SoftRock RXTX Ensemble Transceiver Kit

[n4tlf]

I've built many of the Softrock kits, including this one (starting 
around 2006 or so).  Most of the ones I did were the 80/40 variety.  
These days, they are rather old SDR technology, but still work.  There 
may have been articles on them in back issues of the AMRAD Newsletter.  
A Google search on Softrocks, QSD SDR, etc should help.

This info is not precise, but it gives you an idea.  While Softrocks are 
an early SDR entry, most of the "better" SDRs these days use direct 
sampling instead.  The hardware is only half the radio in this case, the 
software is just as (or maybe more) important.

The Softrocks are a QSD/QSE design, the software on the connected 
computer must be able to handle audio I/Q signals.  An early software 
was/is "Rocky" by Alex VE3NEA (I think).  It was simple but worked 
pretty well.  There are a LOT of other SDR programs that drive these 
QSD/QSE radios.  PoweSDR (originally from Flex Radio) is another popular 
SDR software package - among many.

The QSD (Quadrature Sampling Detector or Decoder) for receive basically 
creates two audio frequency signals (I and Q) from the RF carrier, which 
are 90 degrees out of phase, and requires the software to combine them 
properly.  The QSE (Quadrature Sampling Encoder or Exciter) hardware 
does the reverse, it takes in audio I/Q samples, and puts out a 
hopefully clean RF signal.

The main issue with QSDs and especially QSEs is that they must be fine 
tuned so the I/Q signals are of exactly phased and amplitude level 
combined to reduce images and carrier leakage.  The Softrock hardware is 
rather marginal on these problems.  I would NOT plan to run a Softrock 
rig into a high powered transmit amplifier, it will be very marginal on 
both carrier leakage and multiple images, possibly failing FCC rules.

For a more in-depth discussion of QSD/QSE hardware, look for a series of 
four articles in QST in 2002/2003 or so, by Gerald Youngblood of Flex 
Radio Systems (A Software Defined Radio For the Masses).  That's a good 
start.

73, Terry, N4TLF


On 3/22/2021 4:15 PM, Alex Fraser wrote:
> Has anyone had experience with one of these?  Building or hearsay 
> reports appreciated...
>
>
>   SoftRock RXTX Ensemble Transceiver Kit
>
>
>     $89.00
>
> The SoftRock RXTX Ensemble Transceiver Kit provides a 1 watt SDR 
> transceiver that can be built for one of the following five band groups:
>
>   * 160m
>   * 80m/40m
>   * 40m/30m/20m
>   * 30m/20m/17m
>   * 15m/12m/10m
>
> This is the web site where you buy 'em 
> http://fivedash.com/index.php?main_page=product_info&products_id=7 
> <http://fivedash.com/index.php?main_page=product_info&products_id=7>
>
> There are links to the schematics on the above page.
>
>
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