hardware

[011248163264]

Hi nice project but what is you hardware for the scan ?

[harpinion]

That's a really late answer. :-)

Hopefully you have found the information you searched in the documentation under "Technic". There are links showing the ham project that have been used. It can be build up with a small budget. There is a copy of the circuit diagram for the receiver here.

[rapbando]

Hi,

@harpinion why using the downconverter if almost all RTLSDR dongles can sample directly from Q branch wich in turn gives good tuning ability to virtually 0 Hz ?

[harpinion]

Sorry again that this account / repository is not monitored.

@rapbando This project has been implemented with a cheap USB TV-Stick (RTL2832U chip with R820T2 tuner) that has a tuner, that can not receive such low frequencies without a converter. 2017 there where no other cheap alternatives.

Can you give examples for cheap RTL-SDR dongles that can receive and sample directly from 0 - 10 MHz? Then this project can be easily adapted to it and maybe more receiver stations could document the local HAARP activity.

[rapbando]

Sorry again that this account / repository is not monitored.

@rapbando This project has been implemented with a cheap USB TV-Stick (RTL2832U chip with R820T2 tuner) that has a tuner, that can not receive such low frequencies without a converter. 2017 there where no other cheap alternatives.

Can you give examples for cheap RTL-SDR dongles that can receive and sample directly from 0 - 10 MHz? Then this project can be easily adapted to it and maybe more receiver stations could document the local HAARP activity.

This is the best SDR based on the RTL chip that can go to down to 100 KHz if you select direct sampling from q branch as I stated before.

[harpinion]

This is the best SDR based on the RTL chip that can go to down to 100 KHz if you select direct sampling from q branch as I stated before.

Thank you for the Tip! This will be added to the main page.

First some remarks to the old solution. When you have a look at the datasheet of the R820T2 tuner you will find in https://www.rtl-sdr.com/wp-content/uploads/2013/04/R820T_datasheet-Non_R-20111130_unlocked1.pdf

Typical figures: Frequency range: 42 to 1002 MHz Noise figure : 3.5 dB @ RF_IN Phase noise: -98 dBc/Hz @ 10 kHz Current consumption: ＜178 mA @ 3.3V power supply Max input power: +10 dBm Image rejection: 65 dBc

The TV-sticks with this tuner could not receive below 42 MHz, so a frequency converter was an obvious solution. The advantage of this solution is, that the tuner can still be used to cut out a frequency window. A PCB for the shown converter has been build and it could be build as cheap as the TV-Stick.

In the last years some people have found out some tricks to go beyond the frequency range of the tuner: https://www.rtl-sdr.com/new-experimental-r820t-rtl-sdr-driver-tunes-13-mhz-lower/comment-page-1/

Over on the Reddit RTL-SDR discussion board there has been talk about this patch. Most users are reporting that it works well down to around 15 MHz, but some people are reporting that they have been able to receive signals down to around 4 MHz. That's great but not enough for receiving the complete spectrum of HAARP.

There is an additional trick to receive up to 6 GHz: https://www.rtl-sdr.com/tuning-an-r820t2-rtl-sdr-up-to-6-ghz-via-a-harmonic-mixing-driver-hack/

Your recommended RTL-SDR dongle solves all this problems without a converter. And it seems to do it very good in the frequency range from 100 kHz up to 10 MHz.

A closer look to the datasheet of the Nooelec NESDR SMArt v5 shows, that there is a bypass of the tuner to receive the low frequencies

There is no idea why a tuner is not needed, but when it works everything is fine!

This dongle / stick seems to work with the rtl-sdr package in Linux, so it should be able to be used for this project without problems and no adaption in the software is needed. https://www.nooelec.com/store/downloads/dl/file/id/72/product/0/nesdr_installation_manual_for_ubuntu.pdf