Re: [IRCA] dual receiver SDRs for diversity reception / phasing

[Don Moman VE6JY <ve6jy.1@xxxxxxxxx>]

I haven't seen them mentioned, and they are not inexpensive but some models
of the ANAN line of SDR transceivers   https://apache-labs.com/  have phase
coherent dual receivers with the ability to do phasing in the software.

I have the Flex 6700 which also has the dual receive aspect but no phasing
control in the software.  I know the Flex (and perhaps the ANAN) doesn't
support any kind of spectral recording.

Don
VE6JY

On Wed, Jan 16, 2019 at 4:33 AM Nick Hall-Patch <nhp@xxxxxxxx> wrote:

> Thanks for addressing this Mark, and saving me
> fine tuning my own comments, which were essentially:
>
> Is SDR phasing live any better than hardware
> phasing?  If it's not, then all you're doing is
> replacing a piece of hardware with perhaps a
> heavier duty computer, are you not?
>
> Phasing files as they are played back would be
> the technological game changer.   I suspect that
> doing that means recording a different kind of
> .wav file that includes a counter in its header,
> so that samples recorded from one locked receiver
> can be matched up with samples from the other
> during playback.   More informed folks than I
> could comment on the feasibility of that, or whether it exists already.
>
> Would it make any difference to the average
> DXer?   I don't seem to have time to play back
> some of the files from my good openings at home,
> let alone from DXpeditions.  The
> enhanced  ability to winkle out more DX from
> files that I'm not listening to anyway may not be
> all that helpful, hi.  (of course, if I stopped
> bloviating, there might be more time...)
>
> I seem to recall one SDR manufacturer a few years
> ago thinking that there would be little market
> for such a device, even if you provided all
> manner of hand-holding software, which is the
> quite expensive to produce, especially if you want it to function well.
>
> best wishes,
>
> Nick
>
>
>
>
>
>
> At 04:06 2019-01-16, Mark Connelly via IRCA wrote:
>
>
> >I would be willing to have a receiver that just
> >saved half the MW bandwidth, e.g. 700 kHz, in
> >capture files if it had the I/Q streams from the
> >two receivers.Ã  But with receivers doing 3, 6,
> >and more MHz of capture these days, why can't we
> >get the whole 510-1710 stretch?
> >
> >Basic requirements:
> >
> >*** Phasing can be done after the fact on
> >capture files both manually and, when channels
> >are reasonably similar, automatically.
> >
> >*** The two receivers can be slaved to each
> >other for diversity and phasing applications or tuned independently.
> >
> >*** There must be the provision for separate antenna inputs.
> >
> >*** User can save null solution data to an INI
> >file that can be recalled later.Ã  This file
> >should be plain text suitable for importation
> >into antenna-testing technical articles, DXpedition reports, etc.
> >
> >You need to be able to adjust both gain of each
> >channel and the delta-phase / delta-time between
> >them.Ã  You are not always using identical gain
> >and pattern antennas. In fact you could be using
> >two opposite ends of the same SuperLoop or
> >DKAZ.Ã  East end could have 880 WCBS at S-9 and
> >882 UK at S-8; west end might have WCBS S9+20
> >and UK S-5.Ã  So why should you not be able to
> >put 20 dB attenuation on the west end to make
> >WCBS S-9 and then phase it against the east end
> >to provide vastly cleaner pick-up of 882 UK?Ã  I
> >can certainly do that with the Quantum Phaser and several homebrew models.
> >
> >If you can adjust after the fact on capture
> >files you can run several different gain / phase
> >scenarios on, let's say, a graveyard
> >channel.Ã  By moving the null around the
> >compass, as with a conventional rotatable loop,
> >you could pull as many as 6 to 8 different ID's
> >out of a single channel at a particular time.
> >
> >You could also think about applying a gain /
> >phase curve.Ã  Let's say you used an (A vs. B) 8
> >dB delta gain / 100 ns delta time solution to
> >take down 770 WABC and 6 dB / 90 ns to take out
> >880 WCBS.Ã  In-between frequencies could be
> >adjusted "on the curve".Ã  820 WNYC, in a
> >similar direction as 770 and 880, could be
> >expected to null at something like 7 dB delta
> >gain / 95 ns delta time.Ã  This sort of
> >mathematical manipulation of the data streams
> >could help to broadband the nulling pattern when
> >using two antennas that don't quite fit the
> >textbook scheme of spatially-separated elements
> >of identical gain and pick-up pattern.
> >
> >Phasing only during live DX is not the game
> >changer or killer app here.Ã  It's nice maybe to
> >eliminate one box on the table but what we
> >really want is post facto phasing as well as live DX use.
> >
> >The baby steps are being taken but
> >ready-for-prime-time software and hardware
> >hasn't arrived yet as far as I can tell.Ã  Ham
> >DXpeditions / contest stations, MW guys in
> >Finland etc. would be all over it if it had.
> >
> >Mark Connelly, WA1ION
> >South Yarmouth, MA
> >
> ><<
> >A couple of drawbacks for the Afedri:
> >
> >(1) As of a year ago (I have not checked since),
> >the phasing only worked on the live signals. No
> >phasing was possible on a recorded file.
> >
> >(2) It has only a 12 bit converter so is not top of the line.
> >
> >And something that needs verification: the
> >Afedri was only spec'ed to record 900 kHz of
> >bandwidth. I see it has recently been changed to
> >1100 kHz. That's enough for me if it performs as advertised.
> >
> >Chuck
> > >>
> >
> ><<
> >Did I miss something?Ã  As far as I can tell,
