Contents :

A collection of thoughts, and my notes about experiments and ideas, technical or otherwise, connected to Amateur Radio, Satellite working and monitoring and other electronics.

Saturday, September 19, 2009

RFI hunting.

I have been doing some RFI hunting today, in order to find some of the noisy switch-mode power supplies in the appartment.

I found a rather noisy one (cheap "universal" laptop supply) with wideband "carriers" every 70 kHz and the noise level dropped considerably when that one was disconnected.

I have been considering replacing as many as possible of the switch-mode PS's with linear regulated ones, because it is far too noisy here, Maybe not worth it, since some neighbours probably have some noisy ones as well.

In any case I am enjoying the little bit more quiet environment here.

It is far from over yet, but a good beginning.

Monday, September 7, 2009

New toy : HF3

I could not resist any more, so got me a new LF/MF/HF receiver, the Target HF3 covering 30kHz - 30MHz

It will take a while to get used to the frequency settings, though I can see why it is made like that.

Otherwise the receiver is simple enough to operate, I used the same method of QRSS calibration as I did for the SW-1, so now it is test receiving the 30m QRSS band.

Just had the 50Hz sidebands in here, stopped a few minutes ago, presumable an OTH radar system.

Sunday, September 6, 2009

Mini QRSS system

I am back from a visit to Denmark, and found a nice little setup for watching QRSS.

I was using the Eee 1000H - running SpectrumLab - with a Sony SW-1 receiver (and an audio cable)

Everything can be run from a battery, so no problems with hum.

The SW-1 has AM and SSB reception from 150kHz to 30MHz with 1 kHz steps, so by calibrating with the Russian RWM time signal transmitter I could find the QRSS band on 30m. The SW-1 needs a bit more antenna than the built-in telescopic whip, so a wire antenna was attached to the whip. The SW-1 does have an input jack for an (active) antenna, so that will be tested later. Probably a small tuned loop antenna.

I was not using it a lot, so very few signals were heard. The concept worked well enough, and the frequency drift was not excessive. I set the bandwidth of the "grabber" to 200 Hz, though.

Nice and easy low power portable receiver setup, I may use it at home as well, with external power supply.

Update :

Next step ? : maybe using the Asus Eee4G with linux/WINE, running SpectrumLab - it could hardly get any smaller.

Further, a simple DC-RX - maybe powered by the USB port ?