Digital Preselector for iDEN 800MHz Band

[turbovectorz]

Hi folks!

I need to know if anyone knows of a digital controlled preselector specifically for the 801-824MHz band (or a similar solution). I would like to improve my uplink reception from a radio handset. Apparently, I receive a lot of 800MHz trunking interference which affects the frame error rates on my homebrew repeater/scanner. If possible, I would like to know if I can lock into a certain uplink frequency and reject/notch everything else out. Preferably, I would like to interface with it through a USB or RS-232 Serial port if possible.

Thanks ALL in advance!

Sincerely,

TVZ

[Bill_G]

I've paralleled several window filters and pass reject cans to achieve deep enough rejection of co-channel interference at high sites, but never played with dynamically adjustable front ends. OTOH, my experiences with an autotune combiner were less than stellar. Efficiencies were low and insertion loss was through through the roof. If your interferer is fixed, you can try to notch them out with one or both sections of a low cost reject duplexer. I've done that before, and works fine. Will drop a signal into the neg 100's perfectly especially if you make critical jumpers correctly between the sections.

[turbovectorz]

Bill_G,

Thank you for your response! It's been helpful to me.
In fact, you gave me an idea of building a multi-pole preselector with cascaded digitally controlled potentiometers for the receiver.
On the transmitter side, I will also attempt to implement it with an additional closed-loop RF PA with digital predistortion.

I will keep you posted. Thanks!

TVZ