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This is the last post under callsign SV3DJG.

The reason is that after the last renewal of my license my callsign was changed to SV1DJG. This was quite unexpected and I was totally unaware of the subsequent change when I applied for the renewal.  I will get used to it as time goes by, but I really did not want it to happen.

For the sake of consistency, this blog has already moved to http://sv1djg.wordpress.com and all my previous posts have been transfered there.

I have also created new email accounts under my new callsign (you can see them under the CONTACT page on the new blog)

Please update your bookmarks to http://sv1djg.wordpress.com

See you there,

73, SV1DJG (ex-SV3DJG)

There is no doubt that  Google is a powerful search engine. It handles and indexes enormous amount of data at any given moment. It is so powerful that sometimes provides access into information that we should not be able to get easily or for free.

Yesterday I decided to look-up  some antenna modeling resources. I was interested mainly for information regarding the MININEC and NEC2 engines in depth (differences , capabilities, limitations etc).  A simple Google search returned that the latest release of MININEC is 3.13. using “MININEC 3.13” as the search term returned two surprises!

The first one was a match inside a chapter of the ARRL Antenna Modeling Course book by L.B. Cebik, W4RNL which was accessible online without any restriction! It proved to be reading material for some online course which probably is not free itself. I can guess that there must be some permission from ARRL to use the chapter as reading material but in my opinion it should not be available to everyone as this possibly violates the copyrights of the author and publisher.

However, I was curious enough to see how much of the book was available, so I did another search using the search term “site:wm2.ctdlc.org/webmentor/courses/rds/search/” and voila! the whole book is available online for free! What a surprise!

The second surprise was that the next match in my initial search (“MININEC 3.13”) was a hit inside a chapter of  Low Band DX-ing by ON4UN which is the latest (4th) edition ! By opening that pdf file, gives you access to all the chapters of the book, which means that you can get the whole book for free!

I could not stop! I grabbed my ARRL Antenna Book and ARRL Handbook and searched for a random chapter. Needless to say that are both available online (see here and here)!

No matter how much I dislike copyright infringement, I found this “breach of information” a great opportunity to read all the chapters and get the most I can about antenna modeling. I do not really care about the other three books because I already have them in their latest hard copy version (who hasn’t?).

Maybe you should do the same for as long as it is there…

73,SV3DJG

Today Mr.Postman had a nice gift for me! My FtTuthill80 transceiver kit just arrived! I had been waiting for a month in order this batch of kits to be dispatched.

FTTuthill80 kit arrived

FtTuthill 80 transceiver kit just arrived

This transceiver, designed by Dan Tayloe (N7VE) and kitted by the Arizona ScQRPions QRP Club, is a quite different and interesting design. I bought it not because I lack any equipment on 80m, but because Dan Tayloe’s designs are very different than what most of us are used to  and therefore (the least I can say) extremely educative. I think that Dan has created a unique “school” of receiver/transceiver design and his results are becoming classics ( I was not quite fast to grab an NC2030 kit some days before …)

More info about this transceiver can be found on the Arizona ScQRPions QRP Club page and also at the the dedicated Yahoo! Group

I now have to inventorise the kit and put it on my schedule for this weekend.

73, SV3DJG

Finally, the SW40+ project is over. I did not updated the status for a long time, although a lot of things happened!

After completing the assembly of the kit (toroids and final transistor) I was ready to make all the adjustments. In the mean time, the enclosure had arrived and I chose to install it first and then adjust it. The enclosure kit comes with a BNC antenna connector and at the time, all my other equipment uses PL-259  so  I bought some adapters to use until I make a final cable with a BNC plug.

After connecting my main antenna to the SW40 through the adapter I started adjusting the receiver. It sounded a bit deaf, meaning, that there was not quite big difference whether the antenna was connected or not. This puzzled me a lot but I decided to continue with the transmitter part.(This proved later to be a big mistake!).

I connected the transceiver through my power meter to a mini dummy load and  started keying the transmitter. There was no output at all! No matter what I did, the transmitter was dead.

It took me about 3 hours of thinking and signal tracing to make the discovery. The BNC to PL-259 adapter was faulty…actually, it was shorted! All the transmitter testing was performed with a shorted output! This resulted in a fried output transistor, and I had to order new ones from Small Wonder Labs!

After replacing the output transistor (and disposed the faulty adapter!) all the adjustments were finished within minutes. The transmitter is capable of delivering something more than 2.5 watts  (as displayed on my power meter, with unknown accuracy !) but I set it to about 1.5 Watts for safety.

SW40-finished-front

The SW40+ finished

I have used it a bit, mainly on receiving (yes, my CW skills are still bad…but they are improving fast!) and it is quite a pleasure! The receiver is sensitive enough and can hear almost everything my main rig hears (which means that they are both either very good or very bad!).

