[Skimmertalk] Fwd: QS1R replacement

Pete Smith N4ZR n4zr at contesting.com
Wed Nov 11 12:21:47 EST 2015

Perhaps Skimmer Server could be enhanced to offer more than 7 bands, but 
only at bandwidths of 96 KHz or less.  For most purposes, except 
contests where people stray far outside the usualCW limits, that would 
be adequate, and in contests there's a 6-band limit at HF anyway.

73, Pete N4ZR
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On 11/11/2015 11:31 AM, pcovington . wrote:
> 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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