I wish I was smart enough to implement this. With HF condx as pootr as there are for a few years, knowing the actual MUF would be handy.


  • Depending on your use, I think this is a low cost and low effort solution to the MUF.

    This software works well.
    Ron - KA7U
  • Neither of those things actually measure the "MUF of the minute" however.
  • edited September 2018
    Within the industry we talk about the resurgence of HF, the fact that new sounders are being added proves that.

  • The MUF of the minute is quite a moving target. Real time compilation and computation of the data will require resources! The methods I'm familiar with, while using averaging and interpolation, have proven remarkably accurate for use in the Amateur bands. DX spots are very useful as well but not always providing enough data. So here is a list of current applications using VOACAP, .

    So how do you propose to compile, compute, and present real time MUF data, once it is collected? Is there currently a software providing this service?
    Ron - KA7U
  • If you do a full freq look at the Kiwi WF you can often see the chirp sweep go by. I'd like to be able to pick a chirp TX site by name name, Millstone Hill for example, and knowing it's start time, be abe to ID that sweep that goes by. The highest freq seen would indicate the MUF for it at the Kiwi RX site.
  • I had previously exchanged emails with Peter Martinez, G3PLX, on this subject, here are some more notes on the subject.

    I think it would be possible to use a KiWi to track the Ionosounders, the two sweeps (approx 5 seconds apart) from Cyprus are very strong in Europe and can be seen on most of the KiWi's in that continent.

    There are several operating with known characteristics start time, start frequency, sweep rate etc. so writing a script to tune the KiWi ahead of the sweep and then recording the signal as it passes through the RX passband and time stamping it, then processing captured samples off-line to correct the frequency shift as the signal sweeps through the RX channel and 'stitch' the individually recorded samples back together may be possible. It may be that two or more RX channels would be required in order to ensure a frequency 'overlap' of recordings.

    But I'm not a software guy either :-(

    however I used to work with them, and they always told me that any problem 'could be fixed in the code' :-)


    Martin - G8JNJ
  • So you guys are imagining an extension for the KiwiSDR to plot propagation maps based on the chirp from 2 or more Ionosonde transmitters located at various sites around the world. Then given the site of interest is near the target receiver you want to transmit to or the target transmitter you want to receive from, you could have a near real time propagation forecast to that site? Then perhaps if the data were collected over the course of 24 hours, your propagation forecast could provide the expected MUF at a given time. As this is near real time, the margins of error in a VOCAP system would be reduced, as you are dealing in near real time and actual conditions from the chosen Ionosonde transmitters?

    I think if this were achieved it would render the WSPR network obsolete.
    Ron - KA7U
  • edited September 2018
    Hi Ron,

    I wan't really suggesting any end use of the data, but simply thought that it would be possible to collect it. I'm not sure if what you are proposing would work, but it's an interesting concept.

    Edit - take a look at this page on the sire that Jim highlighted

    The only practical use I'd previously thought of (and discussed with Christoph) was the possibility of using Ionosounders to help calibrate the TDoA propagation models he was developing at the time.


    Martin - G8JNJ
  • VOACAP and most prediction schemes use smoothed SSN and has no knowledge of Geo storms. Real-time empirical data is far better, that's what wspr does. VOACAP does a poor job on NVIS. Collecting the data is a start.
  • +1 on support for this!

    As is mentioned in , a good to implement this would be to have a narrowband IQ receiver channel (bandwidth = maximum observable delay) track the ionosonde sweep precisely. I'm not sure exactly how this would work within the KiwiSDR, but there's already GPS timing available.

    A user would have to provide:
    - Sweep start/end frequency
    - Sweep start time (or a schedule)
    - Sweep Rate (kHz/sec). The ones you often see sweeping up the HF band are 100 or 125 kHz/sec, but there are faster ones too. There's a (very old) list of sounders here: though I expect users will have to fiddle with start times and sweep rates to find the latest information.

    Processing to produce an ionogram is simply to take an FFT of the de-ramped chirp. Of course there are tricks that can be pulled to clean up the resultant plot (see the discussion on non-chirp suppression on the utwente page), but it would be a good start!
  • The ability to superimpose a line on the waterfall that represents a known sounder sweep might be a start. If an actual sweep was received and visually aligned with the superimposed line, you'd know the sounder was being received. That might be easier than trying to sync with the signal. John will have to comment on the viability of my idea.
  • Christoph has been looking into this. We've exchanged some emails and he has a blog post about the topic:
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