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WSPR Autorun Callsigns [info here about GPS antennas & splitters]

Hello,

I am part way through setting up an antenna farm at a very quiet rural location to provide real time antenna performance comparisons using KiwiSDRs and the WSPR-autorun application.

I intend using the Raspberry Pi data processor after each KiwiSDR so that high traffic volumes can be handled without CPU overleads.

The purpose of this project is to demonstrate the real time differences of different antennas that HAMs may choose to use at their home QTHs.

The 40m antenna options will have four antennas operating as follows: a flat top half wave dipole at a half wavelength AGL, an inverted V dipole at a quarter wavelength AGL, a full size quarter wave vertical with ground radials, and a multi-band 80m-10m stub tuned vertical with ground radials. In this particular example these will operate 24 hours a day and use a dedicated KiwiSDR on each antenna. The configuration of the KiwiSDR will be 4 user mode with 1 user being the WSPR-autorun application and the remaining 3 users available for public logins. There will be no need on mono-band antennas for the KiwiSDRs to provide the Raspberry Pi data processor as each radio will be lightly loaded with WSPR traffic.

The 80m antenna options are likely to be the following: a flat top half wave dipole at a quarter wavelength AGL, a full size quarter wave vertical with ground radials, and a multi-band 80m-10m stub tuned vertical with ground radials.

Other band options include an 8 element log periodic at 20m AGL covering 13-30 MHz and and a multi-band 80m-10m stub tuned vertical with ground radials.

Now there looks like some duplication above with the multi-band 80m-10m stub tuned vertical with ground radials - BUT this will be in fact a single antenna with two KiwiSDRs connected to it - one KiwiSDR operating in 8 user mode with WSPR-autorun and the Raspberry Pi data processor - and another KiwiSDR running 4 user mode for public logins.

Same or similar with the log periodic antenna - two KiwiSDRs etc.


I'M TRYING TO MAKE THIS SIMPLE BY EXPLAINING THE WHOLE STORY.


Now the end game of all of this is for people to use the WSPRNET database page view and enter a callsign and band and view the results of the different antennas on a single page.

The Spot Database Query details could be:

Band = 40m

Count = 1000

Callsign = blank (or whatever)

Reporter = VK2PM/40*

In last = Hour (or whatever)

Sort by: Timestamp or Reporter (or whatever)


TO DO THIS I REQUIRE YOUR CONSIDERATION OF A NEW KiwiSDR FEATURE.


On the KiwiSDR / Admin interface / Extensions / WSPR /

I need the Reporter callsign to be manually entered under each of the Autorun 0 to Autorun 7 pulldowns so that each autorun session can be given a different callsign if required.

Hence for the multi-band 80m-10m stub tuned vertical the entries might look like this:

Autorun 0 = 80m / VK2PM/80TV
Autorun 1 = 40m / VK2PM/40TV
Autorun 2 = 30m / VK2PM/30TV
Autorun 3 = 20m / VK2PM/20TV
Autorun 4 = 17m / VK2PM/17TV
Autorun 5 = 15m / VK2PM/15TV
Autorun 6 = 12m / VK2PM/12TV
Autorun 7 = 10m / VK2PM/10TV

where VK2PM/80TV means VK2PM on the 80m trapped vertical.


Does this make sense and is this at all possible ?


Thanks in advance, Jamie VK2YCJ

Attachments:
https://forum.kiwisdr.com/uploads/Uploader/ea/5260fd394d94a2bc9ceb36a0eae10c.png

Comments

  • Sounds like a change better suited for the R-Pi-based kiwiwspr/wsprdaemon script rather than the Kiwi-based WSPR auto-run feature since you probably want something that has much better decode efficiency than what the Kiwi offers. I think this is what you're intending since you mention using R-Pis as a post-processor to all the Kiwis (note that Kiwi WSPR auto-run is entirely different from Rob's wsprdaemon script running on an external processor fed with Kiwi IQ data via kiwiclient.py)
  • Hello John,

    As soon as you said that I realised I mis-stated the case.

    On all mono-band antennas a single instance of WSPR-autorun will operate and the remaining 3 sessions will be available for public users. So no special callsign feature needed.

