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Picture of 30m mept


Picture of my HF (and VHF) balcony antenna

30 meter MEPT: ... a kind of QRSS and QRPp Beacon

During 2006 I headed my interest over the fashinating QRPp world. First building my first qrpp tranceiver, a Rock Mite for 20 meter band, later building my own first transmitter.

What's QRSS & QRPp

If you already know these infos, you can go ahead.
The meaning of QRSS come from Q code, QRS: slow down your speed trasmission. Is an invitation to slow down CW (morse code) trasmission speed. The final "S" means "very very slow!". During these trasmissions the dots and the dashes are very long; if We've a 3 seconds dot lengh, We'll get a QRSS3 transmission type. So We'll have QRSS3, QRSS10, QRSS30, etc...
QRPp at the same of QRSS means transmitting with a very low power, usually under 1 Watt. Here now come the M.E.P.T. = Manned Experimental Propagation Transmitter; usually home made qrpp transmitters.
Signals are to low and to narrow to be listened, so We use PC and software to "read" them. In order to deepen the argument, I invite you to visit this site: What is QRSS?.
One of the thinks I like of QRSS is that if you receive or transmit, you can do it also if you have few time to spend to our hobby. 

My MEPT

Now I give you some information about my 30 meter mept.
I've started first transmission on January 4th 2007, after some off-air test, with great success! After few hours of transmission David, VK6DI, received my signal. Here below there is the capture of David.



A route of about 13,300 Km with only 160 milliWatts in QRSS3!

My mept is based on 74LH240 IC, used as oscillator, buffer and (pre)amplifier. I thought that power of this IC was to low so I used a BD139 to amplify the signal. Now I can get  more that 1 watt with 12 volt of supply.
A 16f84 pic IC create the fskCW keying, the software for this function is by IK2PCB. It control a micro relay that switch a little capacitor to vary the frequency. I used this mode to fsk and not the usual varicap circuit because I would control more mept with only one pic.

This is the picture of my first smoke test.



Because I don't have much space to install full size antennas, I used to transmit the signal my  balcony home made antenna, it run from 15 to 40 meter band. I used it for other qrp qso on 20 but never so low power. It's a very little antenna, a little more than 1 meter long, but is giving to me many satisfactions.

That's all, picture shows the rest. All material came from my junk box!