You are right, for example most of the 802.11 or Bluetooth solutions are
zero-IF, but I don't think that this is ideal for Ham Radio (the main issue
is re-injection of the LO into the RX).

Bernard,

If your goal is to make a kit that uses simple, commonly available
components and exploits a 'powerful microprocessor' for flexibility, then
DSP is definitely the way to go. If properly done, it virtually eliminates
the need for all of the old ham-favorite special function chips.

With respect to 're-injection of the LO into the RX', I'm not quite sure
what you mean. There is the potential for LO leakage out of the antenna port
because the LO is on the receive frequency, but this is pretty easily
managed with careful electrical and electro-mechanical design.

Joe
W3JDR


"Bernard" wrote in message
news:FeBie.17870$ye1.3226@okepread06...
The world seems to be going to direct-conversion I-Q receivers with the
baseband going to a DSP for processing. Reverse for TX. I think this
would work fine for any mode on 2m, including FM if you're clever with
your algorithms.

You are right, for example most of the 802.11 or Bluetooth solutions are
zero-IF, but I don't think that this is ideal for Ham Radio (the main
issue is re-injection of the LO into the RX). A better option (for us) is
the low IF option (like in the DSP10). The DSP10 has an IF at 19.665 MHz
and one at 15 KHz. The concept is excellent but slightly overdesigned for
what I want to achieve. The drawback (when compared to zero-IF) is that
the low-IF receivers still requires dual conversion and IF filters to
achieve any level of performance.