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A OTH can also look like the chineese OTH around 7 MHz http://www.arrl.org/news/chinese-over-the-horizon-radar-qrming-low-end-of-40-meters http://www.arrl.org/images/view/News/Chinese%20OTH-R%20on%206999.JPG As the newsletter reported: “A jumping Chinese OTH radar covered the CW DX-edge of our exclu...

Similar to Coax cable, there are high quality cable and there are cheap low quality cable, though the price of many cable may be high it is not necessarily a way to get a good USB cable. So you might have been just unlucky with the USB cable you bought. You have two (three) reasons for problems: 1. ...

I know of a max. of 40 m (~131 ft) if you cascade active USB 2.0 cables, like Delock Kabel USB 2.0 active 20 m USB cable Art.-No. 82690 price ~30 €. I used one cable with a Haupauge video grabber, but I never checked for RFI. While a USB 3.0 port is rated 900 mAh vs. 500 mA for a 2.0 port it is the ...

I obviously want to minimize any unwanted radio-signals, but I'm not sure if more noise will be picked up by a long USB extension or a long antenna-cable. While wavelength and therefore antenna get smaller with increasing frequency the attenuation of the cable will increase. The higher the frequenc...

I have never built a regen Rx, but from what I read unlike the tube designs solid state designs can be tricky even without trying to load such a circuit with a frequency counter. Maybee you should read up on regen Rx e.g. QST www.arrl.org/files/file/Technology/tis/info/pdf/9811qex026.pdf https://www...

The point of having a preamp as close to the antenna as possible, is to improve the overall noise factor of a receiving system. Any additional attenuation by a cable, (attenuation =length of cable times attenuation of cable type used in dB per meter found in the cable specs operating frequency) will...

The antenna port works only about 30 MHz and up. EIthe use and upconverter or you have to use the direct sampling input. Both are explained can be found on rtl-sdr.

What is a "Satelline tranceiver module"? How do you conclude that the depicted Signals form a 4FSK. Frequency distribution of xFSK are in my understanding symetrical and of same amplitude unless there is additional modulation on the FSK signal itself. Two examples for 2 and 4 FSK are shown in the pi...

At the part of the ATC-COM band only AM DSB (25 kHz or 8.33 kHz spacin) is used so it is very unlikely usebs by civil or military ATC. While Europe is aiming to shift also for the lower airspace to a 8.33 kHz wide channel spacing the rest of the world is using 25 kHz channel spacing, Did you check i...

uses harmonic radar to detect electronics by transmitting highpower uhf 1-3.6 GHZ to specific nearfiled area. A simple explanation and DIY design can be found here https://web.archive.org/web/20130718061802/http://servv89pn0aj.sn.sourcedns.com/~gbpprorg/mil/non/ and a more detailed Tutorial here ht...