SDR-14 vs SDR-IQ

[wb4jfi]

wb4jfi wrote:
> Mike O'Dell wrote:
>> I'm trying to reconcile why the SDR-IQ is so much cheaper
>> than the SDR-14
>>
>> the high-performance ADI parts in both of them are identical -
>> the A/D and the digital downconverter
>>
>> the data delivered across the USB2.0 interface is essentially identical
>>
>> the -IQ has *more* filters and switching
>> the -IQ has *more* computes and digital hardware
>>
>> as a result it's hard to understand how the BOM cost of the -IQ
>> is really any less than the BOM cost of the -14
>>
>> yet the selling price of the -IQ is *half* of the -14
>>
>> true, the -14 looks to have a slightly spiffier case,
>> and it might have a more stable, less noisy clock part,
>> but that doesn't justify a $500 delta in the price
>>
>> what am i missing in this picture??
>>
>>     -mo
>>
>>
>>
>>
>>
>>
> Mike:
> I don't think they are not nearly as similar as you think.  If I 
> remember, the SDR-14 uses a similar A/D (or maybe the same one), but 
> then the similarity ends.  The A/D samples are processed differently, 
> using different DDC chips if I remember.  The SDR-14 can deliver up to 
> a complete 33MHz bandwidth to the computer, if your computer can drink 
> that fast.  The SDR-IQ can only deliver 192kHz, if I remember 
> correctly.  I have an SDR-IQ, but could not afford an SDR-14.
>
> Whether the cost difference is accurate, or some premium is being 
> charged for the SDR-14 above the hardware differences is up to the 
> observer.  I can look at both diagrams and give you more details, as 
> the above is from memory only.
>
> Terry
>
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>
Actually, I had it almost backwards (so much for my memory!).  The A/D 
is different between the two.  Both have the same DDC, but the -14 can 
bypass the DDC, allowing for the fast data rate.  With the DDC 
in-circuit, I believe it's limited to about 160-192kHz as well.  It also 
has a hardware FIFO for the samples.  The SDR-IQ can only do 192kHz 
bandwidth, while it's possible to bypass the internal DDC on the SDR-14 
and go a lot faster.  The SDR-IQ is a pretty neat device for the money.

Another tidbit is that the preamp is after the various LP filters in the 
SDR-IQ, but before filtering in the SDR-14.

Maybe the SDR-14 A/D is much better?

Terry