    On all multi-band antennas up to 8 instances of WSPR-autorun will operate on one KiwiSDR and another Kiwi-SDR will be connected to that same antenna with 4 sessions for public users. So the special callsign feature is needed and the Raspberry Pi add-on is required.

    So does that mean I need to talk to Rob when he returns ?


    Thanks, Jamie VK2YCJ
  • I agree with John, external decoding rather than wspr-autorun is better suited
  • Hello John and Jim,

    Thanks for the answer and clarification.

    Jim, could you elaborate on the gear in your QRZ.COM photo ?

    Is the flat square box on the right a two way splitter for the GPS antenna ?

    And the small blue box to the left of that - is that an HF splitter ?

    If so, can you tell me the part numbers and where to get them ?


    Thanks, Jamie VK2YCJ
  • edited March 2019
    flat square is a GPS 4-way spliiter for 3 kiwiSDR and my nptd RaspPi https://www.gpssource.com/collections/commercial-gps-components/products/s14-1x4-standard-gps-splitter?variant=10809568899 used from eBay
    Blue box is a mini-circuits https://www.minicircuits.com/WebStore/dashboard.html?model=ZSC-3-2+ which I bought used on eBay
  • edited March 2019
    my latest config... visible in this pix are the filters, a DIY 3-notch for MWBC and a NooElec AM band reject. @ kiwiSDR are wspr and one is a 3 channel public unit

  • "Buenos Notches"? lol
  • and fine notches they are..... deals with the killer MW BC TX that are quite close to me. 3X -20 dB notches that are pretty narrow.
  • Hello John and Jim,

    Okay cool. The KiwiSDR population is growing in your photos - same phenomenon here.

    I see from the links that your GPS splitter is available in different sub-models with options for amplifier and connectors and so on.

    Did you go for an amp version or only the 4 way splitter version ?

    I cannot see much on eBay at present but this unit below looks very neat and at a good price. The main drawback that I can see - and I'm not experienced with these gadgets - is that it says the power for the internal preamp comes from each of the GPS connected to the output connectors.

    https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=283194294918&_sacat=0

    Do you have any ideas and suggestions on this ?

    What are the black blobs on the coax on the right side of the KiwiSDRs ? Clip on common mode chokes ? Do you have a brand and part number for those too ?


    Thanks, Jamie VK2YCJ
  • The spliiter is a passive one, the DC applied gos to bias the GPS unit, which is this case is a +40 dB gain unit. https://www.ebay.com/p/PCTEL-GPSL1TMGSPI40NCB-Antenna-Kit-GPS-L1-Surge-Medium-Duty-Mount/2006284562?iid=123183788371&chn=ps

    more info later today....
  • The "black blobs" are 31 Mix Ferrite cores. Something like these https://www.digikey.com.au/product-detail/en/fair-rite-products-corp/0431173951/1934-1429-ND/8593999 75 Mix is good but harder to find and more $
  • These guys have reasonably priced passive splitters https://www.instockwireless.com/gps-splitter-4way-type-N-gps400.htm#
  • Hello Jim,

    Just got this message. Wow - you've included some great info so thanks for all of that. I'll check those links right away.

    One extra BONUS question - does the GPS signal contribute timing and/or frequency stability to the KiwiSDR ? The two KiwiSDRs that I have here are currently not using the GPS (not close enough to a window and hence not plugged in) and are operating 25-29 Hz off frequency, and 40-44 Hz off frequency respectively.


    Thanks, Jamie - VK2YCJ
    WA2ZKD
  • From http://www.kiwisdr.com/ks/using_Kiwi.html
    "The Kiwi also includes a software-defined GPS receiver used to calibrate the SDR frequency and time-of-day. "
  • But WSPR seems to work properly and get Internet time when no GPS is present and an external clock is used.
  • IIRC, the wspr time comes from the kiwi's internet time.... and of course has a fair amount decode freq tolerance, given its wide decode window
  • Very good thanks.

