Hello Rachel, > I need it to detect in the hydrogen band 1427 MHZ. The way > it is done is to have a wide passband receiver like a > spectrum analyzer and use it as the front end with nice > features like YIG tuning then at the widest IF passband > put this sucker in place of the IF strip. Hardware-wize this is an excellent idea. Besides QS1R there are many other alternatives: SDR-14, SDR-IQ, Perseus, SDR-IP and many more.
> Your supposed to get a microwave receiver with incredible > selectivity. In fact I do but the numbers on the QS1R > don't make any sense so the panadapter display on its GUI > is unintelligible and the spectrum display is too dispersive > to use. I don't know what to do. I suggest you replace it with one of the above alternatives. For those ones you can use Linrad, an SDR package that will allow you to select whatever resolution and averaging you would like. The SDR-XX ones can be run with Spectravue also and that software package might be easier for you to use. It is not as flexible as Linrad though (that is why it is easier to use.) > The folks at QS!R group mean well but are not helpful. > Was hoping you guys would be familar with this hardware. > I will try the SDR-IQ group. I have made measurements on the QS1R. The hardware is very good. The firmware version in the unit I tested was mediocre with very low suppression of aliasing spurs. In your application it would not matter at all since your front end would filter out the aliasing signals that are many MHz away from the desired frequency. I have failed to get the information about how to include support for the QS1R in Linrad. It is said to be open source so I assume it is doable, but I have not found any API specification that could meke it reasonably easy for me. In case you can record a wideband .wav file with the QS1R you might download Linrad an analyze the data from the file. That way you can make a judgement whether Linrad and one of the supported hardwares would suit your needs. Linrad is a two channel receiver. With a two channel hardware and two orthogonal antennas you can measure the polarization of the received signal or if there is no polarization you would improve S/N in the spectrum averaging process by receiving twice as much energy in a given time interval. The latest version, linrad-03.14 has a converter option. It assumes that your hardware has a fixed local oscillator and that you do the tuning in your SDR hardware by setting the frequency in Linrad. You can modify this behaviour by a users_hwaredriver.c file. Regards Leif / SM5BSZ
