SoftRock RXTX Ensemble Transceiver Kit

[Alex Fraser]

Thanks.

I got lots of irons in the fire these days.  I got 2 low pass filter 
kits so I can try the Raspberry Pi radio.  I just got in from eyeballing 
a neighbors tree for a possible antenna.  It is best to shoot your 
antenna supports up before the leaves bud, but also when it is getting 
warm, Spring is ideal. I'll dust off my sling shot.

Yeah I'm not sure if spring is the best time to build a kit....

On 3/22/2021 5:03 PM, n4tlf wrote:
>
> 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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