My House View With Antennas

My House View With Antennas

Thursday 30 December 2010

YouTube - SDR Software Defined Radio.

Quick & Short Primer on Starting "Simon Brown - HB9DRV" SDR-Software Defined Radio.

Visit http://www.SDR-Radio.com

P.S. Sorry for low budget video quality, just trying to convey the idea not win any awards ;)

Pat - Ai4W



YouTube - SDR Software Defined Radio.

YouTube - FUNcube Dongle: Out Of The Box test of this highly innovative SDR

An "Out of the box" test of the highly innovative FUNcubeDongle SDR (Software Defined Radio)


YouTube - FUNcube Dongle: Out Of The Box test of this highly innovative SDR

YouTube - Homebrew software defined radio - a demonstration

Testing a very basic software defined radio on the 80 and 40 metre amateur bands.

Uses the easy to use SDRadio software developed by I2PHD (see www.sdradio.org/ ) and a simple hardware interface which is a direct conversion receiver without audio filter or amplifier stages. Apart from an RF amplifier (not really necessary) all the receiver's gain comes from the computer (microphone in used, not Line in).

This is a very 'bare bones' implementation for use with a low-end laptop with a mono soundcard input. Unlike a 'proper' SDR there is no image rejection. Hence signals will appear twice on the spectrum display (one USB and the other LSB) and some juggling may be required to dodge interference. Also signal to noise ratio will never be as good as a single-signal receiver.

The hardware unit comprises of (i) transistor VFO (using ceramic resonators for 3.58 MHz (80m) and 7.2 MHz (40m), (ii) buffer stage, (iii) single balanced diode product detector and (iv) transistor RF amplifier (optional). Your favourite direct conversion receiver circuit without audio filtering or amplification would work fine.

This unit is USB powered but a 9 volt battery would also be OK if you want to keep it independent from the computer (this also helps reduce interference radiated from the computer).

Performance isn't as good as a home station rig but in some aspects is better than a basic direct conversion receiver. The AGC is a bit slow for my liking and it would be good to have an option to switch it off. There is a slight delay between when you adjust a setting and when the resultant audio is produced. A weak signal is generally clearer and less noisy on the commercial rig as well. And tuning can be fiddly when trying to null out an interfering signal on the opposite image (a full SDR with stereo sound card would fix this).

Nevertheless for its simplicity this is a good receiver and would be a good beginners project. As a starting point, build a simple direct conversion receiver without the audio filtering or much audio gain. A strong detector - eg a diode single or double balanced type - is suggested.

In response to questions, I am not in the kit production business however I intend to write it up for a local magazine. These comments will be updated when published.


YouTube - Homebrew software defined radio - a demonstration

YouTube - funcube dongle_0002.wmv

Funcube VHF, UHF and L band USB Dongle all purpose narrow band satellite and terrestrial receiver.



YouTube - funcube dongle_0002.wmv

YouTube - fcd001_0001.wmv

YouTube - fcd001_0001.wmv: "FUNcube Dongle Groundstation receiver"

Progress on the FUNcube Dongle Groundstation receiver. See http://www.funcubedongle.com for more information