Practice some multiple choice questions on resistors

 


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Have you heard of zBITX?

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 Well, I had not heard till I read the program schedule of LARC-7 today. Most of you would be familiar with uBITX which has gone up to version 6. Some of you would be aware of sBITX, which is quite an advance over uBITX. Almost daily I am meeting a new uBITX user on the band, most of them using additional linear amplifiers. That made me join the BITX group on groups.io , where I am getting messages from uBITX and sBITX users from all sides of the globe. Still I was not aware of zBITX and that made me look around and came across two references. One was the video of a talk by VU2ESE at QRP ARCI . Another was an email in the BITX groups.io which was citing the former. zBITX is a new transceiver from VU2ESE based on Raspberry Pi Zero for 20W, having CW skimmer and FT8 modes in addition to the regular SSB mode and waterfall display which the sBITX also has. zBITX is quite small, just 3" x 3" x 1.5" in size. It is a Raspberry Pi Zero based 20 W software defined radio which h...
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Basics of Radio Transmitter

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Every radio amateur should know about the basics of a radio transmitter, whether you are going to operate a commercial one or make one on your own, what we call by the pet name 'homebrew'. A radio transmitter is a device which generates a radiofrequency signal and sents it out as radio waves through the antenna. If only the radio frequency carrier wave is sent with breaks and makes corresponding to Morse Code formerly used in telegraphy, then it is known as a CW (Continuous Wave) transmitter, which is the simplest one. Like many other radio amateurs in the yester years, I had also homebrewed a basic CW transmitter using BD139 transistor as the final RF amplifier, running about 5W, known as QRP transmitter. Initial part of the transmitter is the radio frequency generator known as oscillator, which produces a high frequency oscillating current when you supply it with a direct current power supply. Oscillator section was called a VFO or Variable Frequency Oscillator as the freque...
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Debut Ham Radio Technical Discussion Net on 7065 kHz, 1:45 am UTC (7.15 am IST)

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Started by calling CQ on 7065 kHz using my automated CQ call which I had described yesterday. VU3RFT joined first followed by VU2EHA. Had a good discussion on Center Fed and End Fed Dipole Antennas. VU2EHA and VU3RFT participated. All of us were using inverted V dipole antennas. VU2EHA had 40 and 20m dipoles on same mast. VU3RFT was using 1:1 current balun. I mentioned that I am using 40/10m center fed dipoles with 1:1 current balun. VU2EHA asked about 15m dipole. I suggested that the 40m dipole will work well on 15m as it is an odd harmonic. He mentioned a problem because his IC-718 does not have an autotuner. We lost propagation at around 7.35 am IST. Wonder whether there was a geomagnetic storm? Number of waterfalls on 40m band decreased very much at that time. Planning to try again tomorrow at the same time. SWLs can monitor at  http://vu3wew.ddns.net:8073/ , the OpenWebRX by VU3WEW, located about 10km from here and likely to pick up my signals very well. Being a WebSDR, it can...
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