[hpsdr] sampling and noise

[Robert McGwier]

This will be the fifth test to be done.  I believe, given my analysis, 
that Mercury will have a very good IMD-DR3 and IP2 and IP3.  We need to 
measure MDS on all bands of interest so this will be number 4 and is 
going to be dependent on several factors (immunity to noises in the 
circuit and around it, design of input circuit,etc).  Number 5 will be 
various measurements of the blocking dynamic range: that is "how strong 
a signal is needed to cause the noise floor to rise by 3 dB" type 
measurements and six will be looking for spurs, A/D clock/oscillator 
problems, etc.

I am not asking these to be posted, just saying I will be making these 
measurements for myself after I buy the earliest one I can get my hands on!

If the Mercury gets around 100 dB IMD-DR3,  at least 30 dBm IP3, and 
about 100 dB BDR,  it will be one of the best tools in our arsenal and 
provide fantastic capabilities for mapping use of the amateur bands, 
doing propagation studies, etc.  It remains to be seen if as an overall 
system component (cost, performance, etc.), it competes directly with a 
more traditional mixer/LO type system.  In almost every case, we will 
need to be careful and not give small or half complete answers.  Having 
a 10 dBm IP3 would not be great BUT being able to map propagation over 
all of HF and to follow the MUF, etc. easily,  has a lot to say for it 
irrespective of what the IP3 is!  I can imagine a fantastic system built 
up from a Mercury and more traditional radios if the Mercury does not 
cut it as the narrow band processor of choice.

We are living in the hay day of radio RIGHT NOW in terms of technology. 
The prices will steadily go down and the capabilities are going to go 
steadily up.  It is a lot of fun to watch it.

Bob
N4HY


FRANCIS CARCIA wrote:
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> now that we have the sampling thing taken care of I wonder how Mercury 
> looks when connected to an antenna with hundreds of signals coming 
> compared to a single one off a signal generator. Does the noise floor 
> come up? frank
> 
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AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
"If you're going to be crazy, you have to get paid for it or
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