Thursday, March 26, 2015


I am making and breaking the circuits say around 1994. I made one copper board, hand pained  from the 20 meter band cw transmitter project by VU2ATN in the  Electronics For You Magazine. At that time it was in paper forms only. Then somewhere around 1998 they added the software in the accompanying  CD. Yes sir at that time they were giving the cd and my 386 computer did not have the cd driver. It only had the floppy. Nostalgic. One time I wanted to market the projects I had made. Well now the technology is very cheap for the prototype we still have to depend on the ancient technique for making one or two PCB by hand.

As making the pcb by professional help will cost more. Then take few thousands for taking the job. Then they etc and provide you PCB in a big lot. After that they make it any time. But, the hobby, amateur pcb has very short demand to make them commercial quality. As the end user might not afford it. And gestation time is very high for selling this PCB.

In those days PCB maker, PCB123 , EAGLE PCB etc were being used. They are still used. But I missed that band wagon.

Suddenly I needed to make few pcb for my 14318kc transmitter as I wanted them to provide for my friends. That way I my need was of about 50 pcb. A friend agreed to sale in his store at reasonable cost. I don't plan to earn money from it. Its an extensions  to share my experience and expertise.

I used the EXPRESS PCB, as suggested  by Om daya and few other friends. Tried. It makes the Circuit diagram ok , but not able to make the pcb copper trace.

Then another friend OM Suyog told me to use the DIP-TRACE pcb making software. It comes in the free student version and one fully professional version with more extensive features.

I liked the Dip-trace. http:\\\ download the freeware 300pin version.
The following ckt is the universal RF amplifier board. It can be used for receiving, transmitting and If amp and lots more. mixer et al.... change the components value and make it compatible. more on that in a separate post.

This is the multipurpose board. Used for various RF purposes ie
RF amplifier, Mixing, IF amplifiers, Transmitters mixer, Transmitter Amplifiers......
ideas is this way. Same board repeated for Front end RF,Mixer,two IF amplifiers, Pins at J4-male, which mates to pin at J1-Female, Similarly J2-J3. the power rail. All this mounted on the Copper plane. The same type of board can be used for RF mixer, RF amp chain, Driver amplifier. Then linear has to be different. Thus the same board can be used differently at different place. Idea is this way. Lets see how it turns out.

(to be continued.....)

Tuesday, March 24, 2015

Software Radio, part-2

How to run the RTL-SDR

Recently on the exchange of few components Om D.Prahba Karan, Prinicipal sir gave me 3 RF transistor and RTL-SDR dongle 2832. I feel it as a generous gift as rupee cost of my "rare
: components is not even half of this things. Thanks Sir. I acknowledge this generously.
Here is the picture.

Now software part came, there was the problem. The cd did not contained the software. Ok, the Miss Murphy took her tall lightly. I was waiting and waiting , thinking what to do. Then suddenly I related my problem to Om Aryaji. He immediately sent two links. Gave valuable inputs.

Download the Sharp SDR software.

I downloaded it for my 64bit windows machine. By using different software 32bit and Linux also supported.

Once this software is downloaded. Run it, beware it is just a downloading software so live interet is need. Please allow it to use internet to download further software components. It will take some time. After that your software is completely downloaded.

Now put the dongle into the usb port. It should be detected if you are lucky. Not detected no problem.

Now there is another link. Go to the zadig software. download it.

Remember without internet you will be not able to install the software. Now you can switch off  the internet.

Put out any other usb devices from the computer. Run the zadig you just downloaded. Then it will install the driver software for it. See that it detects the 2832....

If needed , just re-install the driver once again.

Now when you put the rtl dongle it will be detected for icons just see in the devices and printers. Connect  small antenna. Telescopic, wire or a proper antenna. See that there is no big RF source, transmitter near by, otherwise it will damage the dongle forever.

All well see the options on the software. There is not much tinkering we have to do. It will start running and some sort of audio will be coming from your computers speakers. Choose the modulations. If the FM station is available put the freq in the top heading of the screen. With the ARROW KEYS you can increase/decrese the freq more easily.

Now just play with it. You should be seeing something like this image. bingo.... you are receiving...

If some problem comes around just read the help section of the RTL page...
that's it falks we have re-invented the softwareradio use.

Thanks goes to D.Prabhakaran for dongle. Thanks goes to Aryaji, Om. Ashok Shankar Das for software and other inputs.

Prabhakaran sir lightly remarked that once you get use of it, you will be bored. Yes sir, that's right observation. But I will be using it for my personal entertainment qrp station or room bug monitor. Will also try to make the HF radio converter for it.  Just stay tune.... for part-3