Friday, December 26, 2014

7159kc beacon cw-tx

                This is my QRP project which was developed within a minute. This project can be made within an hour. During the testing of the R7 receiver needed on air signal. I did not wanted to test receiver with bench oscillators. 

7,159kc beacon/ cw transmitter, (40 meter band)

Bifiliar transformer wound on the ferrite balun core is a non critical but a very essential part. You can use any other toroid. Use 30swg, enameled copper wire . Give 8 twist per inch with small hand drill or by hand.( don't use power drill).

Had bunch of the BC549c. It is important to use this transistor, particularly c variety. It is also okey to use BC547/BC548 etc but all the c variety has high gain so can be used for 10 meter and have litte more umphhhhh.

First made the collpit oscillator. don't forget to ground the xtals metal case with wire. Sturdy mechanical fabrication is a must. I made it on the Veroboard.  ( will upload the picture). DC input to Q2  is about 180 milli watt. By putting two extra stage of a small linear the power output can reach to comfortable 500mw to 5 watt.

Well box it and use it as a small beacon around my QTH for testing the on air signals.

I had another idea, put a direct conversion receiver strip, shown elsewhere on this blog to make a simple qrp transceiver.

It will be a really big challenge to get a few contacts with this......

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