> >nothing discussed here comes close to what we
> >need - the ability to phase null synchronized RF
> >spectrum captures.Ã  Everything described here
> >is no different than using two receivers (SDR or
> >analog) on different antennas, or
> >phasing/combining two antennas into one
> >receiver, for the purposes of live monitoring
> >and making single RF spectrum captures.Ã  While
> >it is possible to make two RF spectrum captures
> >using two SDR receivers simultaneously, then
> >perfectly synchronizing playback of the two RF
> >spectrum captures for diversity reception (i.e.
> >audio from one RF spectrum capture in the left,
> >the other in the right), it's difficult to get
> >the audio from each spectrum capture in sync and
> >the results usually not worth the effort.Ã  The
> >WiNRADiO Excalibur has three receivers in one,
> >but they all operate off the same antenna.Ã  So
> >the Excalibur can be used for 'diversity
> >reception' of parallel frequencies by tuning Rx1
> >to 1053 TalkSport and Rx2 to 1089 TalkSport,
> >then combining the audio using the Mix functions
> >of the Excalibur for example, but it's not
> >really diversity reception by definition which
> >would have two SDR receivers each with their own
> >antenna.Ã  I see nothing groundbreaking here.
> >
> >--
> >Bruce Conti
> >B.A.Conti Photography www.baconti.com
> >ÃÂBAMLog! www.bamlog.com
> > >>
> >
> ><<
> >Hi Mark, I have one of the newer Afedri V3.0
> >dual input radios here. I bought it out of
> >curiosity and am pleased with how well it
> >phases. It only has a 1.2Mhz span width in dual
> >channel mode, but that gets most of MW. It works
> >as well as phased loops/flags but without as
> >much loss. I use it with HDSDR after setup with
> >the connection tool provided with the Afedri
> >radio. SDR# is another software that works, but
> >I haven't figured out how to get more than a 192K span from it.
> >
> >In the Afedri, the 2 ports can be combined, with
> >the ability to change the phase but not the
> >signal levels. So, your antennas need to be the
> >same and cable lengths need to be equal also (or
> >length adjusted to prebalance the phase).
> >
> >Dave Aichelmanà à à à N7NZHà à à à Grants Pass, Oregon
> >__._,_.___
> > >>
> >
> >The subject of SDRs containing two phase-locked
> >receivers came up recently on the Topband (160m
> >ham) list (
> >http://lists.contesting.com/archives//html/topband/2019-01/threads.html
> ).
> >
> >The discussion dealt primarily with diversity
> >reception: audio from antenna A's RF goes to
> >your left headphone, antenna B to the right.? In
> >some cases a weak or interfered-with signal that
> >isn't quite readable on either channel
> >independently can "pop out of the mud" when both
> >channels are presented, one to the left and one
> >to the right as mentioned. Typically you're on
> >the same frequency, mode, bandwidth, and AGC for
> >this.? Maybe you use USB one channel and LSB the
> >other if the interference is different owing to
> >antenna pick-up patterns.? For MW DX, sometimes
> >two different frequencies would be fed to the
> >headphones for quick comparison of parallel
> >audio content (e.g. Spain 684 & 855, Cuba 670 & 710, Japan 747 & 774).
> >
> >More of interest to me is phasing based in the
> >receiver.? This should be available under
> >complete (manual) operator control of each
> >channel's gain and phase / time delay.? There
> >should be a way to save successful null or peak
> >set-ups to a look-up table text file that can be
> >invoked later to speed up DXing.? The file
> >should also be importable into Excel / Word /
> >Access / PowerPoint for producing technical
> >articles.? Additionally the receiver should
> >provide a degree of auto-nulling, at least when
> >the two synchronized receivers are getting the
> >same dominant "pest" signal (or noise) a
> >reasonable amount above co-channel and adjacent interference.
> >
> >The subject has been chatted up here before and
> >I think that one or more receivers
> >hardware-capable of this were out there but
> >there was no clear software solution, at least
> >anything that has been adequately "road tested"
> >by cutting edge contester hams and the top MW
> >talent in Scandinavia, North America, and east Asia.
> >
> >If there is new information on this topic, feel free to comment.
> >
> >Mark Connelly, WA1ION
> >South Yarmouth, MA
> >
> >These are some posts recently appearing on the
> >Topband list under the "Re: Topband: Dual RX SDR
> >receivers (diversity capable)" header.
> >
> ><<
> >Have you looked at
> >http://www.afedri-sdr.com/index.php/new-afe822x-sdr-net-dual-channel ?
> >
> >73
> >Nick
> >VE7DXR
> > >>
> >
> ><<
> >Cross Country Wireless SDR-4++ dual diversity SDR general coverage
> receiver
> >
> >Digitally signed mail - John? M0ELS
> > >>
> >
> ><<
> >Hi Bjorn
> >
> >If you are interested, I have a dual Softrock
> >160m SDR receiver (two receivers in one diecast
> >box) that was built up about ten years ago or so
> >for diversity reception, using Alex VE3NEA?s
> >Rock 2.0 diversity version ? see http://www.dxatlas.com/Download.asp.
> >
> >Owing to family/business pressures I never got
> >around to using it. My recollection is JC N4IS
> >may have built up something similar?
> >
> >The receiver is just sitting on a shelf here and
> >I am happy to part with it. Also have a M-Audio
> >D44 professional soundcard that was going to used with it.
> >
> >Vy 73
> >
> >Steve, VK6VZ
> > >>
> >
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> Nick Hall-Patch
> Victoria, BC
> Canada
>
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