There are two thing that someone has to get used to. First, is the tuning pot. The tuning range of the VFO is small but for a single turn pot, it stil feels that it tunes too fast! Also, it is a bit non-linear, because, there is a small range at the beginning and a bit smaller at the end that does not actually changes the VFO frequency. It is not very serious though and there are a lot of mods to fix that as well as the tuning range.

The other thing is the lack of AGC , which for someone that has never used an AGC OFF switch on his transceiver, is a bit strange! On the SW40+, most of the time when tuning and the GAIN is on the max setting, very strong signals appear from nowhere  at  very “annoying” levels !!! It takes a little practice to learn to tune with both the TUNE and the GAIN control.

SW40-finished-side

Another view of the SW40+

However, none of the above  issues can degrade the quality of the transceiver and are not at all annoying. It is  just something that take about 2 hours to get used to! The on-the-air performance is very good and it makes a very compact and portable transceiver that I am going to enjoy for a long time!

I hope to meet you on the band, soon!

73, SV3DJG

Homebrewing to the extreme!

I just came across a link I had bookmarked a long time ago!

Enjoy a 17min , truly amazing, journey !

You can also visit the web site of Claude Paillard for more amazing pictures!

73, SV3DJG

From time to time I need urgently to record a QSO or some activity from my transceiver. I have not hooked up my computer permanently to my rigs and when that time comes, I usually run to connect the cables, start the recording software, adjust the levels and so on.  I always wanted a better solution, faster and more versatile.

Last year my MP3 player had a small accident…”someone” step on it and the screen’s protective window was broken, but other than that, it is working perfectly. Due to the ugly appearance, it was retired and stored away. It is a very cheap MP3 Player,the one that each manufacturer buys by 1000’s from China and prints his logo on it. Mine was branded as “SONY”! It runs on a single AAA battery, has 1GB of memory, FM radio, but the most important feature is its ability to record through an internal microphone.

I immediately thought that it would be nice if I could use it to record directly there whatever I want and then transfer it to my PC through the USB port. All I had to do is to replace the microphone with a cable going directly to the source, and adjust the input level accordingly.

Without any guilt, I disassembled the unit and headed for the microphone.

MP3 player broken into parts

MP3 player disassembled

It was really a very small one with very small pads, but it was removed easily and the cable was connected in place of the microphone.

MP3 player microphone replaced

MP3 player microphone replaced with direct cable input

Unfortunately there is no space inside the player to put a level adjustment circuit so it will be either external or the volume of the source will be adjusted  accordingly.

QSO recorder ready

The QSO Recorder is ready.

And  voila! A portable QSO recorder is born! I tested and it works fine, but the volume level must be kept at very low levels for preventing audio distortion. This will be fixed with soon an external circuit.

Using the MP3 player’s “High Quality” recording setting  (which I think is 32Kbps, WAV format) the device can record up to 32 hours of audio! Not bad at all !

73, SV3DJG

SW40+ QRP transceiver

I like portable operation and I have a transceiver allocated exclusively for this purpose. It is a Yaesu FT-890AT which is fine if the operation is something serious ,like a filed day, but it is a bit of overkill for taking along on a weekend or on a business trip just for  fun.

For more relaxed operating I need a transceiver quite small in size, with low output power (QRP) and low power  requirements. I had seriously hard time deciding on the band, I wanted them all! After a lot of though I decided to try 40m and the transceiver should be a kit.

So,  I ordered a SmallWonder Labs SW40+ , one of the most popular single band transceivers available. Believe it or not, after my order was received, I had the kit in my hands in 5 days!!! (After I got it, I was really sorry that I did not also ordered the enclosure, which I did a bit later).

The kit quality is outstanding! There is no missing parts, everything is clearly marked and even a beginner can assemble this kit. The pcb is single layer but with plated-through holes and as I discovered later this adds to the mechanical stability of the kit. When you solder a component, the solder is flowing  through the hole and reaches the other side. When you turn over the PCB on the components’ side it seems like the component is soldered on both sides! Excellent!

I followed the instructions and I was surprised to see that it was easier than I thought, after 2 hours this was my progress

SW40 Two hours later

Progress after 2 hours!

I was amazed at my progress because I was proceeding slowly  ( I prefer to be more careful than required and  double check  everything than coming back because something was misplaced).

I decided to  go on a bit more and after 2 more hours the kit was almost complete,I had soldered everything but the toroids and the final transistor.

SW40 Four hours later

Progress after 4 hours!

Then I had a small shock! I had one resistor lying on the table!!! How did this happen? Did I miss something or did the kit contain one more resistor? I inspected the kit thoroughly but without luck! It must be a spare resistor (at least this is more convenient to me)!

I would have finished it today, but I want to check it tomorrow with a clear mind, just in case I missed something. Besides that, winding toroids is not one of my favorites and it takes (me) a lot of time. So, the project will continue tomorrow!

73, SV3DJG

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