    Jim, what does that Raspberry Pi in the photo do ? The Time Pi probably means it is a GPS synced time standard. Do you have details of that too ? Guessing aloud it possibly gives you the time standard over Ethernet for yiur local PCs and stuff on your local LAN to save having to drag it in over the paid internet connection. So much more civilised I’d reckon.


    Jamie - VK2YCJ
  • Time-Pi is a Pi with an Adafruit GPS board that has been setup to provide a local ntpd with PPS Stratum 1 accuracy. Even if I lose the external network, all time is very accurate.
  • edited March 2019
    Thanks Jim,

    That RPi project sounds very interesting.

    The links you gave above are very good and I’m starting to order those parts.

    With regard to the active GPS antenna:

    1. The specs look like the preamp has a 2.5 dB noise figure with 40 dB of gain and some good narrow bandwidth characteristics. It looks ideal and fit for purpose.

    2. Is it standard practice to have so much gain on an active GPS antenna ? I know nothing about these things.

    3. What do I need to do to power the active GPS antenna with a bias-t ? Can I buy a bias-t injector for this antenna or is there a kit available ?


    Thanks, Jamie - VK2YCJ
  • I used a +40 dB unit to overcome feedline loss and eliminate need for active splitter. Instock wireless (link above) has bias tees.
  • jksjks
    edited March 2019
    Keep in mind that the supplied GPS puck antenna with the Kiwi probably does not supply enough signal to be put through a splitter and/or extended with additional cable (although I think some people have gotten away with this). The Kiwi FAQ has a reference to an excellent document by FEL that explains the issue of GPS antenna system loss in detail: http://kiwisdr.com/quickstart/index.html#id-faq-gps-cable
  • Hello John,

    Thanks for that tip and link. I have ordered a couple of the active GPS antennas suggested by Jim - PCTEL GPSL1-TMG-SPI-40NCB and I’m about to order a couple of the splitters too.

    Thanks John, and thanks Jim.

    Jamie - VK2YCJ
  • At KPH I moved the puck to the roof and ran a 100 foot RG-6 to a 8 way $15 passive MECO splitter I got on eBay. There was plenty of GPS RF for the 8 Kiwis to reliably track 10-12 sats with the puck, but to be safe I upgraded to the 45 dB gain PCTEL GPS which of course raised the RF levels reported on the admin page. With this setup the Kiwis are reliably reporting the ground wave GPSDO K6PZB signal within 3 Hz of his 14.097090 transmit frequency
  • Hello Rob,

    Thanks for that info. It’s always good to find out info from those that have done it before.

    I currently have 4 x KiwiSDRs and I’m waiting for MassDrop to mature so I can get another 2 x KiwiSDRs. Two of the KiwiSDRs have been in service locally for 2+ years and they have been very reliable.

    I have some Raspberry Pi here to do the 8 session WSPR decode thing but I haven’t started on them yet.

    The PCTEL active GPS antennas described by Jim should arrive next week, and I already have some 4 way GPS splitter boxes that I bought locally. I haven’t quite worked out how to power those PCTEL units although Jim has posted some links and ideas above. I should revisit that info - as I thought US $70 for a Bias Tee was pretty expensive.

    For sharing the multi-band antennas with multiple RXs I have 2 x ELAD ASA-15 preamp splitter boxes.

    I must ask you Rob if you have an instruction sheet for setting up the Raspberry Pi WSPR decoder thing because I should get one going ASAP.

    Here is a summary of what the station is about and I have registered a dedicated callsign for it’s RX operation.

    https://www.qrz.com/db/VK2PM


    Thanks, Jamie - VK2YCJ
  • Clint has written up an installation blog at: http://ka7oei.blogspot.com/search/label/KiwiSDR
    However I have a much updated version of wsprdaemon.sh to release in the next few days which I hope will also simplify installation.

    $15 8-way moca splitter works great for me. I got a bag of F to SMA adapters to connect it to the Kiwis. No extra bias-t HW required.

    https://smile.amazon.com/BAMF-8-Way-Splitter-Bi-Directional-5-2300MHz
    WA2ZKD
  • Hello Rob,

    Thanks for the links and suggestions.

    Jamie VK2YCJ
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