[Skimmertalk] Fwd: QS1R replacement

pcovington . p.covington at gmail.com
Wed Nov 11 11:31:00 EST 2015

Hi Jeff,

To use a larger FPGA will drive the cost up significantly.  Once you
go above the current FPGA size, you are in to using the BGA packages
only.  I think the smallest BGA package that is generally available
(meaning in stock) is the 484 pin BGA package.  There would be even a
more minuscule subset of an already  small subset of users that would
be interested in a BGA at a higher cost.   To get the proposed QS1R
replacement down to $499, I will have to produce them on my own
assembly equipment and have enough interest from people who want to do
Skimmer Servers in the first place.   I do not have BGA placement
equipment or x-ray inspection equipment to do BGAs in production.  I
would have to use an external contract assembler and that alone
increases the price considerably (not to mention the increase in price
from going from a 4 layer PCB to a 8 layer PCB.

For the small amount of people who want more receivers than 7, it
would make more sense to implement two virtual QS1Rs in a FPGA
development board.  If it is possible to run two copies of Skimmer
Server at the same time, then you would have 14 receivers.  I have
done 2 and 4 virtual receivers in FPGA development boards for a
specialized project.

73 Phil N8VB

On Tue, Nov 10, 2015 at 1:35 PM, Jeff AC0C <keepwalking188 at ac0c.com> wrote:
> Phil,
> Guys who want to cover the 9 (or 10) HF bands 24x7 have to do some
> gymnastics with the 7 available bands out of Server.
> To that end, I had talked to Alex a few years back regarding what it would
> take to get to a 9 or 10-band skimmer solution working.  And if I remember
> correctly, the gate count of the FPGA was the primary limiting factor.
> I would certainly be willing to pay a bit more if the gate count on the next
> version could let us get another couple of bands added...
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
> -----Original Message----- From: pcovington .
> Sent: Tuesday, November 10, 2015 9:17 AM
> To: skimmertalk at contesting.com
> Subject: [Skimmertalk] QS1R replacement
> Hello all,
> I am trying to get an idea of the demand for an updated QS1R I am
> working on.  The price target is $499.
> Here are the changes:
> 1. It will have the same size FPGA as the current QS1R, but the FPGA
> will be upgraded to a Cyclone IV instead of a Cyclone III.  This will
> reduce power demand, heat, and resolve some of the timing issues some
> people have had with the QS1R in Skimmer Server duty.
> 2. The ADC will be updated to a lower power version with the same SFDR
> as the current ADC. This will result in less heat production.
> 3. The regulators will be updated to a 3A version for the 1.2 volt
> supply and 2A versions for the rest of the supplies.  There is an
> issue in the current QS1R where the 1.2 V 800mA regulator goes into
> shutdown on some units when running Skimmer Server.  The heating of
> the 1.2 regulator will be much less also.
> 4. There will be a clock generator that generates the 125 MHz encode
> clock from an on board 10 MHz oscillator and the option to supply the
> clock generator with an external 10 MHz source without having to mess
> with any solder jumpers.  This eliminates the 125 MHz external clock
> requirement.
> 5. A preamp/ADC driver will be added with a −11.5 dB to +20 dB gain
> range.  This is the same part that is used in the Flex 6700.  This
> part was not available when the QS1R was designed in 2007.
> These changes are specifically for Skimmer Server use.  As some of you
> may know, Skimmer Server was developed after the QS1R was designed and
> in production, so the high power demand was not anticipated.   Alex,
> VE3NEA did an amazing job of fitting 7 receivers into the current
> FPGA.  Skimmer Server taxes the voltage regulators (especially the 1.2
> V regulator) and the FPGA in the current QS1R.
> Please let me if you have any interest in the updated QS1R (model
> number/name TBD).  I am trying to plan a production run.
> 73 Phil N8VB
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