to disappear in the snow and we can hardly see out of the windows anymore. This is a result of having had to shovel the snow off the roof three times so far this winter. And there is yet more to come.

They say that one has to go back to the winter of 1958 for more snow than we have had this winter, and we are still only in February. The snow has also given us an unexpected problem. Our digital TV signal is now gone.

The TV transmitter is at Mount Gaustadtoppen at 1883 m ASL which is about 10 km to the North and with almost free line of sight. It used to be possible to receive the signals from the national TV provider (Riks-TV) with just a simple indoor dipole, i.e. two wires each of length 13-14 cm connected to a coaxial cable. But not so anymore after all the snow has accumulated outside the windows.

Therefore I had to find a good Yagi-antenna calculator and make a better antenna. I put it on a cardboard of length 45 cm and used the antenna calculator of K7MEM (Martin Meserve). It is a little hard to figure out the exact frequency as there are 5 multiplexes in the TV system and for that particular transmitter they range from 506 to 620 MHz (http://www.finnsenderen.no/finnsender). I therefore just designed the antenna for the multiplex in the middle, 563 MHz. The wavelength is 53.3 cm and typical antenna element length is half of that.

The antenna calculator gave me a design with one reflector behind the receiver element, and four directors in front of it. In the picture, the reflector is to the left and the antenna points to the transmitter to the right.

I made the elements from thick wire, and just taped them to the cardboard. The connector to the coaxial cable is under the cardboard and attached to the center of element two from the left – the one which is split into two.

The Yagi antenna was first described by H. Yagi in the paper “Beam Transmission of Ultra Short Waves“, (Proceedings of the Institute of Radio Engineers, 1928). But as the contribution from his colleague Uda was at least as great as Yagi’s, the antenna should really be called the Yagi-Uda antenna. I seem to remember that Uda could not write English (both of them were Japanese), so the article was written in the name of Yagi only.

But what about my Yagi, eh Yagi-Uda antenna, did it work? Yes, actually it did! With digital signals there is a threshold effect and above a certain signal level the signal quality quickly goes to 100% with a low BER (bit error rate) and with this antenna I came above that threshold. The gain of this antenna is in the order of 8 dB or about 6 dB more than the old single element antenna. Luckily, that was enough to compensate for the attenuation through the snow pile. And as you can see, one doesn’t need aluminium to make a working TV antenna.

[In Norwegian:  Verste snøvinter i manns minne og en innendørs TV-antenne]

Sverre Holm, LA3ZA, is a regular contributor to AmateurRadio.com and writes from Norway. Contact him at [email protected].

 

That’s where I found myself tonight, as one of the two Foxes in the 40 Meter QRP Fox Hunt. As a Fox, you try to find a relatively clear frequency, where you can work the Hounds rather easily. And that’s precisely what I thought I did tonight. I found a frequency, called “QRL?”, and hearing no response in the negative, I began working Hounds. For the first few minutes, things were going great. Then I found myself giving the Fox exchange to stations who weren’t coming back to me.

After that sinking-in-the-pit-of-my-stomach “uh oh” feeling quickly passed by, I snuck a peak at the Cluster, to realize that I was being encroached by one of the W1AW/X pileups! A lot of those stations had no interest in me, and probably couldn’t even hear me, for that matter.

So I quickly QSYed to calmer waters and decided to operate simplex instead of split. Even though there was a lot of QRM and the band was treating me to a lot of QSB, a very quick after-the-event count shows that I handed out close to 60 pelts.

A post-hunt e-mail from Todd N9NE informed me that I had managed to position myself right in between W1AW/8 and W1AW/4. I’m glad I didn’t know that! Some things you’re better off not knowing, and I think that is one of them.

My ears hurt a little bit from trying to pull out some weaker call signs from among the loud QRM, but I am pretty satisfied by my effort. I wanted to work at least 60 stations going in, and I made that a goal for myself. Looks like I just made it.

72 de Larry W2LJ
QRP – When you care to send the very least!

Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

For the second time in a few days, I had a 29MHz QSO through the KQ2H repeater on 29.620 (input on 29.520) on the way home from the station. With the days lengthening, the propagation is lasting a little longer too and KQ2H has been a really great signal even at 1830z.

Last Friday I worked M0CGL through the box and then this evening it was nice to have a QSO with Terry G0VHS in Weymouth.

Gear is the Anytone AT5555 at around 20W into the Sirio whip on the car.

The band has been quiet in the morning, although I’ve tried a few CQs on 29.600 at around 0715z – I’m sure it’s open somewhere. Judging by the Russian taxi controllers on 27MHz – it’s good out in that direction!

Good to hear some people making 29MHz AM QSOs today as well – though the AM segment was quiet by the time I got back to the car.

Tim Kirby, G4VXE, is a regular contributor to AmateurRadio.com and writes from Oxfordshire, England. Contact him at [email protected].

I might not be in the best location for the QRP Fox hunts, but I do have to admit that I am blessed when it came to achieving QRP DXCC.  Those of us in the Northeast definitely do not have the edge in Fox hunting that our fellow Hounds from the Midwest have.  When you look at the Hound’s scores, the guys “who get ’em all” are usually, if not exclusively, from the middle of the US.  But those of us in the Northeast, and on the East coast in general have the edge when working Europe and the Caribbean.  I believe that Jim W4QO in Georgia posted that he worked over 100 different DXCC entities just this past weekend.  That’s nothing to sneeze at and is a great accomplishment!

But if your a new QRPer you may be saying to yourself, “That’s all well and good, but I’m just starting out and I don’t have a tower and a beam or a fancy antenna farm.” I’m not saying that those wouldn’t be helpful, but you can achieve a lot with simple antennas.  I posted yesterday that I worked about half a DXCC award this past weekend.  I did it with a Butternut HF9V antenna and a home brewed 88′ Extended Double Zepp antenna.  These antennas are surely within the reach of beginner QRPers (HOAs notwithstanding). With 5 Watts, I worked (in no particular order):

Estonia
Norway
France
Czech Republic
Belgium
Columbia
Italy
Slovenia
Bulgaria
Poland
Spain
Bahamas
Puerto Rico
The Ukraine
European Russia
The Azores
Mexico
Brazil
Chile
Morocco
The Turks & Caicos
The Cayman Islands
Alaska
Madeira Island
Portugal
US Virgin Islands
Sweden
Nicaragua
French Guiana
Lithiuania
Aruba
Curacao
Anguilla
Finland
Atigua & Barbuda
England
Scotland
The Balearic Islands
Germany
Jamaica
Belize
The Canary Islands
Bonaire
Belarus
Denmark

That’s 45 DXCC entities in just around four hours of operating.  So I don’t want to hear about how QRP DXCC is hard or impossible.  I’ve done it and believe me, if a ham and egger like me can work 100 different countries using 5 Watts, then you can do better!  And when you come down to it, my performance this past weekend was really nothing to crow about.  If you want to read a great story, then make sure to read Phil AK2MA’s recount of his ARRL DX Contest effort – 150 QSOs and 57 countries worked with an INDOOR Buddipole on just one band (15 Meters)! THAT my friends is an achievement!

There is a price to pay, however, and that is you’re going to have to work on your Morse Code. Life is not a dish of assorted fancy cashews. QRP DXing and CW go together like hand and glove. Some of these contest stations were sending so fast that it took me 7 or 8 listens to get their calls right.  Normally I am comfortable copying up to 25-28 WPM; and on a good day, I can stretch that to 35 WPM if the code being sent well and the exchange is short (like a contest exchange). Some of these guys were sending around the 40 WPM stratosphere and I had to just pass them by.  But with dedication and practice you can get to the “mere human neighborhood” of 25 WPM without going crazy.

And that’s part of what this is all about, too. Constantly improving your station, your antennas, and yourself!

72 de Larry W2LJ
QRP – When you care to send the very least!

Larry Makoski, W2LJ, is a regular contributor to AmateurRadio.com and writes from New Jersey, USA. Contact him at [email protected].

