A Question For You RF Gurus

[NN5RR]

Hi RF gurus!

I've been working on digitizing and manipulating the AF signals of my transceivers with my PC sound card and .NET programming. I'll be getting a SoftRock receiver shortly and will be working on the I/Q signals instead, probably with a 96 KHz BW.

I'm REALLY interested now in getting a 100 MHz A/D converter and digitizing DC through 10m, then processing the I/Q components with my own program. I like the Perseus radio and seeing the full spectrum on the display!

My question is: What simple front end circuitry would you recommend that I put between the antenna feed and the A/D converter? I'm thinking an RF choke and a preamp. Of course, the preamp will only be used to scale to the dynamic range of the A/D.

Thanks for the help,
Ross NN5RR

[W9GB]

Ross -

IF you have been following the forum discussions for the FunCube Dongle (UK),
you will see discussions of pre-selectors and filtering on the front end.
http://www.funcubedongle.com/

w9gb

[M0NKA]

Hi,

I am nowhere near being rf guru, but i had similar problem some time ago. I wanted to use my USRP for HF, the problem - i have only 900 Mhz daugherboards. So to skip the painful process of buying something from the US, i checked into Basic RX and Basic TX daughterboards schematics. I assume your project is something similar to USRP (using fast ADC, instead of PC soundcard).

So according to the USRP design - they use just few impedance transformers and couple of passive components. I had link before
for some pre-amp project, but not on this computer.

Hope this helps.

73, Chris