Dynamic range questions

GNU Radio
1

I have an application that must operate in the 25MHz to 40MHz region,
with a channel having a nominal bandwidth
of 50Khz to 700KHz or so. The Rx center frequency may be anywhere in
the 25MHz to 40MHz region.

My question is about dynamic range requirements when operating a
receiver in that neighbourhood of the
spectrum. It’s not a neighbourhood I’ve habitually “hung out” in, so
I don’t have any intuitive feel
for how crowded it is, with emphasis on the Rx being in “deep rural”
locations. My suspicion is that
things like GSM receivers have a much worse time of it, and do OK with
14 bits of A/D.

Is it likely that I’ll need to do narrower analog filtering in the RF
front end, to avoid dynamic range issues? It’s more convenient
if I don’t have to do that, but specific Rx locations could have
analog filters installed to more closely match their
specific Rx frequencies.

Cheers

–
Marcus L.
Principal Investigator
Shirleys Bay Radio Astronomy Consortium

2

On Sun, Aug 15, 2010 at 19:12, Marcus D. Leech [email protected]
wrote:

I have an application that must operate in the 25MHz to 40MHz region,
[…]
It’s not a neighbourhood I’ve habitually “hung out” in

The 30-40 MHz region is typically very quiet. Much of the radio
traffic that used to exist there (LMR stuff) has moved up to 150-170
or 450-470 MHz, to avoid “skip” during sunspot cycle highs.

The strongest emitters I’ve seen between 25-30 MHz are shortwave radio
stations and 10M amateur radio band contesters. Well, there is the
citizen’s band radio allocation at 27 MHz one must contend with as
well.

Johnathan