At the start of the year I did some experimentation with cheap DDS modules based on the Analog Devices AD9850 connected to the Arduino board, making a rudimentary WSPR transmitter prototype.

My current licence restrictions prevent me using anything home-brew for transmitting except for commercial kits. So I ordered an Ultimate3 QRSS beacon kit from Hans Summers (G0UPL) thinking that it would be okay. I subsequently learned that any commercially available kit must satisfy IR 2028 which is all a bit vague and unclear but sadly I don't believe this particular kit does.

All was not lost, building this kit should more than satisfy one of the practical assessments of the intermediate examination, which will get me around this problem.

The Ultimate3 kit is extremely popular and so I had to wait a little for delivery and it arrived on Friday. After the last few weekends of non-radio activities I had planned to get my antennas backup and do some proper operating. Like many people I had been forced to take everything down due to the barrage of storms and high winds the UK has been experiencing recently.

A tidy workbench

Saturday saw no let up in the wind, so I decided to spend a few hours building the kit instead.

The instructions were extremely clear and straight forward and soon had it built up, though it is high time I invested in new soldering station. I have a basic Antex 25W iron. I cannot remember exactly when I brought it but it is well over 10 years ago.  It was more than adequate to build this kit and for soldering connectors but I could do with something adjustable and more comfortable.

Taking shape

The only issue I had was winding the first toroid, 25 turns later I realised I had wound it the wrong way round so the leads didn't line up with the holes in the PCB. I could have made it fit but nope I will do it properly so I unwound it and did it again.

I also made the mistake of not scraping the enamel off the toroid wire and tried the heat it and bubble it off method, except I think my iron just isn't hot enough so ended up using a piece of wire wool to remove the enamel.

Lessons learned I soon had the other three toroids correctly wound and wire prepared for the low-pass filter board.

Close up of the LPF

   A final visual check and powered it up and it worked first time!

All built

It works!

Setting it up

Full of confidence I grabbed my trusty GPS module which has been pressed into service on a few Arduino projects including the HAB project. Quickly soldered some connecting wires and powered everything up.. all was well or so it seemed when the display suddenly went blank, backlight was on, just no characters.

Pressing the button I occasionally got some random characters and a flashing cursor! I de-soldered the GPS and still nothing. I suspected the display was faulty but trying it on the HAB prototype board confirmed it was okay. I checked the display connector continuity and everything appeared okay.

Out with the oscilloscope I started probing, everything checked out. Crystal was oscillating and data pulses on the display control lines. Then I checked the supply pin on the display and it was only reading 4.1V, this under-voltage would explain the odd display behaviour.

PSU output was 5V, micro-controller was 5V, DDS module had 5V. All very puzzling till I removed the DDS module and spotted a discoloured track on the PCB, touching it with a screwdriver and the lacquer fell away revealing a tell tale scorch mark, somehow I had made a nice resistor!

Burnt track to right of micro-controller

A quick wire link soldered in place and everything was back to normal.

What caused it? Checking the de-soldered GPS connecting wire I spotted a stray single strand of wire on the ground wire. I suspect this must have shorted to the adjacent 5V line and since I was using a nice beefy ex-PC PSU as a bench supply it had popped the track without the hint of a flicker. The GPS has been rewired properly and is working nicely, now to connect a dummy load and experiment some more.

Sunday was a lovely day, wind dropped so antennas have been put back up and I took the opportunity to tidy up the installation a bit. I also dug out an old fibreglass pole to put the M0CVO HW-20HP back up. I didn't get to do any operating in the end as by the time I had done this and made up a couple of decent patch leads it was time for roast beef and all the trimmings and an evening in front of the TV.

The HW-20HP back up

Putting PL259 and N-Type connectors on coax is also part of the intermediate assessment, so perhaps I should have videoed making up the patch-leads as proof ;-)
Andrew Garratt, MØNRD, is a regular contributor to AmateurRadio.com and writes from East Midlands, England. Contact him at [email protected].