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Hi Everyone,?

Is there any possibility that a future fw for the u3s could support FST4W beacons? Perhaps with the GSPDO it would have the clock stability to be a pretty nice little FST4W beacon, perhaps even up into some of the HF bands, no?

On 27/09/2023 12:40, VA3NCA Wayde via groups.io wrote:

Hi Everyone,
Is there any possibility that a future fw for the u3s could support FST4W beacons? Perhaps with the GSPDO it would have the clock stability to be a pretty nice little FST4W beacon, perhaps even up into some of the HF bands, no?

The minimum requirements for FST4W to be useful is a nice clean signal, the Si5351 is capable of this.
As you realise frequency stability is also required, FST4W decoders do not allow for much drift.
(Another thing that can help is absolute frequency accuracy but stability is more important.)

With the U3 the GPS will not make it more stable, it is set once per calibration cycle, the crystal can drift in between.
The QDX can transmit a signal suitable for spectral width measurement, so therefore the U3S could. It has to have the TCXO or other reference remote so heat does not affect it.
The U3S may have a TCXO fitted, it may be good enough if the TCXO is insulated, it is not so likely to be affected by PA heat.

FST4W is just like WSPR but with extra measurements of the signal. It shows on WSPRnet and could replace WSPR in the U3S.

73 Alan G4ZFQ

Good to hear that it's at least technically possible in some way... Yes, was hoping it might be, with "just" a firmware update ( I don't mean to minimize the work involved in creating a new firmware :-P )

Looks like with the GPSDO input and if you elect the TCXO module, it could be quite a nice little FST4W beacon, even up into the low HF, similar to QDX capabilities!?

W.

I decided to look into this FST4W mode a little more.
Probably not the place to bring it up, but since I saw the discussion here ...
?? The documentation () talks about LF and MF.
?? I downloaded the latest WSJT-X (V2.6.1) and the bands listed are between 2m (144 MHz) and 1.25cm (24 GHz)?

I will go looking on the web, but if anyone has a quick fix:
?? How do I adjust WSJT-X frequency settings for that mode?
???
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Rob KB8RCO

On 28/09/2023 12:51, Rob Giuliano via groups.io wrote:

?? How do I adjust WSJT-X frequency settings for that mode?

Rob,

The manual (WSJT-X download page) gives all.

Just type the MHz into the drop-down box or
Settings - Frequencies- right click - Insert.

73 Alan G4ZFQ

I found??to be a good discussion, for those interested, on using FST4W on QDX, focusing a lot on how important clock stability is as you go up in frequency... Seeing this on U3S would be great, particularly with the TCXO module on the Si5351 synth to get a nice stable clock...

It's a whole day recording (8hrs in total !!) of an SDR conference, but the sessions about FST4W in particular are at:?
Propagation Path Analysis on the HF-Bands Using SDR and FST4W Creating a low-cost high performance FST4W/WSPR beacon site using the RFzero or QRP Labs QDX

On 28/09/2023 12:51, Rob Giuliano via groups.io wrote:

?? I downloaded the latest WSJT-X

If WSJT-X is used to RX FST4W it can show the spectral width of received signals.
To get it to do this an empty file just named "plotspec" is placed in the working directory. In Windows usually the "bin" folder. See picture.

A good local transmission should show 0.005. This is Hz, we are talking fine measurements.
This figure gives clues about the number of ionospheric hops. One hop maybe 0.050, more hops larger figures.
There are not too many FST4W TX stations, receive yourself may be the only way to get a quickish idea of how good your system is. I am lucky to have a GPS disciplined QDX (G3ZIL) 20Km away, usually ground wave.

73 Alan G4ZFQ

Alan,
I tried typing in the "band" combo box on the main screen.
It showed the correct frequency, but turned everything RED and the radio frequency did not change.

Then I went to >File >Settings and the "Frequency" tab and deleted all the entries with "All" in the "Mode" column.
That was where the frequency list was coming form, and all the frequencies were too high for my radio.
?? The old version didn't have them.
I right clicked in the "Working Frequency" table and chose "Insert" to add the 160m frequencies.

Thanks for pointing me in the right direction!? It just took a little more exploration.
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Rob KB8RCO