Re: [softrock40] Does Ham Radio need a $15 two-band SDR receiver kit?
- At 02:07 PM 3/1/2006, you wrote:
>Hi Art,Tony, isn't the response to the second harmonic only 6 db down????
>Band switching is by changing the frequency of the QSD clocking by 2x. If
>the QSD is well balanced then its response to the 2nd harmonic is well down
>so one could listen to 80m signals and not be bothered by 40m signals at the
>same time. This should make it possible to switch between two bands with a
>wide BPF. On the other hand, what you say about having a narrow BPF for the
>desired band makes good sense for a number of reasons.
Even if the second harmonic was 30 db down, signals that are s9 +30db
are not at all uncommon, especially on 40 and 80 meters. That would
leave the out of band signal at s9.