[Skimmertalk] QS1R replacement

Jeff AC0C keepwalking188 at ac0c.com
Tue Nov 10 13:35:31 EST 2015


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...


-----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

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
Skimmertalk mailing list
Skimmertalk at contesting.com

More information about the Skimmertalk mailing list