SDRplay Community Forum

Have started a new thread on pre-selection in "GENERAL".

Gianfranco

BUILDING SELECTIVITY PROTECTION INTO THE RSP FRONT END IN LF/HF 1. GENERAL The RSP Processor is, by definition, a wide band reception device, sporting up to 10 MHz of accessible bandwith. This characteristic is essential when looking at spectrum monitoring and it is not by chance that very many RSP...

BUILDING SELECTIVITY PROTECTION INTO THE RSP FRONT END IN LF/HF

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Hi Phil, Just recovering from the Solstice party (35 of us) with roast and all.... Your sensitivity & SNR checking & comparing scheme looks very interesting and I look forward to your results. This of noise minimisation is really the most imortant issue (and always has been) in radio communications ...

Hi Paul, it is easier to make real HI Q coils....Will go in the wood oven outside and cook for 5 hours, so it is early morning tomorrow, 5 o'clock. - Phil, Very ood show! I am glad of having contributed. I note you did not use the sewing twine. Remember you almost double Qu if you space the turns an...

Phil,

It is true that the larger diameter twine is not good for RF coils, but it can be used for other HI "Q" coils all the same. Have a nice weekend!

Gianfranco

Very good, Phil, I look forward to see what results yo get by the additional selectivity!

Best regards,

Gianfranco

With the double tuned pre-selector on Tuner #1 set at 7150 KHz this evening I received JA5CJZ (Japan) on 20:00 GMT in QSO with IK6BGJ on 7,175 KHz. This confirms that providing extra front end selectivity & attenuating the strong broadcasters above 7,200 KHz really pays a big benefit.

Hi Phil, Just one more note on PC's. If you need, say two or three, the best buy of the world are IBM/LENOVO X61's. At the moment they come at around $ 100 /120 and you can find the docking pads (very useful with many USB ports & the DVD RW) for around $ 15. You stick one RSP to each, they handle W7...

Uploaded below narrow band pre-selector schematic & data.