[hpsdr] FW: SBC Inforce 6410

[Sid Boyce]

Hi Terry,
The HiQSDR is a 4-layer PCB but empirically it performs pretty close to 
Hermes. I call it the little brother to Hermes.
No doubt lab tests would show up numbers indicating deficiencies 
compared to Hermes.
With the Preselector/10W PA + 2-el Cubical Quad I have worked West 
coast, VK/ZL without problems on SSB.

On RX Hermes + eb104.ru BPF vs the HiQSDR based rig I haven't detected 
any real differences.

Hermes-Lite is still a WIP but apart from the fun side of it, a pretty 
decent performer.
73 ... Sid.

On 18/12/15 01:38, Terry Fox wrote:
> ***** High Performance Software Defined Radio Discussion List *****
>
>
>
> Thank you for your concerns Graham.  Laying out what is expected is 
> always a good thing!
> I would welcome others to check out the RP.  I’ve been playing with 
> one for over six months now, and am still impressed with the cost vs 
> abilities as an SDR.  It’s not a Hermes-killer, but I don’t expect 
> it to be.
> As regards to point 2, it already has Nyquist filters that 
> unfortunately limit the RP to about 50MHz (I’ve checked).  I would 
> like to bypass them for subsampling.
> Pavel is handling the 125 MHz vs 122.88 MHz by resampling.  He was 
> going to try the CIC filter up/down resampling, I don’t know what 
> the latest is.  I’m more of the opinion that the oscillator should 
> be changed out, but doing that may be beyond some amateur’s abilities.
> I believe it is an eight-layer board.  This thing was designed by some 
> smart guys playing with particle accelerators.  I don’t really buy 
> into the “lab instrument” usage, due to the rather poor software 
> (so far) and lack of front-end attenuators/amplifiers.
> As Helmut pointed out, the RP is also supported for the HPSDR version 
> of PowerSDR.
> How does the HiQSDR, SDR-IQ, and Hermes-Lite fit into the competitive 
> receiver-exciter domain?  If they are “acceptable”, I think the RP 
> is pretty close to them. (I’m really asking to get a better feel for 
> where it should fit in the SDR world.  I don’t intend to be frivolous)
> 73, Terry, N4TLF
> *From:* Graham / KE9H <mailto:ke9h.graham at gmail.com>
> *Sent:* Thursday, December 17, 2015 7:18 PM
> *To:* Helmut <mailto:dc6ny at gmx.de>
> *Cc:* Terry Fox <mailto:tfox at knology.net> ; HPSDR 
> <mailto:hpsdr at lists.openhpsdr.org>
> *Subject:* Re: [hpsdr] FW: SBC Inforce 6410
> I agree that the Red Pitaya is a great price for a flexible piece of 
> test equipment.
> And it might be a great starting point for a low cost transceiver, but 
> I don't know yet.
> I would like the receiver to get all of the performance it could, out 
> of that A->D converter.
> To be a competitive receiver-exciter, I am concerned about
> 1.) The loss in input NF because of the oscilloscope input versus a 
> properly designed 50 Ohm input.
> 2.) Lack of appropriate Nyquist filters.
> 3.) The poor frequency stability of the on-board sampling clock.
> 4.) The poor phase noise performance of the on-board sampling clock.
> 5.) Moving the sampling clock to the telecom frequency ladder, ie., 
> 122.88 MHz
>
> I don't know that all of these are issues, just what I am worried 
> about, and would need to verify/test.
> I am making assumptions as to how they implemented the oscilloscope 
> inputs, and could easily be wrong.
>
> When I say poor, I don't mean that the Red Pitaya is not good for its 
> intended purpose, which I am
> sure that it is, but poor relative to the performance I personally 
> expect out of an SDR.
>
> It might be possible to hack in a different front end connection to 
> deal with (1 and 2).
>
> It might be possible to hack in a better external sampling reference 
> clock, that would deal with (3, 4, and 5).
>
> I am sure that you would need at least 6 layer board, maybe 8 layers 
> to interface to the Zync BGA, so
> a re-layout would not be trivial.
>
> I am very interested in what Terry finds out about the LF spurs.
>
> Thanks,
> --- Graham
>
> ==
>
>
>
>
> _______________________________________________
> HPSDR Discussion List
> To post msg: hpsdr at openhpsdr.org
> Subscription help: http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org
> HPSDR web page: http://openhpsdr.org
> Archives: http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/


-- 
Sid Boyce ... Hamradio License G3VBV, Licensed Private Pilot
Emeritus IBM/Amdahl Mainframes and Sun/Fujitsu Servers Tech Support
Senior Staff Specialist, Cricket Coach
Microsoft Windows Free Zone - Linux used for all Computing Tasks