VK4ZXI

Satellite TV, RX and positioning Playing with satellites TV or radio is not too hard or expensive. I did a fair bit on it a few years ago (C and K band, ~4 GHz and ~12 GHz) and still have some of the gear. I could see my house in Brisbane on Google maps from the big white C band dish, ex Sky. It was a heavy fixed dish, jerry-rigged with a linear-actuator for position control.   A full new C (and usable on K) band system is around $400 on eBay.   Sometimes they are available for free, migrants and expats used them to get overseas TV. I had one, disassembled, but tossed it when we moved to Gold Coast. Should/may have kept pole, as big steel is expensive. All satellite TV use a LNB (low noise block) to receive and down convert to a standard IF range of about 1 to 2 GHz for a TV set-top box. The coax is used to carry control signals as tones (diseqc) or DC. The coax is very high performance, but cheap because of the massive use of it. The big dishes are controlled by linear act

BladeRF on Haswell i5 running Windows 8 with SDR-Console at 935 MHz 20 MHz bandwidth Screen shot of BladeRF running on Windows 8 with i5 Haswell processor. The BladeRF windows installer uses an unsigned driver. With the extra security of Windows 8 it will not normally even give you the option of installing unsigned drivers, Windows 7 does. However Windows 8 has a special restart where the unsigned driver block can be disabled. I think I described it in earlier blogs. Using the earlier beta of SDR-console V2 per earlier blogs, the bandwidth is 20 MHz rather than 30. I think the narrower bandwidth is more appropriate re Nyquist, about half the 38.5 MHz bandwidth of the BladeRF. At 20 MHz, the CPU is barely busy at about 4 % versus 10 times that of screen shots at 30 MHz in earlier blogs. Simon Brown, the author of SDR-Console said in his Yahoo forum that the FFT runs at 30 MHz too. Dropping the bandwidth to 20 MHz seems to calm everything down.    Screen shot of BladeRF runni

BladeRF receiving DVB-T test transmission from VK4ZXI 1mW at 2 m from UT-100C DVB-T usb TX Well, it works. UT-100C USB DVB-T TX transmission from my laptop being received by BladeRF on 70 cm channel. Not a bad signal with few spurious. Amplifiers will have low pass filter. Now to do the amplifiers and antenna.

BladeRF with SDR-Console- Sceenshots (draft) Just a quick post of some screen shots of the brilliant BladeRF running on the equally impressive SDR-Console by Simon Brown to show cababilities of both and the noy-surprising heavy load on an i5 2500K processor. Free to air TV channel, 7 MHz wide with BladeRF running 30 MHz bandwidth Same signal but one edge with 150 kHz bandwidth to show detail     Machine performance with 30 MHz bandwidth, CPU @ 67 C and fan whizzing. Ran like this for 20 hours, so all quite stable.       CPU load with some interesting signals. Reported stuttering is probably not a fast enough CPU. 30 MHz at 12 bit resolution would push anything.      Plan to try it on Windows 8 machine. Reported problems may be due to Windows  8 not accepting (or telling you) unsigned drivers. Such can be loaded in special restart mode.

Summary of BladeRF SDR TRX BladeRF is a high performance SDR transceiver made by a small start-up company, Nuand http://www.nuand.com/bladeRF . Currently only mainboard is available for US$420, with a HF/VHF transverter due late November to give coverage down to 10 MHz. For receive only, an up-converter for RTL-SDR dongles could be used to go lower. Technical Specifications: •Fully bus-powered USB 3.0 SuperSpeed Software Defined Radio •Portable, handheld form factor: 5" by 3.5" •Extensible gold plated RF SMA connectors •300MHz - 3.8GHz RF frequency range •Independent RX/TX 12-bit 40MSPS quadrature sampling:  LMS6002D is a field programmable RF  transceiver http://www.limemicro.com/products/LMS6002D.php     •Capable of achieving full-duplex 28MHz channels •16-bit DAC factory calibrated 38.4MHz +/-1ppm VCTCXO •On-board 200MHz ARM9 SOC with 512KB embedded

Note: I take no responsibility for any attempts at doing what is described here. I am not an expert with these radios and am following my own interpretation of how this is done. It is shared on the basis of the philosophy of amateur radio. The main advantage of a 1st IF tap is avoiding the problem of sharing one antenna with a RTX and SDR; not simple. As mentioned in an earlier post, I have installed a tap into the 1st IF of my IC-7410. The tap is made into the TRX’s first IF (64,455 kHz), above the roofing filters (the key to a good RX). The ICOM even have a socketed test point to do it (some hesitation playing inside a new $2000 TRX! Much reading of circuit diagrams). With the plug (hard to get but only $1.50 and are used on all main brands of RTX), isolation amplifier- http://www.cliftonlaboratories.com/z10000_buffer_amp.htm (gives details of how it is done), preferably through a bandpass filter (obtained but not installed) then to Funcube. I have it running, but not permanent