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Diversity Reception Filtering with 6600

Dwayne_AB6A
Dwayne_AB6A Member ✭✭
edited August 2019 in FLEX-6000 Signature Series
Has anyone looked at "OR'ing" the outputs of diversity reception so that only a signal that is common from both receivers is passed? 
Anyone know any programs that can take DAX IQ streams and perform these operations? I believe some of the open Source SDR products have modular signal processing capabilities.

Answers

  • Stan VA7NF
    Stan VA7NF President Surrey Amateur Radio Communications Member ✭✭
    edited September 2019
    Dwayne, technically that would be an "AND", and is an interesting suggestion.

    Steve, is it possible to report on the 5 year mission to incorporate 5000 level diversity plus extensions into the 6000 series?

    Stan

  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited August 2019
    Haha - yes it would be an “AND” - before I embark on rolling my own, has anyone else gone down this route? I played with some modular SDR software development kits briefly about 6 months ago and IMO believe this could be achieved fairly easily with the two inputs from the DAX or Slices??
  • szawrotny
    szawrotny Member
    edited August 2019
    Don’t forget that it is the brain that makes DR work, not technology
  • Stan VA7NF
    Stan VA7NF President Surrey Amateur Radio Communications Member ✭✭
    edited August 2019
    Stan to Stan,
    Only the current 6000 implementation uses between the ears diversity by putting the two phase synchronized audio signals on left and right.
    The 5000 implementation permits the user to merge the two antenna streams with level and phase adjustments, as Dwayne was saying to AND the two streams.
  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited August 2019
    Well I have "discovered" Audacity which should provide me endless hours of "fun" as I play with various post processing algorithms. If I find a "recipe" that works well for diversity post processing, I will share with you all... The ideal would be for Audacity to post process using DAX output near real time. 
  • ka7gzr
    ka7gzr Member ✭✭
    edited August 2019

    I have a 6700 and a IC-7850 with 2 receiver inputs. I also have two Pixel magnetic loop antennas. The Rx antennas are about 100 feet apart and physically phased 90 degrees apart. My "mixer" is in my head.
  • szawrotny
    szawrotny Member
    edited August 2019
    I use my brain for diversity reception with my 6600M. No IFs, ANDs OR butts ;-)
  • HCampbell  WB4IVF
    HCampbell WB4IVF Member ✭✭
    edited September 2019

    RE the “5-year mission”  (-:   some discussions from several years ago on the current “poor man’s” diversity reception and possible follow-on DSP-enhanced “optimal combining” diversity:

    https://community.flexradio.com/flexradio/topics/-optimal-combining-diversity

    FWIW, Rx “beam steering” via phase/amplitude adjustments is readily available in outboard units, like the MFJ-1026 and DXE NCC1/2.  These can be highly effective in nulling out locally generated noise and signals under certain conditions. 

    Howard


  • Takeshi Yamada
    Takeshi Yamada Retired Member ✭✭
    edited August 2019
    Ummm! How you guys achieve organic, I mean your brain, diversity reception of FT8/4? 
    It might be OK for SSB, CW and even RTTY for guru.  However, I cannot decode hundreds of FT8 signals simultaneously with my tiny brain and I really want to ask Flex to implement diversity reception capability, not using an organic mean, for digital modes in an early manner to differentiate it from competitors.

    de JA2IYJ, JI1BNU
    Ken Yamada


  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited August 2019
    I'm also working on some phasing experiments together with a third dedicated receive antenna!
  • Dwayne_AB6A
    Dwayne_AB6A Member ✭✭
    edited August 2019
    I agree! IMO, the noise filtering capabilities I believe are pretty average and I like the idea of at least outputting the audio for realtime 3rd party processing.
  • N8AUM
    N8AUM RETIRED Member ✭✭
    edited August 2019
    Guess I'm **** than since one ear doesn't work like it did 50yrs ago.
  • N8AUM
    N8AUM RETIRED Member ✭✭
    edited August 2019
    How many of you had an opportunity to try what I consider true "Diversity Reception" with the 5K series and PowerSDR and would like your opinion?

    N8AUM  Vidas
  • W1XYZ
    W1XYZ Member ✭✭
    [{"insert":"I use the diversity function on the ANAN 8000dle and it allows summing, variable gain and phase change, and all the things you need to actually null noise sources and benefit from HF diversity operation. What the 6600 seems to have is like the two receivers in an FT-1000MP that can maintain phase coherence and route the audio to left and right channels. Am I wrong about this? de W!XYZ\n"}]
  • K5XH
    K5XH Member ✭✭

    Years ago I experimented with diversity reception on RTTY. I had two receivers and two separate antennas. The audio outputs were combined into a single input to old style TU. It worked surprisingly well. There was a QST article back in the 60s or 70s that inspired me to try this. It would be nice if a way could be provided to digitally sum two or more DAX audio streams prior to being sent to the decoding program.

    73, Mark K5XH

  • Bill AB7AA
    Bill AB7AA Member ✭✭

    A signal voter works even better because it eliminates the noise of the lesser channel. It measures the S/N and votes the better for further processing. The mind can do amazing things to differentiate unwanted signals from desirable ones that it was programmed for but has difficulty decoding RTTY, PSK31, FT4 etc.

    I have several JPS SNV-4 signal voters that do well on voice signals on my 6700's but were not designed for narrow digital sigs. It would be good if Flex could tackle this.


    Bill AB7AA

  • Stan VA7NF
    Stan VA7NF President Surrey Amateur Radio Communications Member ✭✭

    Question was raised about the 5000 true diversity.

    That is, one of a stack of reasons, why I purchased the 6700 on first availability. It worked very well then on the 5000 dual receiver and has only been improved. I am still waiting to see how much better the 6700's dual SCA receive path could be, and now the 6600 is waiting for the feature as well. Between the ears diversity works some, but is truly missing what the 5000 has and 6600/6700 could be.

    I've had the hardware for 6 years+ and still waiting for the software. Hint: It could be a very significant military feature - Worth paying the research bill for.

  • K5XH
    K5XH Member ✭✭

    Would a voter be able to keep up with a RTTY signal? Sounds like a good idea if it would work fast enough to pick the stronger M/S tone. Here is a link to the QST article I remembered seeing. Check out the difference between single channel reception and diversity. If this kind of improvement is possible using a bunch of transformers, diodes, and vacuum tubes it should be easy with modern software. After all, it's just a SMOP - Simple Matter of Programming!! If it were really simple I could probably do it :-)

    https://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/qst/1966/04/page40/index.html

    73, Mark K5XH

  • John Orjias
    John Orjias Member ✭✭

    I was told when I bought the 6600 that they have no plans in putting in beam steering. I use an mfj 1026 it works great. and there is no chance in heck you brain can pull s9 noise from a power line out with diversity mode because unless you phase it out you're not hearing a thing on either ear but solid noise

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